Update generation

- Move to global objects for files and validation
- Only write changed files
- Check images for changes before scaling
- Simplify code

WebsiteGenerator.xcodeproj/project.pbxproj

@@ -8,22 +8,11 @@
 
 /* Begin PBXBuildFile section */
 		E22E8763289D84C300E51191 /* main.swift in Sources */ = {isa = PBXBuildFile; fileRef = E22E8762289D84C300E51191 /* main.swift */; };
-		E22E876A289D84FD00E51191 /* Section+Metadata.swift in Sources */ = {isa = PBXBuildFile; fileRef = E22E8769289D84FD00E51191 /* Section+Metadata.swift */; };
 		E22E876C289D855D00E51191 /* ThumbnailStyle.swift in Sources */ = {isa = PBXBuildFile; fileRef = E22E876B289D855D00E51191 /* ThumbnailStyle.swift */; };
-		E22E876E289D868100E51191 /* Site+LocalizedMetadata.swift in Sources */ = {isa = PBXBuildFile; fileRef = E22E876D289D868100E51191 /* Site+LocalizedMetadata.swift */; };
 		E22E8772289D8C2700E51191 /* IndexPageGenerator.swift in Sources */ = {isa = PBXBuildFile; fileRef = E22E8771289D8C2700E51191 /* IndexPageGenerator.swift */; };
-		E22E8778289DA0E100E51191 /* GenerationError.swift in Sources */ = {isa = PBXBuildFile; fileRef = E22E8777289DA0E100E51191 /* GenerationError.swift */; };
-		E22E877A289DA9F900E51191 /* Site.swift in Sources */ = {isa = PBXBuildFile; fileRef = E22E8779289DA9F900E51191 /* Site.swift */; };
 		E22E877D289DBA0A00E51191 /* OverviewSectionGenerator.swift in Sources */ = {isa = PBXBuildFile; fileRef = E22E877C289DBA0A00E51191 /* OverviewSectionGenerator.swift */; };
-		E22E877F289DC11F00E51191 /* Site+Metadata.swift in Sources */ = {isa = PBXBuildFile; fileRef = E22E877E289DC11F00E51191 /* Site+Metadata.swift */; };
-		E22E8782289DCCB600E51191 /* Section.swift in Sources */ = {isa = PBXBuildFile; fileRef = E22E8781289DCCB600E51191 /* Section.swift */; };
-		E22E8784289DCD5E00E51191 /* Section+LocalizedMetadata.swift in Sources */ = {isa = PBXBuildFile; fileRef = E22E8783289DCD5E00E51191 /* Section+LocalizedMetadata.swift */; };
-		E22E8787289DDF4C00E51191 /* Page.swift in Sources */ = {isa = PBXBuildFile; fileRef = E22E8786289DDF4C00E51191 /* Page.swift */; };
-		E22E8789289DDF5700E51191 /* Page+Metadata.swift in Sources */ = {isa = PBXBuildFile; fileRef = E22E8788289DDF5700E51191 /* Page+Metadata.swift */; };
 		E22E878C289E4A8900E51191 /* Ink in Frameworks */ = {isa = PBXBuildFile; productRef = E22E878B289E4A8900E51191 /* Ink */; };
-		E22E8793289E7EC700E51191 /* Page+LocalizedMetadata.swift in Sources */ = {isa = PBXBuildFile; fileRef = E22E8792289E7EC700E51191 /* Page+LocalizedMetadata.swift */; };
+		E22E8795289E81D700E51191 /* URL+Extensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = E22E8794289E81D700E51191 /* URL+Extensions.swift */; };
-		E22E8795289E81D700E51191 /* FileSystem.swift in Sources */ = {isa = PBXBuildFile; fileRef = E22E8794289E81D700E51191 /* FileSystem.swift */; };
-		E22E8798289EA42C00E51191 /* FileProcessor.swift in Sources */ = {isa = PBXBuildFile; fileRef = E22E8797289EA42C00E51191 /* FileProcessor.swift */; };
 		E22E879B289EE02F00E51191 /* Optional+Extensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = E22E879A289EE02F00E51191 /* Optional+Extensions.swift */; };
 		E22E879E289EFDFC00E51191 /* OverviewPageGenerator.swift in Sources */ = {isa = PBXBuildFile; fileRef = E22E879D289EFDFC00E51191 /* OverviewPageGenerator.swift */; };
 		E22E87A0289F008200E51191 /* ThumbnailListGenerator.swift in Sources */ = {isa = PBXBuildFile; fileRef = E22E879F289F008200E51191 /* ThumbnailListGenerator.swift */; };
@@ -33,11 +22,12 @@
 		E22E87AC289F1D3700E51191 /* Template.swift in Sources */ = {isa = PBXBuildFile; fileRef = E22E87AB289F1D3700E51191 /* Template.swift */; };
 		E22E87AE289F1E0000E51191 /* String+Extensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = E22E87AD289F1E0000E51191 /* String+Extensions.swift */; };
 		E22E87B0289F221A00E51191 /* PrefilledTopBarTemplate.swift in Sources */ = {isa = PBXBuildFile; fileRef = E22E87AF289F221A00E51191 /* PrefilledTopBarTemplate.swift */; };
-		E22E87B2289F296700E51191 /* ThumbnailInfo.swift in Sources */ = {isa = PBXBuildFile; fileRef = E22E87B1289F296700E51191 /* ThumbnailInfo.swift */; };
+		E253C87728B767D50076B6D0 /* MediaType.swift in Sources */ = {isa = PBXBuildFile; fileRef = E253C87628B767D50076B6D0 /* MediaType.swift */; };
-		E22E87B6289FF67B00E51191 /* Metadata.swift in Sources */ = {isa = PBXBuildFile; fileRef = E22E87B5289FF67B00E51191 /* Metadata.swift */; };
+		E253C87A28B810090076B6D0 /* ImageOutput.swift in Sources */ = {isa = PBXBuildFile; fileRef = E253C87928B810090076B6D0 /* ImageOutput.swift */; };
-		E253C86928AFD86E0076B6D0 /* FileAccess.swift in Sources */ = {isa = PBXBuildFile; fileRef = E253C86828AFD86E0076B6D0 /* FileAccess.swift */; };
+		E253C87C28B8BFB80076B6D0 /* FileSystem.swift in Sources */ = {isa = PBXBuildFile; fileRef = E253C87B28B8BFB80076B6D0 /* FileSystem.swift */; };
-		E253C86B28AFE0980076B6D0 /* Context.swift in Sources */ = {isa = PBXBuildFile; fileRef = E253C86A28AFE0980076B6D0 /* Context.swift */; };
+		E253C87F28B8FBB00076B6D0 /* Data+Extensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = E253C87E28B8FBB00076B6D0 /* Data+Extensions.swift */; };
-		E26555E428A2C4FA00BAF496 /* LinkPreviewMetadataProvider.swift in Sources */ = {isa = PBXBuildFile; fileRef = E26555E328A2C4FA00BAF496 /* LinkPreviewMetadataProvider.swift */; };
+		E253C88128B8FBFF0076B6D0 /* NSSize+Extensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = E253C88028B8FBFF0076B6D0 /* NSSize+Extensions.swift */; };
+		E253C88328B8FC470076B6D0 /* NSImage+Extensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = E253C88228B8FC470076B6D0 /* NSImage+Extensions.swift */; };
 		E2C5A5D528A0223C00102A25 /* HeaderTemplate.swift in Sources */ = {isa = PBXBuildFile; fileRef = E2C5A5D428A0223C00102A25 /* HeaderTemplate.swift */; };
 		E2C5A5D728A022C500102A25 /* TemplateFactory.swift in Sources */ = {isa = PBXBuildFile; fileRef = E2C5A5D628A022C500102A25 /* TemplateFactory.swift */; };
 		E2C5A5D928A023FA00102A25 /* PageHeadTemplate.swift in Sources */ = {isa = PBXBuildFile; fileRef = E2C5A5D828A023FA00102A25 /* PageHeadTemplate.swift */; };
@@ -47,10 +37,7 @@
 		E2C5A5E328A037F900102A25 /* PageTemplate.swift in Sources */ = {isa = PBXBuildFile; fileRef = E2C5A5E228A037F900102A25 /* PageTemplate.swift */; };
 		E2C5A5E528A03A6500102A25 /* BackNavigationTemplate.swift in Sources */ = {isa = PBXBuildFile; fileRef = E2C5A5E428A03A6500102A25 /* BackNavigationTemplate.swift */; };
 		E2C5A5E928A0451C00102A25 /* LocalizedSiteTemplate.swift in Sources */ = {isa = PBXBuildFile; fileRef = E2C5A5E828A0451C00102A25 /* LocalizedSiteTemplate.swift */; };
-		E2C5A5EC28A055E900102A25 /* SiteElement.swift in Sources */ = {isa = PBXBuildFile; fileRef = E2C5A5EB28A055E900102A25 /* SiteElement.swift */; };
-		E2D55ED928A1BAD800B9453E /* LanguageContainer.swift in Sources */ = {isa = PBXBuildFile; fileRef = E2D55ED828A1BAD800B9453E /* LanguageContainer.swift */; };
 		E2D55EDB28A2511D00B9453E /* OverviewSectionCleanTemplate.swift in Sources */ = {isa = PBXBuildFile; fileRef = E2D55EDA28A2511D00B9453E /* OverviewSectionCleanTemplate.swift */; };
-		E2D55EDF28A2AD4F00B9453E /* LinkPreviewMetadata.swift in Sources */ = {isa = PBXBuildFile; fileRef = E2D55EDE28A2AD4F00B9453E /* LinkPreviewMetadata.swift */; };
 		E2F8FA1E28A539C500632026 /* MarkdownProcessor.swift in Sources */ = {isa = PBXBuildFile; fileRef = E2F8FA1D28A539C500632026 /* MarkdownProcessor.swift */; };
 		E2F8FA2028AB72D900632026 /* PlaceholderTemplate.swift in Sources */ = {isa = PBXBuildFile; fileRef = E2F8FA1F28AB72D900632026 /* PlaceholderTemplate.swift */; };
 		E2F8FA2428ACD0A800632026 /* PageImageTemplate.swift in Sources */ = {isa = PBXBuildFile; fileRef = E2F8FA2328ACD0A800632026 /* PageImageTemplate.swift */; };
@@ -63,7 +50,7 @@
 		E2F8FA3428AD6F3400632026 /* Element.swift in Sources */ = {isa = PBXBuildFile; fileRef = E2F8FA3328AD6F3400632026 /* Element.swift */; };
 		E2F8FA3628AE233600632026 /* Element+LocalizedMetadata.swift in Sources */ = {isa = PBXBuildFile; fileRef = E2F8FA3528AE233600632026 /* Element+LocalizedMetadata.swift */; };
 		E2F8FA3828AE27A500632026 /* ContentError.swift in Sources */ = {isa = PBXBuildFile; fileRef = E2F8FA3728AE27A500632026 /* ContentError.swift */; };
-		E2F8FA3A28AE313A00632026 /* ErrorOutput.swift in Sources */ = {isa = PBXBuildFile; fileRef = E2F8FA3928AE313A00632026 /* ErrorOutput.swift */; };
+		E2F8FA3A28AE313A00632026 /* ValidationLog.swift in Sources */ = {isa = PBXBuildFile; fileRef = E2F8FA3928AE313A00632026 /* ValidationLog.swift */; };
 		E2F8FA3C28AE685C00632026 /* Decodable+Extensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = E2F8FA3B28AE685C00632026 /* Decodable+Extensions.swift */; };
 /* End PBXBuildFile section */
 
