Refactor page content generators

CHDataManagement/Generator/Markdown/MarkdownImageProcessor.swift

@@ -0,0 +1,45 @@
+import Ink
+
+struct MarkdownImageProcessor: MarkdownProcessor {
+
+    static var modifier: Modifier.Target = .images
+
+    private let content: Content
+
+    private let results: PageGenerationResults
+
+    private let language: ContentLanguage
+
+    private let commands: [CommandType : CommandProcessor]
+
+    init(content: Content, results: PageGenerationResults, language: ContentLanguage) {
+        self.content = content
+        self.results = results
+        self.language = language
+
+        self.commands = CommandType.allCases.reduce(into: [:]) { commands, command in
+            commands[command] = command.processor.init(content: content, results: results, language: language)
+        }
+    }
+
+    var html: HtmlCommand {
+        commands[.includedHtml] as! HtmlCommand
+    }
+
+    func process(html: String, markdown: Substring) -> String {
+        let argumentList = markdown.between(first: "](", andLast: ")").percentDecoded()
+        let arguments = argumentList.components(separatedBy: ";")
+
+        let rawCommand = markdown.between("![", and: "]").trimmed.percentDecoded()
+        guard rawCommand != "" else {
+            return commands[.image]!.process(arguments, markdown: markdown)
+        }
+
+        guard let command = CommandType(rawValue: rawCommand) else {
+            // Treat unknown commands as normal links
+            results.invalid(command: nil, markdown)
+            return html
+        }
+        return commands[command]!.process(arguments, markdown: markdown)
+    }
+}