Add command for pretty page links

Sources/Generator/Generators/MarkdownProcessor.swift

@@ -16,7 +16,7 @@ struct PageContentGenerator {
         var hasCodeContent = false
 
         let imageModifier = Modifier(target: .images) { html, markdown in
-            processMarkdownImage(markdown: markdown, html: html, page: page)
+            processMarkdownImage(markdown: markdown, html: html, page: page, language: language)
         }
         let codeModifier = Modifier(target: .codeBlocks) { html, markdown in
             if markdown.starts(with: "```swift") {
@@ -70,7 +70,7 @@ struct PageContentGenerator {
         return html
     }
 
-    private func processMarkdownImage(markdown: Substring, html: String, page: Element) -> String {
+    private func processMarkdownImage(markdown: Substring, html: String, page: Element, language: String) -> String {
         // Split the markdown ![alt](file title)
         // There are several known shorthand commands
         // For images: ![left_title](file right_title)
@@ -78,11 +78,12 @@ struct PageContentGenerator {
         // For svg with custom area: ![x,y,width,height](file.svg)
         // For downloads: ![download](file1, text1; file2, text2, ...)
         // For a simple boxes: ![box](title;body)
+        // A fancy page link: ![page](page_id)
         // External pages: ![external](url1, text1; url2, text2, ...)
         let fileAndTitle = markdown.between("(", and: ")")
         let alt = markdown.between("[", and: "]").nonEmpty
         if let alt = alt, let command = ShorthandMarkdownKey(rawValue: alt) {
-            return handleShortHandCommand(command, page: page, content: fileAndTitle)
+            return handleShortHandCommand(command, page: page, language: language, content: fileAndTitle)
         }
 
         let file = fileAndTitle.dropAfterFirst(" ")
@@ -101,7 +102,7 @@ struct PageContentGenerator {
         return handleFile(page: page, file: file, fileExtension: fileExtension)
     }
 
-    private func handleShortHandCommand(_ command: ShorthandMarkdownKey, page: Element, content: String) -> String {
+    private func handleShortHandCommand(_ command: ShorthandMarkdownKey, page: Element, language: String, content: String) -> String {
         switch command {
         case .downloadButtons:
             return handleDownloadButtons(page: page, content: content)
@@ -111,6 +112,8 @@ struct PageContentGenerator {
             return handleExternalHTML(page: page, file: content)
         case .box:
             return handleSimpleBox(page: page, content: content)
+        case .pageLink:
+            return handlePageLink(page: page, language: language, pageId: content)
         }
     }
 
@@ -250,4 +253,45 @@ struct PageContentGenerator {
         let text = parts.dropFirst().joined(separator: ";")
         return factory.makePlaceholder(title: title, text: text)
     }
+
+    private func handlePageLink(page: Element, language: String, pageId: String) -> String {
+        guard let linkedPage = siteRoot.find(pageId) else {
+            log.add(warning: "Page id '\(pageId)' not found", source: page.path)
+            // Remove link since the page can't be found
+            return ""
+        }
+        var content = [PageLinkTemplate.Key: String]()
+        content[.url] = page.relativePathToOtherSiteElement(file: linkedPage.fullPageUrl(for: language))
+        
+        content[.title] = linkedPage.title(for: language)
+
+        let fullThumbnailPath = linkedPage.thumbnailFilePath(for: language)
+        let relativeImageUrl = page.relativePathToOtherSiteElement(file: fullThumbnailPath)
+        let metadata = linkedPage.localized(for: language)
+
+        if linkedPage.state.hasThumbnailLink {
+            let fullPageUrl = linkedPage.fullPageUrl(for: language)
+            let relativePageUrl = page.relativePathToOtherSiteElement(file: fullPageUrl)
+            content[.url] = "href=\"\(relativePageUrl)\""
+        }
+
+        content[.image] = relativeImageUrl
+        if let suffix = metadata.thumbnailSuffix {
+            content[.title] = factory.html.make(title: metadata.title, suffix: suffix)
+        } else {
+            content[.title] = metadata.title
+        }
+        content[.image2x] = relativeImageUrl.insert("@2x", beforeLast: ".")
+
+        let path = linkedPage.makePath(language: language, from: siteRoot)
+        content[.path] = factory.pageLink.makePath(components: path)
+
+        content[.description] = metadata.relatedContentText
+        if let parent = linkedPage.findParent(from: siteRoot), parent.thumbnailStyle == .large {
+            content[.className] = " related-page-link-large"
+        }
+
+        // We assume that the thumbnail images are already required by overview pages.
+        return factory.pageLink.generate(content)
+    }
 }

Sources/Generator/Generators/ShorthandMarkdownKey.swift

@@ -21,4 +21,9 @@ enum ShorthandMarkdownKey: String {
      A box with a heading and a text description
      */
     case box = "box"
+
+    /**
+     A pretty link to another page on the site.
+     */
+    case pageLink = "page"
 }