Generate list of redirects

CHDataManagement/Model/Content+Generation.swift

@@ -13,6 +13,7 @@ extension Content {
             self.generateRequiredImages()
             self.results.recalculate()
             self.generateListOfExternalFiles()
+            self.generateListOfUrlMappings()
             self.status("Generation completed")
         }
     }
@@ -240,6 +241,10 @@ extension Content {
                 tag: tag)
             let generator = PostListPageGenerator(source: source)
             generator.createPages(for: posts)
+
+            if let originalUrl = tag.localized(in: language).originalUrl {
+                results.redirect(from: originalUrl, to: tag.absoluteUrl(in: language))
+            }
         }
     }
 
@@ -274,11 +279,16 @@ extension Content {
             return
         }
 
-        let path = page.absoluteUrl(in: language) + ".html"
-        guard storage.write(content, to: path) else {
+        let pageUrl = page.absoluteUrl(in: language)
+        let filePath = pageUrl + ".html"
+        guard storage.write(content, to: filePath) else {
             print("Failed to save page \(page.id)")
             return
         }
+
+        if let originalUrl = page.localized(in: language).originalUrl {
+            results.redirect(from: originalUrl, to: pageUrl)
+        }
     }
 
     // MARK: Additional infos
@@ -303,4 +313,27 @@ extension Content {
 
         storage.write(content, to: externalFileListName)
     }
+
+    private var redirectsListFileName: String { "redirects.txt" }
+
+    private func generateListOfUrlMappings() {
+        let redirects = results.redirects.map { "\($0.key) \($0.value);" }
+        guard !redirects.isEmpty else {
+            if storage.hasFileInOutputFolder(redirectsListFileName) {
+                storage.deleteInOutputFolder(redirectsListFileName)
+            }
+            return
+        }
+
+        let list = redirects.sorted().joined(separator: "\n    ")
+
+        let content =
+            """
+            map $request_uri $redirect_uri {
+                \(list)
+            }
+            """
+
+        storage.write(content, to: redirectsListFileName)
+    }
 }