import { Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { firstValueFrom, from, Observable, throwError, timer } from 'rxjs';
import { catchError, map, retry, switchMap } from 'rxjs/operators';
import { DouyinVideo, VideoDownloadTask } from '../models/types';
import { environment } from '../../environments/environment';
import { AuthCreditService } from './auth-credit.service';

@Injectable({ providedIn: 'root' })
export class DouyinService {
  private readonly MAX_RETRIES = environment.douyinApi.maxRetries;

  constructor(private http: HttpClient, private authCredit: AuthCreditService) {}

  // 抖音话题搜索 V2
  searchVideos(
    keyword: string,
    sortType: string = '0',
    cursor: number = 0,
    publishTime: string = '0',
    filterDuration: string = '0',
    contentType: string = '0',
    searchId: string = '',
    backtrace: string = ''
  ): Observable<any> {
    const requestBody = {
      keyword: keyword || '',
      sort_type: sortType || '0',
      cursor: cursor, // 保持为数字，根据API文档示例
      publish_time: publishTime || '0',
      filter_duration: filterDuration || '0',
      content_type: contentType || '0',
      search_id: searchId || '',
      backtrace: backtrace || ''
    };

    return this.withCreditGate('douyin.search', 1, '视频发现', () => this.callDouyin('searchVideos', { payload: requestBody }).pipe(
      retry({
        count: this.MAX_RETRIES,
        delay: (error, retryCount) => {
          console.log(`请求失败，第${retryCount}次重试...`, error);
          return timer(retryCount * 1000); // 递增延迟
        }
      }),
      catchError(this.handleError)
    ));
  }

  // 获取视频详情
  getVideoDetail(awemeId: string): Observable<any> {
    return this.withCreditGate('douyin.videoDetail', 1, '视频详情', () => this.callDouyin('videoDetail', { params: { aweme_id: awemeId } }).pipe(
      retry(this.MAX_RETRIES),
      catchError(this.handleError)
    ));
  }

  getUserProfileByUniqueId(uniqueId: string): Observable<any> {
    return this.withCreditGate('douyin.userProfile', 1, '博主资料', () => this.callDouyin('userProfileWeb', { params: { unique_id: uniqueId } }).pipe(
      retry(this.MAX_RETRIES),
      catchError(this.handleError)
    ));
  }

  getUserProfileBySecUserId(secUserId: string): Observable<any> {
    return this.withCreditGate('douyin.userProfile', 1, '博主资料', () => this.callDouyin('userProfileApp', { params: { sec_user_id: secUserId } }).pipe(
      retry(this.MAX_RETRIES),
      catchError(this.handleError)
    ));
  }

  getUserPostVideos(secUserId: string, maxCursor: string = '0', count: number = 18, filterType: string = '0'): Observable<any> {
    return this.withCreditGate('douyin.userPosts', 1, '博主作品', () => this.callDouyin('userPosts', {
      params: {
        sec_user_id: secUserId,
        max_cursor: maxCursor,
        count,
        filter_type: filterType
      }
    }).pipe(
      retry(this.MAX_RETRIES),
      catchError(this.handleError)
    ));
  }

  extractUserProfileData(payload: any): any {
    const normalizedResponse = this.parseJsonPayload(payload);
    const normalizedData = this.parseJsonPayload(normalizedResponse?.data);
    const nestedData = this.parseJsonPayload(normalizedData?.data);

    return this.parseJsonPayload(
      normalizedData?.user_info
      || normalizedData?.user
      || nestedData?.user_info
      || nestedData?.user
      || nestedData
      || normalizedData
      || null
    );
  }

  extractUserPostVideos(payload: any): { items: any[]; hasMore: boolean; cursor: string } {
    const normalizedResponse = this.parseJsonPayload(payload);
    const normalizedData = this.parseJsonPayload(normalizedResponse?.data);
    const nestedData = this.parseJsonPayload(normalizedData?.data);
    const source = nestedData || normalizedData || normalizedResponse || {};
    const items = Array.isArray(source?.aweme_list)
      ? source.aweme_list
      : Array.isArray(source?.items)
        ? source.items
        : [];
    const hasMore = source?.has_more === 1 || source?.has_more === true;
    const cursor = String(source?.max_cursor ?? source?.cursor ?? '0');

