/**
 * 渲染契约兼容层
 *
 * 把 markdown-it 的默认输出调整到与 v1（以及 tiptap/CSS 消费方）一致的标签契约：
 *   *斜体*        →  <i>          （markdown-it 默认 <em>，v1/CSS 用 <i>）
 *   ~~删除~~      →  <del>        （markdown-it 默认 <s>，v1/CSS 用 <del>）
 *   `行内代码`    →  <code class="single-code">
 *   [链接](url)   →  <a target="_blank">（v1 一致；markdown-it 同时修复 href 引号与 title 支持）
 *   ![alt(WxH)](url) → 注入 width/height style（v1 的图片尺寸扩展语法）
 */

export function rendererCompatPlugin(md: any) {
  // 注意 token 类型是 em_open / s_open（不是 emphasis_open / strikethrough_open）
  md.renderer.rules.em_open = () => "<i>"
  md.renderer.rules.em_close = () => "</i>"
  md.renderer.rules.s_open = () => "<del>"
  md.renderer.rules.s_close = () => "</del>"

  md.renderer.rules.code_inline = (tokens: any[], idx: number) =>
    `<code class="single-code">${md.utils.escapeHtml(tokens[idx].content)}</code>`

  const defaultLinkOpen =
    md.renderer.rules.link_open ||
    ((tokens: any[], idx: number, options: any, env: any, self: any) => self.renderToken(tokens, idx, options))
  md.renderer.rules.link_open = (tokens: any[], idx: number, options: any, env: any, self: any) => {
    tokens[idx].attrSet("target", "_blank")
    return defaultLinkOpen(tokens, idx, options, env, self)
  }

  const defaultImage =
    md.renderer.rules.image ||
    ((tokens: any[], idx: number, options: any, env: any, self: any) => self.renderToken(tokens, idx, options))
  md.renderer.rules.image = (tokens: any[], idx: number, options: any, env: any, self: any) => {
    const token = tokens[idx]
    // v1 扩展：alt 中的 (宽x高) 转为固定尺寸，alt 文本原样保留
    const alt = self.renderInlineAsText(token.children || [], options, env)
    const m = /\((\d+x\d+)\)/.exec(alt)
    if (m) {
      const [w, h] = m[1].split("x").map(Number)
      if (w > 0 && h > 0) token.attrSet("style", `width: ${w}px; height: ${h}px;`)
    }
    return defaultImage(tokens, idx, options, env, self)
  }

  // 代码块语言/行号 class（v1 的 options.highlight / options.lineNumber 行为）
  const defaultFence =
    md.renderer.rules.fence ||
    ((tokens: any[], idx: number, options: any, env: any, self: any) => self.renderToken(tokens, idx, options))
  md.renderer.rules.fence = (tokens: any[], idx: number, options: any, env: any, self: any) => {
    const token = tokens[idx]
    const info = (token.info || "").trim()
    const classes = [
      options.highlight ? `language-${md.utils.escapeHtml(info.split(/\s+/g)[0])}` : "",
      options.lineNumber ? "line-numbers" : "",
    ]
      .filter(Boolean)
      .join(" ")
    if (classes) token.attrJoin("class", classes)
    return defaultFence(tokens, idx, options, env, self)
  }
}