const express = require('express');
const QRCode = require('qrcode');
const db = require('../utils/database');
const { authenticateToken, requireAdmin } = require('../middleware/auth');

const router = express.Router();

// 生成序列号
router.post('/generate', authenticateToken, requireAdmin, async (req, res) => {
  try {
    const { companyName, quantity = 1, validDays = 365 } = req.body;

    if (!companyName) {
      return res.status(400).json({ error: '企业名称不能为空' });
    }

    if (quantity < 1 || quantity > 100) {
      return res.status(400).json({ error: '生成数量必须在1-100之间' });
    }

    // 计算有效期
    const validUntil = new Date();
    validUntil.setDate(validUntil.getDate() + validDays);

    // 确保企业存在
    const existingCompany = await db.get('SELECT * FROM companies WHERE company_name = ?', [companyName]);
    if (!existingCompany) {
      await db.run('INSERT INTO companies (company_name, is_active) VALUES (?, 1)', [companyName]);
    }

    // 生成序列号
    const serials = [];
    const prefix = 'BF';
    const datePart = new Date().getFullYear().toString().substr(2);

    // 批量插入序列号
    const insertPromises = [];
    
    for (let i = 0; i < quantity; i++) {
      // 使用随机数生成序列号，避免重复
      const randomPart = Math.floor(Math.random() * 1000000).toString().padStart(6, '0');
      const serialNumber = `${prefix}${datePart}${randomPart}`;
      
      insertPromises.push(
        db.run(
          'INSERT INTO serials (serial_number, company_name, valid_until, created_by) VALUES (?, ?, ?, ?)',
          [serialNumber, companyName, validUntil.toISOString().slice(0, 19).replace('T', ' '), req.user.id]
        )
      );

      serials.push({
        serialNumber,
        companyName,
        validUntil: validUntil.toISOString(),
        createdAt: new Date().toISOString()
      });
    }

    await Promise.all(insertPromises);

    res.json({
      message: `成功生成${quantity}个序列号`,
      serials
    });
  } catch (error) {
    console.error('生成序列号错误:', error);
    res.status(500).json({ error: '服务器内部错误' });
  }
});

// 生成二维码
router.post('/:serialNumber/qrcode', authenticateToken, async (req, res) => {
  try {
    const { serialNumber } = req.params;
    let { baseUrl } = req.body;

    if (!serialNumber) {
      return res.status(400).json({ error: '序列号不能为空' });
    }

    // 验证序列号是否存在
    const serial = await db.get(
      'SELECT s.*, u.name as created_by_name FROM serials s LEFT JOIN users u ON s.created_by = u.id WHERE s.serial_number = ?',
      [serialNumber.toUpperCase()]
    );

    if (!serial) {
      return res.status(404).json({ error: '序列号不存在' });
    }

    if (!serial.is_active) {
      return res.status(400).json({ error: '序列号已被禁用' });
    }

    // 检查是否过期
    if (serial.valid_until && new Date(serial.valid_until) < new Date()) {
      return res.status(400).json({ error: '序列号已过期' });
    }

    // 生成查询URL
    if (!baseUrl) {
      baseUrl = `${req.protocol}://${req.get('host')}/query.html`;
    }
    
    const queryUrl = baseUrl.includes('?') 
      ? `${baseUrl}&serial=${serial.serial_number}`
      : `${baseUrl}?serial=${serial.serial_number}`;

    // 生成二维码
    const qrCodeData = await QRCode.toDataURL(queryUrl, {
      width: 200,
      color: {
        dark: '#165DFF',
        light: '#ffffff'
      }
    });

    res.json({
      message: '二维码生成成功',
      qrCodeData,
      queryUrl,
      serialNumber: serial.serial_number,
      companyName: serial.company_name,
      validUntil: serial.valid_until
    });
  } catch (error) {
    console.error('生成二维码错误:', error);
    res.status(500).json({ error: '服务器内部错误' });
  }
});

