const express = require('express');
const multer = require('multer');
const path = require('path');
const fs = require('fs');
const dbConnector = require('../utils/dbConnector');
const { asyncHandler } = require('../middlewares/errorHandler');

const router = express.Router();

// 配置multer用于文件上传
const storage = multer.diskStorage({
  destination: (req, file, cb) => {
    const uploadType = req.body.type || 'common';
    const uploadDir = path.join(__dirname, `../uploads/${uploadType}`);
    
    // 确保上传目录存在
    if (!fs.existsSync(uploadDir)) {
      fs.mkdirSync(uploadDir, { recursive: true });
    }
    
    cb(null, uploadDir);
  },
  filename: (req, file, cb) => {
    const uploadType = req.body.type || 'common';
    const uniqueSuffix = Date.now() + '-' + Math.round(Math.random() * 1E9);
    const ext = path.extname(file.originalname);
    const filename = `${uploadType}_${uniqueSuffix}${ext}`;
    cb(null, filename);
  }
});

const upload = multer({
  storage: storage,
  limits: {
    fileSize: 10 * 1024 * 1024, // 10MB限制
  },
  fileFilter: (req, file, cb) => {
    // 允许所有文件类型
    cb(null, true);
  }
});

/**
 * 文件上传接口
 * POST /api/v1/upload
 */
router.post('/', upload.single('file'), asyncHandler(async (req, res) => {
  if (!req.file) {
    return res.status(400).json({
      code: 400,
      message: '请选择要上传的文件'
    });
  }

  const uploadType = req.body.type || 'common';
  const userId = req.user?.id;
  
  // 构建文件访问URL
  const fileUrl = `/uploads/${uploadType}/${req.file.filename}`;
  
  // 保存文件记录到数据库（可选）
  if (userId) {
    try {
      await dbConnector.query(
        `INSERT INTO uploads 
         (user_id, filename, original_name, file_type, file_size, file_url, upload_type, created_at) 
         VALUES (?, ?, ?, ?, ?, ?, ?, NOW())`,
        [
          userId,
          req.file.filename,
          req.file.originalname,
          req.file.mimetype,
          req.file.size,
          fileUrl,
          uploadType
        ]
      );
    } catch (error) {
      console.warn('保存文件记录失败:', error);
      // 不中断上传流程，仅记录警告
    }
  }

  res.json({
    code: 200,
    message: '上传成功',
    data: {
      url: fileUrl,
      filename: req.file.filename,
      original_name: req.file.originalname,
      size: req.file.size,
      mime_type: req.file.mimetype,
      upload_type: uploadType
    }
  });
}));

/**
 * 获取上传文件列表
 * GET /api/v1/upload
 */
router.get('/', asyncHandler(async (req, res) => {
  const userId = req.user.id;
  const { page = 1, limit = 10, type } = req.query;
  const offset = (page - 1) * limit;

  let query = 'SELECT * FROM uploads WHERE user_id = ?';
  let queryParams = [userId];

  if (type) {
    query += ' AND upload_type = ?';
    queryParams.push(type);
  }

  query += ' ORDER BY created_at DESC LIMIT ? OFFSET ?';
  queryParams.push(parseInt(limit), parseInt(offset));

  const files = await dbConnector.query(query, queryParams);
  
  const countResult = await dbConnector.query(
    'SELECT COUNT(*) as count FROM uploads WHERE user_id = ?' + (type ? ' AND upload_type = ?' : ''),
    type ? [userId, type] : [userId]
  );
  
  const total = countResult[0].count;

  res.json({
    code: 200,
    message: '获取成功',
    data: {
      files: files,
      pagination: {
        page: parseInt(page),
        limit: parseInt(limit),
        total: total,
        pages: Math.ceil(total / limit)
      }
    }
  });
}));

/**
 * 删除上传文件
 * DELETE /api/v1/upload/:id
 */
router.delete('/:id', asyncHandler(async (req, res) => {
  const { id } = req.params;
  const userId = req.user.id;

  // 查询文件信息
  const file = await dbConnector.query(
    'SELECT * FROM uploads WHERE id = ? AND user_id = ?',
    [id, userId]
  );

  if (file.length === 0) {
    return res.status(404).json({
      code: 404,
      message: '文件不存在'
    });
  }

  // 删除物理文件
  const filePath = path.join(__dirname, `../${file[0].file_url}`);
  if (fs.existsSync(filePath)) {
    fs.unlinkSync(filePath);
  }

  // 删除数据库记录
  await dbConnector.query(
    'DELETE FROM uploads WHERE id = ? AND user_id = ?',
    [id, userId]
  );

  res.json({
    code: 200,
    message: '删除成功'
  });
}));

module.exports = router;