const express = require('express');
const multer = require('multer');
const path = require('path');
const fs = require('fs');
const { auth } = require('../middleware/auth');
const { authenticateToken } = require('./auth');

const router = express.Router();

// 确保上传目录存在
const uploadDir = path.join(__dirname, '../uploads');
const documentsDir = path.join(uploadDir, 'documents');
const avatarsDir = path.join(uploadDir, 'avatars');
const productsDir = path.join(uploadDir, 'products');

[uploadDir, documentsDir, avatarsDir, productsDir].forEach(dir => {
  if (!fs.existsSync(dir)) {
    fs.mkdirSync(dir, { recursive: true });
  }
});

// 配置multer存储
const storage = multer.diskStorage({
  destination: (req, file, cb) => {
    const type = req.body.type || 'documents';
    let uploadPath;
    
    switch (type) {
      case 'avatar':
        uploadPath = avatarsDir;
        break;
      case 'product':
        uploadPath = productsDir;
        break;
      case 'document':
      default:
        uploadPath = documentsDir;
        break;
    }
    
    cb(null, uploadPath);
  },
  filename: (req, file, cb) => {
    // 生成唯一文件名：时间戳 + 随机数 + 原始扩展名
    const timestamp = Date.now();
    const random = Math.round(Math.random() * 1E9);
    const ext = path.extname(file.originalname);
    const filename = `${timestamp}_${random}${ext}`;
    cb(null, filename);
  }
});

// 文件过滤器
const fileFilter = (req, file, cb) => {
  // 只允许图片文件
  if (file.mimetype.startsWith('image/')) {
    cb(null, true);
  } else {
    cb(new Error('只能上传图片文件'), false);
  }
};

const upload = multer({
  storage: storage,
  fileFilter: fileFilter,
  limits: {
    fileSize: 5 * 1024 * 1024, // 5MB
    files: 1 // 一次只能上传一个文件
  }
});

/**
 * @route POST /api/upload/image
 * @desc 上传图片
 * @access Private
 */
router.post('/image', authenticateToken, (req, res) => {
  upload.single('file')(req, res, (err) => {
    if (err instanceof multer.MulterError) {
      if (err.code === 'LIMIT_FILE_SIZE') {
        return res.status(400).json({
          success: false,
          message: '文件大小不能超过 5MB'
        });
      }
      if (err.code === 'LIMIT_FILE_COUNT') {
        return res.status(400).json({
          success: false,
          message: '一次只能上传一个文件'
        });
      }
      return res.status(400).json({
        success: false,
        message: '文件上传失败：' + err.message
      });
    } else if (err) {
      return res.status(400).json({
        success: false,
        message: err.message
      });
    }
    
    if (!req.file) {
      return res.status(400).json({
        success: false,
        message: '请选择要上传的文件'
      });
    }
    
    // 构建文件访问路径
    const type = req.body.type || 'documents';
    // 确保路径与实际目录结构一致
    let folderName = type;
    if (type === 'product') {
      folderName = 'products'; // 目录是复数形式
    } else if (type === 'avatar') {
      folderName = 'avatars'; // 目录是复数形式
    }
    const relativePath = path.join(folderName, req.file.filename).replace(/\\/g, '/');
    const fileUrl = `/uploads/${relativePath}`;
    
    res.json({
      success: true,
      message: '文件上传成功',
      data: {
        filename: req.file.filename,
        originalname: req.file.originalname,
        mimetype: req.file.mimetype,
        size: req.file.size,
        path: relativePath,
        url: fileUrl
      }
    });
  });
});

// 保持原有的上传接口兼容性
router.post('/', auth, upload.single('file'), (req, res) => {
  try {
    if (!req.file) {
      return res.status(400).json({ success: false, message: '没有上传文件' });
    }

    // 返回文件访问URL
    const type = req.body.type || 'documents';
    // 确保路径与实际目录结构一致
    let folderName = type;
    if (type === 'product') {
      folderName = 'products'; // 目录是复数形式
    } else if (type === 'avatar') {
      folderName = 'avatars'; // 目录是复数形式
    }
    const relativePath = path.join(folderName, req.file.filename).replace(/\\/g, '/');
    const fileUrl = `/uploads/${relativePath}`;
    
    res.json({
      success: true,
      message: '文件上传成功',
      url: fileUrl,
      filename: req.file.filename,
      originalname: req.file.originalname,
      size: req.file.size
    });
  } catch (error) {
    console.error('文件上传错误:', error);
    res.status(500).json({ success: false, message: '文件上传失败' });
  }
});

// 错误处理中间件
router.use((error, req, res, next) => {
  if (error instanceof multer.MulterError) {
    if (error.code === 'LIMIT_FILE_SIZE') {
      return res.status(400).json({ success: false, message: '文件大小不能超过5MB' });
    }
  }
  
  if (error.message === '只能上传图片文件') {
    return res.status(400).json({ success: false, message: error.message });
  }
  
  res.status(500).json({ success: false, message: '上传失败' });
});

module.exports = router;