package repository

import (
	"context"
	"fmt"

	"apskel-pos-be/internal/entities"

	"gorm.io/gorm"
)

type RewardRepository interface {
	Create(ctx context.Context, reward *entities.Reward) error
	GetByID(ctx context.Context, id string) (*entities.Reward, error)
	List(ctx context.Context, req *entities.ListRewardsRequest) ([]entities.Reward, int64, error)
	Update(ctx context.Context, reward *entities.Reward) error
	Delete(ctx context.Context, id string) error
	UpdateStock(ctx context.Context, id string, newStock int) error
	GetByRewardType(ctx context.Context, rewardType entities.RewardType) ([]entities.Reward, error)
}

type rewardRepository struct {
	db *gorm.DB
}

func NewRewardRepository(db *gorm.DB) RewardRepository {
	return &rewardRepository{
		db: db,
	}
}

func (r *rewardRepository) Create(ctx context.Context, reward *entities.Reward) error {
	if err := r.db.WithContext(ctx).Create(reward).Error; err != nil {
		return fmt.Errorf("failed to create reward: %w", err)
	}
	return nil
}

func (r *rewardRepository) GetByID(ctx context.Context, id string) (*entities.Reward, error) {
	var reward entities.Reward
	if err := r.db.WithContext(ctx).Where("id = ?", id).First(&reward).Error; err != nil {
		if err == gorm.ErrRecordNotFound {
			return nil, fmt.Errorf("reward not found")
		}
		return nil, fmt.Errorf("failed to get reward: %w", err)
	}
	return &reward, nil
}

func (r *rewardRepository) List(ctx context.Context, req *entities.ListRewardsRequest) ([]entities.Reward, int64, error) {
	var rewards []entities.Reward
	var total int64

	query := r.db.WithContext(ctx).Model(&entities.Reward{})

	// Apply filters
	if req.Search != "" {
		query = query.Where("name ILIKE ?", "%"+req.Search+"%")
	}

	if req.RewardType != "" {
		query = query.Where("reward_type = ?", req.RewardType)
	}

	if req.MinPoints != nil {
		query = query.Where("cost_points >= ?", *req.MinPoints)
	}

	if req.MaxPoints != nil {
		query = query.Where("cost_points <= ?", *req.MaxPoints)
	}

	if req.HasStock != nil {
		if *req.HasStock {
			query = query.Where("stock > 0 OR stock IS NULL")
		} else {
			query = query.Where("stock <= 0")
		}
	}

	// Count total records
	if err := query.Count(&total).Error; err != nil {
		return nil, 0, fmt.Errorf("failed to count rewards: %w", err)
	}

	// Apply pagination
	if req.Page > 0 && req.Limit > 0 {
		offset := (req.Page - 1) * req.Limit
		query = query.Offset(offset).Limit(req.Limit)
	}

	// Apply sorting
	query = query.Order("created_at DESC")

	if err := query.Find(&rewards).Error; err != nil {
		return nil, 0, fmt.Errorf("failed to list rewards: %w", err)
	}

	return rewards, total, nil
}

func (r *rewardRepository) Update(ctx context.Context, reward *entities.Reward) error {
	if err := r.db.WithContext(ctx).Save(reward).Error; err != nil {
		return fmt.Errorf("failed to update reward: %w", err)
	}
	return nil
}

func (r *rewardRepository) Delete(ctx context.Context, id string) error {
	if err := r.db.WithContext(ctx).Where("id = ?", id).Delete(&entities.Reward{}).Error; err != nil {
		return fmt.Errorf("failed to delete reward: %w", err)
	}
	return nil
}

func (r *rewardRepository) UpdateStock(ctx context.Context, id string, newStock int) error {
	if err := r.db.WithContext(ctx).Model(&entities.Reward{}).Where("id = ?", id).Update("stock", newStock).Error; err != nil {
		return fmt.Errorf("failed to update reward stock: %w", err)
	}
	return nil
}

func (r *rewardRepository) GetByRewardType(ctx context.Context, rewardType entities.RewardType) ([]entities.Reward, error) {
	var rewards []entities.Reward
	if err := r.db.WithContext(ctx).Where("reward_type = ?", rewardType).Find(&rewards).Error; err != nil {
		return nil, fmt.Errorf("failed to get rewards by type: %w", err)
	}
	return rewards, nil
}