package main

import (
	"database/sql"
	"fmt"
	"log"
	"os"
	"os/signal"
	"syscall"
	"strings"

	"github.com/BurntSushi/toml"
	"github.com/bwmarrin/discordgo"
	_ "github.com/lib/pq"
)

var (
	config Config
	client *discordgo.Session
	db     *sql.DB
)

type Config struct {
	Discord  Discord  `toml:"discord"`
	Database Database `toml:"database"`
}

type Discord struct {
	Token   string `toml:"token"`
	AppID	string	`toml:"appid"`
	GuildID string `toml:"guildid"`
}

type Database struct {
	Host     string `toml:"host"`
	Port     int    `toml:"port"`
	Name     string `toml:"name"`
	Username string `toml:"username"`
	Password string `toml:"password"`
}

func loadConfig(filename string) (Config, error) {
	var config Config
	_, err := toml.DecodeFile(filename, &config)
	return config, err
}

func connectDb(config Config) (*sql.DB, error) {
	connectionString := fmt.Sprintf(
		"host=%s port=%d user=%s password=%s dbname=%s sslmode=disable",
		config.Database.Host,
		config.Database.Port,
		config.Database.Username,
		config.Database.Password,
		config.Database.Name,
	)

	db, err := sql.Open("postgres", connectionString)
	if err != nil {
		return nil, fmt.Errorf("error connecting to the database: %v", err)
	}

	err = db.Ping()
	if err != nil {
		db.Close()
		return nil, fmt.Errorf("error pinging the database: %v", err)
	}

	log.Println("Successfully connected to the database.")
	return db, nil
}

func init() {
	var err error
	config, err = loadConfig("config.toml")
	if err != nil {
		log.Println("Error occurred whilst trying to load config:", err)
		return
	}

	client, err = discordgo.New("Bot " + config.Discord.Token)
	if err != nil {
		log.Println("Error initializing bot:", err)
		return
	}

	db, err = connectDb(config)
	if err != nil {
		log.Println("Error initializing db connection:", err)
		return
	}
}

func searchLink(message, format, sep string) string {
	return fmt.Sprintf(format, strings.Join(
		strings.Split(
			message,
			" ",
		),
		sep,
	))
}

var (
	commands = []discordgo.ApplicationCommand{
		{
			Name: "rickroll-em",
			Type: discordgo.UserApplicationCommand,
		},
		{
			Name: "google-it",
			Type: discordgo.MessageApplicationCommand,
		},
		{
			Name: "stackoverflow-it",
			Type: discordgo.MessageApplicationCommand,
		},
		{
			Name: "godoc-it",
			Type: discordgo.MessageApplicationCommand,
		},
		{
			Name: "discordjs-it",
			Type: discordgo.MessageApplicationCommand,
		},
		{
			Name: "discordpy-it",
			Type: discordgo.MessageApplicationCommand,
		},
	}
	commandsHandlers = map[string]func(client *discordgo.Session, i *discordgo.InteractionCreate){
		"rickroll-em": func(client *discordgo.Session, i *discordgo.InteractionCreate) {
			err := client.InteractionRespond(i.Interaction, &discordgo.InteractionResponse{
				Type: discordgo.InteractionResponseChannelMessageWithSource,
				Data: &discordgo.InteractionResponseData{
					Content: "Operation rickroll has begun",
					Flags:   discordgo.MessageFlagsEphemeral,
				},
			})
			if err != nil {
				panic(err)
			}

