/**
 * 计费服务 - 处理租户到期检查、超额计算等
 */

const { Tenant, SubscriptionPlan, Order, PricingConfig } = require('../models');
const { Op } = require('sequelize');
const { logOperation } = require('../utils/logger');

/**
 * 检查并更新租户到期状态
 * 每天执行一次
 */
const checkTenantExpiration = async () => {
  try {
    const now = new Date();
    console.log(`[${now.toISOString()}] 开始检查租户到期状态...`);

    // 1. 检查试用期到期的租户
    const trialExpiredTenants = await Tenant.findAll({
      where: {
        billingStatus: 'trial_active',
        trialEndDate: {
          [Op.lt]: now
        }
      }
    });

    for (const tenant of trialExpiredTenants) {
      await tenant.update({ billingStatus: 'trial_expired' });
      console.log(`租户 ${tenant.name} (ID: ${tenant.id}) 试用期已过期`);
      
      // 记录日志
      await logOperation({
        tenantId: tenant.id,
        module: '计费管理',
        action: '试用期到期',
        description: `租户 ${tenant.name} 试用期已过期`,
        status: 'success'
      });
    }

    // 2. 检查付费期到期的租户
    const paidExpiredTenants = await Tenant.findAll({
      where: {
        billingStatus: 'paid_active',
        paidEndDate: {
          [Op.lt]: now
        }
      }
    });

    for (const tenant of paidExpiredTenants) {
      await tenant.update({ billingStatus: 'paid_expired' });
      console.log(`租户 ${tenant.name} (ID: ${tenant.id}) 付费期已过期`);
      
      // 记录日志
      await logOperation({
        tenantId: tenant.id,
        module: '计费管理',
        action: '付费期到期',
        description: `租户 ${tenant.name} 付费期已过期`,
        status: 'success'
      });
    }

    // 3. 检查数据保留期超过90天的租户（可选：发送提醒或清理）
    const retentionLimit = new Date(now.getTime() - 90 * 24 * 60 * 60 * 1000);
    const longExpiredTenants = await Tenant.findAll({
      where: {
        billingStatus: {
          [Op.in]: ['trial_expired', 'paid_expired']
        },
        updateTime: {
          [Op.lt]: retentionLimit
        }
      }
    });

    if (longExpiredTenants.length > 0) {
      console.log(`发现 ${longExpiredTenants.length} 个租户超过90天数据保留期`);
      // 这里可以添加数据清理逻辑或发送提醒
    }

    console.log(`[${new Date().toISOString()}] 租户到期检查完成`);
    console.log(`- 试用期过期: ${trialExpiredTenants.length} 个`);
    console.log(`- 付费期过期: ${paidExpiredTenants.length} 个`);
    
    return {
      trialExpired: trialExpiredTenants.length,
      paidExpired: paidExpiredTenants.length,
      longExpired: longExpiredTenants.length
    };
  } catch (error) {
    console.error('检查租户到期状态失败:', error);
    throw error;
  }
};

/**
 * 获取即将到期的租户（用于提醒）
 * @param {number} days - 提前多少天提醒
 */
const getUpcomingExpiredTenants = async (days = 7) => {
  try {
    const reminderDate = new Date();
    reminderDate.setDate(reminderDate.getDate() + days);

    const upcomingTenants = await Tenant.findAll({
      where: {
        [Op.or]: [
          {
            billingStatus: 'trial_active',
            trialEndDate: {
              [Op.lte]: reminderDate,
              [Op.gte]: new Date()
            }
          },
          {
            billingStatus: 'paid_active',
            paidEndDate: {
              [Op.lte]: reminderDate,
              [Op.gte]: new Date()
            }
          }
        ]
      },
      include: [{
        model: SubscriptionPlan,
        as: 'subscriptionPlan'
      }]
    });

    return upcomingTenants;
  } catch (error) {
    console.error('获取即将到期租户失败:', error);
    throw error;
  }
};

/**
 * 计算租户的超额使用量
 * @param {number} tenantId - 租户ID
 */
const calculateOverage = async (tenantId) => {
  try {
    const tenant = await Tenant.findByPk(tenantId, {
      include: [{
        model: SubscriptionPlan,
        as: 'subscriptionPlan'
      }]
    });

    if (!tenant || !tenant.subscriptionPlan) {
      throw new Error('租户或套餐不存在');
    }

    const plan = tenant.subscriptionPlan;
    
    // 获取当前使用量
    const { Apartment, Room, User } = require('../models');
    
    const [apartmentCount, roomCount, userCount] = await Promise.all([
      Apartment.count({ where: { tenantId, isDeleted: 0 } }),
      Room.count({ where: { tenantId, isDeleted: 0 } }),
      User.count({ where: { tenantId, isDeleted: 0 } })
    ]);