// 查询序列号
router.get('/:serialNumber/query', async (req, res) => {
  try {
    const { serialNumber } = req.params;

    if (!serialNumber) {
      return res.status(400).json({ error: '序列号不能为空' });
    }

    // 查询序列号
    const serial = await db.get(
      'SELECT s.*, u.name as created_by_name FROM serials s LEFT JOIN users u ON s.created_by = u.id WHERE s.serial_number = ?',
      [serialNumber.toUpperCase()]
    );

    if (!serial) {
      return res.status(404).json({ error: '序列号不存在' });
    }

    // 检查是否过期
    if (serial.valid_until && new Date(serial.valid_until) < new Date()) {
      return res.status(400).json({ error: '序列号已过期' });
    }

    res.json({
      message: '查询成功',
      serial: {
        serialNumber: serial.serial_number,
        companyName: serial.company_name,
        validUntil: serial.valid_until,
        status: serial.is_active ? 'active' : 'disabled',
        isActive: serial.is_active,
        createdAt: serial.created_at,
        createdBy: serial.created_by_name
      }
    });
  } catch (error) {
    console.error('查询序列号错误:', error);
    res.status(500).json({ error: '服务器内部错误' });
  }
});

// 获取序列号列表
router.get('/', authenticateToken, async (req, res) => {
  try {
    const { page = 1, limit = 20, search = '' } = req.query;
    const offset = (page - 1) * limit;

    let query = `
      SELECT s.*, u.name as created_by_name 
      FROM serials s 
      LEFT JOIN users u ON s.created_by = u.id
    `;
    let countQuery = 'SELECT COUNT(*) as total FROM serials s';
    let params = [];

    if (search) {
      query += ' WHERE s.serial_number LIKE ? OR s.company_name LIKE ?';
      countQuery += ' WHERE s.serial_number LIKE ? OR s.company_name LIKE ?';
      const searchParam = `%${search}%`;
      params.push(searchParam, searchParam);
    }

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

    const [serials, countResult] = await Promise.all([
      db.all(query, params),
      db.get(countQuery, params.slice(0, -2))
    ]);

    const total = countResult ? countResult.total : 0;
    const totalPages = Math.ceil(total / limit);

    res.json({
      message: '获取序列号列表成功',
      data: serials.map(s => ({
        serialNumber: s.serial_number,
        companyName: s.company_name,
        validUntil: s.valid_until,
        isActive: s.is_active,
        createdAt: s.created_at,
        createdBy: s.created_by_name
      })),
      pagination: {
        page: parseInt(page),
        limit: parseInt(limit),
        total,
        totalPages
      }
    });
  } catch (error) {
    console.error('获取序列号列表错误:', error);
    res.status(500).json({ error: '服务器内部错误' });
  }
});

// 更新序列号
router.patch('/:serialNumber', authenticateToken, requireAdmin, async (req, res) => {
  try {
    const { serialNumber } = req.params;
    const { companyName, validUntil, isActive } = req.body;

    if (!serialNumber) {
      return res.status(400).json({ error: '序列号不能为空' });
    }

    // 检查序列号是否存在
    const existingSerial = await db.get('SELECT * FROM serials WHERE serial_number = ?', [serialNumber.toUpperCase()]);

    if (!existingSerial) {
      return res.status(404).json({ error: '序列号不存在' });
    }

    // 构建更新字段
    const updateFields = [];
    const params = [];

    if (companyName !== undefined) {
      updateFields.push('company_name = ?');
      params.push(companyName);
    }

    if (validUntil !== undefined) {
      updateFields.push('valid_until = ?');
      params.push(validUntil);
    }

    if (isActive !== undefined) {
      updateFields.push('is_active = ?');
      params.push(isActive ? 1 : 0);
    }

    if (updateFields.length === 0) {
      return res.status(400).json({ error: '没有提供更新字段' });
    }

    updateFields.push('updated_at = CURRENT_TIMESTAMP');
    params.push(serialNumber.toUpperCase());

    await db.run(
      `UPDATE serials SET ${updateFields.join(', ')} WHERE serial_number = ?`,
      params
    );