			ch, err := client.UserChannelCreate(
				i.ApplicationCommandData().TargetID,
			)
			if err != nil {
				_, err = client.FollowupMessageCreate(i.Interaction, true, &discordgo.WebhookParams{
					Content: fmt.Sprintf("Mission failed. Cannot send a message to this user: %q", err.Error()),
					Flags:   discordgo.MessageFlagsEphemeral,
				})
				if err != nil {
					panic(err)
				}
			}
			_, err = client.ChannelMessageSend(
				ch.ID,
				fmt.Sprintf("%s sent you this: https://youtu.be/dQw4w9WgXcQ", i.Member.Mention()),
			)
			if err != nil {
				panic(err)
			}
		},
		"google-it": func(s *discordgo.Session, i *discordgo.InteractionCreate) {
			err := client.InteractionRespond(i.Interaction, &discordgo.InteractionResponse{
				Type: discordgo.InteractionResponseChannelMessageWithSource,
				Data: &discordgo.InteractionResponseData{
					Content: searchLink(
						i.ApplicationCommandData().Resolved.Messages[i.ApplicationCommandData().TargetID].Content,
						"https://google.com/search?q=%s", "+"),
					Flags: discordgo.MessageFlagsEphemeral,
				},
			})
			if err != nil {
				panic(err)
			}
		},
		"stackoverflow-it": func(s *discordgo.Session, i *discordgo.InteractionCreate) {
			err := client.InteractionRespond(i.Interaction, &discordgo.InteractionResponse{
				Type: discordgo.InteractionResponseChannelMessageWithSource,
				Data: &discordgo.InteractionResponseData{
					Content: searchLink(
						i.ApplicationCommandData().Resolved.Messages[i.ApplicationCommandData().TargetID].Content,
						"https://stackoverflow.com/search?q=%s", "+"),
					Flags: discordgo.MessageFlagsEphemeral,
				},
			})
			if err != nil {
				panic(err)
			}
		},
		"godoc-it": func(s *discordgo.Session, i *discordgo.InteractionCreate) {
			err := client.InteractionRespond(i.Interaction, &discordgo.InteractionResponse{
				Type: discordgo.InteractionResponseChannelMessageWithSource,
				Data: &discordgo.InteractionResponseData{
					Content: searchLink(
						i.ApplicationCommandData().Resolved.Messages[i.ApplicationCommandData().TargetID].Content,
						"https://pkg.go.dev/search?q=%s", "+"),
					Flags: discordgo.MessageFlagsEphemeral,
				},
			})
			if err != nil {
				panic(err)
			}
		},
		"discordjs-it": func(s *discordgo.Session, i *discordgo.InteractionCreate) {
			err := client.InteractionRespond(i.Interaction, &discordgo.InteractionResponse{
				Type: discordgo.InteractionResponseChannelMessageWithSource,
				Data: &discordgo.InteractionResponseData{
					Content: searchLink(
						i.ApplicationCommandData().Resolved.Messages[i.ApplicationCommandData().TargetID].Content,
						"https://discord.js.org/#/docs/main/stable/search?query=%s", "+"),
					Flags: discordgo.MessageFlagsEphemeral,
				},
			})
			if err != nil {
				panic(err)
			}
		},
		"discordpy-it": func(s *discordgo.Session, i *discordgo.InteractionCreate) {
			err := client.InteractionRespond(i.Interaction, &discordgo.InteractionResponse{
				Type: discordgo.InteractionResponseChannelMessageWithSource,
				Data: &discordgo.InteractionResponseData{
					Content: searchLink(
						i.ApplicationCommandData().Resolved.Messages[i.ApplicationCommandData().TargetID].Content,
						"https://discordpy.readthedocs.io/en/stable/search.html?q=%s", "+"),
					Flags: discordgo.MessageFlagsEphemeral,
				},
			})
			if err != nil {
				panic(err)
			}
		},
	}
)

func main() {
	if client == nil {
		log.Println("Bot client is not initialized")
		return
	}

	client.AddHandler(func(client *discordgo.Session, r *discordgo.Ready) {
		log.Println("Bot is online")
	})

	
	client.AddHandler(func(client *discordgo.Session, i *discordgo.InteractionCreate) {
		if h, ok := commandsHandlers[i.ApplicationCommandData().Name]; ok {
			h(client, i)
		}
	})

	cmdIDs := make(map[string]string, len(commands))

	for _, cmd := range commands {
		rcmd, err := client.ApplicationCommandCreate(config.Discord.AppID, config.Discord.GuildID, &cmd)
		if err != nil {
			log.Fatalf("Cannot create slash command %q: %v", cmd.Name, err)
		}

		cmdIDs[rcmd.ID] = rcmd.Name

	}

	err := client.Open()
	if err != nil {
		log.Println("Error opening connection:", err)
		return
	}	

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

	log.Println("Gracefully shutting down.")
	client.Close()

	if db != nil {
		db.Close()
	}
}