refactor: Migrate the project functionality and optimize the code structure

src/hooks/markdown.ts

@@ -0,0 +1,49 @@
+import MarkdownIt from 'markdown-it'
+import metadata_block from 'markdown-it-metadata-block'
+import TurndownService from 'turndown'
+import yaml from 'yaml'
+
+interface MarkdownOptions {
+  metadata?: Record<string, any>
+}
+
+export const useMarkdown = (opts?: MarkdownOptions) => {
+  const md = new MarkdownIt({
+    html: true,
+    linkify: true,
+    typographer: true,
+  })
+
+  md.use(metadata_block, {
+    parseMetadata: yaml.parse,
+    meta: opts?.metadata ?? {},
+  })
+
+  md.renderer.rules.link_open = function (tokens, idx, options, env, self) {
+    const aIndex = tokens[idx].attrIndex('target')
+
+    if (aIndex < 0) {
+      tokens[idx].attrPush(['target', '_blank'])
+    } else {
+      tokens[idx].attrs![aIndex][1] = '_blank'
+    }
+
+    return self.renderToken(tokens, idx, options)
+  }
+
+  const turndown = new TurndownService({
+    headingStyle: 'atx',
+    bulletListMarker: '-',
+  })
+
+  turndown.addRule('paragraph', {
+    filter: 'p',
+    replacement: function (content) {
+      return `\n\n${content}`
+    },
+  })
+
+  return { render: md.render.bind(md), parse: turndown.turndown.bind(turndown) }
+}
+
+export type MarkdownTool = ReturnType<typeof useMarkdown>