package service

import (
	"time"

	"kefu-cloud/server/internal/model"
	"kefu-cloud/server/internal/ws"
)

const VisitorOnlineTimeout = 45 * time.Second

// VisitorIsOnline 根据最近心跳和显式离开时间动态判断访客是否在线。
func VisitorIsOnline(session *model.Session, now time.Time) bool {
	if session == nil || session.Status == "ended" || session.Status == "archived" {
		return false
	}
	if session.LastSeenAt == nil {
		return false
	}
	if session.VisitorLeftAt != nil && !session.LastSeenAt.After(*session.VisitorLeftAt) {
		return false
	}
	return now.Sub(*session.LastSeenAt) <= VisitorOnlineTimeout
}

// UpdateVisitorPresence 处理 visible/hidden/leave 状态，并返回切换前后的在线状态。
func UpdateVisitorPresence(session *model.Session, state string, now time.Time) (bool, bool, error) {
	wasOnline := VisitorIsOnline(session, now)
	updates := map[string]interface{}{}
	switch state {
	case "hidden", "leave":
		leftAt := now
		updates["visitor_left_at"] = leftAt
		session.VisitorLeftAt = &leftAt
	default:
		updates["last_seen_at"] = now
		updates["visitor_left_at"] = nil
		session.LastSeenAt = &now
		session.VisitorLeftAt = nil
	}
	if err := model.DB.Model(session).Updates(updates).Error; err != nil {
		return wasOnline, false, err
	}
	return wasOnline, VisitorIsOnline(session, now), nil
}

func broadcastVisitorPresence(session *model.Session, online bool) {
	payload, err := ws.NewEvent("visitor_presence", session.ID, map[string]interface{}{
		"visitor_online":  online,
		"last_seen_at":    session.LastSeenAt,
		"visitor_left_at": session.VisitorLeftAt,
	})
	if err == nil {
		ws.DefaultHub.BroadcastToTenantStaff(session.TenantID, payload)
	}
}