/**
 * 客服云访客 Widget 嵌入脚本
 * 用法: <script src="https://your-host/widget.js" data-id="WK_xxxx"></script>
 *
 * 向 iframe 同步宿主页 URL / 标题，并监听 SPA 路由变化，供客服端展示落地页与浏览轨迹。
 */
(function () {
  if (window.__KEFU_WIDGET_LOADED__) return;
  window.__KEFU_WIDGET_LOADED__ = true;

  var script = document.currentScript;
  if (!script) {
    var scripts = document.getElementsByTagName('script');
    script = scripts[scripts.length - 1];
  }
  var channelKey = (script && script.getAttribute('data-id')) || '';
  if (!channelKey) {
    console.warn('[kefu-widget] missing data-id on script tag');
    return;
  }

  var src = script && script.src ? script.src : '';
  var base = '';
  try {
    var u = new URL(src, window.location.href);
    base = u.origin;
  } catch (e) {
    base = window.location.origin;
  }

  var open = false;
  var iframe = null;
  var lastSentKey = '';
  var lastSentAt = 0;
  var routeTimer = null;

  var btn = document.createElement('button');
  btn.type = 'button';
  btn.setAttribute('aria-label', '打开在线客服');
  btn.style.cssText = [
    'position:fixed', 'right:24px', 'bottom:24px', 'z-index:2147483000',
    'width:56px', 'height:56px', 'border:none', 'border-radius:9999px',
    'background:#2563eb', 'color:#fff', 'cursor:pointer',
    'box-shadow:0 8px 24px rgba(0,0,0,0.12)',
    'display:flex', 'align-items:center', 'justify-content:center',
    'font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC",sans-serif',
  ].join(';');
  btn.innerHTML = '<svg width="22" height="22" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M21 15a2 2 0 0 1-2 2H7l-4 4V5a2 2 0 0 1 2-2h14a2 2 0 0 1 2 2z"/></svg>';

  var panel = document.createElement('div');
  panel.style.cssText = [
    'position:fixed', 'right:24px', 'bottom:24px', 'z-index:2147483001',
    'width:400px', 'height:600px', 'max-width:calc(100vw - 32px)', 'max-height:calc(100vh - 32px)',
    'border-radius:12px', 'overflow:hidden',
    'box-shadow:0 8px 24px rgba(0,0,0,0.12)',
    'display:none', 'background:#fff',
  ].join(';');

  function hostPageInfo() {
    var href = '';
    var title = '';
    var ref = '';
    try {
      href = String(window.location.href || '');
      title = String(document.title || '');
      ref = String(document.referrer || '');
    } catch (e) { /* ignore */ }
    return { url: href, title: title, referrer: ref };
  }

  function buildEmbedURL() {
    var info = hostPageInfo();
    var q =
      'channel_key=' + encodeURIComponent(channelKey) +
      '&embedded=1' +
      '&page_url=' + encodeURIComponent(info.url) +
      '&page_title=' + encodeURIComponent(info.title) +
      '&referrer=' + encodeURIComponent(info.referrer);
    return base + '/widget/embed?' + q;
  }

  function postPageToIframe(force) {
    if (!iframe || !iframe.contentWindow) return;
    var info = hostPageInfo();
    var now = Date.now();
    // url + title 一起去重：SPA 常先改 hash 再改 title，只比 url 会丢掉正确标题
    var key = info.url + '\0' + info.title;
    if (!force && key === lastSentKey && now - lastSentAt < 500) return;
    lastSentKey = key;
    lastSentAt = now;
    try {
      iframe.contentWindow.postMessage({
        type: 'kefu-host-page',
        url: info.url,
        title: info.title,
        referrer: info.referrer,
      }, '*');
    } catch (e) { /* ignore */ }
  }

  /**
   * 路由变化后延迟采集：让宿主 SPA（含 demo-shop）先跑完 render、更新 document.title，
   * 避免轨迹标题永远慢一页（URL 已是新页、title 仍是上一页）。
   */
  function schedulePostPage(force) {
    if (!open && !force) return;
    if (routeTimer) clearTimeout(routeTimer);
    routeTimer = setTimeout(function () {
      routeTimer = null;
      postPageToIframe(!!force);
      // 再补一帧：部分框架 title 在 paint 后才写
      setTimeout(function () { postPageToIframe(false); }, 50);
    }, 0);
  }

  function ensureIframe() {
    if (iframe) return;
    iframe = document.createElement('iframe');
    iframe.title = '在线客服';
    iframe.allow = 'clipboard-write';
    iframe.style.cssText = 'width:100%;height:100%;border:0;display:block;background:#fff;';
    iframe.src = buildEmbedURL();
    iframe.addEventListener('load', function () {
      schedulePostPage(true);
    });
    panel.appendChild(iframe);
  }

  function setOpen(next) {
    open = next;
    if (open) {
      ensureIframe();
      panel.style.display = 'block';
      btn.style.display = 'none';
      schedulePostPage(true);
    } else {
      panel.style.display = 'none';
      btn.style.display = 'flex';
    }
  }

  btn.addEventListener('click', function () { setOpen(true); });

  window.addEventListener('message', function (event) {
    if (!event || !event.data) return;
    if (event.data.type === 'kefu-widget-close' || event.data.type === 'kefu-widget-minimize') {
      setOpen(false);
    }
    // iframe 就绪后可再次同步宿主页
    if (event.data.type === 'kefu-widget-ready') {
      schedulePostPage(true);
    }
  });

  // —— SPA / 浏览器导航监听 ——
  function onRouteMaybeChanged() {
    if (!open) return;
    schedulePostPage(false);
  }

  try {
    var _push = history.pushState;
    var _replace = history.replaceState;
    history.pushState = function () {
      var r = _push.apply(this, arguments);
      onRouteMaybeChanged();
      return r;
    };
    history.replaceState = function () {
      var r = _replace.apply(this, arguments);
      onRouteMaybeChanged();
      return r;
    };
  } catch (e) { /* ignore */ }

  window.addEventListener('popstate', onRouteMaybeChanged);
  window.addEventListener('hashchange', onRouteMaybeChanged);
  // 标题可能异步更新
  try {
    var titleEl = document.querySelector('title');
    if (titleEl && typeof MutationObserver !== 'undefined') {
      new MutationObserver(function () { onRouteMaybeChanged(); }).observe(titleEl, {
        subtree: true, characterData: true, childList: true,
      });
    }
  } catch (e) { /* ignore */ }

  function mount() {
    document.body.appendChild(btn);
    document.body.appendChild(panel);
  }
  if (document.readyState === 'loading') {
    document.addEventListener('DOMContentLoaded', mount);
  } else {
    mount();
  }

  window.KefuWidget = {
    open: function () { setOpen(true); },
    close: function () { setOpen(false); },
    channelKey: channelKey,
  };
})();