    // 获取更新后的序列号信息
    const updatedSerial = await db.get(
      'SELECT s.*, u.name as created_by_name FROM serials s LEFT JOIN users u ON s.created_by = u.id WHERE s.serial_number = ?',
      [serialNumber.toUpperCase()]
    );

    res.json({
      message: '序列号更新成功',
      serial: {
        serialNumber: updatedSerial.serial_number,
        companyName: updatedSerial.company_name,
        validUntil: updatedSerial.valid_until,
        isActive: updatedSerial.is_active,
        createdAt: updatedSerial.created_at,
        updatedAt: updatedSerial.updated_at,
        createdBy: updatedSerial.created_by_name
      }
    });
  } catch (error) {
    console.error('更新序列号错误:', error);
    res.status(500).json({ error: '服务器内部错误' });
  }
});

// 吊销序列号
router.post('/:serialNumber/revoke', authenticateToken, requireAdmin, async (req, res) => {
  try {
    const { serialNumber } = req.params;

    if (!serialNumber) {
      return res.status(400).json({ error: '序列号不能为空' });
    }

    // 检查序列号是否存在
    const existingSerial = await db.get(
      'SELECT * FROM serials WHERE serial_number = ?',
      [serialNumber.toUpperCase()]
    );

    if (!existingSerial) {
      return res.status(404).json({ error: '序列号不存在' });
    }

    // 如果已经吊销，返回提示
    if (!existingSerial.is_active) {
      return res.status(400).json({ error: '序列号已被吊销' });
    }

    // 吊销序列号（将 is_active 设为 0）
    await db.run(
      'UPDATE serials SET is_active = 0, updated_at = CURRENT_TIMESTAMP WHERE serial_number = ?',
      [serialNumber.toUpperCase()]
    );

    res.json({
      message: '序列号已吊销',
      data: {
        serialNumber: serialNumber.toUpperCase()
      }
    });
  } catch (error) {
    console.error('吊销序列号错误:', error);
    res.status(500).json({ error: '服务器内部错误' });
  }
});

// 自定义前缀生成序列号（管理员权限）
router.post('/generate-with-prefix', authenticateToken, requireAdmin, async (req, res) => {
  try {
    const { companyName, quantity = 1, validDays = 365, serialPrefix } = req.body;

    if (!companyName) {
      return res.status(400).json({ error: '企业名称不能为空' });
    }

    if (!serialPrefix || serialPrefix.length > 10) {
      return res.status(400).json({ error: '自定义前缀不能为空且不能超过10个字符' });
    }

    if (quantity < 1 || quantity > 100) {
      return res.status(400).json({ error: '生成数量必须在1-100之间' });
    }

    // 计算有效期
    const validUntil = new Date();
    validUntil.setDate(validUntil.getDate() + validDays);

    // 生成序列号
    const serials = [];
    const prefix = serialPrefix.toUpperCase().replace(/[^A-Z0-9]/g, '');

    if (!prefix) {
      return res.status(400).json({ error: '自定义前缀包含无效字符，只能包含字母和数字' });
    }

    // 批量插入序列号
    const insertPromises = [];
    
    for (let i = 0; i < quantity; i++) {
      // 使用随机数生成序列号，避免重复
      const randomPart = Math.floor(Math.random() * 1000000).toString().padStart(6, '0');
      const serialNumber = `${prefix}${randomPart}`;
      
      insertPromises.push(
        db.run(
          'INSERT INTO serials (serial_number, company_name, valid_until, created_by) VALUES (?, ?, ?, ?)',
          [serialNumber, companyName, validUntil.toISOString(), req.user.id]
        )
      );

      serials.push({
        serialNumber,
        companyName,
        validUntil: validUntil.toISOString(),
        createdAt: new Date().toISOString()
      });
    }

    await Promise.all(insertPromises);

    res.json({
      message: `成功生成${quantity}个序列号`,
      serials
    });
  } catch (error) {
    console.error('生成序列号错误:', error);
    res.status(500).json({ error: '服务器内部错误' });
  }
});

module.exports = router;