@@ -82,21 +69,10 @@
 /* Begin PBXFileReference section */
 		E22E875F289D84C300E51191 /* WebsiteGenerator */ = {isa = PBXFileReference; explicitFileType = "compiled.mach-o.executable"; includeInIndex = 0; path = WebsiteGenerator; sourceTree = BUILT_PRODUCTS_DIR; };
 		E22E8762289D84C300E51191 /* main.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = main.swift; sourceTree = "<group>"; };
-		E22E8769289D84FD00E51191 /* Section+Metadata.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "Section+Metadata.swift"; sourceTree = "<group>"; };
 		E22E876B289D855D00E51191 /* ThumbnailStyle.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ThumbnailStyle.swift; sourceTree = "<group>"; };
-		E22E876D289D868100E51191 /* Site+LocalizedMetadata.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "Site+LocalizedMetadata.swift"; sourceTree = "<group>"; };
 		E22E8771289D8C2700E51191 /* IndexPageGenerator.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = IndexPageGenerator.swift; sourceTree = "<group>"; };
-		E22E8777289DA0E100E51191 /* GenerationError.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = GenerationError.swift; sourceTree = "<group>"; };
-		E22E8779289DA9F900E51191 /* Site.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Site.swift; sourceTree = "<group>"; };
 		E22E877C289DBA0A00E51191 /* OverviewSectionGenerator.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = OverviewSectionGenerator.swift; sourceTree = "<group>"; };
-		E22E877E289DC11F00E51191 /* Site+Metadata.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "Site+Metadata.swift"; sourceTree = "<group>"; };
+		E22E8794289E81D700E51191 /* URL+Extensions.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "URL+Extensions.swift"; sourceTree = "<group>"; };
-		E22E8781289DCCB600E51191 /* Section.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Section.swift; sourceTree = "<group>"; };
-		E22E8783289DCD5E00E51191 /* Section+LocalizedMetadata.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "Section+LocalizedMetadata.swift"; sourceTree = "<group>"; };
-		E22E8786289DDF4C00E51191 /* Page.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Page.swift; sourceTree = "<group>"; };
-		E22E8788289DDF5700E51191 /* Page+Metadata.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "Page+Metadata.swift"; sourceTree = "<group>"; };
-		E22E8792289E7EC700E51191 /* Page+LocalizedMetadata.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "Page+LocalizedMetadata.swift"; sourceTree = "<group>"; };
-		E22E8794289E81D700E51191 /* FileSystem.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FileSystem.swift; sourceTree = "<group>"; };
-		E22E8797289EA42C00E51191 /* FileProcessor.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FileProcessor.swift; sourceTree = "<group>"; };
 		E22E879A289EE02F00E51191 /* Optional+Extensions.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "Optional+Extensions.swift"; sourceTree = "<group>"; };
 		E22E879D289EFDFC00E51191 /* OverviewPageGenerator.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = OverviewPageGenerator.swift; sourceTree = "<group>"; };
 		E22E879F289F008200E51191 /* ThumbnailListGenerator.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ThumbnailListGenerator.swift; sourceTree = "<group>"; };
@@ -106,11 +82,12 @@
 		E22E87AB289F1D3700E51191 /* Template.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Template.swift; sourceTree = "<group>"; };
 		E22E87AD289F1E0000E51191 /* String+Extensions.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "String+Extensions.swift"; sourceTree = "<group>"; };
 		E22E87AF289F221A00E51191 /* PrefilledTopBarTemplate.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PrefilledTopBarTemplate.swift; sourceTree = "<group>"; };
-		E22E87B1289F296700E51191 /* ThumbnailInfo.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ThumbnailInfo.swift; sourceTree = "<group>"; };
+		E253C87628B767D50076B6D0 /* MediaType.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = MediaType.swift; sourceTree = "<group>"; };
-		E22E87B5289FF67B00E51191 /* Metadata.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Metadata.swift; sourceTree = "<group>"; };
+		E253C87928B810090076B6D0 /* ImageOutput.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ImageOutput.swift; sourceTree = "<group>"; };
-		E253C86828AFD86E0076B6D0 /* FileAccess.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FileAccess.swift; sourceTree = "<group>"; };
+		E253C87B28B8BFB80076B6D0 /* FileSystem.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FileSystem.swift; sourceTree = "<group>"; };
-		E253C86A28AFE0980076B6D0 /* Context.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Context.swift; sourceTree = "<group>"; };
+		E253C87E28B8FBB00076B6D0 /* Data+Extensions.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "Data+Extensions.swift"; sourceTree = "<group>"; };
-		E26555E328A2C4FA00BAF496 /* LinkPreviewMetadataProvider.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LinkPreviewMetadataProvider.swift; sourceTree = "<group>"; };
+		E253C88028B8FBFF0076B6D0 /* NSSize+Extensions.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "NSSize+Extensions.swift"; sourceTree = "<group>"; };
+		E253C88228B8FC470076B6D0 /* NSImage+Extensions.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "NSImage+Extensions.swift"; sourceTree = "<group>"; };
 		E2C5A5D428A0223C00102A25 /* HeaderTemplate.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = HeaderTemplate.swift; sourceTree = "<group>"; };
 		E2C5A5D628A022C500102A25 /* TemplateFactory.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TemplateFactory.swift; sourceTree = "<group>"; };
 		E2C5A5D828A023FA00102A25 /* PageHeadTemplate.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PageHeadTemplate.swift; sourceTree = "<group>"; };
@@ -120,10 +97,7 @@
 		E2C5A5E228A037F900102A25 /* PageTemplate.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PageTemplate.swift; sourceTree = "<group>"; };
 		E2C5A5E428A03A6500102A25 /* BackNavigationTemplate.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = BackNavigationTemplate.swift; sourceTree = "<group>"; };
 		E2C5A5E828A0451C00102A25 /* LocalizedSiteTemplate.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LocalizedSiteTemplate.swift; sourceTree = "<group>"; };
-		E2C5A5EB28A055E900102A25 /* SiteElement.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SiteElement.swift; sourceTree = "<group>"; };
-		E2D55ED828A1BAD800B9453E /* LanguageContainer.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LanguageContainer.swift; sourceTree = "<group>"; };
 		E2D55EDA28A2511D00B9453E /* OverviewSectionCleanTemplate.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = OverviewSectionCleanTemplate.swift; sourceTree = "<group>"; };
-		E2D55EDE28A2AD4F00B9453E /* LinkPreviewMetadata.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LinkPreviewMetadata.swift; sourceTree = "<group>"; };
 		E2F8FA1D28A539C500632026 /* MarkdownProcessor.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = MarkdownProcessor.swift; sourceTree = "<group>"; };
 		E2F8FA1F28AB72D900632026 /* PlaceholderTemplate.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PlaceholderTemplate.swift; sourceTree = "<group>"; };
 		E2F8FA2328ACD0A800632026 /* PageImageTemplate.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PageImageTemplate.swift; sourceTree = "<group>"; };
@@ -135,7 +109,7 @@
 		E2F8FA3328AD6F3400632026 /* Element.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Element.swift; sourceTree = "<group>"; };
 		E2F8FA3528AE233600632026 /* Element+LocalizedMetadata.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "Element+LocalizedMetadata.swift"; sourceTree = "<group>"; };
 		E2F8FA3728AE27A500632026 /* ContentError.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ContentError.swift; sourceTree = "<group>"; };
-		E2F8FA3928AE313A00632026 /* ErrorOutput.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ErrorOutput.swift; sourceTree = "<group>"; };
+		E2F8FA3928AE313A00632026 /* ValidationLog.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ValidationLog.swift; sourceTree = "<group>"; };
 		E2F8FA3B28AE685C00632026 /* Decodable+Extensions.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "Decodable+Extensions.swift"; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
@@ -171,17 +145,12 @@
 		E22E8761289D84C300E51191 /* WebsiteGenerator */ = {
 			isa = PBXGroup;
 			children = (
-				E2F8FA2E28AD44FF00632026 /* Generic */,
 				E22E8762289D84C300E51191 /* main.swift */,
-				E22E87A1289F0BF000E51191 /* Content */,
+				E253C87828B80AAF0076B6D0 /* Files */,
+				E2F8FA2E28AD44FF00632026 /* Content */,
 				E22E87A2289F0C6200E51191 /* Generators */,
 				E2C5A5D328A0222B00102A25 /* Templates */,
 				E22E8799289EE02300E51191 /* Extensions */,
-				E22E876B289D855D00E51191 /* ThumbnailStyle.swift */,
-				E22E8797289EA42C00E51191 /* FileProcessor.swift */,
-				E22E8777289DA0E100E51191 /* GenerationError.swift */,
-				E2F8FA2728ACD84400632026 /* VideoType.swift */,
-				E22E8794289E81D700E51191 /* FileSystem.swift */,
 			);
 			path = WebsiteGenerator;
 			sourceTree = "<group>";
@@ -192,36 +161,18 @@
 				E22E879A289EE02F00E51191 /* Optional+Extensions.swift */,
 				E22E87AD289F1E0000E51191 /* String+Extensions.swift */,
 				E2F8FA3B28AE685C00632026 /* Decodable+Extensions.swift */,
+				E253C87E28B8FBB00076B6D0 /* Data+Extensions.swift */,
+				E22E8794289E81D700E51191 /* URL+Extensions.swift */,
+				E253C88028B8FBFF0076B6D0 /* NSSize+Extensions.swift */,
+				E253C88228B8FC470076B6D0 /* NSImage+Extensions.swift */,
 			);
 			path = Extensions;
 			sourceTree = "<group>";
 		};
-		E22E87A1289F0BF000E51191 /* Content */ = {
-			isa = PBXGroup;
-			children = (
-				E2C5A5EB28A055E900102A25 /* SiteElement.swift */,
-				E2D55ED828A1BAD800B9453E /* LanguageContainer.swift */,
-				E26555E328A2C4FA00BAF496 /* LinkPreviewMetadataProvider.swift */,
-				E2D55EDE28A2AD4F00B9453E /* LinkPreviewMetadata.swift */,
-				E22E8786289DDF4C00E51191 /* Page.swift */,
-				E22E8792289E7EC700E51191 /* Page+LocalizedMetadata.swift */,
-				E22E8788289DDF5700E51191 /* Page+Metadata.swift */,
-				E22E8781289DCCB600E51191 /* Section.swift */,
-				E22E8783289DCD5E00E51191 /* Section+LocalizedMetadata.swift */,
-				E22E8769289D84FD00E51191 /* Section+Metadata.swift */,
-				E22E8779289DA9F900E51191 /* Site.swift */,
-				E22E876D289D868100E51191 /* Site+LocalizedMetadata.swift */,
-				E22E877E289DC11F00E51191 /* Site+Metadata.swift */,
-				E22E87B5289FF67B00E51191 /* Metadata.swift */,
-			);
-			path = Content;
-			sourceTree = "<group>";
-		};
 		E22E87A2289F0C6200E51191 /* Generators */ = {
 			isa = PBXGroup;
 			children = (
 				E22E87A9289F1AEE00E51191 /* PageHeadGenerator.swift */,
-				E22E87B1289F296700E51191 /* ThumbnailInfo.swift */,
 				E22E879F289F008200E51191 /* ThumbnailListGenerator.swift */,
 				E22E877C289DBA0A00E51191 /* OverviewSectionGenerator.swift */,
 				E22E87A3289F0C7000E51191 /* SiteGenerator.swift */,
@@ -233,6 +184,19 @@
 			path = Generators;
 			sourceTree = "<group>";
 		};
+		E253C87828B80AAF0076B6D0 /* Files */ = {
+			isa = PBXGroup;
+			children = (
+				E2F8FA3728AE27A500632026 /* ContentError.swift */,
+				E2F8FA3928AE313A00632026 /* ValidationLog.swift */,
+				E253C87928B810090076B6D0 /* ImageOutput.swift */,
+				E253C87B28B8BFB80076B6D0 /* FileSystem.swift */,
+				E253C87628B767D50076B6D0 /* MediaType.swift */,
+				E2F8FA2728ACD84400632026 /* VideoType.swift */,
+			);
+			path = Files;
+			sourceTree = "<group>";
+		};
 		E2C5A5D328A0222B00102A25 /* Templates */ = {
 			isa = PBXGroup;
 			children = (
@@ -279,20 +243,17 @@
 			path = Filled;
 			sourceTree = "<group>";
 		};
-		E2F8FA2E28AD44FF00632026 /* Generic */ = {
+		E2F8FA2E28AD44FF00632026 /* Content */ = {
 			isa = PBXGroup;
 			children = (
-				E253C86A28AFE0980076B6D0 /* Context.swift */,
 				E2F8FA2C28AD2F5300632026 /* GenericMetadata.swift */,
 				E2F8FA3128AD456C00632026 /* GenericMetadata+Localized.swift */,
 				E2F8FA2F28AD450B00632026 /* PageState.swift */,
 				E2F8FA3328AD6F3400632026 /* Element.swift */,
 				E2F8FA3528AE233600632026 /* Element+LocalizedMetadata.swift */,
-				E2F8FA3728AE27A500632026 /* ContentError.swift */,
+				E22E876B289D855D00E51191 /* ThumbnailStyle.swift */,
-				E2F8FA3928AE313A00632026 /* ErrorOutput.swift */,
-				E253C86828AFD86E0076B6D0 /* FileAccess.swift */,
 			);
-			path = Generic;
+			path = Content;
 			sourceTree = "<group>";
 		};
 /* End PBXGroup section */
@@ -363,60 +324,47 @@
 			files = (
 				E2C5A5D728A022C500102A25 /* TemplateFactory.swift in Sources */,
 				E22E8772289D8C2700E51191 /* IndexPageGenerator.swift in Sources */,
-				E2F8FA3A28AE313A00632026 /* ErrorOutput.swift in Sources */,
+				E2F8FA3A28AE313A00632026 /* ValidationLog.swift in Sources */,
-				E22E876E289D868100E51191 /* Site+LocalizedMetadata.swift in Sources */,
 				E2C5A5D528A0223C00102A25 /* HeaderTemplate.swift in Sources */,
 				E22E876C289D855D00E51191 /* ThumbnailStyle.swift in Sources */,
 				E2F8FA2D28AD2F5300632026 /* GenericMetadata.swift in Sources */,
-				E22E8798289EA42C00E51191 /* FileProcessor.swift in Sources */,
-				E26555E428A2C4FA00BAF496 /* LinkPreviewMetadataProvider.swift in Sources */,
 				E22E87AA289F1AEE00E51191 /* PageHeadGenerator.swift in Sources */,
 				E2D55EDB28A2511D00B9453E /* OverviewSectionCleanTemplate.swift in Sources */,
 				E2F8FA2828ACD84400632026 /* VideoType.swift in Sources */,
-				E2D55EDF28A2AD4F00B9453E /* LinkPreviewMetadata.swift in Sources */,
-				E22E876A289D84FD00E51191 /* Section+Metadata.swift in Sources */,
 				E2F8FA2028AB72D900632026 /* PlaceholderTemplate.swift in Sources */,
+				E253C87C28B8BFB80076B6D0 /* FileSystem.swift in Sources */,
 				E2F8FA3428AD6F3400632026 /* Element.swift in Sources */,
+				E253C87F28B8FBB00076B6D0 /* Data+Extensions.swift in Sources */,
 				E22E87AE289F1E0000E51191 /* String+Extensions.swift in Sources */,
 				E22E879E289EFDFC00E51191 /* OverviewPageGenerator.swift in Sources */,
-				E22E8793289E7EC700E51191 /* Page+LocalizedMetadata.swift in Sources */,
 				E22E877D289DBA0A00E51191 /* OverviewSectionGenerator.swift in Sources */,
-				E22E8782289DCCB600E51191 /* Section.swift in Sources */,
-				E22E877F289DC11F00E51191 /* Site+Metadata.swift in Sources */,
 				E2F8FA1E28A539C500632026 /* MarkdownProcessor.swift in Sources */,
 				E22E87A4289F0C7000E51191 /* SiteGenerator.swift in Sources */,
 				E22E87AC289F1D3700E51191 /* Template.swift in Sources */,
 				E22E87A0289F008200E51191 /* ThumbnailListGenerator.swift in Sources */,
 				E2F8FA3028AD450B00632026 /* PageState.swift in Sources */,
-				E22E8784289DCD5E00E51191 /* Section+LocalizedMetadata.swift in Sources */,
+				E253C87728B767D50076B6D0 /* MediaType.swift in Sources */,
-				E22E8789289DDF5700E51191 /* Page+Metadata.swift in Sources */,
-				E2C5A5EC28A055E900102A25 /* SiteElement.swift in Sources */,
 				E22E87B0289F221A00E51191 /* PrefilledTopBarTemplate.swift in Sources */,
 				E22E87A8289F0E7B00E51191 /* PageGenerator.swift in Sources */,
 				E2C5A5E328A037F900102A25 /* PageTemplate.swift in Sources */,
 				E2C5A5DD28A036BE00102A25 /* OverviewSectionTemplate.swift in Sources */,
 				E2C5A5E528A03A6500102A25 /* BackNavigationTemplate.swift in Sources */,
+				E253C88328B8FC470076B6D0 /* NSImage+Extensions.swift in Sources */,
 				E2F8FA2628ACD64500632026 /* PageVideoTemplate.swift in Sources */,
 				E2C5A5DB28A02F9000102A25 /* TopBarTemplate.swift in Sources */,
-				E22E87B6289FF67B00E51191 /* Metadata.swift in Sources */,
-				E22E8778289DA0E100E51191 /* GenerationError.swift in Sources */,
-				E2D55ED928A1BAD800B9453E /* LanguageContainer.swift in Sources */,
 				E2C5A5E928A0451C00102A25 /* LocalizedSiteTemplate.swift in Sources */,
 				E2C5A5E128A0373300102A25 /* ThumbnailTemplate.swift in Sources */,
-				E22E8795289E81D700E51191 /* FileSystem.swift in Sources */,
+				E22E8795289E81D700E51191 /* URL+Extensions.swift in Sources */,
 				E2C5A5D928A023FA00102A25 /* PageHeadTemplate.swift in Sources */,
 				E22E8763289D84C300E51191 /* main.swift in Sources */,
-				E253C86B28AFE0980076B6D0 /* Context.swift in Sources */,
 				E22E879B289EE02F00E51191 /* Optional+Extensions.swift in Sources */,
-				E22E877A289DA9F900E51191 /* Site.swift in Sources */,
 				E2F8FA3228AD456C00632026 /* GenericMetadata+Localized.swift in Sources */,
-				E22E87B2289F296700E51191 /* ThumbnailInfo.swift in Sources */,
 				E2F8FA3C28AE685C00632026 /* Decodable+Extensions.swift in Sources */,
 				E2F8FA2428ACD0A800632026 /* PageImageTemplate.swift in Sources */,
-				E22E8787289DDF4C00E51191 /* Page.swift in Sources */,
+				E253C87A28B810090076B6D0 /* ImageOutput.swift in Sources */,
 				E2F8FA3828AE27A500632026 /* ContentError.swift in Sources */,
 				E2F8FA3628AE233600632026 /* Element+LocalizedMetadata.swift in Sources */,
-				E253C86928AFD86E0076B6D0 /* FileAccess.swift in Sources */,
+				E253C88128B8FBFF0076B6D0 /* NSSize+Extensions.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};

WebsiteGenerator.xcodeproj/xcshareddata/xcschemes/WebsiteGenerator.xcscheme

@@ -0,0 +1,78 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Scheme
+   LastUpgradeVersion = "1340"
+   version = "1.3">
+   <BuildAction
+      parallelizeBuildables = "YES"
+      buildImplicitDependencies = "YES">
+      <BuildActionEntries>
+         <BuildActionEntry
+            buildForTesting = "YES"
+            buildForRunning = "YES"
+            buildForProfiling = "YES"
+            buildForArchiving = "YES"
+            buildForAnalyzing = "YES">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "E22E875E289D84C300E51191"
+               BuildableName = "WebsiteGenerator"
+               BlueprintName = "WebsiteGenerator"
+               ReferencedContainer = "container:WebsiteGenerator.xcodeproj">
+            </BuildableReference>
+         </BuildActionEntry>
+      </BuildActionEntries>
+   </BuildAction>
+   <TestAction
+      buildConfiguration = "Debug"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      shouldUseLaunchSchemeArgsEnv = "YES">
+      <Testables>
+      </Testables>
+   </TestAction>
+   <LaunchAction
+      buildConfiguration = "Debug"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      launchStyle = "0"
+      useCustomWorkingDirectory = "NO"
+      ignoresPersistentStateOnLaunch = "NO"
+      debugDocumentVersioning = "YES"
+      debugServiceExtension = "internal"
+      allowLocationSimulation = "YES">
+      <BuildableProductRunnable
+         runnableDebuggingMode = "0">
+         <BuildableReference
+            BuildableIdentifier = "primary"
+            BlueprintIdentifier = "E22E875E289D84C300E51191"
+            BuildableName = "WebsiteGenerator"
+            BlueprintName = "WebsiteGenerator"
+            ReferencedContainer = "container:WebsiteGenerator.xcodeproj">
+         </BuildableReference>
+      </BuildableProductRunnable>
+   </LaunchAction>
+   <ProfileAction
+      buildConfiguration = "Release"
+      shouldUseLaunchSchemeArgsEnv = "YES"
+      savedToolIdentifier = ""
+      useCustomWorkingDirectory = "NO"
+      debugDocumentVersioning = "YES">
+      <BuildableProductRunnable
+         runnableDebuggingMode = "0">
+         <BuildableReference
+            BuildableIdentifier = "primary"
+            BlueprintIdentifier = "E22E875E289D84C300E51191"
+            BuildableName = "WebsiteGenerator"
+            BlueprintName = "WebsiteGenerator"
+            ReferencedContainer = "container:WebsiteGenerator.xcodeproj">
+         </BuildableReference>
+      </BuildableProductRunnable>
+   </ProfileAction>
+   <AnalyzeAction
+      buildConfiguration = "Debug">
+   </AnalyzeAction>
+   <ArchiveAction
+      buildConfiguration = "Release"
+      revealArchiveInOrganizer = "YES">
+   </ArchiveAction>
+</Scheme>

WebsiteGenerator.xcodeproj/xcuserdata/ch.xcuserdatad/xcschemes/xcschememanagement.plist

@@ -10,5 +10,13 @@
 			<integer>0</integer>
 		</dict>
 	</dict>
+	<key>SuppressBuildableAutocreation</key>
+	<dict>
+		<key>E22E875E289D84C300E51191</key>
+		<dict>
+			<key>primary</key>
+			<true/>
+		</dict>
+	</dict>
 </dict>
 </plist>

WebsiteGenerator/Content/Element+LocalizedMetadata.swift

@@ -41,9 +41,9 @@ extension Element {
         /**
          The file name of the link preview image.
          - Note: The image must be located in the element folder.
-         - Note: If `nil` is specified, then the (localized) thumbnail is used.
+         - Note: If `nil` is specified, then the (localized) thumbnail is used, if available.
          */
-        let linkPreviewImage: String
+        let linkPreviewImage: String?
 
         /**
          The description text for the link preview.
@@ -63,10 +63,16 @@ extension Element {
          The text on the back navigation link of **contained** elements.
 
          This text does not appear on the section page, but on the pages contained within the section.
-         - Note: If this property is not specified, then the `defaultBackLinkText` is used
          */
         let backLinkText: String
 
+        /**
+         The text on the back navigation link of the **parent** element.
+
+         This text appears on the section page, but not on the pages contained within the section.
+         */
+        let parentBackLinkText: String
+
         /**
          The text to show as a title for placeholder boxes
 
@@ -118,8 +124,7 @@ extension Element {
 
 extension Element.LocalizedMetadata {
 
-    init?(atRoot folder: URL, data: GenericMetadata.LocalizedMetadata, with context: Context) {
+    init?(atRoot folder: URL, data: GenericMetadata.LocalizedMetadata) {
-        let validation = context.validation
         // Go through all elements and check them for completeness
         // In the end, check that all required elements are present
         var isComplete = true
@@ -127,43 +132,43 @@ extension Element.LocalizedMetadata {
             isComplete = false
         }
         let source = "root"
-        self.language = validation
+        self.language = log
             .required(data.language, name: "language", source: source)
             .ifNil(markAsIncomplete) ?? ""
-        self.title = validation
+        self.title = log
             .required(data.title, name: "title", source: source)
             .ifNil(markAsIncomplete) ?? ""
         self.subtitle = data.subtitle
         self.description = data.description
         self.linkPreviewTitle = data.linkPreviewTitle ?? data.title ?? ""
-        self.linkPreviewImage = validation
+        self.linkPreviewImage = log
-            .linkPreviewThumbnail(customFile: data.linkPreviewImage, for: language, in: folder, source: source) ?? ""
+            .linkPreviewThumbnail(customFile: data.linkPreviewImage, for: language, in: folder, source: source)
         let linkPreviewDescription = data.linkPreviewDescription ?? data.subtitle ?? data.description
-        self.linkPreviewDescription = validation
+        self.linkPreviewDescription = log
             .required(linkPreviewDescription, name: "linkPreviewDescription", source: source)
             .ifNil(markAsIncomplete) ?? ""
         self.moreLinkText = data.moreLinkText ?? Element.LocalizedMetadata.moreLinkDefaultText
-        self.backLinkText = validation
+        self.backLinkText = log
             .required(data.backLinkText, name: "backLinkText", source: source)
             .ifNil(markAsIncomplete) ?? ""
-        self.placeholderTitle = validation
+        self.parentBackLinkText = "" // Root has no parent
+        self.placeholderTitle = log
             .required(data.placeholderTitle, name: "placeholderTitle", source: source)
             .ifNil(markAsIncomplete) ?? ""
-        self.placeholderText = validation
+        self.placeholderText = log
             .required(data.placeholderText, name: "placeholderText", source: source)
             .ifNil(markAsIncomplete) ?? ""
         self.titleSuffix = data.titleSuffix
-        self.thumbnailSuffix = validation.unused(data.thumbnailSuffix, "thumbnailSuffix", source: source)
+        self.thumbnailSuffix = log.unused(data.thumbnailSuffix, "thumbnailSuffix", source: source)
-        self.cornerText = validation.unused(data.cornerText, "cornerText", source: source)
+        self.cornerText = log.unused(data.cornerText, "cornerText", source: source)
-        self.externalUrl = validation.unexpected(data.externalUrl, name: "externalUrl", source: source)
+        self.externalUrl = log.unexpected(data.externalUrl, name: "externalUrl", source: source)
 
         guard isComplete else {
             return nil
         }
     }
 
-    init?(folder: URL, data: GenericMetadata.LocalizedMetadata, source: String, parent: Element.LocalizedMetadata, with context: Context) {
+    init?(folder: URL, data: GenericMetadata.LocalizedMetadata, source: String, parent: Element.LocalizedMetadata) {
-        let validation = context.validation
         // Go through all elements and check them for completeness
         // In the end, check that all required elements are present
         var isComplete = true
@@ -171,20 +176,21 @@ extension Element.LocalizedMetadata {
             isComplete = false
         }
         self.language = parent.language
-        self.title = validation
+        self.title = log
             .required(data.title, name: "title", source: source)
             .ifNil(markAsIncomplete) ?? ""
         self.subtitle = data.subtitle
         self.description = data.description
         self.linkPreviewTitle = data.linkPreviewTitle ?? data.title ?? ""
-        self.linkPreviewImage = validation
+        self.linkPreviewImage = log
-            .linkPreviewThumbnail(customFile: data.linkPreviewImage, for: language, in: folder, source: source) ?? ""
+            .linkPreviewThumbnail(customFile: data.linkPreviewImage, for: language, in: folder, source: source)
         let linkPreviewDescription = data.linkPreviewDescription ?? data.subtitle ?? data.description
-        self.linkPreviewDescription = validation
+        self.linkPreviewDescription = log
             .required(linkPreviewDescription, name: "linkPreviewDescription", source: source)
             .ifNil(markAsIncomplete) ?? ""
-        self.moreLinkText = validation.moreLinkText(data.moreLinkText, parent: parent.moreLinkText, source: source)
+        self.moreLinkText = log.moreLinkText(data.moreLinkText, parent: parent.moreLinkText, source: source)
         self.backLinkText = data.backLinkText ?? parent.backLinkText
+        self.parentBackLinkText = parent.backLinkText
         self.placeholderTitle = data.placeholderTitle ?? parent.placeholderTitle
         self.placeholderText = data.placeholderText ?? parent.placeholderText
         self.titleSuffix = data.titleSuffix

