package moon

import (
	"bunny-bot/internal/elog"
	"bunny-bot/internal/mylog"

	"github.com/NicoNex/echotron/v3"
	"github.com/davecgh/go-spew/spew"
)

// Telegram main goroutine that implements bot.
//
// It blocks until a termination signal stops it, so the update listener can be
// shut down in a defined order rather than simply abandoned when the process
// exits.
func Telegram(cfg MyConfig) {
	// A signal can arrive during startup; then this must not start at all.
	if !startWorker() {
		mylog.Info("Telegram not started: shutdown already in progress")

		return
	}

	defer stopWorker()

	Tg = echotron.NewAPI(cfg.Token)

	mylog.Info("Starting api update poller loop")

	// The sweeper calls the API too, so it may only start once Tg exists.
	mylog.Info("Starting greeting sweeper periodic task")

	go SweepGreetings()

	updates := echotron.PollingUpdatesOptions(cfg.Token, true, echotron.UpdateOptions{
		AllowedUpdates: allowedUpdates,
	})

	for {
		select {
		// Stop between updates, never inside one: the handler currently running
		// finishes, so nothing is left half-processed when we return.
		case <-stopRequested:
			mylog.Info("Telegram update listener stopped")

			return

		case u, ok := <-updates:
			if !ok {
				mylog.Info("Telegram update poller ended")

				return
			}

			telegramMsgParser(u)
		}
	}
}

// telegramMsgParser parses events generated by echotron.
func telegramMsgParser(msg *echotron.Update) {
	// The one place an update enters the program, and therefore the one place an
	// entity with no id is caught. Everything downstream — the caches, the sweeper,
	// the bans — may then assume the ids it holds are real.
	if !usableUpdate(msg) {
		reportBrokenUpdate(msg)

		return
	}

	switch {
	// Membership status changes: joins, leaves, bans, promotions. Logged only —
	// moderation is the sweeper's job, on a timer, not the dispatcher's.
	//
	// This also catches the membership updates caused by our own bans, so every
	// ban leaves a second record in the chat log.
	case msg.ChatMember != nil:
		elog.LogUserStatus(msg.ChatMember)

	// New members entered to chat. Checked before the text case so that a
	// join service message is never mistaken for ordinary chatter.
	case msg.Message != nil && msg.Message.NewChatMembers != nil:
		newChatMembers(msg)

	// Ordinary text messages, used as greeting answers.
	case msg.Message != nil && msg.Message.Text != "":
		textMessage(msg)

	// Everything else that is still a message: a photo with no caption, a
	// sticker, a location, a leave, a title change. Logged, and deliberately NOT
	// recorded as a greeting answer — an attachment is not an introduction, and
	// letting one satisfy the detector would be a one-key bypass for a spammer.
	//
	// The condition is deliberately just "there is a message": elog already
	// renders every media and service field, and already writes nothing for a
	// message with no describable content, so emptiness is its decision to make.
	// Testing for a field being non-empty here is what lost these messages.
	case msg.Message != nil:
		logOnlyMessage(msg)

	// An edit revises a message already recorded, so it is a chat-log event
	// rather than a moderation one.
	case msg.EditedMessage != nil:
		elog.LogEditedMessage(msg.EditedMessage)

	default:
		mylog.Debug(spew.Sdump(msg))
	}
}

/* vim: set ft=go noet ai ts=4 sw=4 sts=4: */