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
    
    console.log('=== GitHub Service Configuration ===');
    console.log('Token configured:', !!this.token);
    console.log('Token preview:', this.token ? `${this.token.substring(0, 8)}...` : 'Not set');
    console.log('Repositories:', this.repositories);
    console.log('Using memory storage:', this.useMemoryStorage);
    
    if (!this.token) {
      console.warn('GitHub token not configured, using memory storage for development');
    }
  }

  // 验证GitHub连接
  async validateConnection() {
    if (this.useMemoryStorage) {
      return { valid: false, reason: 'No GitHub token configured' };
    }

    try {
      // 测试GitHub API连接
      const response = await axios.get(`${this.apiUrl}/user`, {
        headers: {
          'Authorization': `token ${this.token}`,
          'Accept': 'application/vnd.github.v3+json'
        }
      });
      
      console.log('GitHub API connection successful:', response.data.login);
      
      // 测试仓库访问和权限
      const repoResults = [];
      for (const repoUrl of this.repositories) {
        try {
          const { owner, repo } = this.parseRepoUrl(repoUrl);
          
          // 检查仓库基本信息
          const repoResponse = await axios.get(`${this.apiUrl}/repos/${owner}/${repo}`, {
            headers: {
              'Authorization': `token ${this.token}`,
              'Accept': 'application/vnd.github.v3+json'
            }
          });
          
          // 检查权限
          const permissions = repoResponse.data.permissions;
          console.log(`Repository permissions for ${owner}/${repo}:`, permissions);
          
          // 测试是否可以访问仓库内容
          let canAccessContents = false;
          let repoEmpty = false;
          try {
            await axios.get(`${this.apiUrl}/repos/${owner}/${repo}/contents`, {
              headers: {
                'Authorization': `token ${this.token}`,
                'Accept': 'application/vnd.github.v3+json'
              }
            });
            canAccessContents = true;
          } catch (contentsError) {
            console.log(`Cannot access repository contents: ${contentsError.message}`);
            
            // 如果是409错误，说明仓库为空
            if (contentsError.response?.status === 409) {
              repoEmpty = true;
              console.log('Repository appears to be empty, will initialize when needed');
            }
          }
          
          repoResults.push({ 
            url: repoUrl, 
            accessible: true, 
            name: repoResponse.data.full_name,
            permissions,
            canAccessContents,
            repoEmpty,
            defaultBranch: repoResponse.data.default_branch,
            size: repoResponse.data.size
          });
        } catch (error) {
          console.error(`Repository access error for ${repoUrl}:`, error.response?.data || error.message);
          repoResults.push({ url: repoUrl, accessible: false, error: error.message });
        }
      }
      
      return { valid: true, user: response.data.login, repositories: repoResults };
    } catch (error) {
      console.error('GitHub connection validation failed:', error.message);
      return { valid: false, reason: error.message };
    }
  }

  // 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] };
  }

  // 初始化空仓库
  async initializeRepository(repoIndex = 0) {
    if (this.useMemoryStorage) {
      return { success: false, reason: 'Using memory storage' };
    }

    try {
      const repoUrl = this.repositories[repoIndex];
      const { owner, repo } = this.parseRepoUrl(repoUrl);
      
      console.log(`Initializing empty repository: ${owner}/${repo}`);
      
      // 创建初始README文件
      const readmeContent = Buffer.from(`# PPTist Data Repository

This repository stores PPT data for the PPTist application.

## Structure

\`\`\`
users/
├── PS01/
│   ├── README.md
│   └── *.json (PPT files)
├── PS02/
│   ├── README.md
│   └── *.json (PPT files)
└── ...
\`\`\`

## Auto-generated

This repository is automatically managed by PPTist Huggingface Space.
Do not manually edit files unless you know what you're doing.
`).toString('base64');

      const response = await axios.put(
        `${this.apiUrl}/repos/${owner}/${repo}/contents/README.md`,
        {
          message: 'Initialize repository for PPTist data storage',
          content: readmeContent,
          branch: 'main'
        },
        {
          headers: {
            'Authorization': `token ${this.token}`,
            'Accept': 'application/vnd.github.v3+json'
          }
        }
      );

      console.log(`Repository initialized successfully: ${response.data.commit.sha}`);
      return { success: true, commit: response.data.commit.sha };
    } catch (error) {
      console.error('Repository initialization failed:', error.response?.data || error.message);
      return { success: false, error: error.message };
    }
  }

  // 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}`;

    console.log(`Attempting to save file: ${path} to repo: ${owner}/${repo}`);

    // 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;
        console.log(`Found existing file with SHA: ${sha}`);
      }
    } catch (error) {
      console.log(`No existing file found: ${error.message}`);
    }

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

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

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

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

      console.log(`Successfully saved to GitHub: ${response.data.commit.sha}`);
      return response.data;
    } catch (error) {
      console.error(`GitHub save failed:`, error.response?.data || error.message);
      
      // 特殊处理空仓库的情况
      if (error.response?.status === 409 && error.response?.data?.message?.includes('empty')) {
        console.log('Repository is empty, initializing...');
        const initResult = await this.initializeRepository(repoIndex);
        
        if (initResult.success) {
          console.log('Repository initialized, retrying save...');
          // 等待一会儿让GitHub同步
          await new Promise(resolve => setTimeout(resolve, 2000));
          