WebsiteGenerator/Content/Element.swift

@@ -0,0 +1,429 @@
+import Foundation
+
+struct Element {
+
+    static let overviewItemCountDefault = 6
+
+    /**
+     The author of the content.
+
+     If no author is set, then the author from the parent element is used.
+     */
+    let author: String
+
+    /**
+     The title used in the top bar of the website, next to the logo.
+
+     This title can be HTML content, and only the root level value is used.
+     */
+    let topBarTitle: String
+
+    /**
+     The url where the site will be deployed.
+
+     This value is required to build absolute links for link previews.
+
+     - Note: Only the root level value is used.
+     - Note: The path does not need to contain a trailing slash.
+     */
+    let deployedBaseUrl: String
+
+    /**
+     The (start) date of the element.
+
+     The date is printed on content pages and may also used for sorting elements,
+     depending on the `useManualSorting` property of the parent.
+     */
+    let date: Date?
+
+    /**
+     The end date of the element.
+
+     This property can be used to specify a date range for a content page.
+     */
+    let endDate: Date?
+
+    /**
+     The deployment state of the page.
+
+     - Note: This property defaults to ``PageState.standard`
+     */
+    let state: PageState
+
+    /**
+     The sort index of the page for manual sorting.
+
+     - Note: This property is only used (and must be set) if `useManualSorting` option of the parent is set.
+     */
+    let sortIndex: Int?
+
+    /**
+     All files which may occur in content but is stored externally.
+
+     Missing files which would otherwise produce a warning are ignored when included here.
+     - Note: This property defaults to an empty set.
+     */
+    let externalFiles: Set<String>
+
+    /**
+     Specifies additional files which should be copied to the destination when generating the content.
+     - Note: This property defaults to an empty set.
+     */
+    let requiredFiles: Set<String>
+
+    /**
+     The style of thumbnail to use when generating overviews.
+
+     - Note: This property is only relevant for sections.
+     - Note: This property is inherited from the parent if not specified.
+     */
+    let thumbnailStyle: ThumbnailStyle
+
+    /**
+     Sort the child elements by their `sortIndex` property when generating overviews, instead of using the `date`.
+
+     - Note: This property is only relevant for sections.
+     - Note: This property defaults to `false`
+     */
+    let useManualSorting: Bool
+
+    /**
+     The number of items to show when generating overviews of this element.
+     - Note: This property is only relevant for sections.
+     - Note: This property is inherited from the parent if not specified.
+     */
+    let overviewItemCount: Int
+
+    /**
+     Indicate that no header should be generated automatically.
+
+     This option assumes that custom header code is present in the page source files
+     - Note: If not specified, this property defaults to `false`.
+     */
+    let useCustomHeader: Bool
+
+    /**
+     The localized metadata for each language.
+     */
+    let languages: [LocalizedMetadata]
+
+    /**
+     All elements contained within the element.
+
+     If the element is a section, then this property contains the pages or subsections within.
+     */
+    var elements: [Element] = []
+
+    /**
+     The url of the element's folder in the source hierarchy.
+     - Note: This property is essentially the root folder of the site, appended with the value of the ``path`` property.
+     */
+    let inputFolder: URL
+
+    /**
+     The path to the element's folder in the source hierarchy (without a leading slash).
+     */
+    let path: String
+
+    /**
+     Create the root element of a site.
+
+     The root element will recursively move into subfolders and build the site content
+     by looking for metadata files in each subfolder.
+     - Parameter folder: The root folder of the site content.
+     - Note: Uses global objects.
+     */
+    init?(atRoot folder: URL) throws {
+        self.inputFolder = folder
+        self.path = ""
+
+        let source = GenericMetadata.metadataFileName
+        guard let metadata = GenericMetadata(source: source) else {
+            return nil
+        }
+
+        self.author = log.required(metadata.author, name: "author", source: source) ?? "author"
+        self.topBarTitle = log
+            .required(metadata.topBarTitle, name: "topBarTitle", source: source) ?? "My Website"
+        self.deployedBaseUrl = log
+            .required(metadata.deployedBaseUrl, name: "deployedBaseUrl", source: source) ?? "https://example.com"
+        self.date = log.unused(metadata.date, "date", source: source)
+        self.endDate = log.unused(metadata.endDate, "endDate", source: source)
+        self.state = log.state(metadata.state, source: source)
+        self.sortIndex = log.unused(metadata.sortIndex, "sortIndex", source: source)
+        self.externalFiles = metadata.externalFiles ?? []
+        self.requiredFiles = metadata.requiredFiles ?? [] // Paths are already relative to root
+        self.thumbnailStyle = log.unused(metadata.thumbnailStyle, "thumbnailStyle", source: source) ?? .large
+        self.useManualSorting = log.unused(metadata.useManualSorting, "useManualSorting", source: source) ?? true
+        self.overviewItemCount = metadata.overviewItemCount ?? Element.overviewItemCountDefault
+        self.useCustomHeader = metadata.useCustomHeader ?? false
+        self.languages = log.required(metadata.languages, name: "languages", source: source)?
+            .compactMap { language in
+                    .init(atRoot: folder, data: language)
+            } ?? []
+        try self.readElements(in: folder, source: nil)
+    }
+
+    mutating func readElements(in folder: URL, source: String?) throws {
+        let subFolders: [URL]
+        do {
+            subFolders = try FileManager.default
+                .contentsOfDirectory(at: folder, includingPropertiesForKeys: [.isDirectoryKey])
+                .filter { $0.isDirectory }
+        } catch {
+            log.add(error: "Failed to read subfolders", source: source ?? "root", error: error)
+            return
+        }
+        self.elements = try subFolders.compactMap { subFolder in
+            let s = (source.unwrapped { $0 + "/" } ?? "") + subFolder.lastPathComponent
+            return try Element(parent: self, folder: subFolder, path: s)
+        }
+    }
+
+    init?(parent: Element, folder: URL, path: String) throws {
+        self.inputFolder = folder
+        self.path = path
+
+        let source = path + "/" + GenericMetadata.metadataFileName
+        guard let metadata = GenericMetadata(source: source) else {
+            return nil
+        }
+
+        self.author = metadata.author ?? parent.author
+        self.topBarTitle = log
+            .unused(metadata.topBarTitle, "topBarTitle", source: source) ?? parent.topBarTitle
+        self.deployedBaseUrl = log
+            .unused(metadata.deployedBaseUrl, "deployedBaseUrl", source: source) ?? parent.deployedBaseUrl
+        let date = log.date(from: metadata.date, property: "date", source: source).ifNil {
+            if !parent.useManualSorting {
+                log.add(error: "No 'date', but parent defines 'useManualSorting' = false", source: source)
+            }
+        }
+        self.date = date
+        self.endDate = log.date(from: metadata.endDate, property: "endDate", source: source).ifNotNil {
+            if date == nil {
+                log.add(warning: "Set 'endDate', but no 'date'", source: source)
+            }
+        }
+        self.state = log.state(metadata.state, source: source)
+        self.sortIndex = metadata.sortIndex.ifNil {
+            if parent.useManualSorting {
+                log.add(error: "No 'sortIndex', but parent defines 'useManualSorting' = true", source: source)
+            }
+        }
+        // TODO: Propagate external files from the parent if subpath matches?
+        self.externalFiles = metadata.externalFiles ?? []
+        self.requiredFiles = Set((metadata.requiredFiles ?? []).map { path + "/" + $0 })
+        self.thumbnailStyle = log.thumbnailStyle(metadata.thumbnailStyle, source: source)
+        self.useManualSorting = metadata.useManualSorting ?? false
+        self.overviewItemCount = metadata.overviewItemCount ?? parent.overviewItemCount
+        self.useCustomHeader = metadata.useCustomHeader ?? false
+        self.languages = parent.languages.compactMap { parentData in
+            guard let data = metadata.languages?.first(where: { $0.language == parentData.language }) else {
+                log.add(info: "Language '\(parentData.language)' not found", source: source)
+                return nil
+            }
+            return .init(folder: folder, data: data, source: source, parent: parentData)
+        }
+        // Check that each 'language' tag is present, and that all languages appear in the parent
+        log.required(metadata.languages, name: "languages", source: source)?
+            .compactMap { log.required($0.language, name: "language", source: source) }
+            .filter { language in
+                !parent.languages.contains { $0.language == language }
+            }
+            .forEach {
+                log.add(warning: "Language '\($0)' not found in parent, so not generated", source: source)
+            }
+        try self.readElements(in: folder, source: path)
+    }
+}
+
+// MARK: Paths
+
+extension Element {
+
+    var containsElements: Bool {
+        !elements.isEmpty
+    }
+
+    var hasNestingElements: Bool {
+        elements.contains { $0.containsElements }
+    }
+
+    var sortedItems: [Element] {
+        if useManualSorting {
+            return elements.sorted { $0.sortIndex! < $1.sortIndex! }
+        }
+        return elements.sorted { $0.date! > $1.date! }
+    }
+
+    /**
+     The url of the top-level section of the element.
+     */
+    func sectionUrl(for language: String) -> String {
+        path.components(separatedBy: "/").first! + "/\(language).html"
+    }
+    
+    /**
+     Create an absolute path (relative to the root directory) for a file contained in the elements folder.
+
+     This function is used to copy required input files and to generate images
+     */
+    func pathRelativeToRootForContainedInputFile(_ filePath: String) -> String {
+        guard !filePath.hasSuffix("/") && !filePath.hasSuffix("http") else {
+            return filePath
+        }
+        return "\(path)/\(filePath)"
+    }
+
+    func relativePathToFileWithPath(_ filePath: String) -> String {
+        guard path != "" else {
+            return filePath
+        }
+        guard filePath.hasPrefix(path) else {
+            return filePath
+        }
+        return filePath.replacingOccurrences(of: path + "/", with: "")
+    }
+}
+
+// MARK: Accessing localizations
+
+extension Element {
+
+    /**
+     Get the full path of the thumbnail image for the language (relative to the root folder).
+     */
+    func thumbnailFilePath(for language: String) -> String {
+        guard let thumbnailFile = Element.findThumbnail(for: language, in: inputFolder) else {
+            fatalError()
+        }
+        return pathRelativeToRootForContainedInputFile(thumbnailFile)
+    }
+
+    func fullPageUrl(for language: String) -> String {
+        localized(for: language).externalUrl ?? localizedPath(for: language)
+    }
+
+    func localized(for language: String) -> LocalizedMetadata {
+        languages.first { $0.language == language }!
+    }
+
+    func title(for language: String) -> String {
+        localized(for: language).title
+    }
+
+    /**
+     Get the back link text for the element.
+
+     This text is the one printed for pages of the element, which uses the back text specified by the parent.
+     */
+    func backLinkText(for language: String) -> String {
+        localized(for: language).parentBackLinkText
+    }
+
+    /**
+     The optional text to display in a thumbnail corner.
+     - Note: This text is only displayed for large thumbnails.
+     */
+    func cornerText(for language: String) -> String? {
+        localized(for: language).cornerText
+    }
+
+    /**
+     Returns the full path (relative to the site root for a page of the element in the given language.
+     */
+    func localizedPath(for language: String) -> String {
+        path != "" ? "\(path)/\(language).html" : "\(language).html"
+    }
+
+    /**
+     Get the next language to switch to with the language button.
+     */
+    func nextLanguage(for languageIdentifier: String) -> String? {
+        let langs = languages.map { $0.language }
+        guard let index = langs.firstIndex(of: languageIdentifier) else {
+            return nil
+        }
+        for i in 1..<langs.count {
+            let next = langs[(index + i) % langs.count]
+            guard hasContent(for: next) else {
+                continue
+            }
+            guard next != languageIdentifier else {
+                return nil
+            }
+
+            return next
+        }
+        return nil
+    }
+
+    func linkPreviewImage(for language: String) -> String? {
+        localized(for: language).linkPreviewImage
+    }
+}
+
+// MARK: Page content
+
+extension Element {
+
+    var isExternalPage: Bool {
+        languages.contains { $0.externalUrl != nil }
+    }
+
+    /**
+     Get the url of the content markdown file for a language.
+
+     To check if the file also exists, use `existingContentUrl(for:)`
+     */
+    private func contentUrl(for language: String) -> URL {
+        inputFolder.appendingPathComponent("\(language).md")
+    }
+
+    /**
+     Get the url of existing markdown content for a language.
+     */
+    private func existingContentUrl(for language: String) -> URL? {
+        let url = contentUrl(for: language)
+        guard url.exists else {
+            return nil
+        }
+        return url
+    }
+
+    private func hasContent(for language: String) -> Bool {
+        existingContentUrl(for: language) != nil
+    }
+}
+
+// MARK: Header and Footer
+
+extension Element {
+
+    private var additionalHeadContentPath: String {
+        path + "/head.html"
+    }
+
+    func customHeadContent() -> String? {
+        files.contentOfOptionalFile(atPath: additionalHeadContentPath, source: path)
+    }
+
+    private var additionalFooterContentPath: String {
+        path + "/footer.html"
+    }
+
+    func customFooterContent() -> String? {
+        files.contentOfOptionalFile(atPath: additionalFooterContentPath, source: path)
+    }
+}
+
+// MARK: Debug
+
+extension Element {
+
+    func printTree(indentation: String = "") {
+        print(indentation + "/" + path)
+        elements.forEach { $0.printTree(indentation: indentation + "  ") }
+    }
+}

WebsiteGenerator/Content/GenericMetadata.swift

@@ -100,6 +100,14 @@ struct GenericMetadata {
      */
     let overviewItemCount: Int?
 
+    /**
+     Indicate that no header should be generated automatically.
+
+     This option assumes that custom header code is present in the page source files
+     - Note: If not specified, this property defaults to `false`.
+     */
+    let useCustomHeader: Bool?
+
     /**
      The localized metadata for each language.
      */
@@ -122,7 +130,8 @@ extension GenericMetadata: Codable {
             .thumbnailStyle,
             .useManualSorting,
             .overviewItemCount,
-            .languages
+            .useCustomHeader,
+            .languages,
         ]
     }
 
@@ -136,12 +145,13 @@ extension GenericMetadata {
     /**
      Decode metadata in a folder.
 
+     - Parameter data: The binary data of the metadata file.
      - Parameter source: The path to the metadata file, relative to the source root
-     - Parameter context: The context for the element (validation, file access, etc.)
      - Note: The decoding routine also checks for unknown properties, and writes them to the output.
+     - Note: Uses global objects
      */
-    init?(source: String, with context: Context) throws {
+    init?(source: String) {
-        guard let data = try context.fileSystem.loadDataContent(inputPath: source) else {
+        guard let data = files.dataOfOptionalFile(atPath: source, source: source) else {
             return nil
         }
 
@@ -154,20 +164,21 @@ extension GenericMetadata {
             // Only one key means we are decoding the generic metadata
             guard keys.count > 1 else {
                 if !knownKeys.contains(key.stringValue) {
-                    context.validation.unknown(property: key.stringValue, source: source)
+                    log.unknown(property: key.stringValue, source: source)
                 }
                 return key
             }
             // Two levels means we're decoding the localized metadata
             if !knownLocalizedKeys.contains(key.stringValue) {
-                context.validation.unknown(property: key.stringValue, source: source)
+                log.unknown(property: key.stringValue, source: source)
             }
             return key
         }
         do {
             self = try decoder.decode(from: data)
         } catch {
-            context.validation.failedToOpen(GenericMetadata.metadataFileName, requiredBy: source, error: error)
+            print("Here \(data)")
+            log.failedToOpen(GenericMetadata.metadataFileName, requiredBy: source, error: error)
             return nil
         }
     }

WebsiteGenerator/Content/LanguageContainer.swift

@@ -1,119 +0,0 @@
-import Foundation
-
-protocol LanguageIdentifiable {
-
-    var languageIdentifier: String { get }
-
-    var title: String { get }
-}
-
-protocol LanguageContainer {
-
-    associatedtype LocalizedContainer: LanguageIdentifiable
-
-    var languages: [LocalizedContainer] { get }
-
-}
-
-protocol LocalizedMetadataContainer {
-
-    associatedtype MetadataType: LanguageContainer
-
-    var metadata: MetadataType { get }
-
-    func hasContent(for language: String) -> Bool
-}
-
-// MARK: Default implementations
-
-extension LocalizedMetadataContainer {
-
-    func hasContent(for language: String) -> Bool {
-        true
-    }
-}
-
-// MARK: Extensions
-
-extension LocalizedMetadataContainer {
-
-    func localized(for language: String) -> MetadataType.LocalizedContainer {
-        metadata.localized(for: language)
-    }
-
-    /**
-     The localized title of the element.
-
-     This title is used as large text in overview pages, or as the `<h1>` title on pages. If no separate link preview title is specified using a localized `linkPreview.title`, then this value is also used for link previews.
-     */
-    func title(for language: String) -> String {
-        localized(for: language).title
-    }
-
-
-    func nextLanguage(for languageIdentifier: String) -> String? {
-        let langs = metadata.languages.map { $0.languageIdentifier }
-        guard let index = langs.firstIndex(of: languageIdentifier) else {
-            return nil
-        }
-        for i in 1..<langs.count {
-            let next = langs[(index + i) % langs.count]
-            guard hasContent(for: next) else {
-                continue
-            }
-            guard next != languageIdentifier else {
-                return nil
-            }
-
-            return next
-        }
-        return nil
-    }
-}
-
-extension LanguageContainer {
-
-    var languageIdentifiers: [String] {
-        languages.map { $0.languageIdentifier }
-    }
-
-    #warning("Throw better error for missing language")
-    func localized(for language: String) -> LocalizedContainer {
-        languages.first { $0.languageIdentifier == language }!
-    }
-
-    /**
-     The localized title of the element.
-
-     This title is used as large text in overview pages, or as the `<h1>` title on pages. If no separate link preview title is specified using a localized `linkPreview.title`, then this value is also used for link previews.
-     */
-    func title(for language: String) -> String {
-        localized(for: language).title
-    }
-}
-
-extension LocalizedMetadataContainer where Self: SiteElement, Self.MetadataType.LocalizedContainer: LinkPreviewMetadataProvider {
-
-    private func linkPreviewImageFileName(for language: String) -> String? {
-        if let fileName = localized(for: language).linkPreview?.image {
-            return fileName
-        }
-        // Check for the existence of a localized thumbnail
-        let fileName = Self.thumbnailFileNameLocalized(for: language)
-        if inputFolder.appendingPathComponent(fileName).exists {
-            return fileName
-        }
-        let defaultThumbnail = Self.defaultThumbnailFileName
-        if inputFolder.appendingPathComponent(defaultThumbnail).exists {
-            return defaultThumbnail
-        }
-        return nil
-    }
-
-    func linkPreviewImage(for language: String) -> String? {
-        guard let fileName = linkPreviewImageFileName(for: language) else {
-            return nil
-        }
-        return "/\(path)/\(fileName)"
-    }
-}

WebsiteGenerator/Content/LinkPreviewMetadata.swift

@@ -1,41 +0,0 @@
-import Foundation
-
-/**
- Localized configuration data for link previews of site elements.
-
- This struct is embedded in localized metadata and intended to be filled in the JSON source.
- */
-struct LinkPreviewMetadata {
-
-    /**
-     The title to use for the link preview.
-
-     If `nil` is specified, then the localized element `title` is used.
-     */
-    let title: String?
-
-    /**
-     The file name of the link preview image.
-     - Note: The image must be located in the element folder.
-     - Note: If `nil` is specified, then the (localized) thumbnail is used.
-     */
-    let image: String?
-
-    /**
-     The description text for the link preview.
-     - Note: If `nil` is specified, then first the (localized) element `subtitle` is used.
-     If this is `nil` too, then the localized `description` of the element is used.
-     */
-    let description: String?
-}
-
-extension LinkPreviewMetadata: Codable { }
-
-extension LinkPreviewMetadata {
-
-    static var initial: LinkPreviewMetadata {
-        .init(title: nil,
-              image: nil,
-              description: "The page description for link previews")
-    }
-}

WebsiteGenerator/Content/LinkPreviewMetadataProvider.swift

@@ -1,23 +0,0 @@
-import Foundation
-
-protocol LinkPreviewMetadataProvider {
-
-    var linkPreview: LinkPreviewMetadata? { get }
-
-    var title: String { get }
-
-    var subtitle: String? { get }
-
-    var description: String { get }
-}
-
-extension LinkPreviewMetadataProvider {
-
-    var linkPreviewTitle: String {
-        linkPreview?.title ?? title
-    }
-
-    var linkPreviewDescription: String {
-        linkPreview?.description ?? subtitle ?? description
-    }
-}

WebsiteGenerator/Content/Metadata.swift

@@ -1,29 +0,0 @@
-import Foundation
-
-protocol Metadata: Codable {
-
-    static var fileName: String { get }
-
-    static var initial: Self { get }
-}
-
-extension Metadata {
-
-    static func url(in folder: URL) -> URL {
-        folder.appendingPathComponent(fileName)
-    }
-
-    static func exists(in folder: URL) -> Bool {
-        url(in: folder).exists
-    }
-
-    init?(in folder: URL) throws {
-        let metadataUrl = Self.url(in: folder)
-        guard metadataUrl.exists else {
-            try Self.initial.writeJSON(to: metadataUrl)
-            print("Created metadata in \(folder)")
-            return nil
-        }
-        try self.init(decodeFrom: metadataUrl)
-    }
-}

WebsiteGenerator/Content/Page+LocalizedMetadata.swift

@@ -1,62 +0,0 @@
-import Foundation
-
-extension Page {
-
-    struct LocalizedMetadata {
-
-        let id: String
-
-        let title: String
-
-        #warning("Generate title suffix")
-        let titleSuffix: String?
-
-        let linkPreview: LinkPreviewMetadata?
-
-        let subtitle: String?
-
-        #warning("Generate thumbnail suffix")
-        let thumbnailSuffix: String?
-
-        let cornerText: String?
-
-        /**
-         The external url to use instead of automatically generating the page.
-
-         This property can be used for links to other parts of the site, like additional services.
-         It can also be set to manually write a page.
-         */
-        let externalUrl: String?
-
-    }
-
-}
-extension Page.LocalizedMetadata: Codable {
-
-}
-
-extension Page.LocalizedMetadata: LanguageIdentifiable {
-
-    var languageIdentifier: String {
-        id
-    }
-}
-
-extension Page.LocalizedMetadata {
-
-    static var initial: Page.LocalizedMetadata {
-        .init(id: "en",
-              title: "Page title",
-              titleSuffix: nil,
-              linkPreview: .initial,
-              subtitle: "Some text below the title",
-              thumbnailSuffix: "Project",
-              cornerText: nil,
-              externalUrl: nil)
-    }
-}
-
-extension Page.LocalizedMetadata: LinkPreviewMetadataProvider {
-
-    var description: String { subtitle ?? title }
-}

