// 自定义侧栏工具代码处理：
// - parseMixedWidgetCode / mergeWidgetCode：「混写一框」（内联 <style>/<script>）与分栏三字段互转；
//   三字段存储结构不变，拆分仅发生在管理端提交/切换视图时。
// - scopeWidgetCss：渲染时把工具 CSS 限定在其容器（.j13-widget-{id}）内，
//   逐条规则加前缀，避免污染页面其他区域。

export interface WidgetCodeParts {
  html: string;
  css: string;
  js: string;
}

const STYLE_RE = /<style\b[^>]*>([\s\S]*?)<\/style>/gi;
const SCRIPT_RE = /<script\b([^>]*)>([\s\S]*?)<\/script>/gi;
const TYPE_RE = /\btype\s*=\s*(?:"([^"]*)"|'([^']*)')/i;

const JS_TYPES = new Set(["", "text/javascript", "application/javascript", "module"]);

function isNonJsScript(attrs: string): boolean {
  const m = attrs.match(TYPE_RE);
  if (!m) return false;
  return !JS_TYPES.has((m[1] ?? m[2] ?? "").toLowerCase());
}

/** 混写代码 → 三字段：<style>/<script> 段被摘出，剩余全部视为 HTML */
export function parseMixedWidgetCode(code: string): WidgetCodeParts {
  const cssParts: string[] = [];
  const jsParts: string[] = [];
  let html = code.replace(STYLE_RE, (_m, body: string) => {
    cssParts.push(body);
    return "";
  });
  html = html.replace(SCRIPT_RE, (m: string, attrs: string, body: string) => {
    // 外链脚本、模板/数据脚本（type 非 JS）原样留在 HTML 中
    if (/\bsrc\s*=/i.test(attrs) || isNonJsScript(attrs)) return m;
    jsParts.push(body);
    return "";
  });
  return {
    html: html.trim(),
    css: cssParts.join("\n\n").trim(),
    js: jsParts.join("\n\n").trim(),
  };
}

/** 三字段 → 混写视图：HTML 在前，CSS/JS 分别以标准标签包裹 */
export function mergeWidgetCode(parts: WidgetCodeParts): string {
  const out: string[] = [];
  if (parts.html.trim()) out.push(parts.html.trim());
  if (parts.css.trim()) out.push(`<style>\n${parts.css.trim()}\n</style>`);
  if (parts.js.trim()) out.push(`<script>\n${parts.js.trim()}\n</script>`);
  return out.join("\n\n");
}

/* ─────────────────────────── CSS 作用域 ─────────────────────────── */

// 按 , 分割选择器列表，忽略 () / [] 与引号内的逗号（:is(a,b)、[attr="a,b"]）
function splitSelectorList(sel: string): string[] {
  const out: string[] = [];
  let depth = 0;
  let quote = "";
  let start = 0;
  for (let i = 0; i < sel.length; i++) {
    const ch = sel[i];
    if (quote) {
      if (ch === "\\") i++;
      else if (ch === quote) quote = "";
      continue;
    }
    if (ch === '"' || ch === "'") {
      quote = ch;
      continue;
    }
    if (ch === "(" || ch === "[") depth++;
    else if (ch === ")" || ch === "]") depth = Math.max(0, depth - 1);
    else if (ch === "," && depth === 0) {
      out.push(sel.slice(start, i));
      start = i + 1;
    }
  }
  out.push(sel.slice(start));
  return out;
}

// 单个选择器加前缀：
// - :root / :scope / html / body 开头 → 视作容器本身（变量定义在容器上，板块内可用）；
// - 以伪类/伪元素（:）开头 → 紧贴容器（容器自身状态，如 .j13-widget-1:hover）；
// - 其余 → 后代选择器。
function scopeOneSelector(sel: string, prefix: string): string | null {
  const s = sel.trim();
  if (!s) return null;
  const rootLike = s.match(/^(?::root\b|:scope\b|html\b|body\b)([\s\S]*)$/);
  if (rootLike) {
    const rest = rootLike[1].replace(/^\s+/, "");
    return rest ? `${prefix} ${rest}` : prefix;
  }
  if (s.startsWith(":")) {
    // 功能型伪类开头（:is( / :where( / :has( / :not( ）→ 按容器后代处理；
    // 简单伪类/伪元素（:hover、::before…）→ 紧贴容器（容器自身状态）。
    return /^::?[a-zA-Z-]+\(/.test(s) ? `${prefix} ${s}` : prefix + s;
  }
  return `${prefix} ${s}`;
}