    return { items, hasMore, cursor };
  }

  extractVideoDetailData(videoData: any): any {
    const normalizedResponse = this.parseJsonPayload(videoData);
    const normalizedData = this.parseJsonPayload(normalizedResponse?.data);
    const nestedData = this.parseJsonPayload(normalizedData?.data);

    return this.parseJsonPayload(
      normalizedData?.aweme_detail
      || normalizedData?.aweme_info
      || normalizedData?.aweme_details?.[0]
      || nestedData?.aweme_detail
      || nestedData?.aweme_info
      || nestedData?.aweme_details?.[0]
      || nestedData
      || normalizedData
      || null
    );
  }

  extractVideoPreviewUrl(videoData: any): string | null {
    const detailData = this.extractVideoDetailData(videoData);

    if (!detailData) {
      return null;
    }

    return this.pickPreferredUrl(this.collectPreviewUrls(detailData));
  }

  extractVideoDownloadUrl(videoData: any): string | null {
    return this.pickPreferredUrl(this.extractVideoDownloadUrls(videoData));
  }

  extractVideoDownloadUrls(videoData: any): string[] {
    const detailData = this.extractVideoDetailData(videoData);

    if (!detailData) {
      return [];
    }

    const downloadCandidates = [
      ...(Array.isArray(detailData.download_addr?.url_list) ? detailData.download_addr.url_list : []),
      ...(Array.isArray(detailData.video?.download_addr?.url_list) ? detailData.video.download_addr.url_list : []),
      ...(Array.isArray(detailData.video?.download_suffix_logo_addr?.url_list) ? detailData.video.download_suffix_logo_addr.url_list : [])
    ];

    return this.pickUniqueUrls([...downloadCandidates, ...this.collectPlayableUrls(detailData)]);
  }

  startManagedDownload(payload: {
    url: string;
    urls?: string[];
    filename: string;
    title: string;
    description: string;
    tags: string[];
    thumbnail: string;
    duration: number;
    resolution: string;
    awemeId: string;
    authorName: string;
  }): Observable<any> {
    return this.http.post('/backend/api/download/video', payload);
  }

  getManagedDownloadTask(taskId: string): Observable<any> {
    return this.http.get(`/backend/api/download/video/${taskId}`);
  }

  private collectPreviewUrls(detailData: any): string[] {
    const prioritizedUrls = [
      ...(Array.isArray(detailData.video?.play_addr_lowbr?.url_list) ? detailData.video.play_addr_lowbr.url_list : []),
      ...(Array.isArray(detailData.video?.play_addr_h264?.url_list) ? detailData.video.play_addr_h264.url_list : []),
      ...(Array.isArray(detailData.video?.play_addr?.url_list) ? detailData.video.play_addr.url_list : []),
      ...(Array.isArray(detailData.video?.play_addr_265?.url_list) ? detailData.video.play_addr_265.url_list : [])
    ];

    return this.pickUniqueUrls([...prioritizedUrls, ...this.collectPlayableUrls(detailData)]);
  }

  private collectPlayableUrls(detailData: any): string[] {
    const bitRateUrls = Array.isArray(detailData.video?.bit_rate)
      ? detailData.video.bit_rate.reduce((urls: string[], item: any) => {
          const currentUrls = Array.isArray(item?.play_addr?.url_list) ? item.play_addr.url_list : [];
          return urls.concat(currentUrls);
        }, [])
      : [];

    const directUrls = [
      ...(Array.isArray(detailData.video?.play_addr?.url_list) ? detailData.video.play_addr.url_list : []),
      ...(Array.isArray(detailData.video?.play_addr_h264?.url_list) ? detailData.video.play_addr_h264.url_list : []),
      ...(Array.isArray(detailData.video?.play_addr_265?.url_list) ? detailData.video.play_addr_265.url_list : []),
      ...(Array.isArray(detailData.video?.play_addr_lowbr?.url_list) ? detailData.video.play_addr_lowbr.url_list : []),
      ...(Array.isArray(detailData.video?.download_addr?.url_list) ? detailData.video.download_addr.url_list : []),
      ...(Array.isArray(detailData.download_addr?.url_list) ? detailData.download_addr.url_list : []),
      detailData.video?.play_addr?.uri,
      detailData.video?.download_addr?.uri
    ];