WebsiteGenerator/Content/Page+Metadata.swift

@@ -1,107 +0,0 @@
-import Foundation
-
-extension Page {
-
-    struct Metadata {
-
-        let date: Date
-
-        let endDate: Date?
-
-        let author: String?
-
-        let isDraft: Bool
-
-        let sortIndex: Int?
-
-        let languages: [LocalizedMetadata]
-
-        #warning("Add hideFromOverview property")
-
-        let requiredFiles: [String]
-
-        /**
-         Indicate that no header should be generated automatically.
-
-         This option assumes that custom header code is present in the page source files
-         - Note: If not specified, this property defaults to `false`.
-         */
-        let useCustomHeader: Bool
-
-        #warning("Add files for which errors are ignored when missing")
-    }
-}
-
-extension Page.Metadata: Metadata {
-
-    static let fileName = "page.json"
-
-    static var initial: Page.Metadata {
-        .init(
-            date: .now,
-            endDate: .now,
-            author: nil,
-            isDraft: true,
-            sortIndex: 0,
-            languages: [.initial],
-            requiredFiles: [],
-            useCustomHeader: false)
-    }
-}
-
-extension Page.Metadata: LanguageContainer {
-
-}
-
-extension Page.Metadata: Codable {
-
-    enum CodingKeys: CodingKey {
-        case date
-        case endDate
-        case author
-        case isDraft
-        case sortIndex
-        case languages
-        case requiredFiles
-        case useCustomHeader
-    }
-
-    func encode(to encoder: Encoder) throws {
-        var container = encoder.container(keyedBy: CodingKeys.self)
-        let dateString = Page.metadataDateFormatter.string(from: date)
-        try container.encode(dateString, forKey: .date)
-        if let date = endDate {
-            let endDateString = Page.metadataDateFormatter.string(from: date)
-            try container.encode(endDateString, forKey: .endDate)
-        }
-        try container.encodeIfPresent(author, forKey: .author)
-        try container.encode(isDraft, forKey: .isDraft)
-        try container.encodeIfPresent(sortIndex, forKey: .sortIndex)
-        try container.encode(languages, forKey: .languages)
-        if !requiredFiles.isEmpty {
-            try container.encode(requiredFiles, forKey: .requiredFiles)
-        }
-        if useCustomHeader {
-            try container.encode(true, forKey: .useCustomHeader)
-        }
-    }
-
-    init(from decoder: Decoder) throws {
-        let container = try decoder.container(keyedBy: CodingKeys.self)
-        let dateString = try container.decode(String.self, forKey: .date)
-        self.date = try Page.metadataDateFormatter.date(from: dateString)
-            .unwrap(or: .invalidDateInPageMetadata(dateString))
-        self.author = try container.decodeIfPresent(String.self, forKey: .author)
-        self.languages = try container.decode([Page.LocalizedMetadata].self, forKey: .languages)
-        self.isDraft = try container.decodeIfPresent(Bool.self, forKey: .isDraft) ?? false
-        self.sortIndex = try container.decodeIfPresent(Int.self, forKey: .sortIndex)
-        if let endDateString = try container.decodeIfPresent(String.self, forKey: .endDate) {
-            self.endDate = try Page.metadataDateFormatter.date(from: endDateString)
-                .unwrap(or: .invalidDateInPageMetadata(endDateString))
-        } else {
-            self.endDate = nil
-        }
-        self.requiredFiles = try container.decodeIfPresent([String].self, forKey: .requiredFiles) ?? []
-        self.useCustomHeader = try container.decodeIfPresent(Bool.self, forKey: .useCustomHeader) ?? false
-    }
-}

WebsiteGenerator/Content/Page.swift

@@ -1,83 +0,0 @@
-import Foundation
-
-struct Page {
-
-    let metadata: Metadata
-
-    /// The input folder where the page data is stored
-    let inputFolder: URL
-
-    let path: String
-
-    init?(folder: URL, path: String) throws {
-        self.path = path
-        guard let metadata = try Metadata(in: folder) else {
-            return nil
-        }
-        self.inputFolder = folder
-        self.metadata = metadata
-    }
-}
-
-extension Page {
-
-    static let metadataDateFormatter: DateFormatter = {
-        let df = DateFormatter()
-        df.dateFormat = "dd.MM.yy"
-        return df
-    }()
-}
-
-extension Page: SiteElement {
-
-    var sortIndex: Int? {
-        metadata.sortIndex
-    }
-
-    var sortDate: Date? {
-        metadata.date
-    }
-
-    var elements: [SiteElement] { [] }
-
-    func cornerText(for language: String) -> String? {
-        localized(for: language).cornerText
-    }
-
-    var isExternalPage: Bool {
-        metadata.languages.contains { $0.externalUrl != nil }
-    }
-
-    func fullPageUrl(for language: String) -> String {
-        localized(for: language).externalUrl ?? "\(path)/\(language).html"
-    }
-}
-
-extension Page: LocalizedMetadataContainer {
-
-    /**
-     Get the url of the content markdown file for a language.
-
-     To check if the file also exists, use `existingContentUrl(for:)`
-     */
-    func contentUrl(for language: String) -> URL {
-        inputFolder.appendingPathComponent("\(language).md")
-    }
-
-    /**
-     Get the url of existing markdown content for a language.
-     */
-    func existingContentUrl(for language: String) -> URL? {
-        let url = contentUrl(for: language)
-        guard url.exists else {
-            return nil
-        }
-        return url
-    }
-    
-    func hasContent(for language: String) -> Bool {
-        existingContentUrl(for: language) != nil
-    }
-
-
-}

WebsiteGenerator/Content/Section+LocalizedMetadata.swift

@@ -1,65 +0,0 @@
-import Foundation
-
-extension Section {
-
-    struct LocalizedMetadata {
-
-        let id: String
-
-        let title: String
-
-        let subtitle: String?
-
-        let description: String
-
-        /**
-         The text on the link to show the section page when previewing multiple sections on an overview page.
-         */
-        let moreLinkTitle: String
-
-        /**
-         An optional text to display in the corner of the section thumbnail.
-
-         Can be used to show things like "new", "draft", etc.
-         */
-        let cornerText: String?
-
-        let linkPreview: LinkPreviewMetadata?
-
-        /**
-         The text on the back navigation link of contained elements.
-
-         This text does not appear on the section page, but on the pages contained within the section.
-         */
-        let backLinkText: String?
-    }
-
-}
-extension Section.LocalizedMetadata: Codable {
-
-}
-
-extension Section.LocalizedMetadata: LanguageIdentifiable {
-    
-    var languageIdentifier: String {
-        id
-    }
-}
-
-extension Section.LocalizedMetadata {
-
-    static var initial: Section.LocalizedMetadata {
-        .init(id: "en",
-              title: "Section title",
-              subtitle: "Tag line below the title",
-              description: "The short text below the tagline on the section overview page",
-              moreLinkTitle: "More section items",
-              cornerText: nil,
-              linkPreview: .initial,
-              backLinkText: "Back to section")
-    }
-}
-
-extension Section.LocalizedMetadata: LinkPreviewMetadataProvider {
-    
-}

WebsiteGenerator/Content/Section+Metadata.swift

@@ -1,79 +0,0 @@
-import Foundation
-
-extension Section {
-
-    static let defaultSectionOverviewItemCount = 6
-    
-    struct Metadata {
-
-        let thumbnailStyle: ThumbnailStyle
-
-        let sortByMostRecent: Bool
-
-        let sortIndex: Int?
-
-        let date: Date?
-
-        let languages: [LocalizedMetadata]
-
-        let sectionOverviewItemCount: Int
-    }
-}
-
-extension Section.Metadata: Metadata {
-
-    static let fileName = "section.json"
-
-    static var initial: Section.Metadata {
-        .init(thumbnailStyle: .large,
-              sortByMostRecent: true,
-              sortIndex: nil,
-              date: nil,
-              languages: [.initial],
-              sectionOverviewItemCount: 6)
-    }
-}
-
-extension Section.Metadata: LanguageContainer {
-
-}
-
-extension Section.Metadata: Codable {
-
-    enum CodingKeys: CodingKey {
-        case thumbnailStyle
-        case sortByMostRecent
-        case sortIndex
-        case date
-        case languages
-        case sectionOverviewItemCount
-    }
-
-    func encode(to encoder: Encoder) throws {
-        var container = encoder.container(keyedBy: CodingKeys.self)
-        try container.encode(thumbnailStyle, forKey: .thumbnailStyle)
-        try container.encode(sortByMostRecent, forKey: .sortByMostRecent)
-        try container.encodeIfPresent(sortIndex, forKey: .sortIndex)
-        try container.encode(languages, forKey: .languages)
-        if let date = date {
-            let dateString = Page.metadataDateFormatter.string(from: date)
-            try container.encode(dateString, forKey: .date)
-        }
-    }
-
-    init(from decoder: Decoder) throws {
-        let container = try decoder.container(keyedBy: CodingKeys.self)
-        self.thumbnailStyle = try container.decode(ThumbnailStyle.self, forKey: .thumbnailStyle)
-        self.sortByMostRecent = try container.decode(Bool.self, forKey: .sortByMostRecent)
-        self.sortIndex = try container.decodeIfPresent(Int.self, forKey: .sortIndex)
-        self.languages = try container.decode([Section.LocalizedMetadata].self, forKey: .languages)
-        if let dateString = try container.decodeIfPresent(String.self, forKey: .date) {
-            self.date = try Page.metadataDateFormatter.date(from: dateString)
-                .unwrap(or: .invalidDateInPageMetadata(dateString))
-        } else {
-            self.date = nil
-        }
-        self.sectionOverviewItemCount = try container
-            .decodeIfPresent(Int.self, forKey: .sectionOverviewItemCount) ?? Section.defaultSectionOverviewItemCount
-    }
-}

WebsiteGenerator/Content/Section.swift

@@ -1,74 +0,0 @@
-import Foundation
-
-struct Section {
-
-    let metadata: Metadata
-
-    let inputFolder: URL
-
-    let elements: [SiteElement]
-
-    /// The path to get to the section from the root folder (no leading slash)
-    let path: String
-
-    var folderName: String {
-        inputFolder.lastPathComponent
-    }
-
-    var sortedItems: [SiteElement] {
-        guard metadata.sortByMostRecent else {
-            return elements.sorted { $0.sortIndex! < $1.sortIndex! }
-        }
-        return elements.sorted { $0.sortDate! > $1.sortDate! }
-    }
-
-    init?(folder: URL, path: String) throws {
-        self.path = path
-        guard let metadata = try Metadata(in: folder) else {
-            return nil
-        }
-        self.metadata = metadata
-        self.inputFolder = folder
-        let elements: [SiteElement] = try FileSystem.folders(in: folder)
-            .compactMap {
-                let sectionPath = "\(path)/\($0.lastPathComponent)"
-                if Page.Metadata.exists(in: $0) {
-                    return try Page(folder: $0, path: sectionPath)
-                }
-                if Section.Metadata.exists(in: $0) {
-                    return try Section(folder: $0, path: sectionPath)
-                }
-                return nil
-            }
-        if metadata.sortByMostRecent {
-            self.elements = elements.sorted { $0.sortDate! > $1.sortDate! }
-        } else {
-            self.elements = elements.sorted { $0.sortIndex! < $1.sortIndex! }
-        }
-        #warning("Verify that all sort indices or sort dates are present")
-        print("Section \(folderName): \(elements.count) pages")
-    }
-}
-
-extension Section: SiteElement {
-
-    var sortIndex: Int? {
-        metadata.sortIndex
-    }
-
-    var sortDate: Date? {
-        metadata.date
-    }
-
-    func cornerText(for language: String) -> String? {
-        localized(for: language).cornerText
-    }
-
-    func backLinkText(for language: String) -> String? {
-        localized(for: language).backLinkText
-    }
-}
-
-extension Section: LocalizedMetadataContainer {
-
-}

WebsiteGenerator/Content/Site+LocalizedMetadata.swift

@@ -1,71 +0,0 @@
-import Foundation
-
-extension Site {
-    
-    struct LocalizedMetadata {
-
-        let languageIdentifier: String
-
-        let linkPreview: LinkPreviewMetadata?
-
-        let title: String
-
-        let subtitle: String?
-
-        let description: String
-
-        /**
-         The text on the back navigation link of contained elements.
-
-         This text does not appear on the section page, but on the pages contained within the section.
-         */
-        let backLinkText: String?
-
-        /**
-         The back text to use for element which don't specify a `backLinkText` themselves.
-         */
-        let defaultBackLinkText: String
-
-        /**
-         The text to show as a title for placeholder boxes
-
-         Placeholders are included in missing pages.
-         */
-        let placeholderTitle: String
-
-        /**
-         The text to show as a description for placeholder boxes
-
-         Placeholders are included in missing pages.
-         */
-        let placeholderText: String
-    }
-}
-
-extension Site.LocalizedMetadata: Codable {
-
-}
-
-extension Site.LocalizedMetadata: LanguageIdentifiable {
-
-}
-
-extension Site.LocalizedMetadata {
-
-    static var initial: Site.LocalizedMetadata {
-        .init(
-            languageIdentifier: "en",
-            linkPreview: .initial,
-            title: "Website name on front page",
-            subtitle: "Tag line on front page",
-            description: "Some text below the tag line on the title page",
-            backLinkText: "Back to start",
-            defaultBackLinkText: "Back",
-            placeholderTitle: "Content missing",
-            placeholderText: "This page is incomplete. Content will be added in the coming days.")
-    }
-}
-
-extension Site.LocalizedMetadata: LinkPreviewMetadataProvider {
-
-}

WebsiteGenerator/Content/Site+Metadata.swift

@@ -1,48 +0,0 @@
-import Foundation
-
-extension Site {
-    
-    struct Metadata {
-
-        let author: String
-
-        let ignoredSubFolders: Set<String>
-
-        let topBarTitle: String?
-
-        /**
-         The url where the site will be deployed.
-
-         This value is required to build absolute links for link previews.
-         - Note: The path does not need to contain a trailing slash.
-         */
-        let deployedBaseUrl: String
-
-        let languages: [LocalizedMetadata]
-
-        static func write(to url: URL) throws {
-            try Metadata.initial.writeJSON(to: url)
-        }
-    }
-}
-
-extension Site.Metadata: LanguageContainer {
-
-}
-
-extension Site.Metadata: Codable {
-
-}
-
-extension Site.Metadata: Metadata {
-
-    static let fileName = "site.json"
-
-    static var initial: Self {
-        .init(author: "Author",
-              ignoredSubFolders: ["templates"],
-              topBarTitle: "<b>Title</b>",
-              deployedBaseUrl: "http://example.com",
-              languages: [.initial])
-    }
-}

WebsiteGenerator/Content/Site.swift

@@ -1,54 +0,0 @@
-import Foundation
-
-struct Site {
-
-    static let linkPreviewDesiredImageWidth = 1600
-
-    let elements: [SiteElement]
-
-    let metadata: Metadata
-
-    let inputFolder: URL
-
-    init?(folder: URL) throws {
-        self.inputFolder = folder
-        
-        guard let metadata = try Metadata(in: folder) else {
-            return nil
-        }
-        guard !metadata.languages.isEmpty else {
-            throw GenerationError.invalidLanguageSpecification("No languages specified in site.json")
-        }
-        self.metadata = metadata
-        self.elements = try FileSystem.folders(in: folder)
-            .filter { !metadata.ignoredSubFolders.contains($0.lastPathComponent) }
-            .compactMap { sectionUrl in
-                return try Section(
-                    folder: sectionUrl, path: sectionUrl.lastPathComponent)
-            }
-        print("Loaded site with \(elements.count) sections and \(metadata.languages.count) languages")
-
-        // Create example metadata
-        //_ = try? Page.Metadata(in: folder)
-        //_ = try? Section.Metadata(in: folder)
-    }
-}
-
-extension Site: LocalizedMetadataContainer {
-
-}
-
-extension Site: SiteElement {
-    
-    var sortIndex: Int? { 0 }
-
-    var sortDate: Date? { nil }
-
-    var path: String { "" }
-
-    func cornerText(for language: String) -> String? { nil }
-
-    func backLinkText(for language: String) throws -> String? {
-        localized(for: language).backLinkText
-    }
-}

WebsiteGenerator/Content/SiteElement.swift

@@ -1,199 +0,0 @@
-import Foundation
-
-protocol SiteElement {
-
-    /**
-     The sort index for the element when manual sorting is specified for the parent.
-     - Note: Elements are sorted in ascending order.
-     */
-    var sortIndex: Int? { get }
-
-    /**
-     The date used for sorting of the element, if automatic sorting is specified by the parent.
-     - Note: Elements are sorted by newest first.
-     */
-    var sortDate: Date? { get }
-
-    /**
-     The path to the element's folder in the source hierarchy (without a leading slash).
-     */
-    var path: String { get }
-
-    /**
-     The url of the element's folder in the source hierarchy.
-     - Note: This property is essentially the root folder of the site, appended with the value of the ``path`` property.
-     */
-    var inputFolder: URL { get }
-
-    /**
-     The localized title of the element.
-
-     This title is used as large text in overview pages, or as the `<h1>` title on pages. If no separate link preview title is specified using a localized `linkPreview.title`, then this value is also used for link previews.
-     */
-    func title(for language: String) -> String
-
-    /**
-     The optional text to display in a thumbnail corner.
-     - Note: This text is only displayed for large thumbnails.
-     */
-    func cornerText(for language: String) -> String?
-
-    /**
-     The url to the element in the given language.
-
-     If the `externalUrl` property is not set for the page metadata in the given language, then the standard path is returned.
-     - If this value starts with a slash, it is considered an absolute url to the same domain
-     - If the value starts with `http://` or `https://` it is considered an external url
-     - Otherwise the value is treated as a path from the root of the site.
-     */
-    func fullPageUrl(for language: String) -> String
-
-    /**
-     All elements contained within the element.
-
-     If the element is a section, then this property contains the pages within.
-     */
-    var elements: [SiteElement] { get }
-
-    func backLinkText(for language: String) throws -> String?
-
-}
-
-extension SiteElement {
-
-    func fullPageUrl(for language: String) -> String {
-        localizedPath(for: language)
-    }
-}
-
-extension SiteElement {
-
-    /**
-     The id of the section to which this element contains.
-
-     This property is used to highlight the active section in the top bar.
-
-     The section id is the folder name of the top-level section
-     */
-    var sectionId: String {
-        path.components(separatedBy: "/").first!
-    }
-
-    static var defaultThumbnailFileName: String { "thumbnail.jpg" }
-
-    static func thumbnailFileNameLocalized(for language: String) -> String {
-        defaultThumbnailFileName.insert("-\(language)", beforeLast: ".")
-    }
-
-    var containedFolder: String {
-        inputFolder.lastPathComponent
-    }
-
-    var containsElements: Bool {
-        !elements.isEmpty
-    }
-
-    var hasNestingElements: Bool {
-        elements.contains { $0.containsElements }
-    }
-    
-    /**
-     Get the full path of the thumbnail image for the language (relative to the root folder).
-     */
-    func thumbnailFilePath(for language: String) -> String {
-        let specificImageName = Self.thumbnailFileNameLocalized(for: language)
-        let specificImageUrl = inputFolder.appendingPathComponent(specificImageName)
-        guard specificImageUrl.exists else {
-            return "\(path)/\(Self.defaultThumbnailFileName)"
-        }
-        return "\(path)/\(specificImageName)"
-    }
-
-    /**
-     Gets the thumbnail image for the element.
-
-     If a localized thumbnail exists, then this image name is returned.
-     */
-    func thumbnailName(for language: String) -> String {
-        let specificImageName = "thumbnail-\(language).jpg"
-        let specificImageUrl = inputFolder.appendingPathComponent(specificImageName)
-        guard specificImageUrl.exists else {
-            return "\(inputFolder.lastPathComponent)/thumbnail.jpg"
-        }
-        return "\(inputFolder.lastPathComponent)/\(specificImageName)"
-    }
-    /**
-     Create an absolute path (relative to the root directory) for a file contained in the elements folder.
-
-     This function is used to copy required input files and to generate images
-     */
-    func pathRelativeToRootForContainedInputFile(_ filePath: String) -> String {
-        guard !filePath.hasSuffix("/") && !filePath.hasSuffix("http") else {
-            return filePath
-        }
-        return "\(path)/\(filePath)"
-    }
-
-    func backLinkText(for language: String) throws -> String? { nil }
-
-    /**
-     Returns the full path (relative to the site root for a page of the element in the given language.
-     */
-    func localizedPath(for language: String) -> String {
-        path != "" ? "\(path)/\(language).html" : "\(language).html"
-    }
-
-    func relativePathToFileWithPath(_ filePath: String) -> String {
-        guard path != "" else {
-            return filePath
-        }
-        guard filePath.hasPrefix(path) else {
-            return filePath
-        }
-        return filePath.replacingOccurrences(of: path + "/", with: "")
-    }
-
-    private var additionalHeadContentUrl: URL {
-        inputFolder.appendingPathComponent("head.html")
-    }
-
-    var hasAdditionalHeadContent: Bool {
-        additionalHeadContentUrl.exists
-    }
-
-    func customHeadContent() throws -> String? {
-        let url = additionalHeadContentUrl
-        guard url.exists else {
-            return nil
-        }
-        return try wrap(.failedToOpenFile(url.path)) {
-            try String(contentsOf: url)
-        }
-    }
-
-    private var additionalFooterContentUrl: URL {
-        inputFolder.appendingPathComponent("footer.html")
-    }
-
-    var hasAdditionalFooterContent: Bool {
-        additionalFooterContentUrl.exists
-    }
-
-    func customFooterContent() throws -> String? {
-        let url = additionalFooterContentUrl
-        guard url.exists else {
-            return nil
-        }
-        return try wrap(.failedToOpenFile(url.path)) {
-            try String(contentsOf: url)
-        }
-    }
-}
-
-extension SiteElement {
-
-    func printContents() {
-        print(path)
-        elements.forEach { $0.printContents() }
-    }
-}

