/**
 * Collabora Online 相关的自定义 hooks
 *
 * 功能：
 * - useCollaboraConfig: 加载 Collabora 配置（使用 Remix useFetcher）
 * - useDocumentReady: 监听文档加载完成
 * - useCollaboraUnoCommands: UNO 命令封装
 *
 * @encoding UTF-8
 */

import { RefObject, useCallback, useEffect, useMemo, useState } from 'react';
import { COLLABORA_URL } from '~/config/api-config';
import { toastService } from '../ui/Toast';
import {
  unoScrollToTop,
  unoReplaceAll
} from './lib';
import type { CollaboraConfig } from './types';

// ==================== 1. 配置加载 ====================

/**
 * 加载 Collabora 配置（使用 Remix useFetcher）
 * @param fileId - 文件路径
 * @param mode - 模式（view 或 edit）
 * @param userId - 用户 ID
 * @param userName - 用户名
 * @returns 配置、加载状态、错误信息
 */
export function useCollaboraConfig(
  fileId: string,
  mode: 'view' | 'edit',
  userId: string,
  userName: string
) {
  const [config, setConfig] = useState<CollaboraConfig | null>(null);
  const [loading, setLoading] = useState(false);
  const [error, setError] = useState<string | null>(null);

  useEffect(() => {
    if (!fileId) {
      setConfig(null);
      setError('文件路径不能为空');
      setLoading(false);
      return;
    }

    const controller = new AbortController();
    const params = new URLSearchParams({
      fileId,
      mode,
      userId,
      userName,
    });

    async function loadConfig() {
      setLoading(true);
      setError(null);
      setConfig(null);

      try {
        const response = await fetch(`/api/collabora/config?${params}`, {
          method: 'GET',
          signal: controller.signal,
          headers: {
            Accept: 'application/json',
          },
        });

        const result = (await response.json()) as CollaboraConfig | { error?: string };

        if (!response.ok || ('error' in result && result.error)) {
          const errorMessage =
            ('error' in result && result.error) || `加载配置失败 (${response.status})`;
          setError(errorMessage);
          toastService.error(`加载文档配置失败: ${errorMessage}`);
          return;
        }

        setConfig(result as CollaboraConfig);
      } catch (err) {
        if (controller.signal.aborted) return;
        const errorMessage = err instanceof Error ? err.message : '加载配置失败';
        setError(errorMessage);
        toastService.error(`加载文档配置失败: ${errorMessage}`);
      } finally {
        if (!controller.signal.aborted) {
          setLoading(false);
        }
      }
    }

    void loadConfig();

    return () => controller.abort();
  }, [fileId, mode, userId, userName]);

  return {
    config,
    loading,
    error,
  };
}

// ==================== 2. 文档加载状态监听 ====================

/**
 * 监听文档加载完成
 * @param iframeRef - iframe 引用
 * @returns 文档加载状态
 */
export function useDocumentReady(
  iframeRef: RefObject<HTMLIFrameElement>,
  iframeUrl?: string
) {
  const [isDocumentLoaded, setIsDocumentLoaded] = useState(false);

  useEffect(() => {
    setIsDocumentLoaded(false);

    const iframe = iframeRef.current;
    const expectedOrigin = iframeUrl
      ? new URL(iframeUrl).origin
      : new URL(COLLABORA_URL).origin;
    let fallbackTimer: ReturnType<typeof setTimeout> | null = null;

    const markLoaded = (source: string) => {
      setIsDocumentLoaded((prev) => {
        if (!prev) {
          console.log(`[DocumentReady] 文档已就绪(${source})`);
        }
        return true;
      });
    };

    const handleIframeLoad = () => {
      // 某些环境下 Collabora 不一定会抛出 Document_Loaded 消息，
      // 先在 iframe load 后给一个兜底超时，避免页面一直被遮罩层盖住。
      fallbackTimer = setTimeout(() => {
        markLoaded('iframe-load-fallback');
      }, 1500);
    };

    const handleMessage = (event: MessageEvent) => {
      if (event.origin !== expectedOrigin) {
        return;
      }

      if (iframeRef.current?.contentWindow && event.source !== iframeRef.current.contentWindow) {
        return;
      }

      try {
        const msg = typeof event.data === 'string' ? JSON.parse(event.data) : event.data;

        if (
          msg?.MessageId === 'App_LoadingStatus' &&
          ['Document_Loaded', 'Document_Loaded_Editing', 'UI_Loaded'].includes(msg.Values?.Status)
        ) {
          if (fallbackTimer) {
            clearTimeout(fallbackTimer);
            fallbackTimer = null;
          }
          markLoaded(`postmessage:${msg.Values?.Status}`);
        }
      } catch {
        // Collabora 也会发送非 JSON 消息，这里忽略即可。
      }
    };

    iframe?.addEventListener('load', handleIframeLoad);
    window.addEventListener('message', handleMessage);
    return () => {
      if (fallbackTimer) {
        clearTimeout(fallbackTimer);
      }
      iframe?.removeEventListener('load', handleIframeLoad);
      window.removeEventListener('message', handleMessage);
    };
  }, [iframeRef, iframeUrl]);

  return { isDocumentLoaded };
}

// ==================== 3. UNO 命令封装 ====================

/**
 * UNO 命令封装（React Hook）
 * @param iframeRef - iframe 引用
 * @returns UNO 命令方法集合
 */
export function useCollaboraUnoCommands(iframeRef: RefObject<HTMLIFrameElement>) {
  /**
   * 滚动到文档顶部
   */
  const scrollToTop = useCallback(async () => {
    if (!iframeRef.current?.contentWindow) {
      console.warn('[UNO] iframe 不可用');
      return;
    }

    console.log('[UNO] 滚动到顶部');
    await unoScrollToTop(iframeRef.current.contentWindow);
    await new Promise((resolve) => setTimeout(resolve, 100));
  }, [iframeRef]);

  /**
   * 替换所有匹配项
   * @param searchText 要搜索的文本
   * @param replaceText 替换后的文本
   */
  const replaceAll = useCallback(async (searchText: string, replaceText: string) => {
    if (!iframeRef.current?.contentWindow) {
      console.warn('[UNO] iframe 不可用');
      return;
    }

    console.log('[UNO] 替换全部:', searchText, '->', replaceText);
    await unoReplaceAll(iframeRef.current.contentWindow, searchText, replaceText);
    await new Promise((resolve) => setTimeout(resolve, 100));
  }, [iframeRef]);

  return useMemo(
    () => ({
      scrollToTop,
      replaceAll
    }),
    [
      scrollToTop,
      replaceAll
    ]
  );
}