    return this.pickUniqueUrls([...directUrls, ...bitRateUrls]);
  }

  private pickUniqueUrls(urls: any[]): string[] {
    return urls.filter((url, index, list) => (
      typeof url === 'string'
      && /^https?:\/\//i.test(url)
      && list.indexOf(url) === index
    ));
  }

  private pickPreferredUrl(urls: any[]): string | null {
    const validUrls = urls.filter(url => typeof url === 'string' && url.trim() !== '');
    const preferredUrl = validUrls.find(url => !/watermark|playwm|download_suffix_logo/i.test(url));

    return preferredUrl || validUrls[0] || null;
  }

  private parseJsonPayload(value: any): any {
    let current = value;

    while (typeof current === 'string') {
      const trimmed = current.trim();
      if (!trimmed || (!trimmed.startsWith('{') && !trimmed.startsWith('['))) {
        break;
      }

      try {
        current = JSON.parse(trimmed);
      } catch {
        break;
      }
    }

    return current;
  }

  // 下载视频到本地（改进版本，支持进度跟踪）
  async downloadVideo(videoUrl: string, filename: string, onProgress?: (progress: number) => void): Promise<void> {
    try {
      const response = await fetch(videoUrl, {
        method: 'GET',
        headers: {
          'Accept': 'video/mp4,*/*',
          'Cache-Control': 'no-cache'
        }
      });

      if (!response.ok) {
        throw new Error(`下载失败: ${response.status} ${response.statusText}`);
      }

      const contentLength = response.headers.get('content-length');
      const totalBytes = contentLength ? parseInt(contentLength, 10) : 0;

      const reader = response.body?.getReader();
      if (!reader) {
        throw new Error('无法读取视频流');
      }

      const chunks: Uint8Array[] = [];
      let receivedBytes = 0;

      while (true) {
        const { done, value } = await reader.read();

        if (done) break;

        chunks.push(value);
        receivedBytes += value.length;

        if (onProgress && totalBytes > 0) {
          const progress = Math.round((receivedBytes / totalBytes) * 100);
          onProgress(progress);
        }
      }

      // 合并所有数据块
      const blob = new Blob(chunks as BlobPart[], { type: 'video/mp4' });

      // 创建下载链接
      const url = window.URL.createObjectURL(blob);
      const link = document.createElement('a');
      link.href = url;
      link.download = filename;
      link.style.display = 'none';

      document.body.appendChild(link);
      link.click();

      // 清理
      setTimeout(() => {
        document.body.removeChild(link);
        window.URL.revokeObjectURL(url);
      }, 100);

      if (onProgress) {
        onProgress(100);
      }
    } catch (error) {
      console.error('视频下载错误:', error);
      throw error;
    }
  }

  // 从URL中提取aweme_id（增强版本）
  extractAwemeId(url: string): string | null {
    if (!url) return null;

    // 处理多种抖音链接格式
    const patterns = [
      /douyin\.com\/video\/(\d+)/,                    // https://www.douyin.com/video/1234567890
      /douyin\.com\/\w+\/(\d+)/,                      // https://www.douyin.com/user/123/71891234567890
      /aweme_id=(\d+)/,                                // aweme_id=1234567890
      /^(\d+)$/,                                        // 纯数字ID
      /douyin\.com\/\?modal_id=(\d+)/,                 // 分享链接格式
      /v\.douyin\.com\/\w+\?id=(\d+)/,                 // 短链接格式
      /douyin\.com\/share\/video\/(\d+)/               // 分享页面格式
    ];

    for (const pattern of patterns) {
      const match = url.match(pattern);
      if (match) {
        return match[1];
      }
    }

    return null;
  }

  // 批量获取视频信息
  getBatchVideoDetails(awemeIds: string[]): Observable<any>[] {
    return awemeIds.map(id => this.getVideoDetail(id));
  }

  // 验证视频数据完整性
  validateVideoData(videoData: any): boolean {
    if (!videoData || !videoData.data) {
      return false;
    }

    const data = videoData.data;
    return !!(data.aweme_id && data.desc !== undefined && data.author);
  }

