group_helper/channels/leaveduserchecker.go

package channels

import (
	"git.dragon-labs.de/alphyron/group_helper/logic"
	"git.dragon-labs.de/alphyron/group_helper/message"
	"git.dragon-labs.de/alphyron/group_helper/models"
	tgbotapi "github.com/go-telegram-bot-api/telegram-bot-api"
	"log"
	"time"
)

func CheckForLeavingUser(ticker *time.Ticker, quitChannel <-chan struct{}, groupHelperService logic.GroupHelperService, bot *tgbotapi.BotAPI) {
	for {
		select {
		case <-ticker.C:

			groups, err := groupHelperService.ListGroups()

			if err != nil {
				log.Println("Error while getting all groups in the LeavingChecking routine")
				log.Println(err)
				continue
			}

			for _, group := range groups {
				time.Sleep(500 * time.Millisecond)
				config := tgbotapi.ChatConfig{
					ChatID: group.GroupID,
				}

				teleSize, _ := bot.GetChatMembersCount(config)
				teleSize -= 1
				sqlSize, err := groupHelperService.GetGroupDatabaseSize(group)

				if err != nil {
					log.Println("Error while counting the user in group")
					log.Println(err)
					continue
				}

				if teleSize == sqlSize {
					continue
				}

				if sqlSize < teleSize {
					group.Size = teleSize
					groupHelperService.UpdateGroup(group)
					continue
				}

				if teleSize < sqlSize {
					checkGroupUser(group, groupHelperService, bot)
					groupHelperService.UpdateGroup(group)
				}
			}

		case <-quitChannel:
			ticker.Stop()
			return
		}
	}
}

func checkGroupUser(group *models.Group, groupHelperService logic.GroupHelperService, bot *tgbotapi.BotAPI) {
	rate := time.Second / 5
	throttle := time.Tick(rate)

	users, err := groupHelperService.ListGroupUsers(group)

	if err != nil {
		log.Println("Error while getting the users for group while checking for leaved user")
		log.Println(err)
		return
	}

	for _, user := range users {
		<-throttle // rate limit our Service.Method RPCs

		userConfig := tgbotapi.ChatConfigWithUser{
			ChatID: group.GroupID,
			UserID: int(user.UserID),
		}

		member, _ := bot.GetChatMember(userConfig)

		if !member.HasLeft() {
			continue
		}

		leaveMessage := group.UserLeaveMessage
		leaveMessage = message.ReplaceMessage(leaveMessage, member.User)

		msg := tgbotapi.NewMessage(group.GroupID, leaveMessage)
		msg.ParseMode = "Markdown"
		bot.Send(msg)
		groupHelperService.UserLeaveGroup(user, group)
	}
}