From cd527754a8929aaf0dcb7993a568972cf38d0873 Mon Sep 17 00:00:00 2001
From: Emile Bangma <ewjbangma@hotmail.com>
Date: Thu, 19 Sep 2024 16:32:41 +0000
Subject: [PATCH] Obsidian Parser (YouTube)

---
 quartz/plugins/parsers/obsidian/index.ts   |  1 +
 quartz/plugins/parsers/obsidian/youtube.ts | 80 ++++++++++++++++++++++
 quartz/plugins/transformers/markdown.ts    |  6 +-
 3 files changed, 86 insertions(+), 1 deletion(-)
 create mode 100644 quartz/plugins/parsers/obsidian/youtube.ts

diff --git a/quartz/plugins/parsers/obsidian/index.ts b/quartz/plugins/parsers/obsidian/index.ts
index b1115200f..4c37fe3c0 100644
--- a/quartz/plugins/parsers/obsidian/index.ts
+++ b/quartz/plugins/parsers/obsidian/index.ts
@@ -7,3 +7,4 @@ export { ObsidianMermaid } from "./mermaid"
 export { ObsidianTags } from "./tags"
 export { ObsidianWikilinks } from "./wikilinks"
 export { ObsidianVideo } from "./video"
+export { ObsidianYouTube } from "./youtube"
diff --git a/quartz/plugins/parsers/obsidian/youtube.ts b/quartz/plugins/parsers/obsidian/youtube.ts
new file mode 100644
index 000000000..3da312e04
--- /dev/null
+++ b/quartz/plugins/parsers/obsidian/youtube.ts
@@ -0,0 +1,80 @@
+import { QuartzParser } from "../../types"
+import { ReplaceFunction, findAndReplace as mdastFindReplace } from "mdast-util-find-and-replace"
+import { JSResource } from "../../../util/resources"
+import { visit } from "unist-util-visit"
+import { Root } from "mdast"
+import { Element, Literal, Root as HtmlRoot } from "hast"
+import { Pluggable } from "unified"
+
+interface Options {
+  enabled: Boolean
+}
+
+const defaultOptions: Options = {
+  enabled: true,
+}
+
+const ytLinkRegex = /^.*(youtu.be\/|v\/|u\/\w\/|embed\/|watch\?v=|\&v=)([^#\&\?]*).*/
+const ytPlaylistLinkRegex = /[?&]list=([^#?&]*)/
+
+export const ObsidianYouTube: QuartzParser<Partial<Options>> = (userOpts) => {
+  const opts: Options = { ...defaultOptions, ...userOpts }
+  return {
+    name: "ObsidianYouTube",
+    textTransform(_ctx, src: string | Buffer) {
+      if (src instanceof Buffer) {
+        src = src.toString()
+      }
+      return src
+    },
+    markdownPlugins(_ctx) {
+      const plug: Pluggable = (tree: Root, _file) => {
+        const replacements: [RegExp, string | ReplaceFunction][] = []
+        mdastFindReplace(tree, replacements)
+      }
+      return plug
+    },
+    htmlPlugins() {
+      if (opts.enabled) {
+        const plug: Pluggable = (tree: HtmlRoot, _file) => {
+          visit(tree, "element", (node) => {
+            if (node.tagName === "img" && typeof node.properties.src === "string") {
+              const match = node.properties.src.match(ytLinkRegex)
+              const videoId = match && match[2].length == 11 ? match[2] : null
+              const playlistId = node.properties.src.match(ytPlaylistLinkRegex)?.[1]
+              if (videoId) {
+                // YouTube video (with optional playlist)
+                node.tagName = "iframe"
+                node.properties = {
+                  class: "external-embed youtube",
+                  allow: "fullscreen",
+                  frameborder: 0,
+                  width: "600px",
+                  src: playlistId
+                    ? `https://www.youtube.com/embed/${videoId}?list=${playlistId}`
+                    : `https://www.youtube.com/embed/${videoId}`,
+                }
+              } else if (playlistId) {
+                // YouTube playlist only.
+                node.tagName = "iframe"
+                node.properties = {
+                  class: "external-embed youtube",
+                  allow: "fullscreen",
+                  frameborder: 0,
+                  width: "600px",
+                  src: `https://www.youtube.com/embed/videoseries?list=${playlistId}`,
+                }
+              }
+            }
+          })
+        }
+        return plug
+      }
+      return {} as Pluggable
+    },
+    externalResources() {
+      const js = {} as JSResource
+      return js
+    },
+  }
+}
diff --git a/quartz/plugins/transformers/markdown.ts b/quartz/plugins/transformers/markdown.ts
index f1d6d758e..6c54df83c 100644
--- a/quartz/plugins/transformers/markdown.ts
+++ b/quartz/plugins/transformers/markdown.ts
@@ -47,6 +47,7 @@ import {
   ObsidianTags,
   ObsidianVideo,
   ObsidianWikilinks,
+  ObsidianYouTube,
 } from "../parsers/obsidian"
 
 export interface CommonMarkOptions {
@@ -322,7 +323,10 @@ export const ObsidianFlavoredMarkdown: QuartzTransformerPlugin<Partial<ObsidianO
     htmlPlugins() {
       const plugins: PluggableList = [rehypeRaw]
 
-      plugins.push.apply(ObsidianCheckboxes({ enabled: opts.enableCheckbox }).htmlPlugins())
+      plugins.push(ObsidianYouTube({ enabled: opts.enableYouTubeEmbed }).htmlPlugins() as Pluggable)
+      plugins.push.apply(
+        ObsidianCheckboxes({ enabled: opts.enableCheckbox }).htmlPlugins() as Pluggable[],
+      )
 
       return plugins
     },