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>')
}
}