WebsiteGenerator/Extensions/Data+Extensions.swift

@@ -0,0 +1,9 @@
+import Foundation
+
+extension Data {
+
+    func createFolderAndWrite(to url: URL) throws {
+        try url.ensureParentFolderExistence()
+        try write(to: url)
+    }
+}

WebsiteGenerator/Extensions/NSImage+Extensions.swift

@@ -0,0 +1,15 @@
+import Foundation
+import AppKit
+
+extension NSImage {
+
+    func scaledDown(to size: NSSize) -> NSImage {
+        guard self.size.width > size.width else {
+            return self
+        }
+        return NSImage(size: size, flipped: false) { (resizedRect) -> Bool in
+            self.draw(in: resizedRect)
+            return true
+        }
+    }
+}

WebsiteGenerator/Extensions/NSSize+Extensions.swift

@@ -0,0 +1,28 @@
+import Foundation
+
+extension NSSize {
+
+    func scaledDown(to desiredWidth: CGFloat) -> NSSize {
+        if width == desiredWidth {
+            return self
+        }
+
+        if width < desiredWidth {
+            // Don't scale larger
+            return self
+        }
+
+        let height = height * desiredWidth / width
+        return NSSize(width: desiredWidth, height: height)
+    }
+}
+
+extension NSSize {
+
+    var ratio: CGFloat {
+        guard height != 0 else {
+            return 0
+        }
+        return width / height
+    }
+}

WebsiteGenerator/Extensions/String+Extensions.swift

@@ -32,8 +32,16 @@ extension String {
         components(separatedBy: separator).last!
     }
 
+    /**
+     Insert the new content before the last occurence of the specified separator.
+
+     If the separator does not appear in the string, then the new content is simply appended.
+     */
     func insert(_ content: String, beforeLast separator: String) -> String {
         let parts = components(separatedBy: separator)
+        guard parts.count > 1 else {
+            return self + content
+        }
         return parts.dropLast().joined(separator: separator) + content + separator + parts.last!
     }
 
@@ -53,3 +61,10 @@ extension Substring {
             .components(separatedBy: end).first!
     }
 }
+
+extension String {
+
+    func createFolderAndWrite(to url: URL) throws {
+        try data(using: .utf8)!.createFolderAndWrite(to: url)
+    }
+}

WebsiteGenerator/Extensions/URL+Extensions.swift

@@ -0,0 +1,38 @@
+import Foundation
+
+extension URL {
+
+    func ensureParentFolderExistence() throws {
+        try deletingLastPathComponent().ensureFolderExistence()
+    }
+
+    func ensureFolderExistence() throws {
+        guard !exists else {
+            return
+        }
+        try FileManager.default.createDirectory(at: self, withIntermediateDirectories: true)
+    }
+
+    var isDirectory: Bool {
+        (try? resourceValues(forKeys: [.isDirectoryKey]))?.isDirectory == true
+    }
+
+    var exists: Bool {
+        FileManager.default.fileExists(atPath: path)
+    }
+
+    /**
+     Delete the file at the url.
+     */
+    func delete() throws {
+        try FileManager.default.removeItem(at: self)
+    }
+
+    func copy(to url: URL) throws {
+        if url.exists {
+            try url.delete()
+        }
+        try url.ensureParentFolderExistence()
+        try FileManager.default.copyItem(at: self, to: url)
+    }
+}

WebsiteGenerator/FileProcessor.swift

@@ -1,306 +0,0 @@
-import Foundation
-#if canImport(AppKit)
-import AppKit
-#endif
-
-final class FileProcessor {
-
-    enum MediaType {
-        case image
-        case video
-        case file
-    }
-
-    func mediaType(forExtension fileExtension: String) -> MediaType {
-        if supportedImageExtensions[fileExtension] != nil {
-            return .image
-        }
-        if supportedVideoExtensions.contains(fileExtension) {
-            return .video
-        }
-        return .file
-    }
-
-    private let supportedImageExtensions: [String : NSBitmapImageRep.FileType] = [
-        "jpg" : .jpeg,
-        "jpeg" : .jpeg,
-        "png" : .png,
-    ]
-
-    private let supportedVideoExtensions: Set<String> = [
-        "mp4", "mov"
-    ]
-
-    struct ImageOutput: Hashable {
-
-        let source: String
-
-        let width: Int
-
-        let desiredHeight: Int?
-
-        var ratio: Float? {
-            guard let desiredHeight = desiredHeight else {
-                return nil
-            }
-            return Float(desiredHeight) / Float(width)
-        }
-
-        func hasSimilarRatio(as other: ImageOutput) -> Bool {
-            guard let other = other.ratio, let ratio = ratio else {
-                return true
-            }
-            return abs(other - ratio) < 0.1
-        }
-    }
-
-    let inputFolder: URL
-
-    let outputFolder: URL
-
-    /**
-     The files required by the site.
-
-     The content are the links to the files relative to the source root folder.
-     The files will be placed at the same path relative to the output folder
-     */
-    private var requiredFiles: Set<String> = []
-
-    private var tasks: [String : ImageOutput] = [:]
-
-    init(inputFolder: URL, outputFolder: URL) {
-        self.inputFolder = inputFolder
-        self.outputFolder = outputFolder
-    }
-
-    // MARK: Files
-
-    /**
-     Add a file as required, so that it will be copied to the output directory.
-     */
-    func require(file: String) {
-        requiredFiles.insert(file)
-    }
-
-    func copyRequiredFiles() throws {
-        var missingFiles = [String]()
-        for file in requiredFiles {
-            let sourceUrl = inputFolder.appendingPathComponent(file)
-            guard sourceUrl.exists else {
-                missingFiles.append(file)
-                continue
-            }
-            let destinationUrl = outputFolder.appendingPathComponent(file)
-            try FileSystem.copy(sourceUrl, to: destinationUrl)
-        }
-    }
-
-    // MARK: Images
-
-    @discardableResult
-    func requireImage(source: String, destination: String, width: Int, desiredHeight: Int? = nil, createDoubleVersion: Bool = false) throws -> NSSize {
-        let output = ImageOutput(
-            source: source,
-            width: width,
-            desiredHeight: desiredHeight)
-
-        return try requireImage(output,
-                         for: destination,
-                         createDoubleVersion: createDoubleVersion)
-    }
-
-    private func insert(_ image: ImageOutput, for destination: String) throws -> NSSize {
-        let sourceUrl = inputFolder.appendingPathComponent(image.source)
-        guard sourceUrl.exists else {
-            throw GenerationError.missingImage(sourceUrl.path)
-        }
-        guard let imageSize = NSImage(contentsOfFile: sourceUrl.path)?.size else {
-            let height = image.desiredHeight.unwrapped(CGFloat.init)
-            let width = CGFloat(image.width)
-            return .init(width: width, height: height ?? width / 16 * 9)
-            //throw GenerationError.failedToGenerateImage(sourceUrl.path)
-        }
-        let scaledSize = getScaledSize(of: imageSize, to: CGFloat(image.width))
-
-        guard let existing = tasks[destination] else {
-            //print("Image(\(image.width),\(image.desiredHeight ?? -1)) requested for \(destination)")
-            tasks[destination] = image
-            return scaledSize
-        }
-        guard existing.source == image.source else {
-            throw GenerationError.conflictingImageSources(
-                output: destination, in1: existing.source, in2: image.source)
-        }
-        guard existing.hasSimilarRatio(as: image) else {
-            throw GenerationError.conflictingImageRatios(
-                output: destination, in1: existing.source, in2: image.source)
-        }
-        if image.width > existing.width {
-            //print("Image(\(image.width),\(image.desiredHeight ?? -1)) requested for \(destination)")
-            tasks[destination] = image
-        }
-        return scaledSize
-    }
-
-    @discardableResult
-    func requireImage(_ image: ImageOutput, for destination: String, createDoubleVersion: Bool = false) throws -> NSSize {
-        let size = try insert(image, for: destination)
-        guard createDoubleVersion else {
-            return size
-        }
-
-        _ = try requireImage(
-            source: image.source,
-            destination: destination.insert("@2x", beforeLast: "."),
-            width: image.width * 2,
-            desiredHeight: image.desiredHeight.unwrapped { $0 * 2 } )
-        // Return 1x size
-        return size
-    }
-
-    func createImages() throws {
-        for (destination, image) in tasks {
-            try createImageIfNeeded(image, for: destination)
-        }
-    }
-
-    private func createImageIfNeeded(_ image: ImageOutput, for destination: String) throws {
-        let source = inputFolder.appendingPathComponent(image.source)
-        guard source.exists else {
-            throw GenerationError.missingImage(source.path)
-        }
-        let destination = outputFolder.appendingPathComponent(destination)
-        #warning("Check if source image has changed since last run")
-        guard !destination.exists else {
-            return
-        }
-        
-        // Ensure that image file is supported
-        let ext = destination.pathExtension.lowercased()
-        guard supportedImageExtensions[ext] != nil else {
-            print("Copying file \(source.path)")
-            try FileSystem.copy(source, to: destination)
-            return
-        }
-#if canImport(AppKit)
-        try createImage(
-            destination,
-            from: source,
-            with: CGFloat(image.width),
-            and: image.desiredHeight.unwrapped(CGFloat.init))
-#else
-        throw GenerationError.failedToGenerateImage(destination.path)
-#endif
-    }
-
-#if canImport(AppKit)
-    private func createImage(_ destination: URL, from source: URL, with desiredWidth: CGFloat, and desiredHeight: CGFloat?) throws {
-
-        guard let sourceImage = NSImage(contentsOfFile: source.path) else {
-            print("Failed to load image \(source.path)")
-            throw GenerationError.failedToGenerateImage(source.path)
-        }
-
-        let destinationSize = getScaledSize(of: sourceImage.size, to: desiredWidth)
-        let scaledImage = scale(image: sourceImage, to: destinationSize)
-        let scaledSize = scaledImage.size
-
-        if abs(scaledImage.size.width - desiredWidth) > 2 {
-            print("[WARN] Image \(destination.path) scaled incorrectly (wanted width \(desiredWidth), is \(scaledSize.width))")
-        }
-        if abs(destinationSize.height - scaledImage.size.height) > 2 {
-            print("[WARN] Image \(destination.path) scaled incorrectly (wanted height \(destinationSize.height), is \(scaledSize.height))")
-        }
-        if let desiredHeight = desiredHeight {
-            let desiredRatio = desiredHeight / desiredWidth
-            let adjustedDesiredHeight = scaledSize.width * desiredRatio
-            if abs(adjustedDesiredHeight - scaledSize.height) > 5 {
-                print("[WARN] Image \(source.path): Desired height \(adjustedDesiredHeight) (actually \(desiredHeight)), got \(scaledSize.height) after reduction")
-                throw GenerationError.imageRatioMismatch(destination.path)
-            }
-        }
-        if scaledSize.width > desiredWidth {
-            print("[WARN] Image \(source.path) is too large (expected width \(desiredWidth), got \(scaledSize.width)")
-        }
-
-        try saveImage(scaledImage, atUrl: destination)
-
-        guard let savedImage = NSImage(contentsOfFile: destination.path) else {
-            throw GenerationError.failedToGenerateImage(source.path)
-        }
-        let savedSize = savedImage.size
-        if destination.lastPathComponent.hasSuffix("@2x.jpg") {
-            if abs(savedSize.height - destinationSize.height/2) > 2 || abs(savedSize.width - destinationSize.width/2) > 2 {
-                print("[WARN] Image \(destination.path) (2x): Expected (\(destinationSize.width/2),\(destinationSize.height/2)), got (\(savedSize.width),\(savedSize.height))")
-            }
-        } else if abs(savedSize.height - destinationSize.height) > 2 || abs(savedSize.width - destinationSize.width) > 2 {
-            print("[WARN] Image \(destination.path): Expected (\(destinationSize.width),\(destinationSize.height)), got (\(savedSize.width),\(savedSize.height))")
-        }
-//        print("Source (\(sourceWidth),\(sourceHeight))")
-//        print("Desired (\(desiredWidth),\(desiredHeight!))")
-//        print("Expected (\(expectedScaledWidth),\(expectedScaledHeight))")
-//        print("Scaled (\(scaledWidth),\(scaledImage.size.height))")
-//        print("Saved (\(savedWidth),\(savedHeight))")
-//        print(NSScreen.main!.backingScaleFactor)
-    }
-
-    private func saveImage(_ image: NSImage, atUrl url: URL) throws {
-        let ext = url.pathExtension.lowercased()
-        guard let type = supportedImageExtensions[ext] else {
-            print("No image type for \(url.path)")
-            throw GenerationError.failedToGenerateImage(url.path)
-        }
-        guard let tiff = image.tiffRepresentation, let tiffData = NSBitmapImageRep(data: tiff) else {
-            print("Failed to get data for image \(url.path)")
-            throw GenerationError.failedToGenerateImage(url.path)
-        }
-
-        guard let data = tiffData.representation(using: type, properties: [.compressionFactor: NSNumber(0.7)]) else {
-            print("Failed to get data for image \(url.path)")
-            throw GenerationError.failedToGenerateImage(url.path)
-        }
-        try data.createFolderAndWrite(to: url)
-    }
-#endif
-}
-
-
-private extension Int {
-
-    func multiply(by factor: Int) -> Int {
-        self * factor
-    }
-}
-
-private func getScaledSize(of source: NSSize, to desiredWidth: CGFloat) -> NSSize {
-    if source.width == desiredWidth {
-        return source
-    }
-
-    if source.width < desiredWidth {
-        // Keep existing image if image is too small already
-        return source
-        //print("Image \(destination.path) too small (wanted width \(desiredWidth), has only \(sourceWidth))")
-    }
-
-    let height = source.height * desiredWidth / source.width
-    return NSSize(width: desiredWidth, height: height)
-}
-
-private func scale(image: NSImage, to size: NSSize) -> NSImage {
-    guard image.size.width > size.width else {
-        return image
-    }
-    //resize image
-    return NSImage(size: size, flipped: false) { (resizedRect) -> Bool in
-        image.draw(in: resizedRect)
-        return true
-    }
-}
-
-private extension NSSize {
-
-    var ratio: CGFloat {
-        width / height
-    }
-}

WebsiteGenerator/FileSystem.swift

@@ -1,105 +0,0 @@
-import Foundation
-
-enum FileSystem {
-
-    fileprivate static var fm: FileManager { .default }
-
-    static func folders(in folder: URL) throws -> [URL] {
-        try fm.contentsOfDirectory(at: folder, includingPropertiesForKeys: [.isDirectoryKey])
-            .filter { $0.isDirectory }
-    }
-
-    /**
-     Copy a file to the destination, creating the containing folder if needed
-     */
-    static func copy(_ source: URL, to destination: URL) throws {
-        try destination.ensureParentFolderExistence()
-        try source.copy(to: destination)
-    }
-
-}
-
-extension URL {
-
-    func ensureParentFolderExistence() throws {
-        try deletingLastPathComponent().ensureFolderExistence()
-    }
-
-    func ensureFolderExistence() throws {
-        if !exists {
-            print("Creating directory \(path)")
-            try wrap(.failedToWriteFile(path)) {
-                try FileManager.default.createDirectory(at: self, withIntermediateDirectories: true)
-            }
-        }
-    }
-
-    var isDirectory: Bool {
-        (try? resourceValues(forKeys: [.isDirectoryKey]))?.isDirectory == true
-    }
-
-    var exists: Bool {
-        FileSystem.fm.fileExists(atPath: path)
-    }
-
-    /**
-     Delete the file at the url.
-     */
-    func delete() throws {
-        try FileSystem.fm.removeItem(at: self)
-    }
-
-    func copy(to url: URL) throws {
-        try wrap(.failedToWriteFile(url.path)) {
-            if url.exists {
-                try url.delete()
-            }
-            try url.ensureParentFolderExistence()
-            try FileSystem.fm.copyItem(at: self, to: url)
-        }
-    }
-}
-
-extension Data {
-
-    func createFolderAndWrite(to url: URL) throws {
-        try url.ensureParentFolderExistence()
-//        if url.exists {
-//            print("Overwriting \(url.path)")
-//        }
-        try wrap(.failedToWriteFile(url.path)) {
-            try write(to: url)
-        }
-    }
-}
-
-extension String {
-
-    func createFolderAndWrite(to url: URL) throws {
-        try data(using: .utf8)!.createFolderAndWrite(to: url)
-    }
-}
-
-extension Encodable {
-
-    func writeJSON(to url: URL) throws {
-        let encoder = JSONEncoder()
-        encoder.outputFormatting = .prettyPrinted
-        let content = try wrap(.failedToEncodeJSON(url.path)) {
-            try encoder.encode(self)
-        }
-        try content.createFolderAndWrite(to: url)
-    }
-}
-
-extension Decodable {
-
-    init(decodeFrom url: URL) throws {
-        let data = try wrap(.failedToOpenFile(url.path)) {
-            try Data(contentsOf: url)
-        }
-        self = try wrap({ .failedToDecodeJSON(file: url.path, error: $0.localizedDescription)}) {
-            try JSONDecoder().decode(Self.self, from: data)
-        }
-    }
-}

