Refactor page content generators

CHDataManagement/Generator/Commands/ImageCompareCommand.swift

@@ -0,0 +1,53 @@
+
+struct ImageCompareCommand: CommandProcessor {
+
+    static let commandType: CommandType = .imageCompare
+
+    let content: Content
+
+    let results: PageGenerationResults
+
+    let language: ContentLanguage
+
+    init(content: Content, results: PageGenerationResults, language: ContentLanguage) {
+        self.content = content
+        self.results = results
+        self.language = language
+    }
+
+    func process(_ arguments: [String], markdown: Substring) -> String {
+        guard arguments.count == 2 else {
+            invalid(markdown)
+            return ""
+        }
+        let leftImageId = arguments[0]
+        let rightImageId = arguments[1]
+        guard let leftImage = content.image(leftImageId) else {
+            results.missing(file: leftImageId, source: "Image compare")
+            return ""
+        }
+        guard let rightImage = content.image(rightImageId) else {
+            results.missing(file: rightImageId, source: "Image compare")
+            return ""
+        }
+
+        let size = content.settings.pages.contentWidth
+
+        let leftImageSet = leftImage.imageSet(
+            width: size, height: size,
+            language: language,
+            extraAttributes: ImageCompare.extraAttributes)
+
+        let rightImageSet = rightImage.imageSet(
+            width: size, height: size,
+            language: language,
+            extraAttributes: ImageCompare.extraAttributes)
+
+        results.require(imageSet: leftImageSet)
+        results.require(imageSet: rightImageSet)
+        results.require(icon: ImageCompare.requiredIcon)
+        results.require(headers: .imageCompareJs, .imageCompareCss)
+
+        return ImageCompare(left: leftImageSet, right: rightImageSet).content
+    }
+}