    // 计算超额
    const overageApartments = Math.max(0, apartmentCount - plan.maxApartments);
    const overageRooms = Math.max(0, roomCount - plan.maxRooms);
    const overageUsers = Math.max(0, userCount - plan.maxUsers);

    return {
      usage: {
        apartments: apartmentCount,
        rooms: roomCount,
        users: userCount
      },
      limits: {
        apartments: plan.maxApartments,
        rooms: plan.maxRooms,
        users: plan.maxUsers
      },
      overage: {
        apartments: overageApartments,
        rooms: overageRooms,
        users: overageUsers
      }
    };
  } catch (error) {
    console.error('计算超额使用量失败:', error);
    throw error;
  }
};

/**
 * 计算续费订单金额
 * @param {number} tenantId - 租户ID
 * @param {number} planId - 套餐ID
 * @param {number} months - 购买月数
 */
const calculateRenewalAmount = async (tenantId, planId, months) => {
  try {
    // 获取套餐信息
    const plan = await SubscriptionPlan.findByPk(planId);
    if (!plan) {
      throw new Error('套餐不存在');
    }

    // 获取当前价格配置
    const pricingConfig = await PricingConfig.findOne({
      where: { isActive: true },
      order: [['effectiveDate', 'DESC']]
    });

    if (!pricingConfig) {
      throw new Error('价格配置不存在');
    }

    // 计算超额使用费
    const overage = await calculateOverage(tenantId);
    
    // 基础费用 = 套餐月费 × 月数
    const baseAmount = plan.monthlyPrice * months;
    
    // 超额费用 = (超额公寓×单价 + 超额房间×单价 + 超额用户×单价) × 月数
    const overageAmount = (
      overage.overage.apartments * pricingConfig.overageApartmentPrice +
      overage.overage.rooms * pricingConfig.overageRoomPrice +
      overage.overage.users * pricingConfig.overageUserPrice
    ) * months;

    const totalAmount = baseAmount + overageAmount;

    return {
      baseAmount: parseFloat(baseAmount.toFixed(2)),
      overageAmount: parseFloat(overageAmount.toFixed(2)),
      totalAmount: parseFloat(totalAmount.toFixed(2)),
      details: {
        planName: plan.name,
        monthlyPrice: plan.monthlyPrice,
        months,
        overage
      }
    };
  } catch (error) {
    console.error('计算续费金额失败:', error);
    throw error;
  }
};

/**
 * 处理支付成功后的租户状态更新
 * @param {number} tenantId - 租户ID
 * @param {number} months - 续费月数
 * @param {number} planId - 套餐ID（可选，用于更新资源配置）
 */
const processPaymentSuccess = async (tenantId, months, planId = null) => {
  try {
    const tenant = await Tenant.findByPk(tenantId);
    if (!tenant) {
      throw new Error('租户不存在');
    }

    const now = new Date();
    let paidStartDate, paidEndDate, billingStatus;

    // 如果当前是付费期，则延长
    if (tenant.billingStatus === 'paid_active' && tenant.paidEndDate && tenant.paidEndDate > now) {
      paidStartDate = tenant.paidStartDate;
      paidEndDate = new Date(tenant.paidEndDate.getTime() + months * 30 * 24 * 60 * 60 * 1000);
      billingStatus = 'paid_active';
    } else {
      // 新付费期或从过期状态恢复
      paidStartDate = now;
      paidEndDate = new Date(now.getTime() + months * 30 * 24 * 60 * 60 * 1000);
      billingStatus = 'paid_active';
    }

    // 构建更新数据
    const updateData = {
      billingStatus,
      paidStartDate,
      paidEndDate,
      currentPeriodStart: paidStartDate,
      currentPeriodEnd: paidEndDate
    };

    // 如果有套餐ID，更新租户套餐和资源配置
    if (planId) {
      const plan = await SubscriptionPlan.findByPk(planId);
      if (plan) {
        updateData.planId = planId;
        updateData.maxApartments = plan.maxApartments;
        updateData.maxRooms = plan.maxRooms;
        updateData.maxUsers = plan.maxUsers;
      }
    }

    await tenant.update(updateData);

    console.log(`租户 ${tenant.name} (ID: ${tenantId}) 续费成功，有效期至 ${paidEndDate.toISOString()}`);

    // 记录日志
    await logOperation({
      tenantId: tenant.id,
      module: '计费管理',
      action: '续费成功',
      description: `租户续费 ${months} 个月，有效期至 ${paidEndDate.toLocaleDateString()}`,
      status: 'success'
    });

    return {
      billingStatus,
      paidStartDate,
      paidEndDate
    };
  } catch (error) {
    console.error('处理支付成功失败:', error);
    throw error;
  }
};

module.exports = {
  checkTenantExpiration,
  getUpcomingExpiredTenants,
  calculateOverage,
  calculateRenewalAmount,
  processPaymentSuccess
};