package radio

import (
	"errors"

	"sundynix-go/global"
	"sundynix-go/model/radio"
	radioReq "sundynix-go/model/radio/request"

	"gorm.io/gorm"
)

type ChannelService struct{}

// GetChannelList 获取频道列表
func (s *ChannelService) GetChannelList(userId string, info radioReq.GetChannelList) ([]radio.RadioChannel, int64, error) {
	db := global.DB.Model(&radio.RadioChannel{})
	var list []radio.RadioChannel
	var total int64

	if info.CategoryId != "" {
		db = db.Where("category_id = ?", info.CategoryId)
	}
	if info.Name != "" {
		db = db.Where("name LIKE ?", "%"+info.Name+"%")
	}
	if info.Status > 0 {
		db = db.Where("status = ?", info.Status)
	}

	err := db.Count(&total).Error
	if err != nil {
		return nil, 0, err
	}

	offset := (info.Current - 1) * info.PageSize
	err = db.Offset(offset).Limit(info.PageSize).Order("sort ASC").Find(&list).Error
	if err != nil {
		return nil, 0, err
	}

	// 批量查询用户订阅的频道，避免N+1问题
	if userId != "" {
		subService := &SubscriptionService{}
		subscribedChannelIds, _ := subService.GetUserSubscriptionHistory(userId)
		// 转换为map以便快速查找
		subscribedMap := make(map[string]bool)
		for _, cid := range subscribedChannelIds {
			subscribedMap[cid] = true
		}
		// 填充HasSubscribed字段
		for i := range list {
			if subscribedMap[list[i].Id] {
				list[i].HasSubscribed = 1
			} else {
				list[i].HasSubscribed = 0
			}
		}
	}

	return list, total, nil
}

// GetChannelById 获取频道详情
func (s *ChannelService) GetChannelById(userId, id string) (radio.RadioChannel, error) {
	var channel radio.RadioChannel
	err := global.DB.Where("id = ?", id).Preload("Cover").First(&channel).Error
	if err != nil {
		return channel, err
	}

	// 填充HasSubscribed字段
	if userId != "" {
		subService := &SubscriptionService{}
		hasSub, _ := subService.HasSubscription(userId, channel.Id)
		if hasSub {
			channel.HasSubscribed = 1
		} else {
			channel.HasSubscribed = 0
		}
	}

	return channel, nil
}

// SaveChannel 保存频道
func (s *ChannelService) SaveChannel(req radioReq.SaveChannel) error {
	channel := radio.RadioChannel{
		CategoryId:  req.CategoryId,
		Name:        req.Name,
		Description: req.Description,
		CoverId:     req.CoverId,
		Tags:        req.Tags,
		IsVipOnly:   req.IsVipOnly,
		Sort:        req.Sort,
		Status:      req.Status,
	}
	return global.DB.Create(&channel).Error
}

// UpdateChannel 更新频道
func (s *ChannelService) UpdateChannel(req radioReq.UpdateChannel) error {
	updates := map[string]interface{}{
		"category_id": req.CategoryId,
		"name":        req.Name,
		"description": req.Description,
		"cover_id":    req.CoverId,
		"tags":        req.Tags,
		"is_vip_only": req.IsVipOnly,
		"sort":        req.Sort,
		"status":      req.Status,
	}
	return global.DB.Model(&radio.RadioChannel{}).Where("id = ?", req.Id).Updates(updates).Error
}

// DeleteChannel 删除频道
func (s *ChannelService) DeleteChannel(id string) error {
	return global.DB.Transaction(func(tx *gorm.DB) error {
		// 检查是否有节目使用此频道
		var count int64
		tx.Model(&radio.RadioProgram{}).Where("channel_id = ?", id).Count(&count)
		if count > 0 {
			return errors.New("该频道下存在节目，无法删除")
		}
		return tx.Where("id = ?", id).Delete(&radio.RadioChannel{}).Error
	})
}