WebsiteGenerator/Files/FileSystem.swift

@@ -0,0 +1,378 @@
+import Foundation
+import CryptoKit
+import AppKit
+
+typealias SourceFile = (data: Data, didChange: Bool)
+typealias SourceTextFile = (content: String, didChange: Bool)
+
+final class FileSystem {
+
+    private static let hashesFileName = "hashes.json"
+
+    private let input: URL
+
+    private let output: URL
+
+    private let source = "FileChangeMonitor"
+
+    private var hashesFile: URL {
+        input.appendingPathComponent(FileSystem.hashesFileName)
+    }
+
+    /**
+     The hashes of all accessed files from the previous run
+
+     The key is the relative path to the file from the source
+     */
+    private var previousFiles: [String : Data] = [:]
+
+    /**
+     The paths of all files which were accessed, with their new hashes
+
+     This list is used to check if a file was modified, and to write all accessed files back to disk
+     */
+    private var accessedFiles: [String : Data] = [:]
+
+    /**
+     All files which should be copied to the output folder
+     */
+    private var requiredFiles: Set<String> = []
+
+    /**
+     The image creation tasks.
+
+     The key is the destination path.
+     */
+    private var imageTasks: [String : ImageOutput] = [:]
+
+    init(in input: URL, to output: URL) {
+        self.input = input
+        self.output = output
+
+        guard exists(hashesFile) else {
+            log.add(info: "No file hashes loaded, regarding all content as new", source: source)
+            return
+        }
+        let data: Data
+        do {
+            data = try Data(contentsOf: hashesFile)
+        } catch {
+            log.add(
+                warning: "File hashes could not be read, regarding all content as new",
+                source: source,
+                error: error)
+            return
+        }
+        do {
+            self.previousFiles = try JSONDecoder().decode(from: data)
+        } catch {
+            log.add(
+                warning: "File hashes could not be decoded, regarding all content as new",
+                source: source,
+                error: error)
+            return
+        }
+    }
+
+    func urlInOutputFolder(_ path: String) -> URL {
+        output.appendingPathComponent(path)
+    }
+
+    func urlInContentFolder(_ path: String) -> URL {
+        input.appendingPathComponent(path)
+    }
+
+    /**
+     Get the current hash of file data at a path.
+
+     If the hash has been computed previously during the current run, then this function directly returns it.
+     */
+    private func hash(_ data: Data, at path: String) -> Data {
+        accessedFiles[path] ?? SHA256.hash(data: data).data
+    }
+
+    private func exists(_ url: URL) -> Bool {
+        FileManager.default.fileExists(atPath: url.path)
+    }
+
+    func dataOfRequiredFile(atPath path: String, source: String) -> Data? {
+        let url = input.appendingPathComponent(path)
+        guard exists(url) else {
+            log.failedToOpen(path, requiredBy: source, error: nil)
+            return nil
+        }
+
+        do {
+            return try Data(contentsOf: url)
+        } catch {
+            log.failedToOpen(path, requiredBy: source, error: error)
+            return nil
+        }
+    }
+
+    func dataOfOptionalFile(atPath path: String, source: String) -> Data? {
+        let url = input.appendingPathComponent(path)
+        guard exists(url) else {
+            return nil
+        }
+
+        do {
+            return try Data(contentsOf: url)
+        } catch {
+            log.failedToOpen(path, requiredBy: source, error: error)
+            return nil
+        }
+    }
+
+    func contentOfOptionalFile(atPath path: String, source: String) -> String? {
+        let url = input.appendingPathComponent(path)
+        guard exists(url) else {
+            return nil
+        }
+
+        do {
+            return try String(contentsOf: url)
+        } catch {
+            log.failedToOpen(path, requiredBy: source, error: error)
+            return nil
+        }
+    }
+
+    private func getData(atPath path: String) -> SourceFile? {
+        let url = input.appendingPathComponent(path)
+        guard exists(url) else {
+            return nil
+        }
+        let data: Data
+        do {
+            data = try Data(contentsOf: url)
+        } catch {
+            log.add(error: "Failed to read data at \(path)", source: source, error: error)
+            return nil
+        }
+        let newHash = hash(data, at: path)
+        defer {
+            accessedFiles[path] = newHash
+        }
+        guard let oldHash = previousFiles[path] else {
+            return (data: data, didChange: true)
+        }
+        return (data: data, didChange: oldHash != newHash)
+    }
+
+    func writeHashes() {
+        do {
+            let encoder = JSONEncoder()
+            encoder.outputFormatting = .prettyPrinted
+            let data = try encoder.encode(accessedFiles)
+            try data.write(to: hashesFile)
+        } catch {
+            log.add(warning: "Failed to save file hashes", source: source, error: error)
+        }
+    }
+
+    // MARK: Images
+
+    private func loadImage(atPath path: String) -> (image: NSImage, changed: Bool)? {
+        guard let (data, changed) = getData(atPath: path) else {
+            print("Failed to load image data \(path)")
+            return nil
+        }
+        guard let image = NSImage(data: data) else {
+            print("Failed to read image \(path)")
+            return nil
+        }
+        return (image, changed)
+    }
+
+    @discardableResult
+    func requireImage(source: String, destination: String, width: Int, desiredHeight: Int? = nil, createDoubleVersion: Bool = false)  -> NSSize {
+        let height = desiredHeight.unwrapped(CGFloat.init)
+        let sourceUrl = input.appendingPathComponent(source)
+        let image = ImageOutput(source: source, width: width, desiredHeight: desiredHeight)
+
+        let standardSize = NSSize(width: CGFloat(width), height: height ?? CGFloat(width) / 16 * 9)
+        guard sourceUrl.exists else {
+            log.add(error: "Missing image \(source) with size (\(width),\(desiredHeight ?? -1)",
+                            source: "Image Processor")
+            return standardSize
+        }
+        guard let imageSize = loadImage(atPath: image.source)?.image.size else {
+            log.add(error: "Unreadable image \(source) with size (\(width),\(desiredHeight ?? -1)",
+                            source: "Image Processor")
+            return standardSize
+        }
+        let scaledSize = imageSize.scaledDown(to: CGFloat(width))
+
+        guard let existing = imageTasks[destination] else {
+            //print("Image(\(image.width),\(image.desiredHeight ?? -1)) requested for \(destination)")
+            imageTasks[destination] = image
+            return scaledSize
+        }
+        guard existing.source == source else {
+            log.add(error: "Multiple sources (\(existing.source),\(source)) for image \(destination)",
+                            source: "Image Processor")
+            return scaledSize
+        }
+        guard existing.hasSimilarRatio(as: image) else {
+            log.add(error: "Multiple ratios (\(existing.ratio!),\(image.ratio!)) for image \(destination)",
+                            source: "Image Processor")
+            return scaledSize
+        }
+        if image.width > existing.width {
+            log.add(info: "Increasing size of image \(destination) from \(existing.width) to \(width)",
+                            source: "Image Processor")
+            imageTasks[destination] = image
+        }
+        return scaledSize
+    }
+
+    #warning("Implement image functions")
+    func createImages() {
+        for (destination, image) in imageTasks.sorted(by: { $0.key < $1.key }) {
+            createImageIfNeeded(image, for: destination)
+        }
+    }
+
+    private func createImageIfNeeded(_ image: ImageOutput, for destination: String) {
+        guard let (sourceImageData, sourceImageChanged) = getData(atPath: image.source) else {
+            log.add(error: "Failed to open image \(image.source)", source: "Image Processor")
+            return
+        }
+
+        let destinationUrl = output.appendingPathComponent(destination)
+
+        // Check if image needs to be updated
+        guard !destinationUrl.exists || sourceImageChanged else {
+            return
+        }
+
+        // Ensure that image file is supported
+        let ext = destinationUrl.pathExtension.lowercased()
+        guard MediaType.isProcessableImage(ext) else {
+            log.add(info: "Copying image \(image.source)", source: "Image Processor")
+            do {
+                let sourceUrl = input.appendingPathComponent(image.source)
+                try destinationUrl.ensureParentFolderExistence()
+                try sourceUrl.copy(to: destinationUrl)
+            } catch {
+                log.add(error: "Failed to copy image \(image.source) to \(destination)", source: "Image Processor")
+            }
+            return
+        }
+        guard let sourceImage = NSImage(data: sourceImageData) else {
+            print("Failed to read image \(image.source)")
+            return
+        }
+
+        let desiredWidth = CGFloat(image.width)
+        let desiredHeight = image.desiredHeight.unwrapped(CGFloat.init)
+
+        let destinationSize = sourceImage.size.scaledDown(to: desiredWidth)
+        let scaledImage = sourceImage.scaledDown(to: destinationSize)
+        let scaledSize = scaledImage.size
+
+        if abs(scaledImage.size.width - desiredWidth) > 2 {
+            print("[WARN] Image \(destination) scaled incorrectly (wanted width \(desiredWidth), is \(scaledSize.width))")
+        }
+        if abs(destinationSize.height - scaledImage.size.height) > 2 {
+            print("[WARN] Image \(destination) scaled incorrectly (wanted height \(destinationSize.height), is \(scaledSize.height))")
+        }
+        if let desiredHeight = desiredHeight {
+            let desiredRatio = desiredHeight / desiredWidth
+            let adjustedDesiredHeight = scaledSize.width * desiredRatio
+            if abs(adjustedDesiredHeight - scaledSize.height) > 5 {
+                log.add(warning: "Image \(image.source): Desired height \(adjustedDesiredHeight) (actually \(desiredHeight)), got \(scaledSize.height) after reduction", source: "Image Processor")
+                return
+            }
+        }
+        if scaledSize.width > desiredWidth {
+            print("[WARN] Image \(image.source) is too large (expected width \(desiredWidth), got \(scaledSize.width)")
+        }
+
+        let destinationExtension = destinationUrl.pathExtension.lowercased()
+        guard let type = MediaType.supportedImage(destinationExtension) else {
+            log.add(error: "No image type for \(destination) with extension \(destinationExtension)",
+                            source: "Image Processor")
+            return
+        }
+        guard let tiff = scaledImage.tiffRepresentation, let tiffData = NSBitmapImageRep(data: tiff) else {
+            log.add(error: "Failed to get data for image \(image.source)", source: "Image Processor")
+            return
+        }
+
+        guard let data = tiffData.representation(using: type, properties: [.compressionFactor: NSNumber(0.7)]) else {
+            log.add(error: "Failed to get data for image \(image.source)", source: "Image Processor")
+            return
+        }
+        do {
+            try data.createFolderAndWrite(to: destinationUrl)
+        } catch {
+            log.add(error: "Failed to write image \(destination)", source: "Image Processor", error: error)
+            return
+        }
+    }
+
+    // MARK: File copying
+
+    /**
+     Add a file as required, so that it will be copied to the output directory.
+     */
+    func require(file: String) {
+        requiredFiles.insert(file)
+    }
+
+    func copyRequiredFiles() {
+        var missingFiles = [String]()
+        for file in requiredFiles {
+            let sourceUrl = input.appendingPathComponent(file)
+            guard sourceUrl.exists else {
+                missingFiles.append(file)
+                continue
+            }
+            let data: Data
+            do {
+                data = try Data(contentsOf: sourceUrl)
+            } catch {
+                log.add(error: "Failed to read data at \(sourceUrl.path)", source: source, error: error)
+                continue
+            }
+            let destinationUrl = output.appendingPathComponent(file)
+            write(data, to: destinationUrl)
+        }
+    }
+
+    // MARK: Writing files
+
+    @discardableResult
+    func write(_ data: Data, to url: URL) -> Bool {
+        // Only write changed files
+        if url.exists, let oldContent = try? Data(contentsOf: url), data == oldContent {
+            return false
+        }
+        do {
+            try data.createFolderAndWrite(to: url)
+            return true
+        } catch {
+            log.add(error: "Failed to write file", source: url.path, error: error)
+            return false
+        }
+    }
+
+    @discardableResult
+    func write(_ string: String, to url: URL) -> Bool {
+        let data = string.data(using: .utf8)!
+        return write(data, to: url)
+    }
+}
+
+private extension Digest {
+
+    var bytes: [UInt8] { Array(makeIterator()) }
+
+    var data: Data { Data(bytes) }
+
+    var hexStr: String {
+        bytes.map { String(format: "%02X", $0) }.joined()
+    }
+}

WebsiteGenerator/Files/ImageOutput.swift

@@ -0,0 +1,24 @@
+import Foundation
+
+struct ImageOutput: Hashable {
+
+    let source: String
+
+    let width: Int
+
+    let desiredHeight: Int?
+
+    var ratio: Float? {
+        guard let desiredHeight = desiredHeight else {
+            return nil
+        }
+        return Float(desiredHeight) / Float(width)
+    }
+
+    func hasSimilarRatio(as other: ImageOutput) -> Bool {
+        guard let other = other.ratio, let ratio = ratio else {
+            return true
+        }
+        return abs(other - ratio) < 0.1
+    }
+}

WebsiteGenerator/Files/MediaType.swift

@@ -0,0 +1,36 @@
+import Foundation
+import AppKit
+
+private let supportedImageExtensions: [String : NSBitmapImageRep.FileType] = [
+    "jpg" : .jpeg,
+    "jpeg" : .jpeg,
+    "png" : .png,
+]
+
+private let supportedVideoExtensions: Set<String> = [
+    "mp4", "mov"
+]
+
+enum MediaType {
+    case image
+    case video
+    case file
+
+    init(fileExtension: String) {
+        if supportedImageExtensions[fileExtension] != nil {
+            self = .image
+        } else if supportedVideoExtensions.contains(fileExtension) {
+            self = .video
+        } else {
+            self = .file
+        }
+    }
+
+    static func isProcessableImage(_ fileExtension: String) -> Bool {
+        supportedImage(fileExtension) != nil
+    }
+
+    static func supportedImage(_ fileExtension: String) -> NSBitmapImageRep.FileType? {
+        supportedImageExtensions[fileExtension]
+    }
+}

WebsiteGenerator/Files/ValidationLog.swift

@@ -1,6 +1,6 @@
 import Foundation
 
-final class ErrorOutput {
+final class ValidationLog {
 
     private enum LogLevel: String {
         case error = "ERROR"
@@ -138,7 +138,7 @@ final class ErrorOutput {
         guard let string = string else {
             return nil
         }
-        guard let date = ErrorOutput.metadataDate.date(from: string) else {
+        guard let date = ValidationLog.metadataDate.date(from: string) else {
             add(warning: "Invalid date string '\(string)' for property '\(property)'", source: source)
             return nil
         }

WebsiteGenerator/GenerationError.swift

@@ -1,51 +0,0 @@
-import Foundation
-
-enum GenerationError: Error {
-    case missingMarkerInTemplate(String)
-    case failedToLoadTemplate(String)
-    case failedToWriteFile(String)
-    case failedToOpenFile(String)
-    case failedToDecodeJSON(file: String, error: String)
-    case invalidLanguageSpecification(String)
-    case invalidDateInPageMetadata(String)
-    case failedToEncodeJSON(String)
-    case missingSectionMetadata(section: String, language: String)
-    case missingPageMetadata(page: String, language: String)
-    case missingPage(page: String, language: String)
-    case missingImage(String)
-    case conflictingImageSources(output: String, in1: String, in2: String)
-    case conflictingImageRatios(output: String, in1: String, in2: String)
-    case failedToGenerateImage(String)
-    case imageRatioMismatch(String)
-
-}
-
-func wrap<T>(_ error: GenerationError, execute: () throws -> T) rethrows -> T {
-    do {
-        return try execute()
-    } catch let underlyingError {
-        print(underlyingError)
-        throw error
-    }
-}
-
-func wrap<T>(_ error: (Error) -> GenerationError, execute: () throws -> T) rethrows -> T {
-    do {
-        return try execute()
-    } catch let underlyingError {
-        print(underlyingError)
-        throw error(underlyingError)
-    }
-}
-
-extension Optional {
-
-    func unwrap(or error: GenerationError) throws -> Wrapped {
-        switch self {
-        case .none:
-            throw error
-        case .some(let wrapped):
-            return wrapped
-        }
-    }
-}

WebsiteGenerator/Generators/IndexPageGenerator.swift

@@ -1,21 +1,5 @@
 import Foundation
 
-private struct AboveRootDummy: SiteElement {
-    var sortIndex: Int? { nil }
-
-    var sortDate: Date? { nil }
-
-    var path: String { "" }
-
-    let inputFolder: URL
-
-    func title(for language: String) -> String { "" }
-
-    func cornerText(for language: String) -> String? { nil }
-
-    var elements: [SiteElement] { [] }
-}
-
 struct IndexPageGenerator {
 
     private let factory: LocalizedSiteTemplate
@@ -25,41 +9,34 @@ struct IndexPageGenerator {
     }
 
     func generate(
-        site: Site,
+        site: Element,
         language: String,
         languageButton: String?,
         sectionItemCount: Int,
-        to url: URL) throws {
+        to url: URL) {
             let localized = site.localized(for: language)
 
             var content = [PageTemplate.Key : String]()
-            content[.head] = try makeHead(site: site, language: language)
+            content[.head] = factory.pageHead.generate(page: site, language: language)
-            content[.topBar] = factory.topBar.generate(section: nil, languageButton: languageButton)
+            content[.topBar] = factory.topBar.generate(sectionUrl: nil, languageButton: languageButton)
             content[.contentClass] = "overview"
             content[.header] = makeHeader(localized: localized)
-            let sections = site.elements.compactMap { $0 as? Section }
+            content[.content] = factory.overviewSection.generate(
-            content[.content] = try factory.overviewSection.generate(
+                sections: site.elements,
-                sections: sections,
                 in: site,
                 language: language,
                 sectionItemCount: sectionItemCount)
-            content[.footer] = try site.customFooterContent()
+            content[.footer] = site.customFooterContent()
-            try factory.page.generate(content, to: url)
+            guard factory.page.generate(content, to: url) else {
+                return
+            }
+            log.add(info: "Generated \(url.lastPathComponent)", source: site.path)
     }
 
-    private func makeHead(site: Site, language: String) throws -> String {
+    private func makeHeader(localized: Element.LocalizedMetadata) -> String {
-        let localized = site.localized(for: language)
-        return try factory.pageHead.generate(page: PageHeadInfo(
-            author: site.metadata.author,
-            linkPreviewTitle: localized.linkPreviewTitle,
-            linkPreviewDescription: localized.linkPreviewDescription,
-            linkPreviewImage: site.linkPreviewImage(for: language),
-            customHeadContent: try site.customHeadContent()))
-    }
-
-    private func makeHeader(localized: Site.LocalizedMetadata) -> String {
         var content = [HeaderKey : String]()
         content[.title] = localized.title
+        #warning("Add title suffix")
         content[.subtitle] = localized.subtitle
         content[.titleText] = localized.description
         return factory.factory.centeredHeader.generate(content)

WebsiteGenerator/Generators/MarkdownProcessor.swift

@@ -9,31 +9,18 @@ struct PageContentGenerator {
 
     private let factory: TemplateFactory
 
-    private let files: FileProcessor
-
     private let swift = SyntaxHighlighter(format: HTMLOutputFormat())
 
-    init(factory: TemplateFactory, files: FileProcessor) {
+    init(factory: TemplateFactory) {
         self.factory = factory
-        self.files = files
     }
 
-    func generate(page: Page, language: String, at url: URL) throws -> String {
+    func generate(page: Element, language: String, content: String) -> String {
-        var errorToThrow: Error? = nil
-
-        let content = try wrap(.missingPage(page: url.path, language: language)) {
-            try String(contentsOf: url)
-        }
 
         var hasCodeContent = false
 
         let imageModifier = Modifier(target: .images) { html, markdown in
-            do {
+            processMarkdownImage(markdown: markdown, html: html, page: page)
-                return try processMarkdownImage(markdown: markdown, html: html, page: page)
-            } catch {
-                errorToThrow = error
-                return ""
-            }
         }
         let codeModifier = Modifier(target: .codeBlocks) { html, markdown in
             if markdown.starts(with: "```swift") {
@@ -51,17 +38,13 @@ struct PageContentGenerator {
         let parser = MarkdownParser(modifiers: [imageModifier, codeModifier, linkModifier])
 
         if hasCodeContent {
-            #warning("Automatically add hljs hightlighting if code samples are found")
+            #warning("Automatically add hljs highlighting if code samples are found")
         }
 
-        let result = parser.html(from: content)
+        return parser.html(from: content)
-        if let error = errorToThrow {
-            throw error
-        }
-        return result
     }
 
-    private func processMarkdownImage(markdown: Substring, html: String, page: Page) throws -> String {
+    private func processMarkdownImage(markdown: Substring, html: String, page: Element) -> String {
         // Split the markdown ![alt](file "title")
         // For images: ![left_title](file "right_title")
         // For videos: ![option...](file)
@@ -72,27 +55,27 @@ struct PageContentGenerator {
         let alt = markdown.between("[", and: "]").nonEmpty
 
         let fileExtension = file.lastComponentAfter(".").lowercased()
-        switch files.mediaType(forExtension: fileExtension) {
+        switch MediaType(fileExtension: fileExtension) {
         case .image:
-            return try handleImage(page: page, file: file, rightTitle: title, leftTitle: alt)
+            return handleImage(page: page, file: file, rightTitle: title, leftTitle: alt)
         case .video:
-            return try handleVideo(page: page, file: file, optionString: alt)
+            return handleVideo(page: page, file: file, optionString: alt)
         case .file:
             if fileExtension == "svg" {
-                return try handleSvg(page: page, file: file)
+                return handleSvg(page: page, file: file)
             }
-            return try handleFile(page: page, file: file, fileExtension: fileExtension)
+            return handleFile(page: page, file: file, fileExtension: fileExtension)
         }
     }
 
-    private func handleImage(page: Page, file: String, rightTitle: String?, leftTitle: String?) throws -> String {
+    private func handleImage(page: Element, file: String, rightTitle: String?, leftTitle: String?) -> String {
         let imagePath = page.pathRelativeToRootForContainedInputFile(file)
 
-        let size = try files.requireImage(source: imagePath, destination: imagePath, width: pageImageWidth)
+        let size = files.requireImage(source: imagePath, destination: imagePath, width: pageImageWidth)
 
         let imagePath2x = imagePath.insert("@2x", beforeLast: ".")
         let file2x = file.insert("@2x", beforeLast: ".")
-        try files.requireImage(source: imagePath, destination: imagePath2x, width: 2 * pageImageWidth)
+        files.requireImage(source: imagePath, destination: imagePath2x, width: 2 * pageImageWidth)
 
         let content: [PageImageTemplate.Key : String] = [
             .image: file,
@@ -104,7 +87,7 @@ struct PageContentGenerator {
         return factory.image.generate(content)
     }
 
-    private func handleVideo(page: Page, file: String, optionString: String?) throws -> String {
+    private func handleVideo(page: Element, file: String, optionString: String?) -> String {
         let options: [PageVideoTemplate.VideoOption] = optionString.unwrapped { string in
             string.components(separatedBy: " ").compactMap { optionText in
                 guard let optionText = optionText.trimmed.nonEmpty else {
@@ -125,7 +108,7 @@ struct PageContentGenerator {
         return factory.video.generate(sources: sources, options: options)
     }
 
-    private func handleSvg(page: Page, file: String) throws -> String {
+    private func handleSvg(page: Element, file: String) -> String {
         let imagePath = page.pathRelativeToRootForContainedInputFile(file)
         files.require(file: imagePath)
 
