package listingstatus

import (
	"strings"
	"time"

	"hfb_sys/backend/internal/model"
	"hfb_sys/backend/internal/timeutil"

	"gorm.io/gorm"
)

// 统计用的事件类型（与 to_status 对齐时优先用这些标准值）。
const (
	EventPublished = "published"
	EventOffline   = "offline"
	EventRented    = "rented"
	EventCompleted = "completed"
	EventSealed    = "sealed"
	EventAbnormal  = "abnormal"
)

// 来源
const (
	SourceSeller  = "seller"
	SourceAdmin   = "admin"
	SourceReview  = "review"
	SourceOrder   = "order"
	SourcePickup  = "pickup"
	SourceDispute = "dispute"
	SourceSystem  = "system"
)

// 操作者类型
const (
	ActorUser   = "user"
	ActorAdmin  = "admin"
	ActorSystem = "system"
)

// Entry 单次状态变更事件。
type Entry struct {
	ListingID  uint64
	OwnerID    uint64
	EventType  string
	FromStatus string
	ToStatus   string
	Source     string
	ActorType  string
	ActorID    uint64
	Remark     string
	// CreatedAt 为空时使用上海时间当前时刻。
	CreatedAt time.Time
}

// Append 写入一条状态事件。from==to 或 event 无法识别时跳过。
func Append(tx *gorm.DB, entry Entry) error {
	if tx == nil {
		return nil
	}
	from := strings.TrimSpace(entry.FromStatus)
	to := strings.TrimSpace(entry.ToStatus)
	if to == "" {
		to = strings.TrimSpace(entry.EventType)
	}
	if to == "" || from == to {
		return nil
	}
	eventType := strings.TrimSpace(entry.EventType)
	if eventType == "" {
		eventType = normalizeEventType(to)
	}
	if eventType == "" {
		return nil
	}
	createdAt := entry.CreatedAt
	if createdAt.IsZero() {
		createdAt = timeutil.ShanghaiNow()
	}
	row := model.ListingStatusEvent{
		ListingID:  entry.ListingID,
		OwnerID:    entry.OwnerID,
		EventType:  eventType,
		FromStatus: from,
		ToStatus:   to,
		Source:     strings.TrimSpace(entry.Source),
		ActorType:  strings.TrimSpace(entry.ActorType),
		ActorID:    entry.ActorID,
		Remark:     strings.TrimSpace(entry.Remark),
		CreatedAt:  createdAt,
	}
	return tx.Create(&row).Error
}

// AppendTransition 根据 listing 变更前后状态写事件。
func AppendTransition(
	tx *gorm.DB,
	listing *model.RentalListing,
	fromStatus string,
	source string,
	actorType string,
	actorID uint64,
	remark string,
) error {
	if listing == nil {
		return nil
	}
	return Append(tx, Entry{
		ListingID:  listing.ID,
		OwnerID:    listing.OwnerID,
		EventType:  normalizeEventType(listing.Status),
		FromStatus: fromStatus,
		ToStatus:   listing.Status,
		Source:     source,
		ActorType:  actorType,
		ActorID:    actorID,
		Remark:     remark,
	})
}

func normalizeEventType(status string) string {
	switch strings.TrimSpace(status) {
	case EventPublished, EventOffline, EventRented, EventCompleted, EventSealed, EventAbnormal:
		return status
	default:
		return ""
	}
}