package main

import (
	"flag"
	"fmt"
	"github.com/bwmarrin/discordgo"
	"log"
	"math/rand"
	"os"
	"os/signal"
	"strings"
	"syscall"
)

//Session for DiscordGo
var Session, _ = discordgo.New()
var testPtr = flag.Bool("test", false, "Test mode")
var botToken string
var botChannel string

func init() {
	flag.StringVar(&botToken, "t", "", "Discord Authentication Token")
	flag.StringVar(&botChannel, "bc", "", "Bot status channel")
	flag.Parse()
	if os.Getenv("DISCORD_TOKEN") != "" {
		Session.Token = "Bot " + os.Getenv("DISCORD_TOKEN")
	} else {
		Session.Token = "Bot " + botToken
	}
	if os.Getenv("DISCORD_BOT_CHANNEL") != "" {
		botChannel = os.Getenv("DISCORD_BOT_CHANNEL")
	}
}

func main() {
	var err error
	fmt.Println("butts!")
	flag.Parse()
	if Session.Token == "" {
		log.Println("You must provide a Discord auth token!")
		return
	}

	//Handlers
	Session.AddHandler(ready)
	Session.AddHandler(messageCreate)

	//Open a connection to Discord
	err = Session.Open()
	if err != nil {
		log.Printf("Error opening connection to Discord, %s\n", err)
		os.Exit(1)
	}

	//Wait for a CTRL-C
	log.Printf("Now running. Press CTRL-C to exit.")
	sc := make(chan os.Signal, 1)
	signal.Notify(sc, syscall.SIGINT, syscall.SIGTERM, os.Interrupt, os.Kill)
	<-sc
	Session.Close()
}

func ready(s *discordgo.Session, event *discordgo.Ready) {
	if *testPtr == true {
		s.ChannelMessageSend(botChannel, "Test complete: discord-buttsbot-go")
		log.Printf("Test successful! Now quiting.")
		s.Close()
		os.Exit(0)
	}
	s.UpdateStatus(0, "with butts!")
	if os.Getenv("BUTTSBOT_STARTUP_MESSAGE") == "TRUE" {
		s.ChannelMessageSend(botChannel, "This isn't a butt...")
	}
}

func messageCreate(s *discordgo.Session, m *discordgo.MessageCreate) {
	//Ignore messages by itself
	if m.Author.ID == s.State.User.ID {
		return
	}

	//Check if the bot was mentioned
	if isUserMentioned(m, s.State.User) == true {
		s.ChannelMessageSend(m.ChannelID, textToButt(m, s))
		return
	}

	//Replace words in random messages
	if rand.Intn(100) > 85 {
		s.ChannelMessageSend(m.ChannelID, textToButt(m, s))
		return
	}
}

//Easy way to check if a user was mentioned in a message
func isUserMentioned(m *discordgo.MessageCreate, u *discordgo.User) bool {
	//mentioned := false
	for _, user := range m.Mentions {
		if user.ID == u.ID {
			return true
		}
	}
	return false
}

//Replace words with butt
func textToButt(m *discordgo.MessageCreate, s *discordgo.Session) string {
	cleanmessage, _ := m.ContentWithMoreMentionsReplaced(s)
	words := strings.Fields(cleanmessage)
	for i := range words {
		if rand.Intn(10) > 7 {
			words[i] = "butt"
		}
	}
	return strings.Join(words, " ")
}