@@ -136,7 +119,7 @@ struct PageContentGenerator {
         """
     }
 
-    private func handleFile(page: Page, file: String, fileExtension: String) throws -> String {
+    private func handleFile(page: Element, file: String, fileExtension: String) -> String {
         #warning("Handle other files in markdown")
         print("[WARN] Unhandled file \(file) with extension \(fileExtension)")
         return ""

WebsiteGenerator/Generators/OverviewPageGenerator.swift

@@ -4,65 +4,53 @@ struct OverviewPageGenerator {
 
     private let factory: LocalizedSiteTemplate
 
-    let outputFolder: URL
+    init(factory: LocalizedSiteTemplate) {
-
-    init(factory: LocalizedSiteTemplate, files: FileProcessor) {
         self.factory = factory
-        self.outputFolder = files.outputFolder
     }
 
     func generate(
-        section: Section,
+        section: Element,
         language: String,
-        backText: String?) throws {
+        backText: String?) {
-            let url = outputFolder.appendingPathComponent(section.localizedPath(for: language))
+            let path = section.localizedPath(for: language)
+            let url = files.urlInOutputFolder(path)
 
             let metadata = section.localized(for: language)
 
             var content = [PageTemplate.Key : String]()
-            content[.head] = try makeHead(section: section, language: language)
+            content[.head] = factory.pageHead.generate(page: section, language: language)
             let languageButton = section.nextLanguage(for: language)
             content[.topBar] = factory.topBar.generate(
-                section: section.sectionId,
+                sectionUrl: section.sectionUrl(for: language),
                 languageButton: languageButton)
             content[.contentClass] = "overview"
             content[.header] = makeHeader(metadata: metadata, language: language, backText: backText)
-            content[.content] = try makeContent(section: section, language: language)
+            content[.content] = makeContent(section: section, language: language)
-            content[.footer] = try section.customFooterContent()
+            content[.footer] = section.customFooterContent()
-            try factory.page.generate(content, to: url)
+            guard factory.page.generate(content, to: url) else {
+                return
+            }
+            log.add(info: "Generated \(path)", source: section.path)
     }
 
-    private func makeContent(section: Section, language: String) throws -> String {
+    private func makeContent(section: Element, language: String) -> String {
         if section.hasNestingElements {
-            let sections = section.elements.compactMap { $0 as? Section }
+            return factory.overviewSection.generate(
-            return try factory.overviewSection.generate(
+                sections: section.elements,
-                sections: sections,
                 in: section,
                 language: language,
-                sectionItemCount: section.metadata.sectionOverviewItemCount)
+                sectionItemCount: section.overviewItemCount)
         } else {
-            return try factory.overviewSection.generate(section: section, language: language)
+            return factory.overviewSection.generate(section: section, language: language)
         }
     }
 
-    private func makeHead(section: Section, language: String) throws -> String {
+    private func makeHeader(metadata: Element.LocalizedMetadata,
-        let localized = section.localized(for: language)
-
-        let image = section.linkPreviewImage(for: language)
-        let info = PageHeadInfo(
-            author: factory.author,
-            linkPreviewTitle: localized.title,
-            linkPreviewDescription: localized.linkPreviewDescription,
-            linkPreviewImage: image,
-            customHeadContent: try section.customHeadContent())
-        return try factory.pageHead.generate(page: info)
-    }
-
-    private func makeHeader(metadata: Section.LocalizedMetadata,
                             language: String,
                             backText: String?) -> String {
         var content = [HeaderKey : String]()
         content[.title] = metadata.title
+        #warning("Add title suffix")
         content[.subtitle] = metadata.subtitle
         content[.titleText] = metadata.description
         content[.backLink] = backText.unwrapped { factory.makeBackLink(text: $0, language: language) }

WebsiteGenerator/Generators/OverviewSectionGenerator.swift

@@ -6,19 +6,16 @@ struct OverviewSectionGenerator {
 
     private let singleSectionsTemplate: OverviewSectionCleanTemplate
 
-    let files: FileProcessor
-
     private let generator: ThumbnailListGenerator
 
-    init(factory: TemplateFactory, files: FileProcessor) {
+    init(factory: TemplateFactory) {
         self.multipleSectionsTemplate = factory.overviewSection
         self.singleSectionsTemplate = factory.overviewSectionClean
-        self.files = files
+        self.generator = ThumbnailListGenerator(factory: factory)
-        self.generator = ThumbnailListGenerator(factory: factory, files: files)
     }
 
-    func generate(sections: [Section], in parent: SiteElement, language: String, sectionItemCount: Int) throws -> String {
+    func generate(sections: [Element], in parent: Element, language: String, sectionItemCount: Int) -> String {
-        try sections.map { section in
+        sections.map { section in
             let metadata = section.localized(for: language)
             let fullUrl = section.fullPageUrl(for: language)
             let relativeUrl = parent.relativePathToFileWithPath(fullUrl)
@@ -26,44 +23,31 @@ struct OverviewSectionGenerator {
             var content = [OverviewSectionTemplate.Key : String]()
             content[.url] = relativeUrl
             content[.title] = metadata.title
-            content[.items] = try sectionContent(section: section, in: parent, language: language, shownItemCount: sectionItemCount)
+            content[.items] = sectionContent(section: section, in: parent, language: language, shownItemCount: sectionItemCount)
-            content[.more] = metadata.moreLinkTitle
+            content[.more] = metadata.moreLinkText
 
             return multipleSectionsTemplate.generate(content)
         }
         .joined(separator: "\n")
     }
 
-    func generate(section: Section, language: String) throws -> String {
+    func generate(section: Element, language: String) -> String {
         var content = [OverviewSectionCleanTemplate.Key : String]()
-        content[.items] = try sectionContent(section: section, in: section, language: language, shownItemCount: nil)
+        content[.items] = sectionContent(section: section, in: section, language: language, shownItemCount: nil)
         return singleSectionsTemplate.generate(content)
     }
 
-    private func sectionContent(section: Section, in parent: SiteElement, language: String, shownItemCount: Int?) throws -> String {
+    private func sectionContent(section: Element, in parent: Element, language: String, shownItemCount: Int?) -> String {
-        let sectionItems: [SiteElement]
+        let sectionItems: [Element]
         if let shownItemCount = shownItemCount {
             sectionItems = Array(section.sortedItems.prefix(shownItemCount))
         } else {
             sectionItems = section.sortedItems
         }
-
+        return generator.generateContent(
-        let items: [ThumbnailInfo] = sectionItems.map { item in
+            items: sectionItems,
-            #warning("Check if page exists for the language")
+            parent: parent,
-            let fullPageUrl = item.fullPageUrl(for: language)
+            language: language,
-            let relativePageUrl = parent.relativePathToFileWithPath(fullPageUrl)
+            style: section.thumbnailStyle)
-            let fullThumbnailPath = item.thumbnailFilePath(for: language)
-            let relativeImageUrl = parent.relativePathToFileWithPath(fullThumbnailPath)
-
-            return ThumbnailInfo(
-                url: relativePageUrl,
-                imageFilePath: fullThumbnailPath,
-                imageHtmlUrl: relativeImageUrl,
-                title: item.title(for: language),
-                cornerText: item.cornerText(for: language))
-        }
-        return try generator.generateContent(
-            items: items,
-            style: section.metadata.thumbnailStyle)
     }
 }

WebsiteGenerator/Generators/PageGenerator.swift

@@ -12,70 +12,67 @@ struct PageGenerator {
 
     private let factory: LocalizedSiteTemplate
 
-    private let files: FileProcessor
+    init(factory: LocalizedSiteTemplate) {
-
-    init(factory: LocalizedSiteTemplate, files: FileProcessor) {
         self.factory = factory
-        self.files = files
     }
 
-    func generate(page: Page, language: String, backText: String, nextPage: NavigationLink?, previousPage: NavigationLink?) throws {
+    func generate(page: Element, language: String, backText: String, nextPage: NavigationLink?, previousPage: NavigationLink?) {
         guard !page.isExternalPage else {
             return
         }
-        guard !page.metadata.isDraft else {
+        guard page.state != .draft else {
             return
         }
         let path = page.fullPageUrl(for: language)
-        let inputContentUrl = page.inputFolder.appendingPathComponent("\(language).md")
+        let inputContentPath = page.path + "/\(language).md"
         #warning("Make prev and next navigation relative")
         let metadata = page.localized(for: language)
         let nextLanguage = page.nextLanguage(for: language)
         var content = [PageTemplate.Key : String]()
-        content[.head] = try makeHead(page: page, language: language)
+        content[.head] = factory.pageHead.generate(page: page, language: language)
-        content[.topBar] = factory.topBar.generate(section: page.sectionId, languageButton: nextLanguage)
+        let sectionUrl = page.sectionUrl(for: language)
+        content[.topBar] = factory.topBar.generate(sectionUrl: sectionUrl, languageButton: nextLanguage)
         content[.contentClass] = "content"
-        if !page.metadata.useCustomHeader {
+        if !page.useCustomHeader {
-            content[.header] = makeHeader(page: page.metadata, metadata: metadata, language: language, backText: backText)
+            content[.header] = makeHeader(page: page, metadata: metadata, language: language, backText: backText)
         }
-        content[.content] = try makeContent(page: page, language: language, url: inputContentUrl)
+        let pageContent = makeContent(page: page, language: language, path: inputContentPath)
+        content[.content] = pageContent ?? factory.placeholder
         content[.previousPageLinkText] = previousPage.unwrapped { factory.makePrevText($0.text) }
         content[.previousPageUrl] = previousPage?.link
         content[.nextPageLinkText] = nextPage.unwrapped { factory.makeNextText($0.text) }
         content[.nextPageUrl] = nextPage?.link
-        content[.footer] = try page.customFooterContent()
+        content[.footer] = page.customFooterContent()
 
-        let url = files.outputFolder.appendingPathComponent(path)
+        let url = files.urlInOutputFolder(path)
-        try factory.page.generate(content, to: url)
+        guard factory.page.generate(content, to: url) else {
-    }
+            return
-
-    private func makeContent(page: Page, language: String, url: URL) throws -> String {
-        guard url.exists else {
-            print("Generated empty page \(page.path)")
-            return factory.placeholder
         }
-        print("Generated page \(page.path)")
+        log.add(info: "Generated \(pageContent == nil ? "empty page " : "")\(path)", source: page.path)
-        return try PageContentGenerator(factory: factory.factory, files: files)
-            .generate(page: page, language: language, at: url)
     }
 
-    private func makeHead(page: Page, language: String) throws -> String {
+    private func makeContent(page: Element, language: String, path: String) -> String? {
-        let metadata = page.localized(for: language)
+        guard let content = files.contentOfOptionalFile(atPath: path, source: page.path) else {
-        let info = PageHeadInfo(
+            return nil
-            author: page.metadata.author ?? factory.author,
+        }
-            linkPreviewTitle: metadata.linkPreviewTitle,
+        return PageContentGenerator(factory: factory.factory)
-            linkPreviewDescription: metadata.linkPreviewDescription,
+            .generate(page: page, language: language, content: content)
-            linkPreviewImage: page.linkPreviewImage(for: language),
-            customHeadContent: try page.customHeadContent())
-        return try factory.pageHead.generate(page: info)
     }
 
-    private func makeHeader(page: Page.Metadata, metadata: Page.LocalizedMetadata, language: String, backText: String) -> String {
+    private func makeHeader(page: Element, metadata: Element.LocalizedMetadata, language: String, backText: String) -> String {
         var content = [HeaderKey : String]()
         content[.backLink] = factory.makeBackLink(text: backText, language: language)
-        content[.title] = metadata.title
+        if let suffix = metadata.titleSuffix {
+            content[.title] = make(title: metadata.title, suffix: suffix)
+        } else {
+            content[.title] = metadata.title
+        }
         content[.subtitle] = metadata.subtitle
         content[.date] = factory.makeDateString(start: page.date, end: page.endDate)
         return factory.factory.leftHeader.generate(content)
     }
+
+    private func make(title: String, suffix: String) -> String {
+        "\(title)<span class=\"suffix\">\(suffix)</span>"
+    }
 }

WebsiteGenerator/Generators/PageHeadGenerator.swift

@@ -1,60 +1,36 @@
 import Foundation
 
-protocol PageHeadInfoProvider {
-
-    var author: String { get }
-
-    var linkPreviewTitle: String { get }
-
-    var linkPreviewDescription: String { get }
-
-    var linkPreviewImage: String? { get }
-
-    var customHeadContent: String? { get }
-}
-
-struct PageHeadInfo: PageHeadInfoProvider {
-
-    let author: String
-
-    let linkPreviewTitle: String
-
-    let linkPreviewDescription: String
-
-    let linkPreviewImage: String?
-
-    let customHeadContent: String?
-}
-
 struct PageHeadGenerator {
 
+    static let linkPreviewDesiredImageWidth = 1600
+
     let template: PageHeadTemplate
 
-    let files: FileProcessor
+    init(factory: TemplateFactory) {
-
-    init(factory: TemplateFactory, files: FileProcessor) {
         self.template = factory.pageHead
-        self.files = files
     }
 
-    func generate(page: PageHeadInfoProvider) throws -> String {
+    func generate(page: Element, language: String) -> String {
+        let metadata = page.localized(for: language)
+
         var content = [PageHeadTemplate.Key : String]()
         content[.author] = page.author
-        content[.title] = page.linkPreviewTitle
+        content[.title] = metadata.linkPreviewTitle
-        content[.description] = page.linkPreviewDescription
+        content[.description] = metadata.linkPreviewDescription
-        if let image = page.linkPreviewImage {
+        if let image = page.linkPreviewImage(for: language) {
             // Note: Generate separate destination link for the image,
             // since we don't want a single large image for thumbnails.
             // Warning: Link preview source path must be relative to root
-            let linkPreviewImagePath = image.insert("-link", beforeLast: ".")
+            let linkPreviewImageName = image.insert("-link", beforeLast: ".")
-            try files.requireImage(
+            let sourceImagePath = page.pathRelativeToRootForContainedInputFile(image)
-                source: image,
+            let destinationImagePath = page.pathRelativeToRootForContainedInputFile(linkPreviewImageName)
-                destination: linkPreviewImagePath,
+            files.requireImage(
-                width: Site.linkPreviewDesiredImageWidth)
+                source: sourceImagePath,
-            #warning("Make link preview image path absolute")
+                destination: destinationImagePath,
-            content[.image] = "<meta property=\"og:image\" content=\"\(linkPreviewImagePath)\" />"
+                width: PageHeadGenerator.linkPreviewDesiredImageWidth)
+            content[.image] = "<meta property=\"og:image\" content=\"\(linkPreviewImageName)\" />"
         }
-        content[.customPageContent] = page.customHeadContent
+        content[.customPageContent] = page.customHeadContent()
 
         return template.generate(content)
     }

WebsiteGenerator/Generators/SiteGenerator.swift

@@ -2,60 +2,45 @@ import Foundation
 
 struct SiteGenerator {
 
-    let site: Site
-
     let templates: TemplateFactory
 
-    private let files: FileProcessor
+    init() throws {
-
+        let templatesFolder = files.urlInContentFolder("templates")
-    private var outputFolder: URL {
-        files.outputFolder
-    }
-
-    init(site: Site, files: FileProcessor) throws {
-        self.site = site
-        let templatesFolder = site.inputFolder.appendingPathComponent("templates")
         self.templates = try TemplateFactory(templateFolder: templatesFolder)
-        self.files = files
     }
 
-    func generate() throws {
+    func generate(site: Element) throws {
-        try site.metadata.languages.forEach { metadata in
+        try site.languages.forEach { metadata in
-            let language = metadata.languageIdentifier
+            let language = metadata.language
             let template = try LocalizedSiteTemplate(
                 factory: templates,
                 language: language,
-                site: site,
+                site: site)
-                files: files)
-
 
             // Generate sections
-            let overviewGenerator = OverviewPageGenerator(factory: template, files: files)
+            let overviewGenerator = OverviewPageGenerator(factory: template)
-            let pageGenerator = PageGenerator(factory: template, files: files)
+            let pageGenerator = PageGenerator(factory: template)
-            let backLinkText = try site.backLinkText(for: language)
+            var elementsToProcess: [Element] = site.elements
-            var elementsToProcess: [(element: SiteElement, backText: String?)] = site.elements.map { ($0, backLinkText) }
+            while let element = elementsToProcess.popLast() {
-            while let (element, backText) = elementsToProcess.popLast() {
+                // Move recursively down to all pages
-                if let section = element as? Section {
+                elementsToProcess.append(contentsOf: element.elements)
-                    try overviewGenerator.generate(
+
-                        section: section,
+                element.requiredFiles.forEach(files.require)
+
+                let backLinkText = element.backLinkText(for: language)
+                if !element.elements.isEmpty {
+                    overviewGenerator.generate(
+                        section: element,
                         language: language,
-                        backText: backText)
+                        backText: backLinkText)
-                    let elementBackText = try element.backLinkText(for: language)
+                } else {
-                    let nestedElements = section.elements.map { ($0, elementBackText) }
-                    elementsToProcess.append(contentsOf: nestedElements)
-                }
-                if let page = element as? Page {
                     #warning("Determine previous and next pages")
-                    try pageGenerator.generate(
+                    pageGenerator.generate(
-                        page: page,
+                        page: element,
                         language: language,
-                        backText: backText ?? metadata.defaultBackLinkText,
+                        backText: backLinkText,
                         nextPage: nil,
                         previousPage: nil)
-                    for file in page.metadata.requiredFiles {
-                        let relativePath = page.path + "/" + file
-                        files.require(file: relativePath)
-                    }
                 }
             }
 
@@ -63,9 +48,9 @@ struct SiteGenerator {
 
             // Generate front page
             let relativeUrl = site.localizedPath(for: language)
-            let indexPageUrl = outputFolder.appendingPathComponent(relativeUrl)
+            let indexPageUrl = files.urlInOutputFolder(relativeUrl)
             let button = site.nextLanguage(for: language)
-            try generator.generate(
+            generator.generate(
                 site: site,
                 language: language,
                 languageButton: button,

WebsiteGenerator/Generators/ThumbnailInfo.swift

@@ -1,14 +0,0 @@
-import Foundation
-
-struct ThumbnailInfo {
-
-    let url: String?
-
-    let imageFilePath: String
-
-    let imageHtmlUrl: String
-
-    let title: String
-
-    let cornerText: String?
-}

WebsiteGenerator/Generators/ThumbnailListGenerator.swift

@@ -4,35 +4,37 @@ struct ThumbnailListGenerator {
 
     private let factory: TemplateFactory
 
-    let files: FileProcessor
+    init(factory: TemplateFactory) {
-
-    init(factory: TemplateFactory, files: FileProcessor) {
         self.factory = factory
-        self.files = files
     }
 
-    func generateContent(items: [ThumbnailInfo], style: ThumbnailStyle) throws -> String {
+    func generateContent(items: [Element], parent: Element, language: String, style: ThumbnailStyle) -> String {
-        try items.map { try itemContent($0, style: style) }
+        items.map { itemContent($0, parent: parent, language: language, style: style) }
             .joined(separator: "\n")
     }
 
-    private func itemContent(_ thumbnail: ThumbnailInfo, style: ThumbnailStyle) throws -> String {
+    private func itemContent(_ item: Element, parent: Element, language: String, style: ThumbnailStyle) -> String {
+        let fullPageUrl = item.fullPageUrl(for: language)
+        let relativePageUrl = parent.relativePathToFileWithPath(fullPageUrl)
+        let fullThumbnailPath = item.thumbnailFilePath(for: language)
+        let relativeImageUrl = parent.relativePathToFileWithPath(fullThumbnailPath)
+        
         var content = [ThumbnailKey : String]()
-        content[.url] = thumbnail.url.unwrapped { "href=\"\($0)\"" }
+        content[.url] = "href=\"\(relativePageUrl)\""
-        content[.image] = thumbnail.imageHtmlUrl
+        content[.image] = relativeImageUrl
-        content[.title] = thumbnail.title
+        content[.title] = item.title(for: language)
-        content[.image2x] = thumbnail.imageHtmlUrl.insert("@2x", beforeLast: ".")
+        #warning("Generate thumbnail suffix")
-        content[.corner] = thumbnail.cornerText.unwrapped {
+        content[.image2x] = relativeImageUrl.insert("@2x", beforeLast: ".")
+        content[.corner] = item.cornerText(for: language).unwrapped {
             factory.largeThumbnail.makeCorner(text: $0)
         }
 
-        try files.requireImage(
+        files.requireImage(
-            source: thumbnail.imageFilePath,
+            source: fullThumbnailPath,
-            destination: thumbnail.imageFilePath,
+            destination: fullThumbnailPath,
             width: style.width,
             desiredHeight: style.height,
             createDoubleVersion: true)
-
+        return factory.thumbnail(style: style).generate(content, shouldIndent: false)
-        return try factory.thumbnail(style: style).generate(content, shouldIndent: false)
     }
 }

