import { URL_EMBED_MSG } from "./urlEmbedMessages.js";
import { isWeChatBrowser } from "./urlEmbedEnv.js";
import {
  cancelUrlEmbedClientFocusBurst,
  restoreUrlEmbedClientFocus,
  scheduleUrlEmbedClientRestoreForEnv,
} from "./urlEmbedWechatFocus.js";

export {
  restoreUrlEmbedClientFocus,
  scheduleUrlEmbedClientRestoreForEnv,
} from "./urlEmbedWechatFocus.js";

function resolveUrl(url) {
  try {
    return new URL(url, typeof window !== "undefined" ? window.location.href : undefined);
  } catch {
    return null;
  }
}

/** 是否运行在 urlEmbed 抽屉 iframe 内 */
export function isUrlEmbedFrame() {
  if (typeof window === "undefined") return false;
  try {
    return window.parent !== window;
  } catch {
    return true;
  }
}

function isSafeHttpUrl(url) {
  const parsed = resolveUrl(url);
  if (!parsed) return false;
  return parsed.protocol === "http:" || parsed.protocol === "https:";
}

/**
 * 请求父页面打开 URL（iframe 内 window.open / target=_blank 常被拦截时使用）
 * @param {string} url
 * @param {{
 *   title?: string,
 *   showToolbar?: boolean,
 *   openInNewWindow?: boolean,
 *   showNewWindowButton?: boolean,
 * }} [options]
 * @returns {boolean} 是否已发出请求或已在顶层直接打开
 */
export function requestOpenUrl(url, options = {}) {
  const nextUrl = typeof url === "string" ? url.trim() : "";
  if (!nextUrl || !isSafeHttpUrl(nextUrl)) return false;

  if (!isUrlEmbedFrame()) {
    if (options.openInNewWindow === true) {
      window.open(nextUrl, "_blank", "noopener,noreferrer");
      return true;
    }
    window.location.href = nextUrl;
    return true;
  }

  window.parent.postMessage(
    {
      type: URL_EMBED_MSG.OPEN_URL,
      url: nextUrl,
      title: options.title,
      showToolbar: options.showToolbar,
      openInNewWindow: options.openInNewWindow,
      showNewWindowButton: options.showNewWindowButton,
    },
    "*",
  );
  return true;
}

function handleNavMessage(data, onNav) {
  if (data.type !== URL_EMBED_MSG.NAV || typeof onNav !== "function") return;
  if (data.action === "back") {
    onNav("back");
    return;
  }
  if (data.action === "forward") {
    onNav("forward");
  }
}

function createLinkClickHandler(getOpenOptions) {
  return function onDocumentClick(ev) {
    const anchor = ev.target?.closest?.("a[href]");
    if (!anchor || !isUrlEmbedFrame()) return;

    const href = anchor.getAttribute("href");
    if (!href || href.startsWith("#") || href.startsWith("javascript:")) return;

    const target = (anchor.getAttribute("target") || "").toLowerCase();
    const opensExternally =
      target === "_blank" || target === "_top" || target === "_parent";
    if (!opensExternally) return;

    const url = anchor.href;
    if (!isSafeHttpUrl(url)) return;

    ev.preventDefault();
    ev.stopPropagation();

    const extra = typeof getOpenOptions === "function" ? getOpenOptions(anchor) : {};
    requestOpenUrl(url, {
      openInNewWindow: target === "_blank" ? true : undefined,
      ...extra,
    });
  };
}

/**
 * 嵌入页初始化：响应父页导航查询，并可选拦截链接 / window.open
 * @param {{
 *   onNav?: (action: 'back' | 'forward') => void,
 *   interceptLinks?: boolean,
 *   interceptWindowOpen?: boolean,
 *   getOpenOptions?: (anchor: HTMLAnchorElement) => Record<string, unknown>,
 * }} [options]
 * @returns {() => void} 卸载监听
 */
export function initUrlEmbedClient(options = {}) {
  if (typeof window === "undefined") return () => {};

  const onNav = options.onNav;
  const getOpenOptions = options.getOpenOptions;

  function onWindowMessage(ev) {
    const data = ev.data;
    if (!data || typeof data !== "object") return;

    if (data.type === URL_EMBED_MSG.QUERY_NAV) {
      window.parent.postMessage({ type: URL_EMBED_MSG.NAV_AVAILABLE }, "*");
      return;
    }

    if (data.type === URL_EMBED_MSG.RESTORE_FOCUS) {
      scheduleUrlEmbedClientRestoreForEnv();
      return;
    }

    handleNavMessage(data, onNav);
  }

  window.addEventListener("message", onWindowMessage);

  if (isUrlEmbedFrame()) {
    window.parent.postMessage({ type: URL_EMBED_MSG.NAV_AVAILABLE }, "*");
  }

  let removeTouchStartListener = () => {};
  if (isWeChatBrowser() && document.body) {
    const onTouchStart = () => {};
    document.body.addEventListener("touchstart", onTouchStart, { passive: true, capture: true });
    removeTouchStartListener = () => {
      document.body.removeEventListener("touchstart", onTouchStart, { capture: true });
    };
  }

  let removeWechatLifecycleListeners = () => {};
  if (isWeChatBrowser() && isUrlEmbedFrame()) {
    function onClientPageShow() {
      scheduleUrlEmbedClientRestoreForEnv();
    }

    function onClientPopState() {
      scheduleUrlEmbedClientRestoreForEnv();
    }

    function onClientVisibilityChange() {
      if (document.visibilityState !== "visible") return;
      scheduleUrlEmbedClientRestoreForEnv();
    }

    window.addEventListener("pageshow", onClientPageShow);
    window.addEventListener("popstate", onClientPopState);
    document.addEventListener("visibilitychange", onClientVisibilityChange);
    removeWechatLifecycleListeners = () => {
      window.removeEventListener("pageshow", onClientPageShow);
      window.removeEventListener("popstate", onClientPopState);
      document.removeEventListener("visibilitychange", onClientVisibilityChange);
      cancelUrlEmbedClientFocusBurst();
    };
  }

  let removeLinkListener = () => {};
  if (options.interceptLinks === true) {
    const onClick = createLinkClickHandler(getOpenOptions);
    document.addEventListener("click", onClick, true);
    removeLinkListener = () => document.removeEventListener("click", onClick, true);
  }

  let restoreWindowOpen = null;
  if (options.interceptWindowOpen === true && isUrlEmbedFrame()) {
    const nativeOpen = window.open.bind(window);
    restoreWindowOpen = nativeOpen;
    window.open = (url, target, features) => {
      const nextUrl = typeof url === "string" ? url.trim() : "";
      if (nextUrl && isSafeHttpUrl(nextUrl)) {
        requestOpenUrl(nextUrl, { openInNewWindow: true });
        return null;
      }
      return nativeOpen(url, target, features);
    };
  }

  return function disposeUrlEmbedClient() {
    window.removeEventListener("message", onWindowMessage);
    removeTouchStartListener();
    removeWechatLifecycleListeners();
    removeLinkListener();
    if (restoreWindowOpen) {
      window.open = restoreWindowOpen;
    }
  };
}