package main

import (
	"fmt"
	"log"
	"os"
	"os/signal"
	"strconv"
	"strings"
	"syscall"

	"github.com/bwmarrin/discordgo"
)

const TriggerWord = "!syl-"

var points = map[rune]int{
	'A': 1, 'O': 1, 'I': 1, 'E': 1,
	'C': 2, 'R': 2, 'S': 2, 'T': 2,
	'L': 3, 'M': 3, 'N': 3, 'U': 3,
	'W': 4, 'Y': 4,
	'B': 5, 'D': 5, 'F': 5, 'P': 5, 'V': 5, 'K': 5,
	'G': 8, 'H': 8, 'Z': 8, 'J': 8, 'X': 8,
	'Q': 10,
}

func scrabbleScore(letters string) int {
	letters = strings.ToUpper(letters)
	totalScore := 0
	for _, glyph := range letters {
		letterScore, ok := points[glyph]
		if ok {
			totalScore += letterScore
		}
	}
	return totalScore
}

func scrabbleToStr(letters string) string {
	letters = strings.ToUpper(letters)
	arr := []string{}
	for _, glyph := range letters {
		letterScore, ok := points[glyph]
		if ok {
			arr = append(arr, fmt.Sprintf("%s=%d", string(glyph), letterScore))
		}
	}
	return strings.Join(arr, " + ")
}

func main() {
	token := os.Getenv("TOKEN")
	if token == "" {
		panic("TOKEN env var is missing")
	}

	// Create a new Discordgo session
	dg, err := discordgo.New(token)
	checkErr(err)

	dg.AddHandler(func(s *discordgo.Session, m *discordgo.MessageCreate) {
		// Ignore bot commands
		if m.Author.Bot {
			return
		}

		if strings.HasPrefix(m.Content, TriggerWord) {
			msg := m.Content[len(TriggerWord):]
			parts := strings.SplitN(msg, " ", 2)
			if len(parts) < 2 {
				return
			}
			maxsize, err := strconv.Atoi(parts[0])
			if err != nil {
				return
			}
			score := scrabbleScore(parts[1])
			slot := score % maxsize
			_, err = s.ChannelMessageSendEmbed(m.ChannelID, &discordgo.MessageEmbed{
				Author: &discordgo.MessageEmbedAuthor{
					Name: "Scrabble Sylladex",
				},
				Title:       fmt.Sprintf("Risultato: %d", slot+1),
				Description: fmt.Sprintf("\"%s\" va nello slot %d (di %d)", parts[1], slot+1, maxsize),
				Fields: []*discordgo.MessageEmbedField{
					{
						Name:  "Valore parola",
						Value: fmt.Sprintf("%s = %d", scrabbleToStr(parts[1]), score),
					}, {
						Name:  "Posizionamento",
						Value: fmt.Sprintf("%d mod %d = %d → %d", score, maxsize, slot, slot+1),
					},
				},
			})
			if err != nil {
				log.Printf("Error: %s\n", err.Error())
			}
		}
	})

	dg.AddHandler(func(s *discordgo.Session, m *discordgo.Ready) {
		log.Print("ready")
	})

	checkErr(dg.Open())
	defer dg.Close()

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

func checkErr(err error) {
	if err != nil {
		log.Fatalf("FATAL ERROR: %s", err.Error())
		os.Exit(1)
	}
}