WebsiteGenerator/Generic/Context.swift

@@ -1,14 +0,0 @@
-import Foundation
-
-final class Context {
-
-    let validation: ErrorOutput
-
-    let fileSystem: FileAccess
-
-    init(inputFolder: URL, outputFolder: URL) {
-        let validation = ErrorOutput()
-        self.validation = validation
-        self.fileSystem = FileAccess(in: inputFolder, errorOutput: validation)
-    }
-}

WebsiteGenerator/Generic/Element.swift

@@ -1,238 +0,0 @@
-import Foundation
-
-struct Element {
-
-    static let overviewItemCountDefault = 6
-
-    /**
-     The author of the content.
-
-     If no author is set, then the author from the parent element is used.
-     */
-    let author: String
-
-    /**
-     The title used in the top bar of the website, next to the logo.
-
-     This title can be HTML content, and only the root level value is used.
-     */
-    let topBarTitle: String
-
-    /**
-     The url where the site will be deployed.
-
-     This value is required to build absolute links for link previews.
-
-     - Note: Only the root level value is used.
-     - Note: The path does not need to contain a trailing slash.
-     */
-    let deployedBaseUrl: String
-
-    /**
-     The (start) date of the element.
-
-     The date is printed on content pages and may also used for sorting elements,
-     depending on the `useManualSorting` property of the parent.
-     */
-    let date: Date?
-
-    /**
-     The end date of the element.
-
-     This property can be used to specify a date range for a content page.
-     */
-    let endDate: Date?
-
-    /**
-     The deployment state of the page.
-
-     - Note: This property defaults to ``PageState.standard`
-     */
-    let state: PageState
-
-    /**
-     The sort index of the page for manual sorting.
-
-     - Note: This property is only used (and must be set) if `useManualSorting` option of the parent is set.
-     */
-    let sortIndex: Int?
-
-    /**
-     All files which may occur in content but is stored externally.
-
-     Missing files which would otherwise produce a warning are ignored when included here.
-     - Note: This property defaults to an empty set.
-     */
-    let externalFiles: Set<String>
-
-    /**
-     Specifies additional files which should be copied to the destination when generating the content.
-     - Note: This property defaults to an empty set.
-     */
-    let requiredFiles: Set<String>
-
-    /**
-     The style of thumbnail to use when generating overviews.
-
-     - Note: This property is only relevant for sections.
-     - Note: This property is inherited from the parent if not specified.
-     */
-    let thumbnailStyle: ThumbnailStyle
-
-    /**
-     Sort the child elements by their `sortIndex` property when generating overviews, instead of using the `date`.
-
-     - Note: This property is only relevant for sections.
-     - Note: This property defaults to `false`
-     */
-    let useManualSorting: Bool
-
-    /**
-     The number of items to show when generating overviews of this element.
-     - Note: This property is only relevant for sections.
-     - Note: This property is inherited from the parent if not specified.
-     */
-    let overviewItemCount: Int
-
-    /**
-     The localized metadata for each language.
-     */
-    let languages: [LocalizedMetadata]
-
-    /**
-     All elements contained within the element.
-
-     If the element is a section, then this property contains the pages or subsections within.
-     */
-    var elements: [Element] = []
-
-    /**
-     The url of the element's folder in the source hierarchy.
-     - Note: This property is essentially the root folder of the site, appended with the value of the ``path`` property.
-     */
-    let inputFolder: URL
-
-    /**
-     The path to the element's folder in the source hierarchy (without a leading slash).
-     */
-    let path: String
-
-    /**
-     Create the root element of a site.
-
-     The root element will recursively move into subfolders and build the site content
-     by looking for metadata files in each subfolder.
-     - Parameter folder: The root folder of the site content.
-     - Parameter context: The context to create the element (validation, file access, etc.)
-     */
-    init?(atRoot folder: URL, with context: Context) throws {
-        let validation = context.validation
-        self.inputFolder = folder
-        self.path = ""
-
-        let source = GenericMetadata.metadataFileName
-        guard let metadata = try GenericMetadata(source: source, with: context) else {
-            return nil
-        }
-
-        self.author = validation.required(metadata.author, name: "author", source: source) ?? "author"
-        self.topBarTitle = validation
-            .required(metadata.topBarTitle, name: "topBarTitle", source: source) ?? "My Website"
-        self.deployedBaseUrl = validation
-            .required(metadata.deployedBaseUrl, name: "deployedBaseUrl", source: source) ?? "https://example.com"
-        self.date = validation.unused(metadata.date, "date", source: source)
-        self.endDate = validation.unused(metadata.endDate, "endDate", source: source)
-        self.state = validation.state(metadata.state, source: source)
-        self.sortIndex = validation.unused(metadata.sortIndex, "sortIndex", source: source)
-        self.externalFiles = metadata.externalFiles ?? []
-        self.requiredFiles = metadata.requiredFiles ?? []
-        self.thumbnailStyle = validation.unused(metadata.thumbnailStyle, "thumbnailStyle", source: source) ?? .large
-        self.useManualSorting = validation.unused(metadata.useManualSorting, "useManualSorting", source: source) ?? true
-        self.overviewItemCount = metadata.overviewItemCount ?? Element.overviewItemCountDefault
-        self.languages = validation.required(metadata.languages, name: "languages", source: source)?
-            .compactMap { language in
-                    .init(atRoot: folder, data: language, with: context)
-            } ?? []
-        try self.readElements(in: folder, source: nil, with: context)
-    }
-
-    mutating func readElements(in folder: URL, source: String?, with context: Context) throws {
-        let subFolders: [URL]
-        do {
-            subFolders = try FileSystem.folders(in: folder)
-        } catch {
-            context.validation.add(error: "Failed to read subfolders", source: source ?? "root", error: error)
-            return
-        }
-        self.elements = try subFolders.compactMap { subFolder in
-            let s = (source.unwrapped { $0 + "/" } ?? "") + subFolder.lastPathComponent
-            return try Element(parent: self, folder: subFolder, with: context, path: s)
-        }
-    }
-
-    init?(parent: Element, folder: URL, with: Context, path: String) throws {
-        let validation = context.validation
-        self.inputFolder = folder
-        self.path = path
-
-        let source = path + "/" + GenericMetadata.metadataFileName
-        guard let metadata = try GenericMetadata(source: source, with: context) else {
-            return nil
-        }
-        self.author = metadata.author ?? parent.author
-        self.topBarTitle = validation
-            .unused(metadata.topBarTitle, "topBarTitle", source: source) ?? parent.topBarTitle
-        self.deployedBaseUrl = validation
-            .unused(metadata.deployedBaseUrl, "deployedBaseUrl", source: source) ?? parent.deployedBaseUrl
-        let date = validation.date(from: metadata.date, property: "date", source: source).ifNil {
-            if !parent.useManualSorting {
-                validation.add(error: "No 'date', but parent defines 'useManualSorting' = false", source: source)
-            }
-        }
-        self.date = date
-        self.endDate = validation.date(from: metadata.endDate, property: "endDate", source: source).ifNotNil {
-            if date == nil {
-                validation.add(warning: "Set 'endDate', but no 'date'", source: source)
-            }
-        }
-        self.state = validation.state(metadata.state, source: source)
-        self.sortIndex = metadata.sortIndex.ifNil {
-            if parent.useManualSorting {
-                validation.add(error: "No 'sortIndex', but parent defines 'useManualSorting' = true", source: source)
-            }
-        }
-        // TODO: Propagate external files from the parent if subpath matches?
-        self.externalFiles = metadata.externalFiles ?? []
-        self.requiredFiles = metadata.requiredFiles ?? []
-        self.thumbnailStyle = validation.thumbnailStyle(metadata.thumbnailStyle, source: source)
-        self.useManualSorting = metadata.useManualSorting ?? false
-        self.overviewItemCount = metadata.overviewItemCount ?? parent.overviewItemCount
-        self.languages = parent.languages.compactMap { parentData in
-            guard let data = metadata.languages?.first(where: { $0.language == parentData.language }) else {
-                validation.add(info: "Language '\(parentData.language)' not found", source: source)
-                return nil
-            }
-            return .init(folder: folder, data: data, source: source, parent: parentData, with: context)
-        }
-        // Check that each 'language' tag is present, and that all languages appear in the parent
-        validation.required(metadata.languages, name: "languages", source: source)?
-            .compactMap { validation.required($0.language, name: "language", source: source) }
-            .filter { language in
-                !parent.languages.contains { $0.language == language }
-            }
-            .forEach {
-                validation.add(warning: "Language '\($0)' not found in parent, so not generated", source: source)
-            }
-        try self.readElements(in: folder, source: path, with: context)
-    }
-}
-
-// MARK: Debug
-
-extension Element {
-
-    func printTree(indentation: String = "") {
-        print(indentation + "/" + path)
-        elements.forEach { $0.printTree(indentation: indentation + "  ") }
-    }
-}

WebsiteGenerator/Generic/FileAccess.swift

@@ -1,173 +0,0 @@
-import Foundation
-
-enum FileAccessError: Error {
-    case failedToReadFile(String, Error)
-}
-
-final class FileAccess {
-
-    static let accessTimesFileName = "access.json"
-
-    let errorOutput: ErrorOutput
-
-    let sourceFolder: URL
-
-    private let source = "FileAccess"
-
-    private var modificationTimeCacheFile: URL {
-        sourceFolder.appendingPathComponent(FileAccess.accessTimesFileName)
-    }
-
-    /**
-     The time stamps of last modified times for all accessed source files.
-
-     The key is the relative path to the file from the source
-     */
-    private var sourceLastModifiedTimes: [String : Date] = [:]
-
-    private var changedFiles: Set<String> = []
-
-    private var accessedFiles: Set<String> = []
-
-    init(in root: URL, errorOutput: ErrorOutput) {
-        self.sourceFolder = root
-        self.errorOutput = errorOutput
-
-        loadSavedModificationTimes()
-    }
-
-    private func loadSavedModificationTimes() {
-        let url = modificationTimeCacheFile
-        guard url.exists else {
-            errorOutput.add(info: "No file modification times loaded, regarding all content as new", source: source)
-            return
-        }
-        let data: Data
-        do {
-            data = try Data(contentsOf: url)
-        } catch {
-            errorOutput.add(
-                warning: "File modification times data not read, regarding all content as new",
-                source: source,
-                error: error)
-            return
-        }
-        do {
-            self.sourceLastModifiedTimes = try JSONDecoder().decode(from: data)
-        } catch {
-            errorOutput.add(
-                warning: "File modification times not decoded, regarding all content as new",
-                source: source,
-                error: error)
-            try? url.delete()
-            return
-        }
-    }
-
-    private func didAccess(inputPath: String, modified lastModified: Date, source: String) {
-        accessedFiles.insert(inputPath)
-        guard let previousDate = sourceLastModifiedTimes[inputPath] else {
-            // File not processed before, so mark as changed
-            changedFiles.insert(inputPath)
-            return
-        }
-        guard lastModified > previousDate else {
-            // File is unchanged
-            return
-        }
-        changedFiles.insert(inputPath)
-    }
-
-    private func lastModifiedTime(of url: URL) -> Date? {
-        guard url.exists else {
-            return nil
-        }
-        do {
-            let attributes = try FileManager.default.attributesOfItem(atPath: url.path)
-            guard let date = attributes[.modificationDate] as? Date else {
-                errorOutput.add(warning: "Failed to read modification time of \(url.path)", source: source)
-                return nil
-            }
-            return date
-        } catch {
-            errorOutput.add(warning: "Failed to read file attributes of \(url.path)", source: source)
-            return nil
-        }
-    }
-
-    func loadStringContent(inputPath: String) throws -> String? {
-        try load(inputPath: inputPath, String.init)
-    }
-
-    func loadDataContent(inputPath: String) throws -> Data? {
-        try load(inputPath: inputPath) { try Data(contentsOf: $0) }
-    }
-
-    private func load<T>(inputPath: String, _ closure: (URL) throws -> T) rethrows -> T? {
-        let url = sourceFolder.appendingPathComponent(inputPath)
-        guard let modifiedDate = lastModifiedTime(of: url) else {
-            sourceLastModifiedTimes[inputPath] = nil
-            return nil
-        }
-        do {
-            let content = try closure(url)
-            didAccess(inputPath: inputPath, modified: modifiedDate, source: source)
-            return content
-        } catch {
-            throw FileAccessError.failedToReadFile(inputPath, error)
-        }
-    }
-
-    func didGenerateAllFiles() {
-        for file in changedFiles {
-            let url = sourceFolder.appendingPathComponent(file)
-            guard let date = lastModifiedTime(of: url) else {
-                continue
-            }
-            sourceLastModifiedTimes[file] = date
-        }
-        do {
-            let data = try JSONEncoder().encode(sourceLastModifiedTimes)
-            try data.write(to: modificationTimeCacheFile)
-        } catch {
-            errorOutput.add(warning: "Failed to save modification times", source: source, error: error)
-        }
-    }
-
-    func printChangedFilesOverview() {
-        let count = changedFiles.count
-        guard count > 0 else {
-            print("No files modified")
-            return
-        }
-        print("\(count) files modified:")
-        changedFiles.prefix(10).forEach { print("  " + $0) }
-        if count > 10 {
-            print("  ...")
-        }
-    }
-
-    func printAccessedFilesOverview() {
-        let count = accessedFiles.count
-        guard count > 0 else {
-            print("No files accessed")
-            return
-        }
-        print("\(count) files accessed:")
-        accessedFiles.prefix(10).forEach { print("  " + $0) }
-        if count > 10 {
-            print("  ...")
-        }
-    }
-
-    func printAllTouchedFiles() {
-        print("\(accessedFiles.count) files accessed:")
-        accessedFiles.sorted().forEach { file in
-            if changedFiles.contains(file) {
-                print("  \(file) (changed)")
-            } else {
-                print("  " + file)
-            }
-        }
-    }
-}

WebsiteGenerator/Templates/Elements/ThumbnailTemplate.swift

@@ -2,7 +2,7 @@ import Foundation
 
 protocol ThumbnailTemplate {
 
-    func generate(_ content: [ThumbnailKey : String], shouldIndent: Bool) throws -> String
+    func generate(_ content: [ThumbnailKey : String], shouldIndent: Bool) -> String
 }
 
 enum ThumbnailKey: String, CaseIterable {

WebsiteGenerator/Templates/Filled/LocalizedSiteTemplate.swift

@@ -31,27 +31,14 @@ struct LocalizedSiteTemplate {
         topBar.language
     }
 
-    // MARK: Thumbnails
-
-    func thumbnail(style: ThumbnailStyle) -> ThumbnailTemplate {
-        switch style {
-        case .large:
-            return factory.largeThumbnail
-        case .square:
-            return factory.squareThumbnail
-        case .small:
-            return factory.smallThumbnail
-        }
-    }
-
     // MARK: Pages
 
     var page: PageTemplate {
         factory.page
     }
 
-    init(factory: TemplateFactory, language: String, site: Site, files: FileProcessor) throws {
+    init(factory: TemplateFactory, language: String, site: Element) throws {
-        self.author = site.metadata.author
+        self.author = site.author
         self.factory = factory
 
         let df = DateFormatter()
@@ -70,28 +57,23 @@ struct LocalizedSiteTemplate {
         df3.locale = Locale(identifier: language)
         self.day = df3
 
+        let metadata = site.localized(for: language)
+
         let sections = site.elements.map {
             PrefilledTopBarTemplate.SectionInfo(
-                id: $0.sectionId,
                 name: $0.title(for: language),
                 url: "\($0.path)/\(language).html")
         }
 
-        let metadata = site.localized(for: language)
-
-        let title = site.metadata.topBarTitle ?? metadata.linkPreviewTitle
-
         self.topBar = try .init(
             template: factory.topBar,
             language: language,
             sections: sections,
-            topBarWebsiteTitle: title)
+            topBarWebsiteTitle: site.topBarTitle)
         self.pageHead = PageHeadGenerator(
-            factory: factory,
+            factory: factory)
-            files: files)
         self.overviewSection = OverviewSectionGenerator(
-            factory: factory,
+            factory: factory)
-            files: files)
 
         self.placeholder = factory.placeholder.generate([
             .title: metadata.placeholderTitle,
@@ -108,8 +90,6 @@ struct LocalizedSiteTemplate {
         return backNavigation.generate(content)
     }
 
-    #warning("Move HTML code to single location")
-
     func makePrevText(_ text: String) -> String {
         "<span class=\"icon-back\"></span>\(text)"
     }
@@ -118,7 +98,10 @@ struct LocalizedSiteTemplate {
         "\(text)<span class=\"icon-next\"></span>"
     }
 
-    func makeDateString(start: Date, end: Date?) -> String {
+    func makeDateString(start: Date?, end: Date?) -> String {
+        guard let start = start else {
+            return ""
+        }
         guard let end = end else {
             return fullDateFormatter.string(from: start)
         }

WebsiteGenerator/Templates/Filled/PrefilledTopBarTemplate.swift

@@ -17,19 +17,19 @@ struct PrefilledTopBarTemplate {
         self.topBarWebsiteTitle = topBarWebsiteTitle
     }
 
-    func generate(section: String?, languageButton: String?) -> String {
+    func generate(sectionUrl: String?, languageButton: String?) -> String {
         var content = [TopBarTemplate.Key : String]()
         content[.title] = topBarWebsiteTitle
         content[.titleLink] = topBarWebsiteTitle(language: language)
-        content[.elements] = elements(activeSection: section)
+        content[.elements] = elements(activeSectionUrl: sectionUrl)
         content[.languageButton] = languageButton.unwrapped(topBarLanguageButton) ?? ""
         return topBar.generate(content)
     }
 
-    private func elements(activeSection: String?) -> String {
+    private func elements(activeSectionUrl: String?) -> String {
         sections
             .map {
-                topBarNavigationLink(url: $0.url, text: $0.name, isActive: activeSection == $0.id)
+                topBarNavigationLink(url: $0.url, text: $0.name, isActive: activeSectionUrl == $0.url)
             }
             .joined(separator: "\n")
     }
@@ -49,8 +49,6 @@ struct PrefilledTopBarTemplate {
 
     struct SectionInfo {
 
-        let id: String
-
         let name: String
 
         let url: String

WebsiteGenerator/Templates/Template.swift

@@ -20,17 +20,13 @@ extension Template {
     }
 
     init(from url: URL) throws {
-        let raw = try wrap(.failedToLoadTemplate(url.lastPathComponent)) {
+        let raw = try String(contentsOf: url)
-            try String(contentsOf: url)
-        }
         self.init(raw: raw)
     }
 
-    func generate(_ content: [Key : String], to url: URL) throws {
+    func generate(_ content: [Key : String], to url: URL) -> Bool {
         let content = generate(content)
-        try wrap(.failedToWriteFile(url.path)) {
+        return files.write(content, to: url)
-            try content.createFolderAndWrite(to: url)
-        }
     }
 
     func generate(_ content: [Key : String], shouldIndent: Bool = false) -> String {

WebsiteGenerator/main.swift

@@ -1,13 +1,14 @@
 import Foundation
 
-let contentDirectory = URL(fileURLWithPath: "/Users/ch/Projects/MakerSpace")
+private let contentDirectory = URL(fileURLWithPath: "/Users/ch/Projects/MakerSpace")
-let outputDirectory = URL(fileURLWithPath: "/Users/ch/Projects/MakerSpace/Site")
+private let outputDirectory = URL(fileURLWithPath: "/Users/ch/Projects/MakerSpace/Site")
 
-let context = Context(inputFolder: contentDirectory, outputFolder: outputDirectory)
+let log = ValidationLog()
+let files = FileSystem(in: contentDirectory, to: outputDirectory)
 
-let siteData: Element
+private let siteData: Element
 do {
-    guard let element = try Element(atRoot: contentDirectory, with: context) else {
+    guard let element = try Element(atRoot: contentDirectory) else {
         exit(0)
     }
     siteData = element
@@ -17,26 +18,13 @@ do {
 }
 
 siteData.printTree()
-context.fileSystem.printAllTouchedFiles()
-context.fileSystem.didGenerateAllFiles()
 
-exit(0)
+private let siteGenerator = try SiteGenerator()
-
+try siteGenerator.generate(site: siteData)
-let files = FileProcessor(
-    inputFolder: contentDirectory, outputFolder: outputDirectory)
-
-// 1: Load all site content
-guard let site = try Site(folder: contentDirectory) else {
-    exit(0)
-}
-// site.printContents()
-let siteGenerator = try SiteGenerator(site: site, files: files)
-try siteGenerator.generate()
 
 print("Pages generated")
-try files.createImages()
+files.createImages()
 print("Images generated")
-try files.copyRequiredFiles()
+files.copyRequiredFiles()
 print("Required files copied")
-
+files.writeHashes()
-#warning("Check that all metadata for each language is present")