main.go

package main

import (
	"flag"
	"fmt"
	"log"
	"os"
	"os/signal"
	"regexp"
	"strings"
	"syscall"
	"time"

	"github.com/BurntSushi/toml"
	"github.com/bwmarrin/discordgo"
)

type config struct {
	Token  string `toml:"token"`
	Prefix string `toml:"prefix"`
}

var (
	// Zero width whitespace to replace message content
	content    = "​"
	conf       = new(config)
	emojiRegex = regexp.MustCompile("<(a)?:.*?:(.*?)>")
	loginTime  time.Time
	dg         *discordgo.Session
	errorLog   *log.Logger
	infoLog    *log.Logger
	logF       *os.File
	is2Cloud   *bool
)

func init() {
	is2Cloud = flag.Bool("c", false, "if set, the program will exit if no config is found or is invalid")
	flag.Parse()
}

func createConfig() error {
	fmt.Println("Welcome and thanks for downloading 2Bot2Go!")
	fmt.Println("As I couldn't find a file called config.toml, I'll assume this is your first time starting the bot, so lets get it setup!")

	if err := inputToken(); err != nil {
		return err
	}

	inputPrefix()

	file, err := os.OpenFile("config/config.toml", os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0660)
	if err != nil {
		fmt.Println("Error creating config\n", err)
		return err
	}
	defer file.Close()

	err = toml.NewEncoder(file).Encode(conf)
	if err != nil {
		fmt.Println("Error creating config\n", err)
		return err
	}

	return nil
}

func inputToken() error {
	fmt.Println("\nFirst, I'll need your user token. To do that, follow these instructions:\n1. Type Ctrl-Shift-i\n2. Click on the tab labelled 'Application'\n3. Click 'Local Storage', and then https://discordapp.com")
	fmt.Print("4. Then copy paste the long string of random characters here, but WITHOUT THE QUOTATION MARKS! Thats very important\nPaste your token here: ")

	fmt.Scanln(&conf.Token)
	if err := testLogin(); err != nil {
		fmt.Println("There was an issue logging you in. Check your token and try again")
		return err
	}

	return nil
}

func inputPrefix() {
	fmt.Println("\nNext up, I'll need a prefix of your preference! This will be used to call your commands.\nYou can choose to have a space between your prefix and command after you input your prefix")
	fmt.Println("Example: prefix => ||\n||help => shows the help menu")
	fmt.Print("\nType your chosen prefix here: ")

	fmt.Scanln(&conf.Prefix)
	var ws string
	for {
		fmt.Print("Do you want a space at the end of your prefix? (y/n) ")
		fmt.Scanln(&ws)
		switch strings.ToLower(ws) {
		case "y":
			conf.Prefix += " "
			return
		case "n":
			return
		default:
			fmt.Println("\nPlease type y or n")
		}
	}
}

func testLogin() error {
	fmt.Println("Trying to login...")
	infoLog.Println("Trying to login...")

	var err error
	dg, err = discordgo.New(conf.Token)
	if err != nil {
		return err
	}

	if _, err = dg.User("@me"); err != nil {
		return err
	}

	fmt.Println("\rToken is valid!")
	infoLog.Println("\rToken is valid!")

	return nil
}

func loadConfig() error {
	if _, err := toml.DecodeFile("config/config.toml", conf); err != nil {
		return err
	}
	return nil
}

func openLog() *os.File {
	f, err := os.OpenFile("log.txt", os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
	if err != nil {
		fmt.Println(err)
		os.Exit(2)
	}
	return f
}

func main() {
	logF = openLog()
	defer logF.Close()

	log.SetOutput(logF)

	infoLog = log.New(logF, "INFO: ", log.Ldate|log.Ltime)
	errorLog = log.New(logF, "ERROR: ", log.Ldate|log.Ltime)

	infoLog.Println("log opened")

	err := loadConfig()
	switch {
	case os.IsNotExist(err):
		if !*is2Cloud {
			if err = createConfig(); err != nil {
				fmt.Println(err)
				errorLog.Fatalln(err)
			}
		} else {
			fmt.Println("config doesnt exist")
			errorLog.Fatalln("config doesnt exist")
		}
	case err != nil:
		fmt.Println(err)
		errorLog.Fatalln(err)
	}

	if conf.Prefix == "" || conf.Token == "" {
		fmt.Println("bad config")
		errorLog.Fatalln("bad config")
	}

	fmt.Println("Prefix is " + conf.Prefix)
	//infoLog.Println("Prefix is " + conf.Prefix)

	if dg == nil {
		if err := testLogin(); err != nil {
			fmt.Println(err)
			errorLog.Fatalln(err)
		}
	}

	loginTime = time.Now()
	if err := dg.Open(); err != nil {
		fmt.Println(err)
		errorLog.Fatalln(err)
	}
	defer dg.Close()

	prepareCommands()

	dg.AddHandlerOnce(ready)
	dg.AddHandler(message)

	sc := make(chan os.Signal, 1)
	signal.Notify(sc, syscall.SIGINT, syscall.SIGTERM, os.Interrupt, os.Kill)
	<-sc
}

func ready(s *discordgo.Session, m *discordgo.Ready) {
	fmt.Printf("Log-in successful! Log-in time: %.2f\n", time.Since(loginTime).Seconds())
	fmt.Printf("Joined %d guilds\n", len(m.Guilds))
	fmt.Println("Type Ctrl+C to quit 2Bot2Go")

	infoLog.Printf("Log-in successful! Log-in time: %.2f\n", time.Since(loginTime).Seconds())
	infoLog.Printf("Joined %d guilds\n", len(m.Guilds))
}

func message(s *discordgo.Session, m *discordgo.MessageCreate) {
	if m.Author.ID != s.State.User.ID || !strings.HasPrefix(m.Content, conf.Prefix) || len(strings.TrimPrefix(m.Content, conf.Prefix)) == 0 {
		return
	}

	parseCommand(s, m, strings.TrimPrefix(m.Content, conf.Prefix))
}