const express = require('express');
const router = express.Router();
const Order = require('../models/Order');
const Vehicle = require('../models/Vehicle');
const Customer = require('../models/Customer');

// 获取所有订单
router.get('/', async (req, res) => {
  try {
    const orders = await Order.find()
      .populate('customer', 'name phone')
      .populate('vehicle', 'model vehicleId');
    res.json({ success: true, data: orders });
  } catch (error) {
    res.status(500).json({ success: false, message: error.message });
  }
});

// 获取单个订单
router.get('/:id', async (req, res) => {
  try {
    const order = await Order.findById(req.params.id)
      .populate('customer')
      .populate('vehicle');
    if (!order) {
      return res.status(404).json({ success: false, message: '订单不存在' });
    }
    res.json({ success: true, data: order });
  } catch (error) {
    res.status(500).json({ success: false, message: error.message });
  }
});

// 创建订单（支持门店端新客创建订单）
router.post('/', async (req, res) => {
  try {
    const {
      customerName, customer,       // customerName=新客姓名（字符串），customer=已有客户ID
      vehicleId, vehicle,           // vehicleId=前端字段名，vehicle=后端字段名
      contractMonths, startDate, endDate, rentalFee, deposit, orderType
    } = req.body;

    // 解析车辆 ID（兼容前端 vehicleId 字段名）
    const vehicleObjectId = vehicle || vehicleId;

    // 解析客户：优先用已有客户ID，否则用姓名查找或创建新客户
    let customerObjectId = customer;
    if (!customerObjectId && customerName) {
      // 查找同名客户
      let customerDoc = await Customer.findOne({ name: customerName });
      if (!customerDoc) {
        // 创建新客户（phone 必填，设为默认值）
        customerDoc = await Customer.create({
          name: customerName,
          phone: '00000000000',
          customerId: `CUST${Date.now()}`
        });
      }
      customerObjectId = customerDoc._id;
    }

    // 检查车辆是否存在
    const vehicleDoc = await Vehicle.findById(vehicleObjectId);
    if (!vehicleDoc) {
      return res.status(404).json({ success: false, message: '车辆不存在' });
    }
    if (vehicleDoc.status !== '空闲') {
      return res.status(400).json({ success: false, message: '车辆不可用，当前状态：' + vehicleDoc.status });
    }

    // 日期处理：startDate/endDate 或根据 contractMonths 计算
    const start = startDate ? new Date(startDate) : new Date();
    let end = endDate ? new Date(endDate) : null;
    let months = Number(contractMonths) || 0;

    if (!end && months > 0) {
      end = new Date(start);
      end.setMonth(end.getMonth() + months);
    }

    // 租金计算：使用传入的 rentalFee，若未传则为 0
    let fee = Number(rentalFee) || 0;

    const depositAmt = Number(deposit) || 0;
    const totalAmount = fee + depositAmt;

    // 创建订单
    const order = new Order({
      customer: customerObjectId,
      vehicle: vehicleObjectId,
      startDate: start,
      endDate: end || new Date(start.getTime() + 30 * 24 * 60 * 60 * 1000),
      rentalFee: fee,
      deposit: depositAmt,
      totalAmount,
      status: '进行中'
    });

    await order.save();

    // 更新车辆状态
    vehicleDoc.status = '在租';
    vehicleDoc.isRented = true;
    vehicleDoc.currentOrderId = order._id;
    await vehicleDoc.save();

    // 更新客户统计（如客户已存在）
    if (customerObjectId) {
      const cust = await Customer.findById(customerObjectId);
      if (cust) {
        cust.totalRentals += 1;
        cust.currentRentals = (cust.currentRentals || 0) + 1;
        cust.totalSpent = (cust.totalSpent || 0) + totalAmount;
        await cust.save();
      }
    }

    res.status(201).json({ success: true, data: order });
  } catch (error) {
    res.status(400).json({ success: false, message: error.message });
  }
});

// 更新订单
router.put('/:id', async (req, res) => {
  try {
    const order = await Order.findByIdAndUpdate(
      req.params.id,
      req.body,
      { new: true, runValidators: true }
    );
    if (!order) {
      return res.status(404).json({ success: false, message: '订单不存在' });
    }
    res.json({ success: true, data: order });
  } catch (error) {
    res.status(400).json({ success: false, message: error.message });
  }
});

// 结束订单
router.patch('/:id/complete', async (req, res) => {
  try {
    const order = await Order.findById(req.params.id);
    if (!order) {
      return res.status(404).json({ success: false, message: '订单不存在' });
    }

    order.status = '已完成';
    order.actualEndDate = new Date();
    await order.save();

    // 更新车辆状态
    const vehicle = await Vehicle.findById(order.vehicle);
    if (vehicle) {
      vehicle.status = '空闲';
      vehicle.isRented = false;
      vehicle.currentOrderId = null;
      vehicle.totalRentDays += Math.ceil((new Date(order.endDate) - new Date(order.startDate)) / (1000 * 60 * 60 * 24));
      await vehicle.save();
    }

    // 更新客户信息
    const customer = await Customer.findById(order.customer);
    if (customer) {
      customer.currentRentals -= 1;
      await customer.save();
    }

    res.json({ success: true, data: order });
  } catch (error) {
    res.status(500).json({ success: false, message: error.message });
  }
});

// 取消订单
router.patch('/:id/cancel', async (req, res) => {
  try {
    const order = await Order.findById(req.params.id);
    if (!order) {
      return res.status(404).json({ success: false, message: '订单不存在' });
    }
    if (order.status === '已完成' || order.status === '已取消') {
      return res.status(400).json({ success: false, message: '当前状态无法取消' });
    }

    order.status = '已取消';
    order.actualEndDate = new Date();
    await order.save();

    // 更新车辆状态
    const vehicle = await Vehicle.findById(order.vehicle);
    if (vehicle) {
      vehicle.status = '空闲';
      vehicle.isRented = false;
      vehicle.currentOrderId = null;
      await vehicle.save();
    }

    // 更新客户信息
    const customer = await Customer.findById(order.customer);
    if (customer) {
      customer.currentRentals = Math.max((customer.currentRentals || 0) - 1, 0);
      await customer.save();
    }

    res.json({ success: true, data: order });
  } catch (error) {
    res.status(500).json({ success: false, message: error.message });
  }
});

// 获取逾期订单
router.get('/status/overdue', async (req, res) => {
  try {
    const now = new Date();
    const orders = await Order.find({
      status: '进行中',
      endDate: { $lt: now }
    })
      .populate('customer', 'name phone')
      .populate('vehicle', 'model vehicleId');

    // 更新逾期天数和费用
    for (const order of orders) {
      const overdueDays = Math.ceil((now - order.endDate) / (1000 * 60 * 60 * 24));
      order.overdueDays = overdueDays;
      order.overdueFee = overdueDays * order.rentalFee * 0.1; // 10% 滞纳金
      order.status = '逾期';
      await order.save();
    }

    res.json({ success: true, data: orders });
  } catch (error) {
    res.status(500).json({ success: false, message: error.message });
  }
});

// 按状态筛选订单
router.get('/status/:status', async (req, res) => {
  try {
    const orders = await Order.find({ status: req.params.status })
      .populate('customer', 'name phone')
      .populate('vehicle', 'model vehicleId');
    res.json({ success: true, data: orders });
  } catch (error) {
    res.status(500).json({ success: false, message: error.message });
  }
});

module.exports = router;