  // 格式化视频信息用于显示
  formatVideoInfo(videoData: DouyinVideo): DouyinVideo {
    return {
      ...videoData,
      statistics: {
        digg_count: videoData.statistics?.digg_count || 0,
        play_count: videoData.statistics?.play_count || 0,
        comment_count: videoData.statistics?.comment_count || 0,
        share_count: videoData.statistics?.share_count || 0
      },
      author: {
        nickname: videoData.author?.nickname || '未知作者',
        sec_uid: videoData.author?.sec_uid || '',
        avatar_thumb: videoData.author?.avatar_thumb
      }
    };
  }

  // 生成安全的文件名
  generateSafeFilename(video: DouyinVideo): string {
    const author = video.author?.nickname || '未知作者';
    const title = video.desc || `视频_${video.aweme_id}`;
    const safeTitle = title
      .replace(/[<>:"/\\|?*]/g, '_')  // 移除Windows文件名非法字符
      .replace(/\s+/g, '_')           // 空格替换为下划线
      .substring(0, 50);              // 限制标题长度

    return `${author}_${safeTitle}_${video.aweme_id}.mp4`;
  }

  private callDouyin(route: string, params: { payload?: Record<string, any>; params?: Record<string, any> }): Observable<any> {
    return from(this.callDouyinLocalFirst(route, params));
  }

  private async callDouyinLocalFirst(route: string, params: { payload?: Record<string, any>; params?: Record<string, any> }): Promise<any> {
    try {
      const local = await firstValueFrom(this.http.post<{ success?: boolean; data?: any; error?: string }>('/backend/api/douyin/call', {
        route,
        ...params,
      }));
      if (local?.success) return local.data;
      throw new Error(local?.error || '本地抖音数据代理返回失败');
    } catch (localError) {
      const message = this.readLocalProxyError(localError);
      throw new Error(`本地抖音数据代理调用失败，请确认已启动 npm run server：${message}`);
    }
  }

  private readLocalProxyError(error: any): string {
    return error?.error?.error || error?.error?.message || error?.message || '本地抖音数据代理不可用';
  }

  private withCreditGate<T>(
    operation: string,
    cost: number,
    title: string,
    run: () => Observable<T>
  ): Observable<T> {
    if (!this.authCredit.isLoggedIn) {
      this.authCredit.requestLogin(title);
      return throwError(() => new Error('请先登录后使用该功能'));
    }
    let reservationId = '';
    return from(this.authCredit.reserveCredit(operation, cost, title)).pipe(
      switchMap((reserved) => {
        reservationId = reserved.reservationId;
        return run().pipe(
          switchMap((value) => from(this.authCredit.commitReservation(reservationId, { title })).pipe(map(() => value))),
          catchError((err) => from(this.authCredit.refundReservation(reservationId, err?.message || '任务失败')).pipe(
            switchMap(() => throwError(() => err))
          ))
        );
      })
    );
  }

  // 错误处理
  private handleError(error: any): Observable<never> {
    let errorMessage = '';

    if (error.error instanceof ErrorEvent) {
      // 客户端错误
      errorMessage = `网络错误: ${error.error.message}`;
    } else {
      // 服务端错误
      switch (error.status) {
        case 401:
          errorMessage = '认证失败 (401): Token无效或已过期';
          break;
        case 403:
          errorMessage = '访问被拒绝 (403): 权限不足';
          break;
        case 429:
          errorMessage = '请求过于频繁 (429): 请稍后重试';
          break;
        case 500:
          errorMessage = '服务器内部错误 (500): 请稍后重试';
          break;
        case 400:
          errorMessage = '请求参数错误 (400): 请检查请求参数格式';
          break;
        case 0:
          errorMessage = '网络连接失败: 请检查网络设置';
          break;
        default:
          errorMessage = `请求失败 (${error.status}): ${error.message || '未知错误'}`;
      }

      // 检查API返回的具体错误信息
      if (error.error) {
        console.log('🔍 详细错误信息:', {
          status: error.status,
          statusText: error.statusText,
          error: error.error,
          message: error.message,
          url: error.url
        });

        if (error.error.msg) {
          errorMessage += ` | API错误: ${error.error.msg}`;
        }
        if (error.error.data) {
          errorMessage += ` | 错误数据: ${JSON.stringify(error.error.data)}`;
        }
      }
    }

    console.error('Douyin API Error:', errorMessage, error);
    return throwError(() => new Error(errorMessage));
  }
}