import axios from 'axios';
import { GITHUB_CONFIG } from '../config/users.js';
import memoryStorageService from './memoryStorageService.js';

class GitHubService {
  constructor() {
    this.apiUrl = GITHUB_CONFIG.apiUrl;
    this.token = GITHUB_CONFIG.token;
    this.repositories = GITHUB_CONFIG.repositories;
    this.useMemoryStorage = !this.token; // 如果没有token，使用内存存储
    
    if (!this.token) {
      console.warn('GitHub token not configured, using memory storage for development');
    }
  }

  // 获取仓库信息
  parseRepoUrl(repoUrl) {
    const match = repoUrl.match(/github\.com\/([^\/]+)\/([^\/]+)/);
    if (!match) throw new Error('Invalid GitHub repository URL');
    return { owner: match[1], repo: match[2] };
  }

  // 获取文件内容
  async getFile(userId, fileName, repoIndex = 0) {
    // 如果使用内存存储
    if (this.useMemoryStorage) {
      return await memoryStorageService.getFile(userId, fileName);
    }

    // 原有的GitHub逻辑
    try {
      const repoUrl = this.repositories[repoIndex];
      const { owner, repo } = this.parseRepoUrl(repoUrl);
      const path = `users/${userId}/${fileName}`;

      const response = await axios.get(
        `${this.apiUrl}/repos/${owner}/${repo}/contents/${path}`,
        {
          headers: {
            'Authorization': `token ${this.token}`,
            'Accept': 'application/vnd.github.v3+json'
          }
        }
      );

      const content = Buffer.from(response.data.content, 'base64').toString('utf8');
      return {
        content: JSON.parse(content),
        sha: response.data.sha
      };
    } catch (error) {
      if (error.response?.status === 404) {
        return null;
      }
      throw error;
    }
  }

  // 保存文件
  async saveFile(userId, fileName, data, repoIndex = 0) {
    // 如果使用内存存储
    if (this.useMemoryStorage) {
      return await memoryStorageService.saveFile(userId, fileName, data);
    }

    // 原有的GitHub逻辑
    const repoUrl = this.repositories[repoIndex];
    const { owner, repo } = this.parseRepoUrl(repoUrl);
    const path = `users/${userId}/${fileName}`;

    // 先尝试获取现有文件的SHA
    let sha = null;
    try {
      const existing = await this.getFile(userId, fileName, repoIndex);
      if (existing) {
        sha = existing.sha;
      }
    } catch (error) {
      // 忽略获取SHA的错误
    }

    const content = Buffer.from(JSON.stringify(data, null, 2)).toString('base64');

    const payload = {
      message: `Update ${fileName} for user ${userId}`,
      content: content,
      branch: 'main'
    };

    if (sha) {
      payload.sha = sha;
    }

    const response = await axios.put(
      `${this.apiUrl}/repos/${owner}/${repo}/contents/${path}`,
      payload,
      {
        headers: {
          'Authorization': `token ${this.token}`,
          'Accept': 'application/vnd.github.v3+json'
        }
      }
    );

    return response.data;
  }

  // 获取用户的所有PPT列表
  async getUserPPTList(userId) {
    // 如果使用内存存储
    if (this.useMemoryStorage) {
      return await memoryStorageService.getUserPPTList(userId);
    }

    // 原有的GitHub逻辑
    const results = [];
    
    for (let i = 0; i < this.repositories.length; i++) {
      try {
        const repoUrl = this.repositories[i];
        const { owner, repo } = this.parseRepoUrl(repoUrl);
        const path = `users/${userId}`;

        const response = await axios.get(
          `${this.apiUrl}/repos/${owner}/${repo}/contents/${path}`,
          {
            headers: {
              'Authorization': `token ${this.token}`,
              'Accept': 'application/vnd.github.v3+json'
            }
          }
        );

        const files = response.data
          .filter(item => item.type === 'file' && item.name.endsWith('.json'));

        // 获取每个PPT文件的实际内容以读取标题
        for (const file of files) {
          try {
            const pptId = file.name.replace('.json', '');
            const fileContent = await this.getFile(userId, file.name, i);
            
            if (fileContent && fileContent.content) {
              results.push({
                name: pptId,
                title: fileContent.content.title || '未命名演示文稿',
                lastModified: fileContent.content.updatedAt || fileContent.content.createdAt,
                repoIndex: i,
                repoUrl: repoUrl
              });
            }
          } catch (error) {
            // 如果读取单个文件失败，使用文件名作为标题
            console.warn(`Failed to read PPT content for ${file.name}:`, error.message);
            results.push({
              name: file.name.replace('.json', ''),
              title: file.name.replace('.json', ''),
              lastModified: new Date().toISOString(),
              repoIndex: i,
              repoUrl: repoUrl
            });
          }
        }
      } catch (error) {
        if (error.response?.status !== 404) {
          console.error(`Error fetching files from repo ${i}:`, error.message);
        }
      }
    }

    return results;
  }

  // 删除文件
  async deleteFile(userId, fileName, repoIndex = 0) {
    // 如果使用内存存储
    if (this.useMemoryStorage) {
      return await memoryStorageService.deleteFile(userId, fileName);
    }

    // 原有的GitHub逻辑
    const existing = await this.getFile(userId, fileName, repoIndex);
    if (!existing) {
      throw new Error('File not found');
    }

    const repoUrl = this.repositories[repoIndex];
    const { owner, repo } = this.parseRepoUrl(repoUrl);
    const path = `users/${userId}/${fileName}`;

    const response = await axios.delete(
      `${this.apiUrl}/repos/${owner}/${repo}/contents/${path}`,
      {
        data: {
          message: `Delete ${fileName} for user ${userId}`,
          sha: existing.sha,
          branch: 'main'
        },
        headers: {
          'Authorization': `token ${this.token}`,
          'Accept': 'application/vnd.github.v3+json'
        }
      }
    );

    return response.data;
  }
}

export default new GitHubService();