package main

import (
	"encoding/json"
	"strconv"
	"time"

	"github.com/tinode/chat/server/logs"
	"github.com/tinode/chat/server/store"
	"github.com/tinode/chat/server/store/types"
)

// dispatchIMGroupEvents delivers committed outbox events to online topic
// sessions. Events remain pending when the hub is unavailable or its queue is
// full, so the next successful group mutation retries them.
func dispatchIMGroupEvents(tenantID types.TenantID) {
	if tenantID.IsZero() || globals.hub == nil || store.GroupBusiness == nil {
		return
	}
	now := time.Now().UTC().Round(time.Millisecond)
	events, err := store.GroupBusiness.ListPendingEvents(tenantID, 100, now)
	if err != nil {
		logs.Warn.Printf("group outbox: list tenant=%d: %v", tenantID, err)
		return
	}
	for _, event := range events {
		members, memberErr := store.Topics.GetUsers(tenantID, event.Topic, &types.QueryOpt{Limit: 1000})
		if memberErr != nil {
			logs.Warn.Printf("group outbox: list members event=%s: %v", event.EventID, memberErr)
			return
		}
		for _, member := range members {
			uid := types.ParseUid(member.User)
			if uid.IsZero() {
				if decoded, parseErr := strconv.ParseInt(member.User, 10, 64); parseErr == nil && decoded > 0 {
					uid = store.EncodeUid(decoded)
				}
			}
			if uid.IsZero() || uid == event.ActorUserID {
				continue
			}
			if err = createIMSystemNotification(tenantID, uid,
				stableIMEventID(event.EventID, uid.UserId(), "notification"), event.EventType,
				"群聊动态", event.EventType, types.KVMap{"topic": event.Topic}); err != nil {
				logs.Warn.Printf("group outbox: create notification event=%s user=%s: %v", event.EventID, uid.UserId(), err)
				return
			}
		}
		payload := json.RawMessage(event.Payload)
		if len(payload) == 0 {
			payload = json.RawMessage(`{}`)
		}
		from := ""
		if !event.ActorUserID.IsZero() {
			from = event.ActorUserID.UserId()
		}
		message := &ServerComMessage{
			TenantID:  tenantID,
			RcptTo:    event.Topic,
			AsUser:    from,
			Timestamp: event.CreatedAt,
			Info: &MsgServerInfo{
				Topic:   event.Topic,
				From:    from,
				What:    "group",
				Event:   event.EventType,
				Payload: payload,
			},
		}
		select {
		case globals.hub.routeSrv <- message:
			if err = store.GroupBusiness.MarkEventDelivered(tenantID, event.EventID, now); err != nil {
				logs.Warn.Printf("group outbox: mark delivered event=%s: %v", event.EventID, err)
				return
			}
		default:
			logs.Warn.Printf("group outbox: hub queue full event=%s", event.EventID)
			return
		}
	}
}