package model

import "time"

const (
	ListingCollectionKindHistory  = "history"
	ListingCollectionKindFavorite = "favorite"
)

// ListingCollection 记录用户对商品的浏览足迹或收藏关系。
// 同一用户 + 商品 + 类型唯一，重复浏览只更新时间，不新增行。
type ListingCollection struct {
	ID         uint64    `gorm:"primaryKey" json:"id"`
	UserID     uint64    `gorm:"not null;uniqueIndex:uk_listing_collections_user_listing_kind,priority:1;index:idx_listing_collections_user_kind_time,priority:1" json:"user_id"`
	ListingID  uint64    `gorm:"not null;uniqueIndex:uk_listing_collections_user_listing_kind,priority:2;index:idx_listing_collections_user_kind_time,priority:3;index:idx_listing_collections_listing" json:"listing_id"`
	Kind       string    `gorm:"size:16;not null;uniqueIndex:uk_listing_collections_user_listing_kind,priority:3;index:idx_listing_collections_user_kind_time,priority:2" json:"kind"`
	OccurredAt time.Time `gorm:"not null;index:idx_listing_collections_user_kind_time,priority:4" json:"occurred_at"`
	CreatedAt  time.Time `json:"created_at"`
	UpdatedAt  time.Time `json:"updated_at"`
}

func (ListingCollection) TableName() string {
	return "listing_collections"
}