package repository

import (
	"errors"
	"fmt"

	"gorm.io/gorm"

	"wx_service/internal/marketing/model"
)

var ErrDownloadNotFound = errors.New("marketing download not found")

type DownloadRepository struct {
	db *gorm.DB
}

func NewDownloadRepository(db *gorm.DB) *DownloadRepository {
	return &DownloadRepository{db: db}
}

func (r *DownloadRepository) Create(dl *model.MarketingDownload) error {
	if err := r.db.Create(dl).Error; err != nil {
		return fmt.Errorf("create marketing download: %w", err)
	}
	return nil
}

func (r *DownloadRepository) FindByID(id uint) (*model.MarketingDownload, error) {
	var dl model.MarketingDownload
	err := r.db.First(&dl, id).Error
	if err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return nil, ErrDownloadNotFound
		}
		return nil, fmt.Errorf("find marketing download: %w", err)
	}
	return &dl, nil
}

func (r *DownloadRepository) MarkAdCompleted(id uint) error {
	tx := r.db.Model(&model.MarketingDownload{}).Where("id = ?", id).Update("ad_completed", true)
	if tx.Error != nil {
		return fmt.Errorf("mark ad completed: %w", tx.Error)
	}
	if tx.RowsAffected == 0 {
		return ErrDownloadNotFound
	}
	return nil
}

func (r *DownloadRepository) FindByUser(userID uint, page, pageSize int) ([]model.MarketingDownload, int64, error) {
	if page <= 0 {
		page = 1
	}
	if pageSize <= 0 {
		pageSize = 20
	}
	if pageSize > 100 {
		pageSize = 100
	}

	query := r.db.Model(&model.MarketingDownload{}).Where("user_id = ?", userID)

	var total int64
	if err := query.Count(&total).Error; err != nil {
		return nil, 0, fmt.Errorf("count marketing downloads: %w", err)
	}

	var downloads []model.MarketingDownload
	offset := (page - 1) * pageSize
	if err := query.Preload("Template").Order("id DESC").Offset(offset).Limit(pageSize).Find(&downloads).Error; err != nil {
		return nil, 0, fmt.Errorf("list marketing downloads: %w", err)
	}

	return downloads, total, nil
}

type DownloadStats struct {
	TotalDownloads int64
	TodayDownloads int64
}

func (r *DownloadRepository) GetStats() (*DownloadStats, error) {
	var total int64
	if err := r.db.Model(&model.MarketingDownload{}).Count(&total).Error; err != nil {
		return nil, fmt.Errorf("count total downloads: %w", err)
	}

	var today int64
	if err := r.db.Model(&model.MarketingDownload{}).
		Where("DATE(created_at) = CURDATE()").
		Count(&today).Error; err != nil {
		return nil, fmt.Errorf("count today downloads: %w", err)
	}

	return &DownloadStats{TotalDownloads: total, TodayDownloads: today}, nil
}