package service

import (
	"github.com/freefire/jiang13-bbs/model"
	"gorm.io/gorm"
)

// NotificationService 通知服务
type NotificationService struct {
	db *gorm.DB
	// OnNotifyNew 落库成功后回调（用于 WS 推送红点）；可为 nil
	OnNotifyNew func(userID uint)
}

func NewNotificationService(db *gorm.DB) *NotificationService {
	return &NotificationService{db: db}
}

// Create 创建通知（actorID == userID 时跳过，不通知自己）
func (s *NotificationService) Create(userID, actorID uint, notifType string, postID, commentID uint, content string) {
	if userID == 0 || actorID == 0 || userID == actorID {
		return
	}
	// 截断内容预览
	if len(content) > 200 {
		content = content[:200]
	}
	n := &model.Notification{
		UserID:    userID,
		ActorID:   actorID,
		Type:      notifType,
		PostID:    postID,
		CommentID: commentID,
		Content:   content,
		IsRead:    false,
	}
	// 通知创建失败不影响主流程，忽略错误
	if err := s.db.Create(n).Error; err != nil {
		return
	}
	if s.OnNotifyNew != nil {
		s.OnNotifyNew(userID)
	}
}

// CreateMention 创建群聊 @ 提醒（PostID=0，用 RoomID/MessageID 关联）。
// 返回创建出的通知 ID（0 表示未创建），供 handler 实时推送。
func (s *NotificationService) CreateMention(userID, actorID, roomID, messageID uint, content string) uint {
	if userID == 0 || actorID == 0 || userID == actorID || roomID == 0 {
		return 0
	}
	if runes := []rune(content); len(runes) > 100 {
		content = string(runes[:100])
	}
	n := &model.Notification{
		UserID:    userID,
		ActorID:   actorID,
		Type:      model.NotificationTypeMention,
		RoomID:    roomID,
		MessageID: messageID,
		Content:   content,
	}
	if err := s.db.Create(n).Error; err != nil {
		return 0
	}
	if s.OnNotifyNew != nil {
		s.OnNotifyNew(userID)
	}
	return n.ID
}

// List 获取用户通知列表（分页，按时间倒序）
func (s *NotificationService) List(userID uint, page, size int) ([]model.Notification, int64, error) {
	if page < 1 {
		page = 1
	}
	if size < 1 || size > 50 {
		size = 20
	}
	query := s.db.Model(&model.Notification{}).Where("user_id = ?", userID)
	var total int64
	if err := query.Count(&total).Error; err != nil {
		return nil, 0, err
	}
	var list []model.Notification
	offset := (page - 1) * size
	if err := query.Order("created_at DESC").Offset(offset).Limit(size).
		Preload("Actor").Preload("Post").Preload("Room").Find(&list).Error; err != nil {
		return nil, 0, err
	}
	return list, total, nil
}

// UnreadCount 获取未读通知数
func (s *NotificationService) UnreadCount(userID uint) (int64, error) {
	var total int64
	err := s.db.Model(&model.Notification{}).Where("user_id = ? AND is_read = ?", userID, false).Count(&total).Error
	return total, err
}

// MarkRead 标记单条通知为已读（校验归属）
func (s *NotificationService) MarkRead(id, userID uint) error {
	result := s.db.Model(&model.Notification{}).
		Where("id = ? AND user_id = ?", id, userID).
		Update("is_read", true)
	return result.Error
}

// MarkAllRead 标记用户所有通知为已读
func (s *NotificationService) MarkAllRead(userID uint) error {
	result := s.db.Model(&model.Notification{}).
		Where("user_id = ? AND is_read = ?", userID, false).
		Update("is_read", true)
	return result.Error
}