Added option to decorate tag links in forum posts

src/lib/booru/tag-utils.ts

@@ -1,3 +1,5 @@
+import { namespaceCategories } from "$config/tags";
+
 /**
  * Build the map containing both real tags and their aliases.
  *
@@ -31,3 +33,52 @@ export function buildTagsAndAliasesMap(realAndAliasedTags: string[], realTags: s
 
   return tagsAndAliasesMap;
 }
+
+const tagLinkRegExp = /\/tags\/(?<encodedTagName>[^/?#]+)/;
+
+/**
+ * List of encoded characters from Philomena.
+ *
+ * @see https://github.com/philomena-dev/philomena/blob/6086757b654da8792ae52adb2a2f501ea6c30d12/lib/philomena/slug.ex#L52-L57
+ */
+const slugEncodedCharacters: Map<string, string> = new Map([
+  ['-dash-', '-'],
+  ['-fwslash-', '/'],
+  ['-bwslash-', '\\'],
+  ['-colon-', ':'],
+  ['-dot-', '.'],
+  ['-plus-', '+'],
+]);
+
+/**
+ * Decode the tag name from its link path.
+ *
+ * @param tagLink Full or partial link to the tag.
+ *
+ * @return Tag name or NULL if function is failed to recognize the link as tag-related link.
+ */
+export function decodeTagNameFromLink(tagLink: string): string | null {
+  tagLinkRegExp.lastIndex = 0;
+
+  const result = tagLinkRegExp.exec(tagLink);
+  const encodedTagName = result?.groups?.encodedTagName;
+
+  if (!encodedTagName) {
+    return null;
+  }
+
+  return decodeURIComponent(encodedTagName)
+    .replaceAll(/-[a-z]+-/gi, match => slugEncodedCharacters.get(match) ?? match)
+    .replaceAll('-', ' ');
+}
+
+/**
+ * Try to resolve the category from the tag name.
+ *
+ * @param tagName Name of the tag.
+ */
+export function resolveTagCategoryFromTagName(tagName: string): string | null {
+  const namespace = tagName.split(':')[0];
+
+  return namespaceCategories.get(namespace) ?? null;
+}

src/lib/extension/settings/TagSettings.ts

@@ -2,6 +2,7 @@ import CacheableSettings from "$lib/extension/base/CacheableSettings";
 
 interface TagSettingsFields {
   groupSeparation: boolean;
+  replaceLinks: boolean;
 }
 
 export default class TagSettings extends CacheableSettings<TagSettingsFields> {
@@ -13,7 +14,15 @@ export default class TagSettings extends CacheableSettings<TagSettingsFields> {
     return this._resolveSetting("groupSeparation", true);
   }
 
+  async resolveReplaceLinks() {
+    return this._resolveSetting("replaceLinks", false);
+  }
+
   async setGroupSeparation(value: boolean) {
     return this._writeSetting("groupSeparation", Boolean(value));
   }
+
+  async setReplaceLinks(value: boolean) {
+    return this._writeSetting("replaceLinks", Boolean(value));
+  }
 }