import type MarkdownIt from 'markdown-it'

export interface MarkdownItGitHubAlertsOptions {
  /**
   * Prefix for the class names.
   *
   * @default 'markdown-alert'
   */
  classPrefix?: string
  /**
   * Custom icons for each marker. The key is the marker name, and the value is the html script represent the icon.
   * The key is always lowercase.
   *
   * @default inline svg icons from GitHub
   */
  icons?: Record<string, string>
  /**
   * If the alert should be rendered as a blockquote,
   * this makes sense when content is displayed in a RSS reader, where you don´t have
   * control about the rendering
   * @default true
   */
  keepBlockquote?: boolean
  /**
   * List of markers to match.
   * @default ['TIP', 'NOTE', 'IMPORTANT', 'WARNING', 'CAUTION']
   */
  markers?: string[] | '*'
  /**
   * If markers case sensitively on matching.
   * @default false
   */
  matchCaseSensitive?: boolean
  /**
   * The styling for the title.
   * Other than a css class, this styling will be available as an inline style even in the RSS reader.
   * @default "display: flex; align-items: center;"
   */
  titleStyle?: string
  /**
   * Custom titles for each marker. The key is the marker name, and the value is the title.
   * The key is always lowercase.
   *
   * When the title is not specified, the default title is the capitalized marker name.
   */
  titles?: Record<string, string>
}

const DEFAULT_GITHUB_ICONS = {
  note: `<svg class="octicon octicon-info" fill="currentColor" viewBox="0 0 16 16" version="1.1" width="16" height="16" aria-hidden="true"><path d="M0 8a8 8 0 1 1 16 0A8 8 0 0 1 0 8Zm8-6.5a6.5 6.5 0 1 0 0 13 6.5 6.5 0 0 0 0-13ZM6.5 7.75A.75.75 0 0 1 7.25 7h1a.75.75 0 0 1 .75.75v2.75h.25a.75.75 0 0 1 0 1.5h-2a.75.75 0 0 1 0-1.5h.25v-2h-.25a.75.75 0 0 1-.75-.75ZM8 6a1 1 0 1 1 0-2 1 1 0 0 1 0 2Z"></path></svg>`,
  tip: `<svg class="octicon octicon-light-bulb" fill="currentColor" viewBox="0 0 16 16" version="1.1" width="16" height="16" aria-hidden="true"><path d="M8 1.5c-2.363 0-4 1.69-4 3.75 0 .984.424 1.625.984 2.304l.214.253c.223.264.47.556.673.848.284.411.537.896.621 1.49a.75.75 0 0 1-1.484.211c-.04-.282-.163-.547-.37-.847a8.456 8.456 0 0 0-.542-.68c-.084-.1-.173-.205-.268-.32C3.201 7.75 2.5 6.766 2.5 5.25 2.5 2.31 4.863 0 8 0s5.5 2.31 5.5 5.25c0 1.516-.701 2.5-1.328 3.259-.095.115-.184.22-.268.319-.207.245-.383.453-.541.681-.208.3-.33.565-.37.847a.751.751 0 0 1-1.485-.212c.084-.593.337-1.078.621-1.489.203-.292.45-.584.673-.848.075-.088.147-.173.213-.253.561-.679.985-1.32.985-2.304 0-2.06-1.637-3.75-4-3.75ZM5.75 12h4.5a.75.75 0 0 1 0 1.5h-4.5a.75.75 0 0 1 0-1.5ZM6 15.25a.75.75 0 0 1 .75-.75h2.5a.75.75 0 0 1 0 1.5h-2.5a.75.75 0 0 1-.75-.75Z"></path></svg>`,
  important: `<svg class="octicon octicon-report" fill="currentColor" viewBox="0 0 16 16" version="1.1" width="16" height="16" aria-hidden="true"><path d="M0 1.75C0 .784.784 0 1.75 0h12.5C15.216 0 16 .784 16 1.75v9.5A1.75 1.75 0 0 1 14.25 13H8.06l-2.573 2.573A1.458 1.458 0 0 1 3 14.543V13H1.75A1.75 1.75 0 0 1 0 11.25Zm1.75-.25a.25.25 0 0 0-.25.25v9.5c0 .138.112.25.25.25h2a.75.75 0 0 1 .75.75v2.19l2.72-2.72a.749.749 0 0 1 .53-.22h6.5a.25.25 0 0 0 .25-.25v-9.5a.25.25 0 0 0-.25-.25Zm7 2.25v2.5a.75.75 0 0 1-1.5 0v-2.5a.75.75 0 0 1 1.5 0ZM9 9a1 1 0 1 1-2 0 1 1 0 0 1 2 0Z"></path></svg>`,
  warning: `<svg class="octicon octicon-alert" fill="currentColor" viewBox="0 0 16 16" version="1.1" width="16" height="16" aria-hidden="true"><path d="M6.457 1.047c.659-1.234 2.427-1.234 3.086 0l6.082 11.378A1.75 1.75 0 0 1 14.082 15H1.918a1.75 1.75 0 0 1-1.543-2.575Zm1.763.707a.25.25 0 0 0-.44 0L1.698 13.132a.25.25 0 0 0 .22.368h12.164a.25.25 0 0 0 .22-.368Zm.53 3.996v2.5a.75.75 0 0 1-1.5 0v-2.5a.75.75 0 0 1 1.5 0ZM9 11a1 1 0 1 1-2 0 1 1 0 0 1 2 0Z"></path></svg>`,
  caution: `<svg class="octicon octicon-stop" fill="currentColor" viewBox="0 0 16 16" version="1.1" width="16" height="16" aria-hidden="true"><path d="M4.47.22A.749.749 0 0 1 5 0h6c.199 0 .389.079.53.22l4.25 4.25c.141.14.22.331.22.53v6a.749.749 0 0 1-.22.53l-4.25 4.25A.749.749 0 0 1 11 16H5a.749.749 0 0 1-.53-.22L.22 11.53A.749.749 0 0 1 0 11V5c0-.199.079-.389.22-.53Zm.84 1.28L1.5 5.31v5.38l3.81 3.81h5.38l3.81-3.81V5.31L10.69 1.5ZM8 4a.75.75 0 0 1 .75.75v3.5a.75.75 0 0 1-1.5 0v-3.5A.75.75 0 0 1 8 4Zm0 8a1 1 0 1 1 0-2 1 1 0 0 1 0 2Z"></path></svg>`,
}

