package main

import (
	"context"
	"fmt"
	"os"
	"os/signal"
	"syscall"
	"time"

	"github.com/disgoorg/disgo"
	"github.com/disgoorg/disgo/bot"
	"github.com/disgoorg/disgo/cache"
	"github.com/disgoorg/disgo/discord"
	"github.com/disgoorg/disgo/events"
	"github.com/disgoorg/disgo/gateway"
	"github.com/disgoorg/log"
	"github.com/disgoorg/snowflake/v2"
)

var (
	token           = os.Getenv("disgo_token")
	registerGuildID = snowflake.GetEnv("disgo_guild_id")
)

var (
	channelRulesMention string
	channelInfoMention  string
	channelWelcomeID    snowflake.ID
	roleAppleID         snowflake.ID
	roleAppleCoreID     snowflake.ID
)

func main() {
	log.SetLevel(log.LevelInfo)
	log.Info("starting welcomebot...")
	log.Info("disgo version: ", disgo.Version)

	// permissions: Manage Roles
	// intent: Server Members Intent
	client, err := disgo.New(token,
		bot.WithGatewayConfigOpts(
			gateway.WithIntents(gateway.IntentGuildMembers),
		),
		bot.WithCacheConfigOpts(
			cache.WithCaches(
				cache.FlagsNone,
			),
		),
		bot.WithEventListenerFunc(joinListener),
		bot.WithEventListenerFunc(leaveListener),
		bot.WithEventListenerFunc(reactionListener),
	)
	if err != nil {
		log.Fatal("error while building disgo instance: ", err)
		return
	}

	defer client.Close(context.TODO())

	if err = client.OpenGateway(context.TODO()); err != nil {
		log.Fatal("error while connecting to gateway: ", err)
	}

	channels, err := client.Rest().GetGuildChannels(registerGuildID)
	for _, channel := range channels {
		switch channel.Name() {
		case "🔨-rules":
			channelRulesMention = channel.Mention()
		case "❕-info":
			channelInfoMention = channel.Mention()
		case "👋-welcome":
			channelWelcomeID = channel.ID()
		}
	}
	if channelRulesMention == "" || channelInfoMention == "" || channelWelcomeID == 0 {
		log.Fatal("couldn't find needed channel")
	}

	roles, err := client.Rest().GetRoles(registerGuildID)
	for _, role := range roles {
		switch role.Name {
		case "Apple":
			roleAppleID = role.ID
		case "Apple Core":
			roleAppleCoreID = role.ID
		}
	}
	if roleAppleID == 0 || roleAppleCoreID == 0 {
		log.Fatal("couldn't find needed role")
	}

	log.Infof("welcomebot is now running. Press CTRL-C to exit.")
	s := make(chan os.Signal, 1)
	signal.Notify(s, syscall.SIGINT, syscall.SIGTERM, os.Interrupt)
	<-s
}

func joinListener(event *events.GuildMemberJoin) {
	// on join send message in welcome
	user := event.Member.User
	if event.GuildID.String() != registerGuildID.String() {
		event.Client().Logger().Error("join from an other guild")
		return
	}
	guild, err := event.Client().Rest().GetGuild(registerGuildID, false)
	if err != nil {
		event.Client().Logger().Error("could not find guild: ", err)
		return
	}

	_, err = event.Client().Rest().CreateMessage(channelWelcomeID,
		discord.NewMessageCreateBuilder().
			SetContent(user.Mention()).
			SetEphemeral(false).
			AddActionRow(discord.NewSecondaryButton("approve", "approve")).
			SetEmbeds(discord.NewEmbedBuilder().
				SetColor(16068661).
				SetTimestamp(time.Now()).
				SetThumbnail(user.EffectiveAvatarURL(discord.WithSize(1024))).
				AddField(
					fmt.Sprintf("Welcome to the %v Server", guild.Name),
					fmt.Sprintf("Welcome %v (`%v`) on %v 🍎", user.Mention(), user.Username, guild.Name), false).
				AddField("Next Step", fmt.Sprintf("schau dir die %v und spaeter die %v an", channelRulesMention, channelInfoMention), false).
				Build()).
			Build(),
	)
	if err != nil {
		event.Client().Logger().Error("on sending join message: ", err)
		return
	}
}

func leaveListener(event *events.GuildMemberLeave) {
	user := event.User

	if event.GuildID.String() != registerGuildID.String() {
		event.Client().Logger().Error("leave from an other guild")
		return
	}
	guild, err := event.Client().Rest().GetGuild(registerGuildID, false)
	if err != nil {
		event.Client().Logger().Error("could not find guild: ", err)
		return
	}

	_, err = event.Client().Rest().CreateMessage(channelWelcomeID,
		discord.NewMessageCreateBuilder().
			SetContent(
				fmt.Sprintf("%v (`%v`) left %v", user.Mention(), user.Username, guild.Name)).
			Build(),
	)
	if err != nil {
		event.Client().Logger().Error("on sending leave message: ", err)
		return
	}
}

func reactionListener(event *events.ComponentInteractionCreate) {

	if event.ChannelID() != channelWelcomeID {
		// reaction is not in welcome chat
		return
	}

	approverID := event.User().ID
	if approverID.String() == event.Client().ID().String() {
		// reaction user is bot itself
		return
	}
	if event.ButtonInteractionData().CustomID() != "approve" {
		// not approve button
		return
	}
	approver, err := event.Client().Rest().GetMember(registerGuildID, approverID)
	if err != nil {
		event.Client().Logger().Error("could not find user: ", err)
		return
	}
	hasPermission := func() bool {
		for _, roleID := range approver.RoleIDs {
			if roleID.String() == roleAppleCoreID.String() {
				return true
			}
		}
		return false
	}()

	if hasPermission == false {
		err = event.CreateMessage(discord.NewMessageCreateBuilder().
			SetEphemeral(true).
			SetContent("you don't have permissions to do this").
			Build())
		if err != nil {
			event.Client().Logger().Error("could not respond to reaction: ", err)
			return
		}
		return
	}

	messageID := event.Message.ID
	message, err := event.Client().Rest().GetMessage(channelWelcomeID, messageID)
	if err != nil {
		event.Client().Logger().Error("could not find message: ", err)
		return
	}
	if len(message.Mentions) != 1 {
		// there should be only one mention in the message
		return
	}
	user := message.Mentions[0]

	// add role to user (bot role needs to be above roleAppleID)
	err = event.Client().Rest().AddMemberRole(registerGuildID, user.ID, roleAppleID)
	if err != nil {
		event.Client().Logger().Error("not able to add role: ", err)
		return
	}

	// update embed (and time)
	if len(message.Embeds) != 1 {
		// there should be only one embed in the message
		return
	}
	embed := message.Embeds[0]
	updatedMessage := discord.NewEmbedBuilder().
		SetColor(16068661).
		SetTimestamp(time.Now()).
		SetThumbnail(embed.Thumbnail.URL).
		AddFields(embed.Fields...).
		AddField("Approval", fmt.Sprintf("%v approved by %v (`%v`)", user.Mention(), approver.Mention(), approver.User.Username), false).
		Build()

	err = event.UpdateMessage(discord.NewMessageUpdateBuilder().
		SetContent(message.Content).
		SetEmbeds(updatedMessage).
		ClearContainerComponents().
		Build())
	if err != nil {
		event.Client().Logger().Error("could not update message: ", err)
		return
	}
}