/**
 * 支付控制器
 *
 * 功能：处理支付和发票管理的业务逻辑
 */

const { Payment, Invoice } = require('../models/Payment');
const Order = require('../models/Order');
const { validateRequired, validateEmail, validateBatch } = require('../utils/validator');
const { success } = require('../utils/response');
const { BusinessError, ValidationError, AuthorizationError } = require('../middleware/errorHandler');

// ========================================
// 支付相关控制器
// ========================================

/**
 * 获取支付记录列表
 * GET /api/payments
 * 需要管理员权限
 */
const getPayments = async (req, res, next) => {
  try {
    const {
      page = 1,
      pageSize = 10,
      payment_method,
      status,
      start_date,
      end_date
    } = req.query;

    const result = await Payment.findAll({
      page: parseInt(page),
      pageSize: parseInt(pageSize),
      payment_method,
      status,
      start_date,
      end_date
    });

    res.json(success({
      list: result.list,
      pagination: {
        total: result.total,
        page: result.page,
        pageSize: result.pageSize,
        totalPages: Math.ceil(result.total / result.pageSize)
      }
    }, '获取支付记录成功'));
  } catch (err) {
    next(err);
  }
};

/**
 * 获取支付详情
 * GET /api/payments/:id
 */
const getPaymentById = async (req, res, next) => {
  try {
    const { id } = req.params;

    const payment = await Payment.findById(id);
    if (!payment) {
      throw new BusinessError('支付记录不存在', 404);
    }

    // 权限控制：顾客只能查看自己的支付记录
    if (req.user.role === 'customer' && payment.customer_id !== req.user.id) {
      throw new AuthorizationError('您没有权限查看此支付记录');
    }

    res.json(success(payment, '获取支付详情成功'));
  } catch (err) {
    next(err);
  }
};

/**
 * 创建支付（发起支付）
 * POST /api/payments
 */
const createPayment = async (req, res, next) => {
  try {
    const { order_id, payment_method } = req.body;

    // 数据验证
    const validation = validateBatch([
      validateRequired(order_id, '订单ID'),
      validateRequired(payment_method, '支付方式')
    ]);

    if (!validation.valid) {
      throw new ValidationError('数据验证失败', validation.errors);
    }

    // 验证支付方式
    const validMethods = ['cash', 'card', 'wechat', 'alipay'];
    if (!validMethods.includes(payment_method)) {
      throw new ValidationError(`支付方式必须是以下之一: ${validMethods.join(', ')}`);
    }

    // 检查订单是否存在
    const order = await Order.findById(order_id);
    if (!order) {
      throw new BusinessError('订单不存在', 404);
    }

    // 权限控制：只能支付自己的订单
    if (req.user.role === 'customer' && order.customer_id !== req.user.id) {
      throw new AuthorizationError('您没有权限支付此订单');
    }

    // 检查订单状态
    if (['paid', 'cancelled', 'refunded'].includes(order.status)) {
      throw new BusinessError('该订单无法支付');
    }

    // 检查是否已有支付记录
    const existingPayment = await Payment.findByOrderId(order_id);
    if (existingPayment && existingPayment.status === 'paid') {
      throw new BusinessError('该订单已支付');
    }

    // 创建支付记录
    const payment = await Payment.create({
      order_id,
      payment_method,
      amount: order.final_amount
    });

    res.status(201).json(success(payment, '创建支付成功'));
  } catch (err) {
    next(err);
  }
};

/**
 * 确认支付（模拟支付成功）
 * POST /api/payments/:id/confirm
 */
const confirmPayment = async (req, res, next) => {
  try {
    const { id } = req.params;
    const { third_party_transaction_no } = req.body;

    // 检查支付记录是否存在
    const payment = await Payment.findById(id);
    if (!payment) {
      throw new BusinessError('支付记录不存在', 404);
    }

    // 检查支付状态
    if (payment.status === 'paid') {
      throw new BusinessError('该支付已完成');
    }

    if (payment.status === 'refunded') {
      throw new BusinessError('该支付已退款');
    }