          // 继续执行原来的目录创建逻辑
          return this.saveFileWithDirectoryCreation(userId, fileName, data, repoIndex, payload);
        }
      }
      
      // 详细的错误处理
      if (error.response?.status === 404) {
        return this.saveFileWithDirectoryCreation(userId, fileName, data, repoIndex, payload);
      } else if (error.response?.status === 403) {
        throw new Error(`GitHub permission denied. Check if the token has 'repo' permissions: ${error.response.data.message}`);
      } else {
        throw new Error(`GitHub API error (${error.response?.status}): ${error.response?.data?.message || error.message}`);
      }
    }
  }

  // 带目录创建的保存文件方法
  async saveFileWithDirectoryCreation(userId, fileName, data, repoIndex, payload) {
    const repoUrl = this.repositories[repoIndex];
    const { owner, repo } = this.parseRepoUrl(repoUrl);
    const path = `users/${userId}/${fileName}`;
    
    console.log('404 error - attempting to create directory structure...');
    
    try {
      // 方法1: 先检查仓库是否存在和可访问
      const repoCheckResponse = await axios.get(`${this.apiUrl}/repos/${owner}/${repo}`, {
        headers: {
          'Authorization': `token ${this.token}`,
          'Accept': 'application/vnd.github.v3+json'
        }
      });
      console.log(`Repository exists: ${repoCheckResponse.data.full_name}`);
      
      // 方法2: 检查users目录是否存在
      try {
        await axios.get(`${this.apiUrl}/repos/${owner}/${repo}/contents/users`, {
          headers: {
            'Authorization': `token ${this.token}`,
            'Accept': 'application/vnd.github.v3+json'
          }
        });
        console.log('Users directory exists');
      } catch (usersDirError) {
        console.log('Users directory does not exist, creating...');
        
        // 创建users目录的README
        const usersReadmePath = 'users/README.md';
        const usersReadmeContent = Buffer.from('# Users Directory\n\nThis directory contains user-specific PPT files.\n').toString('base64');
        
        await axios.put(
          `${this.apiUrl}/repos/${owner}/${repo}/contents/${usersReadmePath}`,
          {
            message: 'Create users directory',
            content: usersReadmeContent,
            branch: 'main'
          },
          {
            headers: {
              'Authorization': `token ${this.token}`,
              'Accept': 'application/vnd.github.v3+json'
            }
          }
        );
        console.log('Users directory created');
      }
      
      // 方法3: 检查用户目录是否存在
      try {
        await axios.get(`${this.apiUrl}/repos/${owner}/${repo}/contents/users/${userId}`, {
          headers: {
            'Authorization': `token ${this.token}`,
            'Accept': 'application/vnd.github.v3+json'
          }
        });
        console.log(`User directory exists: users/${userId}`);
      } catch (userDirError) {
        console.log(`User directory does not exist, creating: users/${userId}`);
        
        // 创建用户目录的README
        const userReadmePath = `users/${userId}/README.md`;
        const userReadmeContent = Buffer.from(`# PPT Files for User ${userId}\n\nThis directory contains PPT files for user ${userId}.\n`).toString('base64');
        
        await axios.put(
          `${this.apiUrl}/repos/${owner}/${repo}/contents/${userReadmePath}`,
          {
            message: `Create user directory for ${userId}`,
            content: userReadmeContent,
            branch: 'main'
          },
          {
            headers: {
              'Authorization': `token ${this.token}`,
              'Accept': 'application/vnd.github.v3+json'
            }
          }
        );
        console.log(`User directory created: users/${userId}`);
      }
      
      // 等待一小会儿让GitHub同步
      await new Promise(resolve => setTimeout(resolve, 1000));
      
      // 重试保存PPT文件
      console.log('Retrying PPT file save...');
      const retryResponse = await axios.put(
        `${this.apiUrl}/repos/${owner}/${repo}/contents/${path}`,
        payload,
        {
          headers: {
            'Authorization': `token ${this.token}`,
            'Accept': 'application/vnd.github.v3+json'
          }
        }
      );
      
      console.log(`Successfully saved to GitHub after retry: ${retryResponse.data.commit.sha}`);
      return retryResponse.data;
      
    } catch (retryError) {
      console.error(`Comprehensive retry also failed:`, retryError.response?.data || retryError.message);
      
      // 如果GitHub彻底失败，fallback到内存存储
      console.log('GitHub save completely failed, falling back to memory storage...');
      try {
        const memoryResult = await memoryStorageService.saveFile(userId, fileName, data);
        console.log('Successfully saved to memory storage as fallback');
        return {
          ...memoryResult,
          warning: 'Saved to temporary memory storage due to GitHub issues'
        };
      } catch (memoryError) {
        console.error('Memory storage fallback also failed:', memoryError.message);
        throw new Error(`All storage methods failed. GitHub: ${retryError.message}, Memory: ${memoryError.message}`);
      }
    }
  }

  // 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();