sundynix-radio-be/service/radio/subscription_service.go

package radio

import (
	"errors"
	"sundynix-go/global"
	common "sundynix-go/model/commom/request"
	"sundynix-go/model/radio"
	"time"

	"gorm.io/gorm"
)

type SubscriptionService struct{}

const MaxFreeSubscription = 2

// GetUserSubscription 获取用户订阅列表
func (s *SubscriptionService) GetUserSubscription(userId string, info common.PageInfo) ([]radio.RadioSubscription, int64, error) {
	db := global.DB.Model(&radio.RadioSubscription{}).Where("user_id = ?", userId)
	var list []radio.RadioSubscription
	var total int64

	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("created_at DESC").Find(&list).Error
	return list, total, err
}

// GetUserSubscriptionHistory 获取用户历史订阅过的频道ID列表
func (s *SubscriptionService) GetUserSubscriptionHistory(userId string) ([]string, error) {
	var channelIds []string
	err := global.DB.Model(&radio.RadioSubscription{}).
		Where("user_id = ?", userId).
		Pluck("channel_id", &channelIds).Error
	return channelIds, err
}

// HasEverSubscribed 检查用户是否曾经订阅过该频道（包括已取消的）
func (s *SubscriptionService) HasEverSubscribed(userId, channelId string) (bool, error) {
	var count int64
	// 使用Unscoped查询包括已软删除的记录
	err := global.DB.Unscoped().Model(&radio.RadioSubscription{}).
		Where("user_id = ? AND channel_id = ?", userId, channelId).
		Count(&count).Error
	return count > 0, err
}

// HasSubscription 检查用户当前是否订阅该频道（未取消的）
func (s *SubscriptionService) HasSubscription(userId, channelId string) (bool, error) {
	var count int64
	err := global.DB.Model(&radio.RadioSubscription{}).
		Where("user_id = ? AND channel_id = ?", userId, channelId).
		Count(&count).Error
	return count > 0, err
}

// CanSubscribe 检查是否可以订阅
// 规则：
// 1. 如果用户是VIP且未过期，可以订阅任意频道
// 2. 如果用户曾经订阅过该频道（取消后再订阅），可以免费订阅
// 3. 否则检查当前有效订阅数量是否达到上限(2个)
func (s *SubscriptionService) CanSubscribe(userId, channelId string) (bool, string, error) {
	// 检查是否已经是订阅用户（未取消的订阅）
	var existing radio.RadioSubscription
	err := global.DB.Where("user_id = ? AND channel_id = ?", userId, channelId).First(&existing).Error
	if err == nil {
		return false, "您已订阅该频道", nil
	}
	if !errors.Is(err, gorm.ErrRecordNotFound) {
		return false, "", err
	}

	// 获取radio_user检查VIP状态
	var radioUser radio.RadioUser
	err = global.DB.Where("user_id = ?", userId).First(&radioUser).Error
	if err == nil && radioUser.IsVip == 1 {
		// 检查VIP是否过期
		if radioUser.VipExpireAt != nil && *radioUser.VipExpireAt > time.Now().Unix() {
			return true, "", nil
		}
	}

	// 检查用户是否曾经订阅过该频道（取消后又订阅的情况）
	hasEverSubscribed, err := s.HasEverSubscribed(userId, channelId)
	if err != nil {
		return false, "", err
	}
	if hasEverSubscribed {
		// 曾今订阅过，可以免费再次订阅
		return true, "", nil
	}

	// 非VIP用户，检查当前有效订阅数量（排除已取消的）
	var count int64
	err = global.DB.Model(&radio.RadioSubscription{}).Where("user_id = ?", userId).Count(&count).Error
	if err != nil {
		return false, "", err
	}
	if count >= MaxFreeSubscription {
		return false, "免费订阅数量已达上限(2个)，请开通VIP或订阅付费频道", nil
	}

	return true, "", nil
}

// Subscribe 订阅频道
func (s *SubscriptionService) Subscribe(userId, channelId string, subType int) error {
	subscription := radio.RadioSubscription{
		UserId:    userId,
		ChannelId: channelId,
	}
	return global.DB.Create(&subscription).Error
}

// Unsubscribe 退订频道（逻辑删除，更新删除时间表示已取消）
func (s *SubscriptionService) Unsubscribe(userId, channelId string) error {
	// 软删除：将DeletedAt设置为当前时间，表示已取消订阅
	// 这样用户可以再次免费订阅该频道
	return global.DB.Model(&radio.RadioSubscription{}).
		Where("user_id = ? AND channel_id = ?", userId, channelId).
		Update("deleted_at", time.Now()).Error
}

// GetVipStatus 获取VIP状态
func (s *SubscriptionService) GetVipStatus(userId string) (bool, int64, error) {
	var radioUser radio.RadioUser
	err := global.DB.Where("user_id = ?", userId).First(&radioUser).Error
	if err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return false, 0, nil
		}
		return false, 0, err
	}

	if radioUser.IsVip == 1 && radioUser.VipExpireAt != nil && *radioUser.VipExpireAt > time.Now().Unix() {
		return true, *radioUser.VipExpireAt, nil
	}

	return false, 0, nil
}