const couchdbService = require("../services/couchdbService");

class Reward {
  static async create(rewardData) {
    const reward = {
      _id: `reward_${Date.now()}_${Math.random().toString(36).substr(2, 9)}`,
      type: "reward",
      name: rewardData.name,
      description: rewardData.description,
      cost: rewardData.cost,
      isPremium: rewardData.isPremium || false,
      isActive: rewardData.isActive !== undefined ? rewardData.isActive : true,
      createdAt: new Date().toISOString(),
      updatedAt: new Date().toISOString()
    };

    return await couchdbService.create(reward);
  }

  static async findById(rewardId) {
    return await couchdbService.getById(rewardId);
  }

  static async find(query = {}, options = {}) {
    const defaultQuery = {
      type: "reward",
      ...query
    };

    return await couchdbService.find({
      selector: defaultQuery,
      ...options
    });
  }

  static async findOne(query) {
    const rewards = await this.find(query, { limit: 1 });
    return rewards[0] || null;
  }

  static async update(rewardId, updateData) {
    const reward = await this.findById(rewardId);
    if (!reward) {
      throw new Error("Reward not found");
    }

    const updatedReward = {
      ...reward,
      ...updateData,
      updatedAt: new Date().toISOString()
    };

    return await couchdbService.update(rewardId, updatedReward);
  }

  static async delete(rewardId) {
    return await couchdbService.delete(rewardId);
  }

  static async findByCostRange(minCost, maxCost) {
    return await couchdbService.find({
      selector: {
        type: "reward",
        cost: { $gte: minCost, $lte: maxCost }
      },
      sort: [{ cost: "asc" }]
    });
  }

  static async findByPremiumStatus(isPremium) {
    return await this.find({ isPremium });
  }

  static async getActiveRewards() {
    return await this.find({ isActive: true });
  }

  static async getPremiumRewards() {
    return await this.find({ isPremium: true, isActive: true });
  }

  static async getRegularRewards() {
    return await this.find({ isPremium: false, isActive: true });
  }

  static async getAllPaginated(page = 1, limit = 10) {
    const skip = (page - 1) * limit;
    
    const rewards = await couchdbService.find({
      selector: { type: "reward" },
      sort: [{ cost: "asc" }],
      skip,
      limit
    });

    // Get total count
    const totalCount = await couchdbService.find({
      selector: { type: "reward" },
      fields: ["_id"]
    });

    return {
      rewards,
      pagination: {
        page,
        limit,
        totalCount: totalCount.length,
        totalPages: Math.ceil(totalCount.length / limit)
      }
    };
  }

  static async redeemReward(userId, rewardId) {
    const reward = await this.findById(rewardId);
    if (!reward) {
      throw new Error("Reward not found");
    }

    if (!reward.isActive) {
      throw new Error("Reward is not available");
    }

    const user = await couchdbService.findUserById(userId);
    if (!user) {
      throw new Error("User not found");
    }

    if (user.points < reward.cost) {
      throw new Error("Not enough points");
    }

    if (reward.isPremium && !user.isPremium) {
      throw new Error("Premium reward not available");
    }

    // Deduct points using couchdbService method
    const updatedUser = await couchdbService.updateUserPoints(
      userId,
      -reward.cost,
      `Redeemed reward: ${reward.name}`,
      {
        entityType: 'Reward',
        entityId: rewardId,
        entityName: reward.name
      }
    );

    // Create redemption record
    const redemption = {
      _id: `redemption_${Date.now()}_${Math.random().toString(36).substr(2, 9)}`,
      type: "reward_redemption",
      user: {
        userId: userId,
        name: user.name
      },
      reward: {
        rewardId: rewardId,
        name: reward.name,
        description: reward.description,
        cost: reward.cost
      },
      pointsDeducted: reward.cost,
      balanceAfter: updatedUser.points,
      redeemedAt: new Date().toISOString()
    };

    await couchdbService.create(redemption);

    return {
      redemption,
      pointsDeducted: reward.cost,
      newBalance: updatedUser.points
    };
  }

  static async getUserRedemptions(userId, limit = 20) {
    return await couchdbService.find({
      selector: {
        type: "reward_redemption",
        "user.userId": userId
      },
      sort: [{ redeemedAt: "desc" }],
      limit
    });
  }

  static async getRewardStats(rewardId) {
    const redemptions = await couchdbService.find({
      selector: {
        type: "reward_redemption",
        "reward.rewardId": rewardId
      }
    });

    return {
      totalRedemptions: redemptions.length,
      totalPointsSpent: redemptions.reduce((sum, r) => sum + r.pointsDeducted, 0),
      lastRedeemed: redemptions.length > 0 ? redemptions[0].redeemedAt : null
    };
  }

  static async getCatalogStats() {
    const rewards = await this.getActiveRewards();
    const premium = await this.getPremiumRewards();
    const regular = await this.getRegularRewards();

    return {
      totalRewards: rewards.length,
      premiumRewards: premium.length,
      regularRewards: regular.length,
      averageCost: rewards.reduce((sum, r) => sum + r.cost, 0) / rewards.length || 0,
      minCost: Math.min(...rewards.map(r => r.cost)),
      maxCost: Math.max(...rewards.map(r => r.cost))
    };
  }

  static async searchRewards(searchTerm, options = {}) {
    const query = {
      selector: {
        type: "reward",
        isActive: true,
        $or: [
          { name: { $regex: searchTerm, $options: "i" } },
          { description: { $regex: searchTerm, $options: "i" } }
        ]
      },
      ...options
    };

    return await couchdbService.find(query);
  }

  // Migration helper
  static async migrateFromMongo(mongoReward) {
    const rewardData = {
      name: mongoReward.name,
      description: mongoReward.description,
      cost: mongoReward.cost,
      isPremium: mongoReward.isPremium || false,
      isActive: true
    };

    return await this.create(rewardData);
  }

  // Bulk operations for admin
  static async bulkCreate(rewardsData) {
    const rewards = rewardsData.map(data => ({
      _id: `reward_${Date.now()}_${Math.random().toString(36).substr(2, 9)}`,
      type: "reward",
      name: data.name,
      description: data.description,
      cost: data.cost,
      isPremium: data.isPremium || false,
      isActive: data.isActive !== undefined ? data.isActive : true,
      createdAt: new Date().toISOString(),
      updatedAt: new Date().toISOString()
    }));

    return await couchdbService.bulkDocs(rewards);
  }

  static async toggleActiveStatus(rewardId) {
    const reward = await this.findById(rewardId);
    if (!reward) {
      throw new Error("Reward not found");
    }

    return await this.update(rewardId, { isActive: !reward.isActive });
  }
}

module.exports = Reward;