From 7790db45c4ff7cae2a63542fca304c45156022b2 Mon Sep 17 00:00:00 2001
From: Emile Bangma <ewjbangma@hotmail.com>
Date: Thu, 19 Sep 2024 15:09:56 +0000
Subject: [PATCH] Obsidian Parser (Tags)

---
 quartz/plugins/parsers/obsidian/index.ts |  1 +
 quartz/plugins/parsers/obsidian/tags.ts  | 82 ++++++++++++++++++++++++
 quartz/plugins/transformers/markdown.ts  |  2 +
 3 files changed, 85 insertions(+)

diff --git a/quartz/plugins/parsers/obsidian/index.ts b/quartz/plugins/parsers/obsidian/index.ts
index baf0fd627..4f1555b84 100644
--- a/quartz/plugins/parsers/obsidian/index.ts
+++ b/quartz/plugins/parsers/obsidian/index.ts
@@ -4,4 +4,5 @@ export { ObsidianCheckboxes } from "./checkboxes"
 export { ObsidianComments } from "./comments"
 export { ObsidianHighlights } from "./highlights"
 export { ObsidianMermaid } from "./mermaid"
+export { ObsidianTags } from "./tags"
 export { ObsidianWikilinks } from "./wikilinks"
diff --git a/quartz/plugins/parsers/obsidian/tags.ts b/quartz/plugins/parsers/obsidian/tags.ts
index e69de29bb..7f30d5911 100644
--- a/quartz/plugins/parsers/obsidian/tags.ts
+++ b/quartz/plugins/parsers/obsidian/tags.ts
@@ -0,0 +1,82 @@
+import { QuartzParser } from "../../types"
+import { ReplaceFunction, findAndReplace as mdastFindReplace } from "mdast-util-find-and-replace"
+import { FilePath, pathToRoot, slugTag, slugifyFilePath } from "../../../util/path"
+import { JSResource } from "../../../util/resources"
+import { Root } from "mdast"
+import { Pluggable } from "unified"
+
+interface Options {
+  enabled: Boolean
+}
+
+const defaultOptions: Options = {
+  enabled: true,
+}
+
+// (?:^| )              -> non-capturing group, tag should start be separated by a space or be the start of the line
+// #(...)               -> capturing group, tag itself must start with #
+// (?:[-_\p{L}\d\p{Z}])+       -> non-capturing group, non-empty string of (Unicode-aware) alpha-numeric characters and symbols, hyphens and/or underscores
+// (?:\/[-_\p{L}\d\p{Z}]+)*)   -> non-capturing group, matches an arbitrary number of tag strings separated by "/"
+const tagRegex = new RegExp(
+  /(?:^| )#((?:[-_\p{L}\p{Emoji}\p{M}\d])+(?:\/[-_\p{L}\p{Emoji}\p{M}\d]+)*)/gu,
+)
+
+export const ObsidianTags: QuartzParser<Partial<Options>> = (userOpts) => {
+  const opts: Options = { ...defaultOptions, ...userOpts }
+  return {
+    name: "ObsidianTags",
+    textTransform(_ctx, src: string | Buffer) {
+      if (src instanceof Buffer) {
+        src = src.toString()
+      }
+      return src
+    },
+    markdownPlugins(_ctx) {
+      const plug: Pluggable = (tree: Root, file) => {
+        const base = pathToRoot(file.data.slug!)
+        const replacements: [RegExp, string | ReplaceFunction][] = []
+        replacements.push([
+          tagRegex,
+          (_value: string, tag: string) => {
+            // Check if the tag only includes numbers and slashes
+            if (/^[\/\d]+$/.test(tag)) {
+              return false
+            }
+
+            tag = slugTag(tag)
+            if (file.data.frontmatter) {
+              const noteTags = file.data.frontmatter.tags ?? []
+              file.data.frontmatter.tags = [...new Set([...noteTags, tag])]
+            }
+
+            return {
+              type: "link",
+              url: base + `/tags/${tag}`,
+              data: {
+                hProperties: {
+                  className: ["tag-link"],
+                },
+              },
+              children: [
+                {
+                  type: "text",
+                  value: tag,
+                },
+              ],
+            }
+          },
+        ])
+        mdastFindReplace(tree, replacements)
+      }
+      return plug
+    },
+    htmlPlugins() {
+      const plug: Pluggable = () => {}
+      return plug
+    },
+    externalResources() {
+      const js = {} as JSResource
+      return js
+    },
+  }
+}
diff --git a/quartz/plugins/transformers/markdown.ts b/quartz/plugins/transformers/markdown.ts
index c40e47336..681169306 100644
--- a/quartz/plugins/transformers/markdown.ts
+++ b/quartz/plugins/transformers/markdown.ts
@@ -44,6 +44,7 @@ import {
   ObsidianComments,
   ObsidianHighlights,
   ObsidianMermaid,
+  ObsidianTags,
   ObsidianWikilinks,
 } from "../parsers/obsidian"
 
@@ -267,6 +268,7 @@ export const ObsidianFlavoredMarkdown: QuartzTransformerPlugin<Partial<ObsidianO
       plugins.push(ObsidianWikilinks({ enabled: opts.wikilinks }).markdownPlugins(ctx))
       plugins.push(ObsidianHighlights({ enabled: opts.highlight }).markdownPlugins(ctx))
       plugins.push(ObsidianArrow({ enabled: opts.parseArrows }).markdownPlugins(ctx))
+      plugins.push(ObsidianTags({ enabled: opts.parseTags }).markdownPlugins(ctx))
       plugins.push(ObsidianCallouts({ enabled: opts.callouts }).markdownPlugins(ctx))
       plugins.push(ObsidianMermaid({ enabled: opts.mermaid }).markdownPlugins(ctx))