package main

import (
	"context"
	"log"
	"os"
	"os/signal"
	"sync"
	"syscall"
	"time"

	"github.com/bwmarrin/discordgo"
)

func main() {
	token := os.Getenv("DISCORD_TOKEN")
	channelID := os.Getenv("CHANNEL_ID")
	if token == "" || channelID == "" {
		log.Fatal("DISCORD_TOKEN and CHANNEL_ID are required")
	}

	session, err := discordgo.New("Bot " + token)
	if err != nil {
		log.Fatal(err)
	}
	session.Identify.Intents = discordgo.IntentsGuilds | discordgo.IntentsGuildVoiceStates

	if err := session.Open(); err != nil {
		log.Fatal(err)
	}
	defer session.Close()

	channel, err := session.Channel(channelID)
	if err != nil {
		log.Fatal(err)
	}
	if channel.Type != discordgo.ChannelTypeGuildVoice {
		log.Fatal("CHANNEL_ID must identify a guild voice channel")
	}

	var joinMu sync.Mutex
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	join := func() {
		joinMu.Lock()
		defer joinMu.Unlock()

		for {
			select {
			case <-ctx.Done():
				return
			default:
			}

			if _, err := session.ChannelVoiceJoin(ctx, channel.GuildID, channelID, false, true); err == nil {
				log.Printf("joined voice channel %s", channelID)
				return
			} else {
				log.Printf("voice join failed: %v; retrying in 5s", err)
			}

			select {
			case <-ctx.Done():
				return
			case <-time.After(5 * time.Second):
			}
		}
	}

	session.AddHandler(func(s *discordgo.Session, update *discordgo.VoiceStateUpdate) {
		if s.State.User == nil || update.UserID != s.State.User.ID || update.ChannelID == channelID {
			return
		}
		log.Print("bot left target voice channel; reconnecting")
		go join()
	})

	join()

	signals := make(chan os.Signal, 1)
	signal.Notify(signals, os.Interrupt, syscall.SIGTERM)
	<-signals
	cancel()

	session.RLock()
	voice := session.VoiceConnections[channel.GuildID]
	session.RUnlock()
	if voice != nil {
		_ = voice.Disconnect(context.Background())
	}
	log.Print("bot stopped")
}