package service

import (
	"FileRelay/internal/bootstrap"
	"FileRelay/internal/model"
	"FileRelay/internal/storage"
	"context"
	"errors"
	"time"

	"gorm.io/gorm"
)

type BatchService struct {
	db *gorm.DB
}

func NewBatchService() *BatchService {
	return &BatchService{db: bootstrap.DB}
}

func (s *BatchService) GetBatchByPickupCode(code string) (*model.FileBatch, error) {
	var batch model.FileBatch
	err := s.db.Preload("FileItems").Where("pickup_code = ? AND status = ?", code, "active").First(&batch).Error
	if err != nil {
		return nil, err
	}

	// 检查是否过期
	if s.IsExpired(&batch) {
		s.MarkAsExpired(&batch)
		return nil, errors.New("batch expired")
	}

	return &batch, nil
}

func (s *BatchService) IsExpired(batch *model.FileBatch) bool {
	if batch.Status != "active" {
		return true
	}

	switch batch.ExpireType {
	case "time":
		if batch.ExpireAt != nil && time.Now().After(*batch.ExpireAt) {
			return true
		}
	case "download":
		if batch.MaxDownloads > 0 && batch.DownloadCount >= batch.MaxDownloads {
			return true
		}
	}
	return false
}

func (s *BatchService) MarkAsExpired(batch *model.FileBatch) error {
	return s.db.Model(batch).Update("status", "expired").Error
}

func (s *BatchService) DeleteBatch(ctx context.Context, batchID uint) error {
	var batch model.FileBatch
	if err := s.db.Preload("FileItems").First(&batch, batchID).Error; err != nil {
		return err
	}

	// 删除物理文件
	for _, item := range batch.FileItems {
		_ = storage.GlobalStorage.Delete(ctx, item.StoragePath)
	}

	// 删除数据库记录 (软删除 Batch)
	return s.db.Transaction(func(tx *gorm.DB) error {
		if err := tx.Where("batch_id = ?", batch.ID).Delete(&model.FileItem{}).Error; err != nil {
			return err
		}
		if err := tx.Delete(&batch).Error; err != nil {
			return err
		}
		return nil
	})
}

func (s *BatchService) IncrementDownloadCount(batchID uint) error {
	return s.db.Model(&model.FileBatch{}).Where("id = ?", batchID).
		UpdateColumn("download_count", gorm.Expr("download_count + ?", 1)).Error
}