const multer = require('multer');
const path = require('path');
const fs = require('fs');

/**
 * Upload Controller - Quản lý upload file
 */
class UploadController {
  constructor() {
    // Danh sách các extension cho từng loại file
    this.imageExtensions = ['.jpg', '.jpeg', '.png', '.gif', '.bmp', '.webp', '.svg', '.ico'];
    this.audioExtensions = ['.mp3', '.wav', '.ogg', '.m4a', '.aac', '.flac', '.wma'];
    this.videoExtensions = ['.mp4', '.avi', '.mov', '.wmv', '.flv', '.mkv', '.webm'];
    
    // Tạo các thư mục nếu chưa tồn tại
    this.ensureDirectories();
    
    // Cấu hình multer storage
    this.storage = multer.diskStorage({
      destination: (req, file, cb) => {
        const fileExt = path.extname(file.originalname).toLowerCase();
        let uploadPath = 'public/files';
        
        if (this.imageExtensions.includes(fileExt)) {
          uploadPath = 'public/images';
        } else if (this.audioExtensions.includes(fileExt) || this.videoExtensions.includes(fileExt)) {
          uploadPath = 'public/media';
        }
        
        cb(null, uploadPath);
      },
      filename: (req, file, cb) => {
        // Tạo tên file unique: timestamp-random-originalname
        const uniqueSuffix = Date.now() + '-' + Math.round(Math.random() * 1E9);
        const ext = path.extname(file.originalname);
        const nameWithoutExt = path.basename(file.originalname, ext);
        const sanitizedName = nameWithoutExt.replace(/[^a-zA-Z0-9]/g, '_');
        cb(null, `${sanitizedName}-${uniqueSuffix}${ext}`);
      }
    });
    
    // Cấu hình multer với giới hạn kích thước
    this.upload = multer({
      storage: this.storage,
      limits: {
        fileSize: 50 * 1024 * 1024, // 50MB max file size
      },
      fileFilter: (req, file, cb) => {
        // Cho phép tất cả các loại file
        cb(null, true);
      }
    });
  }
  
  /**
   * Đảm bảo các thư mục upload tồn tại
   */
  ensureDirectories() {
    const directories = [
      'public/images',
      'public/media',
      'public/files'
    ];
    
    directories.forEach(dir => {
      if (!fs.existsSync(dir)) {
        fs.mkdirSync(dir, { recursive: true });
      }
    });
  }
  
  /**
   * Upload single file
   */
  uploadSingle(req, res, next) {
    const uploadHandler = this.upload.single('file');
    
    uploadHandler(req, res, (err) => {
      if (err instanceof multer.MulterError) {
        return res.status(400).json({
          success: false,
          message: 'Upload error',
          error: err.message,
        });
      } else if (err) {
        return res.status(500).json({
          success: false,
          message: 'Server error during upload',
          error: err.message,
        });
      }
      
      if (!req.file) {
        return res.status(400).json({
          success: false,
          message: 'No file uploaded',
        });
      }
      
      // Xác định loại file
      const fileExt = path.extname(req.file.originalname).toLowerCase();
      let fileType = 'file';
      
      if (this.imageExtensions.includes(fileExt)) {
        fileType = 'image';
      } else if (this.audioExtensions.includes(fileExt)) {
        fileType = 'audio';
      } else if (this.videoExtensions.includes(fileExt)) {
        fileType = 'video';
      }
      
      // Tạo URL truy cập file
      const fileUrl = `/${req.file.path.replace(/\\/g, '/')}`;
      
      res.status(201).json({
        success: true,
        message: 'File uploaded successfully',
        data: {
          filename: req.file.filename,
          originalname: req.file.originalname,
          mimetype: req.file.mimetype,
          size: req.file.size,
          type: fileType,
          path: req.file.path,
          url: fileUrl,
        },
      });
    });
  }
  
  /**
   * Upload multiple files
   */
  uploadMultiple(req, res, next) {
    const uploadHandler = this.upload.array('files', 10); // Max 10 files
    
    uploadHandler(req, res, (err) => {
      if (err instanceof multer.MulterError) {
        return res.status(400).json({
          success: false,
          message: 'Upload error',
          error: err.message,
        });
      } else if (err) {
        return res.status(500).json({
          success: false,
          message: 'Server error during upload',
          error: err.message,
        });
      }
      
      if (!req.files || req.files.length === 0) {
        return res.status(400).json({
          success: false,
          message: 'No files uploaded',
        });
      }
      
      const uploadedFiles = req.files.map(file => {
        const fileExt = path.extname(file.originalname).toLowerCase();
        let fileType = 'file';
        
        if (this.imageExtensions.includes(fileExt)) {
          fileType = 'image';
        } else if (this.audioExtensions.includes(fileExt)) {
          fileType = 'audio';
        } else if (this.videoExtensions.includes(fileExt)) {
          fileType = 'video';
        }
        
        const fileUrl = `/${file.path.replace(/\\/g, '/')}`;
        
        return {
          filename: file.filename,
          originalname: file.originalname,
          mimetype: file.mimetype,
          size: file.size,
          type: fileType,
          path: file.path,
          url: fileUrl,
        };
      });
      
      res.status(201).json({
        success: true,
        message: `${uploadedFiles.length} files uploaded successfully`,
        data: uploadedFiles,
      });
    });
  }
  
  /**
   * Delete file
   */
  async deleteFile(req, res, next) {
    try {
      const { filepath } = req.body;
      
      if (!filepath) {
        return res.status(400).json({
          success: false,
          message: 'Filepath is required',
        });
      }
      
      // Kiểm tra file có tồn tại không
      if (!fs.existsSync(filepath)) {
        return res.status(404).json({
          success: false,
          message: 'File not found',
        });
      }
      
      // Xóa file
      fs.unlinkSync(filepath);
      
      res.json({
        success: true,
        message: 'File deleted successfully',
      });
    } catch (error) {
      next(error);
    }
  }
  
  /**
   * Get file info
   */
  async getFileInfo(req, res, next) {
    try {
      const { filepath } = req.query;
      
      if (!filepath) {
        return res.status(400).json({
          success: false,
          message: 'Filepath is required',
        });
      }
      
      // Kiểm tra file có tồn tại không
      if (!fs.existsSync(filepath)) {
        return res.status(404).json({
          success: false,
          message: 'File not found',
        });
      }
      
      const stats = fs.statSync(filepath);
      const fileExt = path.extname(filepath).toLowerCase();
      let fileType = 'file';
      
      if (this.imageExtensions.includes(fileExt)) {
        fileType = 'image';
      } else if (this.audioExtensions.includes(fileExt)) {
        fileType = 'audio';
      } else if (this.videoExtensions.includes(fileExt)) {
        fileType = 'video';
      }
      
      res.json({
        success: true,
        data: {
          path: filepath,
          size: stats.size,
          type: fileType,
          created: stats.birthtime,
          modified: stats.mtime,
        },
      });
    } catch (error) {
      next(error);
    }
  }
}

module.exports = new UploadController();