import { Injectable } from '@angular/core';
import { HttpClient, HttpHeaders } from '@angular/common/http';
import { Observable, throwError } from 'rxjs';
import { catchError, retry } from 'rxjs/operators';
import { environment } from '../../environments/environment';

// 抖音API接口定义
interface DouyinSearchParams {
  keyword: string;
  cursor?: number | string; // 支持数字或字符串
  sort_type?: string;
  publish_time?: string;
  filter_duration?: string;
  content_type?: string;
  search_id?: string;
}

interface DouyinVideoDetailParams {
  aweme_id: string;
}

interface DouyinCommentsParams {
  aweme_id: string;
  cursor?: number | string;
  count?: number | string;
}

@Injectable({
  providedIn: 'root'
})
export class DouyinApiService {
  private readonly BASE_URL = environment.douyinApi.baseUrl;
  private readonly TIMEOUT = environment.douyinApi.timeout;
  private readonly MAX_RETRIES = environment.douyinApi.maxRetries;

  constructor(private http: HttpClient) {}

  /**
   * 抖音综合搜索
   * @param params 搜索参数
   * @returns 搜索结果
   */
  searchVideos(params: DouyinSearchParams): Observable<any> {
    const url = `${this.BASE_URL}/api/v1/douyin/search/fetch_challenge_search_v2`;

    const defaultParams = {
      cursor: 0,
      sort_type: '0',
      publish_time: '0',
      filter_duration: '0',
      content_type: '0',
      search_id: ''
    };

    const requestParams = {
      ...defaultParams,
      ...params,
      cursor: params.cursor || 0 // 保持cursor为数字，根据API文档
    };

    return this.http.post(url, requestParams, {
      headers: this.getHeaders(),
      timeout: this.TIMEOUT
    }).pipe(
      retry(this.MAX_RETRIES),
      catchError(this.handleError)
    );
  }

  /**
   * 获取单个视频详情
   * @param aweme_id 视频ID
   * @returns 视频详情
   */
  getVideoDetail(aweme_id: string): Observable<any> {
    const url = `${this.BASE_URL}/api/v1/douyin/app/v3/fetch_one_video_v3`;

    return this.http.get(url, {
      params: { aweme_id },
      headers: this.getHeaders(),
      timeout: this.TIMEOUT
    }).pipe(
      retry(this.MAX_RETRIES),
      catchError(this.handleError)
    );
  }

  /**
   * 获取视频评论
   * @param params 评论参数
   * @returns 评论列表
   */
  getVideoComments(params: DouyinCommentsParams): Observable<any> {
    const url = `${this.BASE_URL}/app/v3/fetch_video_comments`;

    const defaultParams = {
      cursor: 0,
      count: 20
    };

    const requestParams = {
      ...defaultParams,
      ...params,
      cursor: params.cursor || 0,
      count: params.count || 20
    };

    return this.http.get(url, {
      params: requestParams,
      headers: this.getHeaders(),
      timeout: this.TIMEOUT
    }).pipe(
      retry(this.MAX_RETRIES),
      catchError(this.handleError)
    );
  }

  /**
   * 获取评论回复
   * @param item_id 视频ID
   * @param comment_id 评论ID
   * @param cursor 游标
   * @returns 回复列表
   */
  getCommentReplies(item_id: string, comment_id: string, cursor: number = 0): Observable<any> {
    const url = `${this.BASE_URL}/comment/reply/list`;

    return this.http.post(url, {
      item_id,
      comment_id,
      cursor,
      count: 20
    }, {
      headers: this.getHeaders(),
      timeout: this.TIMEOUT
    }).pipe(
      retry(this.MAX_RETRIES),
      catchError(this.handleError)
    );
  }

  /**
   * 获取用户信息
   * @param sec_uid 用户sec_uid
   * @returns 用户信息
   */
  getUserProfile(sec_uid: string): Observable<any> {
    const url = `${this.BASE_URL}/app/v3/handler_user_profile`;

    return this.http.get(url, {
      params: { sec_user_id: sec_uid },
      headers: this.getHeaders(),
      timeout: this.TIMEOUT
    }).pipe(
      retry(this.MAX_RETRIES),
      catchError(this.handleError)
    );
  }

  /**
   * 获取请求头（使用环境配置）
   */
  private getHeaders(): HttpHeaders {
    return new HttpHeaders({
      'Content-Type': 'application/json',
      'Accept': 'application/json',
      'Authorization': `Bearer ${environment.douyinApi.token}`
    });
  }

  /**
   * 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 && error.error.msg) {
        errorMessage += ` | API错误: ${error.error.msg}`;
      }
    }

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