    // 处理支付成功（包含积分奖励）
    const updatedPayment = await Payment.handlePaymentSuccess(
      id,
      third_party_transaction_no || null
    );

    res.json(success(updatedPayment, '支付成功'));
  } catch (err) {
    next(err);
  }
};

/**
 * 申请退款
 * POST /api/payments/:id/refund
 */
const requestRefund = async (req, res, next) => {
  try {
    const { id } = req.params;
    const { reason } = req.body;

    // 数据验证
    const validation = validateRequired(reason, '退款原因');
    if (!validation.valid) {
      throw new ValidationError('数据验证失败', validation.errors);
    }

    // 检查支付记录是否存在
    const payment = await Payment.findById(id);
    if (!payment) {
      throw new BusinessError('支付记录不存在', 404);
    }

    // 权限控制：只能退款自己的订单
    if (req.user.role === 'customer' && payment.customer_id !== req.user.id) {
      throw new AuthorizationError('您没有权限申请退款');
    }

    // 检查支付状态
    if (payment.status !== 'paid') {
      throw new BusinessError('只有已支付的订单才能申请退款');
    }

    const updatedPayment = await Payment.requestRefund(id, reason);

    res.json(success(updatedPayment, '退款申请已提交'));
  } catch (err) {
    next(err);
  }
};

/**
 * 完成退款
 * POST /api/payments/:id/complete-refund
 * 需要管理员权限
 */
const completeRefund = async (req, res, next) => {
  try {
    const { id } = req.params;

    // 检查支付记录是否存在
    const payment = await Payment.findById(id);
    if (!payment) {
      throw new BusinessError('支付记录不存在', 404);
    }

    // 检查支付状态
    if (payment.status !== 'refunding') {
      throw new BusinessError('该支付未申请退款');
    }

    const updatedPayment = await Payment.completeRefund(id);

    res.json(success(updatedPayment, '退款完成'));
  } catch (err) {
    next(err);
  }
};

/**
 * 获取支付统计
 * GET /api/payments/statistics
 * 需要管理员权限
 */
const getPaymentStatistics = async (req, res, next) => {
  try {
    const { start_date, end_date } = req.query;

    const stats = await Payment.getStatistics(
      start_date || null,
      end_date || null
    );

    res.json(success(stats, '获取支付统计成功'));
  } catch (err) {
    next(err);
  }
};

// ========================================
// 发票相关控制器
// ========================================

/**
 * 获取发票列表
 * GET /api/payments/invoices
 */
const getInvoices = async (req, res, next) => {
  try {
    const {
      page = 1,
      pageSize = 10,
      status
    } = req.query;

    // 权限控制：顾客只能查看自己的发票
    if (req.user.role === 'customer') {
      const invoices = await Invoice.getUserInvoices(req.user.id);
      return res.json(success({
        count: invoices.length,
        invoices
      }, '获取发票列表成功'));
    }

    // 管理员可以查看所有发票
    const result = await Invoice.findAll({
      page: parseInt(page),
      pageSize: parseInt(pageSize),
      status
    });

    res.json(success({
      list: result.list,
      pagination: {
        total: result.total,
        page: result.page,
        pageSize: result.pageSize,
        totalPages: Math.ceil(result.total / result.pageSize)
      }
    }, '获取发票列表成功'));
  } catch (err) {
    next(err);
  }
};

/**
 * 获取发票详情
 * GET /api/payments/invoices/:id
 */
const getInvoiceById = async (req, res, next) => {
  try {
    const { id } = req.params;

    const invoice = await Invoice.findById(id);
    if (!invoice) {
      throw new BusinessError('发票不存在', 404);
    }

    // 权限控制：需要通过payment查找customer_id
    const payment = await Payment.findById(invoice.payment_id);
    if (req.user.role === 'customer' && payment.customer_id !== req.user.id) {
      throw new AuthorizationError('您没有权限查看此发票');
    }

    res.json(success(invoice, '获取发票详情成功'));
  } catch (err) {
    next(err);
  }
};

