Reorganize client shared modules

client/src/app/core/renderer/markdown.service.ts

@@ -0,0 +1,145 @@
+import * as MarkdownIt from 'markdown-it'
+import { buildVideoLink } from 'src/assets/player/utils'
+import { Injectable } from '@angular/core'
+import { HtmlRendererService } from './html-renderer.service'
+
+type MarkdownParsers = {
+  textMarkdownIt: MarkdownIt
+  textWithHTMLMarkdownIt: MarkdownIt
+
+  enhancedMarkdownIt: MarkdownIt
+  enhancedWithHTMLMarkdownIt: MarkdownIt
+
+  completeMarkdownIt: MarkdownIt
+}
+
+type MarkdownConfig = {
+  rules: string[]
+  html: boolean
+  escape?: boolean
+}
+
+type MarkdownParserConfigs = {
+  [id in keyof MarkdownParsers]: MarkdownConfig
+}
+
+@Injectable()
+export class MarkdownService {
+  static TEXT_RULES = [
+    'linkify',
+    'autolink',
+    'emphasis',
+    'link',
+    'newline',
+    'list'
+  ]
+  static TEXT_WITH_HTML_RULES = MarkdownService.TEXT_RULES.concat([ 'html_inline', 'html_block' ])
+
+  static ENHANCED_RULES = MarkdownService.TEXT_RULES.concat([ 'image' ])
+  static ENHANCED_WITH_HTML_RULES = MarkdownService.TEXT_WITH_HTML_RULES.concat([ 'image' ])
+
+  static COMPLETE_RULES = MarkdownService.ENHANCED_WITH_HTML_RULES.concat([ 'block', 'inline', 'heading', 'paragraph' ])
+
+  private markdownParsers: MarkdownParsers = {
+    textMarkdownIt: null,
+    textWithHTMLMarkdownIt: null,
+    enhancedMarkdownIt: null,
+    enhancedWithHTMLMarkdownIt: null,
+    completeMarkdownIt: null
+  }
+  private parsersConfig: MarkdownParserConfigs = {
+    textMarkdownIt: { rules: MarkdownService.TEXT_RULES, html: false },
+    textWithHTMLMarkdownIt: { rules: MarkdownService.TEXT_WITH_HTML_RULES, html: true, escape: true },
+
+    enhancedMarkdownIt: { rules: MarkdownService.ENHANCED_RULES, html: false },
+    enhancedWithHTMLMarkdownIt: { rules: MarkdownService.ENHANCED_WITH_HTML_RULES, html: true, escape: true },
+
+    completeMarkdownIt: { rules: MarkdownService.COMPLETE_RULES, html: true }
+  }
+
+  constructor (private htmlRenderer: HtmlRendererService) {}
+
+  textMarkdownToHTML (markdown: string, withHtml = false) {
+    if (withHtml) return this.render('textWithHTMLMarkdownIt', markdown)
+
+    return this.render('textMarkdownIt', markdown)
+  }
+
+  enhancedMarkdownToHTML (markdown: string, withHtml = false) {
+    if (withHtml) return this.render('enhancedWithHTMLMarkdownIt', markdown)
+
+    return this.render('enhancedMarkdownIt', markdown)
+  }
+
+  completeMarkdownToHTML (markdown: string) {
+    return this.render('completeMarkdownIt', markdown)
+  }
+
+  async processVideoTimestamps (html: string) {
+    return html.replace(/((\d{1,2}):)?(\d{1,2}):(\d{1,2})/g, function (str, _, h, m, s) {
+      const t = (3600 * +(h || 0)) + (60 * +(m || 0)) + (+(s || 0))
+      const url = buildVideoLink({ startTime: t })
+      return `<a class="video-timestamp" href="${url}">${str}</a>`
+    })
+  }
+
+  private async render (name: keyof MarkdownParsers, markdown: string) {
+    if (!markdown) return ''
+
+    const config = this.parsersConfig[ name ]
+    if (!this.markdownParsers[ name ]) {
+      this.markdownParsers[ name ] = await this.createMarkdownIt(config)
+    }
+
+    let html = this.markdownParsers[ name ].render(markdown)
+    html = this.avoidTruncatedTags(html)
+
+    if (config.escape) return this.htmlRenderer.toSafeHtml(html)
+
+    return html
+  }
+
+  private async createMarkdownIt (config: MarkdownConfig) {
+    // FIXME: import('...') returns a struct module, containing a "default" field
+    const MarkdownItClass: typeof import ('markdown-it') = (await import('markdown-it') as any).default
+
+    const markdownIt = new MarkdownItClass('zero', { linkify: true, breaks: true, html: config.html })
+
+    for (const rule of config.rules) {
+      markdownIt.enable(rule)
+    }
+
+    this.setTargetToLinks(markdownIt)
+
+    return markdownIt
+  }
+
+  private setTargetToLinks (markdownIt: MarkdownIt) {
+    // Snippet from markdown-it documentation: https://github.com/markdown-it/markdown-it/blob/master/docs/architecture.md#renderer
+    const defaultRender = markdownIt.renderer.rules.link_open || function (tokens, idx, options, env, self) {
+      return self.renderToken(tokens, idx, options)
+    }
+
+    markdownIt.renderer.rules.link_open = function (tokens, index, options, env, self) {
+      const token = tokens[index]
+
+      const targetIndex = token.attrIndex('target')
+      if (targetIndex < 0) token.attrPush([ 'target', '_blank' ])
+      else token.attrs[targetIndex][1] = '_blank'
+
+      const relIndex = token.attrIndex('rel')
+      if (relIndex < 0) token.attrPush([ 'rel', 'noopener noreferrer' ])
+      else token.attrs[relIndex][1] = 'noopener noreferrer'
+
+      // pass token to default renderer.
+      return defaultRender(tokens, index, options, env, self)
+    }
+  }
+
+  private avoidTruncatedTags (html: string) {
+    return html.replace(/\*\*?([^*]+)$/, '$1')
+      .replace(/<a[^>]+>([^<]+)<\/a>\s*...((<\/p>)|(<\/li>)|(<\/strong>))?$/mi, '$1...')
+      .replace(/\[[^\]]+\]\(([^\)]+)$/m, '$1')
+      .replace(/\s?\[[^\]]+\]?[.]{3}<\/p>$/m, '...</p>')
+  }
+}