const MarkdownItGitHubAlerts: MarkdownIt.PluginWithOptions<MarkdownItGitHubAlertsOptions> = (md, options = {}) => {
  const {
    markers = ['TIP', 'NOTE', 'IMPORTANT', 'WARNING', 'CAUTION'],
    icons = DEFAULT_GITHUB_ICONS,
    keepBlockquote = true,
    matchCaseSensitive = false,
    titles = {},
    titleStyle = 'display: flex; align-items: center;',
    classPrefix = 'markdown-alert',
  } = options

  const markerNameRE = markers === '*' ? '\\w+' : markers.join('|')
  const RE = new RegExp(`^\\[\\!(${markerNameRE})\\]([^\\n\\r]*)`, matchCaseSensitive ? '' : 'i')

  md.core.ruler.after('block', 'github-alerts', (state) => {
    const tokens = state.tokens
    for (let i = 0; i < tokens.length; i++) {
      if (tokens[i].type === 'blockquote_open') {
        const open = tokens[i]
        const startIndex = i
        while (tokens[i]?.type !== 'blockquote_close' && i <= tokens.length)
          i += 1
        const close = tokens[i]
        const endIndex = i
        const firstContent = tokens.slice(startIndex, endIndex + 1).find(token => token.type === 'inline')
        if (!firstContent)
          continue
        const match = firstContent.content.match(RE)
        if (!match)
          continue
        const type = match[1].toLowerCase() as keyof typeof icons
        const title = match[2].trim() || (titles[type] ?? capitalize(type))
        const icon = icons[type] ?? ''
        firstContent.content = firstContent.content.slice(match[0].length).trimStart()
        open.type = 'alert_open'
        open.tag = keepBlockquote ? 'blockquote' : 'div'
        open.meta = {
          title,
          type,
          icon,
        }
        close.type = 'alert_close'
        close.tag = keepBlockquote ? 'blockquote' : 'div'
      }
    }
  })
  md.renderer.rules.alert_open = function (tokens, idx) {
    const { title, type, icon } = tokens[idx].meta
    return `<${keepBlockquote ? 'blockquote' : 'div'} class="${classPrefix} ${classPrefix}-${type}"><p class="${classPrefix}-title" ${titleStyle ? `style="${titleStyle}"` : ''}>${icon ? `${icon}&nbsp;` : ''}${title}</p>`
  }
}

function capitalize(str: string) {
  return str.charAt(0).toUpperCase() + str.slice(1)
}

export default MarkdownItGitHubAlerts