const { SubscriptionPlan, UserSubscription, UsersAuth } = require('../models');
const { cacheUtils } = require('../config/redis');
const { v4: uuidv4 } = require('uuid');

/**
 * Subscription Controller - Quản lý gói thẻ tháng
 */
class SubscriptionController {
  /**
   * GET /api/subscriptions/plans - Danh sách các gói subscription
   */
  async getPlans(req, res, next) {
    try {
      const { target_role } = req.query;
      const cacheKey = `subscription:plans:${target_role || 'all'}`;
      
      const cached = await cacheUtils.get(cacheKey);
      if (cached) {
        return res.json({
          success: true,
          data: cached,
          cached: true,
        });
      }
      
      const where = { is_active: true };
      if (target_role) where.target_role = target_role;
      
      const plans = await SubscriptionPlan.findAll({
        where,
        order: [['price', 'ASC']],
      });
      
      await cacheUtils.set(cacheKey, plans, 1800); // Cache 30 min
      
      res.json({
        success: true,
        data: plans,
      });
    } catch (error) {
      next(error);
    }
  }

  /**
   * POST /api/subscriptions/purchase - Mua gói subscription
   */
  async purchaseSubscription(req, res, next) {
    try {
      const { user_id, plan_id, payment_method, transaction_id } = req.body;
      
      if (!user_id || !plan_id || !payment_method || !transaction_id) {
        return res.status(400).json({
          success: false,
          message: 'Missing required fields: user_id, plan_id, payment_method, transaction_id',
        });
      }
      
      // Kiểm tra plan có tồn tại không
      const plan = await SubscriptionPlan.findByPk(plan_id);
      if (!plan || !plan.is_active) {
        return res.status(404).json({
          success: false,
          message: 'Subscription plan not found or inactive',
        });
      }
      
      // Kiểm tra user có subscription đang active không
      const existingSubscription = await UserSubscription.findOne({
        where: {
          user_id,
          status: 'active',
        },
      });
      
      if (existingSubscription) {
        return res.status(400).json({
          success: false,
          message: 'User already has an active subscription',
        });
      }
      
      const start_date = new Date();
      const end_date = new Date(start_date);
      end_date.setDate(end_date.getDate() + plan.duration_days);
      
      const subscriptionData = {
        id: uuidv4(),
        user_id,
        plan_id,
        start_date,
        end_date,
        status: 'active',
        transaction_id,
        payment_method,
        payment_amount: plan.price,
        auto_renew: req.body.auto_renew || false,
      };
      
      const newSubscription = await UserSubscription.create(subscriptionData);
      
      // Clear cache
      await cacheUtils.del(`subscription:user:${user_id}`);
      
      res.status(201).json({
        success: true,
        message: 'Subscription purchased successfully',
        data: newSubscription,
      });
    } catch (error) {
      next(error);
    }
  }

  /**
   * GET /api/subscriptions/user/:user_id - Kiểm tra subscription status của user
   */
  async getUserSubscription(req, res, next) {
    try {
      const { user_id } = req.params;
      const cacheKey = `subscription:user:${user_id}`;
      
      const cached = await cacheUtils.get(cacheKey);
      if (cached) {
        return res.json({
          success: true,
          data: cached,
          cached: true,
        });
      }
      
      const subscription = await UserSubscription.findOne({
        where: { user_id },
        include: [
          {
            model: SubscriptionPlan,
            as: 'plan',
            attributes: ['name', 'price', 'features', 'duration_days'],
          },
        ],
        order: [['created_at', 'DESC']],
      });
      
      if (!subscription) {
        return res.status(404).json({
          success: false,
          message: 'No subscription found for this user',
        });
      }
      
      // Check nếu subscription đã hết hạn
      const now = new Date();
      if (subscription.status === 'active' && new Date(subscription.end_date) < now) {
        await subscription.update({ status: 'expired' });
      }
      
      await cacheUtils.set(cacheKey, subscription, 900); // Cache 15 min
      
      res.json({
        success: true,
        data: subscription,
      });
    } catch (error) {
      next(error);
    }
  }

  /**
   * POST /api/subscriptions/:id/cancel - Hủy subscription
   */
  async cancelSubscription(req, res, next) {
    try {
      const { id } = req.params;
      const { reason } = req.body;
      
      const subscription = await UserSubscription.findByPk(id);
      
      if (!subscription) {
        return res.status(404).json({
          success: false,
          message: 'Subscription not found',
        });
      }
      
      if (subscription.status === 'cancelled') {
        return res.status(400).json({
          success: false,
          message: 'Subscription already cancelled',
        });
      }
      
      // Update subscription
      await subscription.update({
        status: 'cancelled',
        auto_renew: false,
      });
      
      // Clear cache
      await cacheUtils.del(`subscription:user:${subscription.user_id}`);
      
      res.status(200).json({
        success: true,
        message: 'Subscription cancelled successfully',
        data: subscription,
      });
    } catch (error) {
      next(error);
    }
  }

  /**
   * GET /api/subscriptions/stats - Thống kê subscription
   */
  async getSubscriptionStats(req, res, next) {
    try {
      const cacheKey = 'subscription:stats';
      
      const cached = await cacheUtils.get(cacheKey);
      if (cached) {
        return res.json({
          success: true,
          data: cached,
          cached: true,
        });
      }
      
      const stats = await UserSubscription.findAll({
        attributes: [
          'status',
          [require('sequelize').fn('COUNT', require('sequelize').col('id')), 'count'],
        ],
        group: ['status'],
      });
      
      await cacheUtils.set(cacheKey, stats, 300); // Cache 5 min
      
      res.json({
        success: true,
        data: stats,
      });
    } catch (error) {
      next(error);
    }
  }
}

module.exports = new SubscriptionController();