/**
 * 把 CSS 限定到容器内：
 * - 普通规则：选择器逐个加 `.j13-widget-{id}` 前缀；
 * - @media/@supports/@container/@layer 块：头部原样，内部规则递归前缀化；
 * - @keyframes/@font-face/@property 等：整块原样（内部是帧/描述符，不是选择器）；
 * - 注释、引号内容（如 content:"{"）不影响括号配对。
 * 已知取舍：同名 @keyframes 在多个工具间仍是全局的，命名请自带区分。
 */
export function scopeWidgetCss(css: string, id: number): string {
  const prefix = `.j13-widget-${id}`;
  const n = css.length;
  let out = "";
  let i = 0;

  // 从 from 起读一个平衡的 {...} 块（引号与转义内的括号不计入深度）
  const readBlock = (from: number): { body: string; end: number } => {
    let depth = 0;
    let quote = "";
    for (let j = from; j < n; j++) {
      const ch = css[j];
      if (quote) {
        if (ch === "\\") j++;
        else if (ch === quote) quote = "";
        continue;
      }
      if (ch === '"' || ch === "'") quote = ch;
      else if (ch === "{") depth++;
      else if (ch === "}") {
        depth--;
        if (depth === 0) return { body: css.slice(from, j + 1), end: j + 1 };
      }
    }
    return { body: css.slice(from), end: n };
  };

  while (i < n) {
    if (css.startsWith("/*", i)) {
      const close = css.indexOf("*/", i + 2);
      const stop = close === -1 ? n : close + 2;
      out += css.slice(i, stop);
      i = stop;
      continue;
    }
    if (css[i] === "}") {
      // 多余闭括号容错，原样透传
      out += css[i];
      i++;
      continue;
    }
    // 读取选择器/语句头直到 { ; } 或结尾（引号内不截断）
    let j = i;
    let quote = "";
    for (; j < n; j++) {
      const c = css[j];
      if (quote) {
        if (c === "\\") j++;
        else if (c === quote) quote = "";
        continue;
      }
      if (c === '"' || c === "'") {
        quote = c;
        continue;
      }
      if (c === "{" || c === ";" || c === "}") break;
    }
    const head = css.slice(i, j);
    if (j >= n) {
      out += head;
      break;
    }
    if (css[j] === ";") {
      // @import / @charset / @layer a, b; 等语句原样保留
      out += head + ";";
      i = j + 1;
      continue;
    }
    if (css[j] === "}") {
      out += head;
      i = j + 1;
      continue;
    }
    const { body, end } = readBlock(j);
    const trimmedHead = head.trim();
    if (trimmedHead.startsWith("@")) {
      const at = trimmedHead.split(/[\s(]/)[0].toLowerCase();
      if (at === "@media" || at === "@supports" || at === "@container" || at === "@layer") {
        const inner = body.slice(1, -1);
        out += head + "{" + scopeWidgetCss(inner, id) + "}";
      } else {
        out += head + body;
      }
    } else {
      const scoped = splitSelectorList(head)
        .map((s) => scopeOneSelector(s, prefix))
        .filter((s): s is string => s !== null);
      if (scoped.length) {
        // 保留选择器前后的原始空白，尽量不改变站长代码的排版
        const lead = head.match(/^\s*/)?.[0] ?? "";
        const trail = head.match(/\s*$/)?.[0] ?? "";
        out += lead + scoped.join(", ") + trail + body;
      } else {
        out += head + body;
      }
    }
    i = end;
  }
  return out;
}