Refactor page content generators

CHDataManagement/Generator/Markdown/MarkdownLinkProcessor.swift

@@ -0,0 +1,84 @@
+import Ink
+
+struct MarkdownLinkProcessor: MarkdownProcessor {
+
+    static let modifier: Modifier.Target = .links
+
+    private let content: Content
+
+    private let results: PageGenerationResults
+
+    private let language: ContentLanguage
+
+    init(content: Content, results: PageGenerationResults, language: ContentLanguage) {
+        self.content = content
+        self.results = results
+        self.language = language
+    }
+
+    private let pageLinkMarker = "page:"
+
+    private let tagLinkMarker = "tag:"
+
+    private let fileLinkMarker = "file:"
+
+    func process(html: String, markdown: Substring) -> String {
+        let url = markdown.between("(", and: ")")
+        if url.hasPrefix(pageLinkMarker) {
+            return handleInlinePageLink(url: url, html: html, markdown: markdown)
+        }
+        if url.hasPrefix(tagLinkMarker) {
+            return handleInlineTagLink(url: url, html: html, markdown: markdown)
+        }
+        if url.hasPrefix(fileLinkMarker) {
+            return handleInlineFileLink(url: url, html: html, markdown: markdown)
+        }
+        results.externalLink(to: url)
+        return html
+    }
+
+    private func handleInlinePageLink(url: String, html: String, markdown: Substring) -> String {
+        // Retain links pointing to elements within a page
+        let textToChange = url.dropAfterFirst("#")
+        let pageId = textToChange.replacingOccurrences(of: pageLinkMarker, with: "")
+        guard let page = content.page(pageId) else {
+            results.missing(page: pageId, source: "Inline page link")
+            // Remove link since the page can't be found
+            return markdown.between("[", and: "]")
+        }
+        guard !page.isDraft else {
+            return markdown.between("[", and: "]")
+        }
+
+        results.linked(to: page)
+        let pagePath = page.absoluteUrl(in: language)
+        return html.replacingOccurrences(of: textToChange, with: pagePath)
+    }
+
+    private func handleInlineTagLink(url: String, html: String, markdown: Substring) -> String {
+        // Retain links pointing to elements within a page
+        let textToChange = url.dropAfterFirst("#")
+        let tagId = textToChange.replacingOccurrences(of: tagLinkMarker, with: "")
+        guard let tag = content.tag(tagId) else {
+            results.missing(tag: tagId, source: "Inline tag link")
+            // Remove link since the tag can't be found
+            return markdown.between("[", and: "]")
+        }
+        results.linked(to: tag)
+        let tagPath = tag.absoluteUrl(in: language)
+        return html.replacingOccurrences(of: textToChange, with: tagPath)
+    }
+
+    private func handleInlineFileLink(url: String, html: String, markdown: Substring) -> String {
+        // Retain links pointing to elements within a page
+        let fileId = url.replacingOccurrences(of: fileLinkMarker, with: "")
+        guard let file = content.file(fileId) else {
+            results.missing(file: fileId, source: "Inline file link")
+            // Remove link since the file can't be found
+            return markdown.between("[", and: "]")
+        }
+        results.require(file: file)
+        let filePath = file.absoluteUrl
+        return html.replacingOccurrences(of: url, with: filePath)
+    }
+}