/**
 * 申请开票
 * POST /api/payments/invoices
 */
const createInvoice = async (req, res, next) => {
  try {
    const {
      payment_id,
      invoice_type,
      invoice_title,
      tax_no,
      email
    } = req.body;

    // 数据验证
    const validation = validateBatch([
      validateRequired(payment_id, '支付ID'),
      validateRequired(invoice_type, '发票类型'),
      validateRequired(invoice_title, '发票抬头'),
      validateRequired(email, '邮箱'),
      validateEmail(email, '邮箱')
    ]);

    if (!validation.valid) {
      throw new ValidationError('数据验证失败', validation.errors);
    }

    // 验证发票类型
    const validTypes = ['personal', 'company'];
    if (!validTypes.includes(invoice_type)) {
      throw new ValidationError('发票类型必须是 personal 或 company');
    }

    // 企业发票需要税号
    if (invoice_type === 'company' && !tax_no) {
      throw new ValidationError('企业发票需要提供税号');
    }

    // 检查支付记录是否存在
    const payment = await Payment.findById(payment_id);
    if (!payment) {
      throw new BusinessError('支付记录不存在', 404);
    }

    // 权限控制：只能为自己的支付开票
    if (req.user.role === 'customer' && payment.customer_id !== req.user.id) {
      throw new AuthorizationError('您没有权限为此支付开票');
    }

    // 检查支付状态
    if (payment.status !== 'paid') {
      throw new BusinessError('只有已支付的订单才能开具发票');
    }

    // 检查是否已开票
    const existingInvoice = await Invoice.findByPaymentId(payment_id);
    if (existingInvoice) {
      throw new BusinessError('该支付已申请开票');
    }

    const invoice = await Invoice.create({
      payment_id,
      invoice_type,
      invoice_title,
      tax_no: tax_no || null,
      email
    });

    res.status(201).json(success(invoice, '申请开票成功'));
  } catch (err) {
    next(err);
  }
};

/**
 * 更新发票状态（开具发票）
 * PUT /api/payments/invoices/:id/status
 * 需要管理员权限
 */
const updateInvoiceStatus = async (req, res, next) => {
  try {
    const { id } = req.params;
    const { status } = req.body;

    // 数据验证
    const validation = validateRequired(status, '状态');
    if (!validation.valid) {
      throw new ValidationError('数据验证失败', validation.errors);
    }

    // 验证状态值
    const validStatuses = ['pending', 'issued', 'cancelled'];
    if (!validStatuses.includes(status)) {
      throw new ValidationError(`状态必须是以下之一: ${validStatuses.join(', ')}`);
    }

    // 检查发票是否存在
    const invoice = await Invoice.findById(id);
    if (!invoice) {
      throw new BusinessError('发票不存在', 404);
    }

    const updatedInvoice = await Invoice.updateStatus(id, status);

    const messages = {
      pending: '发票已标记为待处理',
      issued: '发票已开具',
      cancelled: '发票已取消'
    };

    res.json(success(updatedInvoice, messages[status]));
  } catch (err) {
    next(err);
  }
};

/**
 * 获取我的发票列表
 * GET /api/payments/my/invoices
 */
const getMyInvoices = async (req, res, next) => {
  try {
    const invoices = await Invoice.getUserInvoices(req.user.id);

    res.json(success({
      count: invoices.length,
      invoices
    }, '获取我的发票成功'));
  } catch (err) {
    next(err);
  }
};

// 导出所有控制器函数
module.exports = {
  // 支付相关
  getPayments,
  getPaymentById,
  createPayment,
  confirmPayment,
  requestRefund,
  completeRefund,
  getPaymentStatistics,

  // 发票相关
  getInvoices,
  getInvoiceById,
  createInvoice,
  updateInvoiceStatus,
  getMyInvoices
};