// discord – Discord-Bot für my-brain-importer
// Unterstützt /ask, /ingest und @Mention
package main

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

	"github.com/bwmarrin/discordgo"

	"my-brain-importer/internal/brain"
	"my-brain-importer/internal/config"
)

var (
	dg      *discordgo.Session
	botUser *discordgo.User

	commands = []*discordgo.ApplicationCommand{
		{
			Name:        "ask",
			Description: "Stelle eine Frage an deinen AI Brain (mit Wissensdatenbank)",
			Options: []*discordgo.ApplicationCommandOption{
				{
					Type:        discordgo.ApplicationCommandOptionString,
					Name:        "frage",
					Description: "Die Frage, die du stellen möchtest",
					Required:    true,
				},
			},
		},
		{
			Name:        "asknobrain",
			Description: "Stelle eine Frage direkt ans LLM (ohne Wissensdatenbank)",
			Options: []*discordgo.ApplicationCommandOption{
				{
					Type:        discordgo.ApplicationCommandOptionString,
					Name:        "frage",
					Description: "Die Frage, die du stellen möchtest",
					Required:    true,
				},
			},
		},
		{
			Name:        "ingest",
			Description: "Importiert Markdown-Notizen aus brain_root in die Wissensdatenbank",
		},
		{
			Name:        "remember",
			Description: "Speichert eine Nachricht in der Wissensdatenbank",
			Options: []*discordgo.ApplicationCommandOption{
				{
					Type:        discordgo.ApplicationCommandOptionString,
					Name:        "text",
					Description: "Der Text, der gespeichert werden soll",
					Required:    true,
				},
			},
		},
	}
)

func main() {
	config.LoadConfig()

	token := config.Cfg.Discord.Token
	if token == "" || token == "dein-discord-bot-token" {
		log.Fatal("❌ Kein Discord-Token in config.yml konfiguriert (discord.token)")
	}

	var err error
	dg, err = discordgo.New("Bot " + token)
	if err != nil {
		log.Fatalf("❌ Discord-Session konnte nicht erstellt werden: %v", err)
	}

	dg.AddHandler(onReady)
	dg.AddHandler(onInteraction)
	dg.AddHandler(onMessage)

	dg.Identify.Intents = discordgo.IntentsGuilds |
		discordgo.IntentsGuildMessages |
		discordgo.IntentMessageContent

	if err = dg.Open(); err != nil {
		log.Fatalf("❌ Verbindung zu Discord fehlgeschlagen: %v", err)
	}
	defer dg.Close()

	registerCommands()

	fmt.Println("✅ Bot läuft. Drücke CTRL+C zum Beenden.")
	stop := make(chan os.Signal, 1)
	signal.Notify(stop, syscall.SIGINT, syscall.SIGTERM)
	<-stop
	fmt.Println("\n👋 Bot wird beendet...")
}

func onReady(s *discordgo.Session, r *discordgo.Ready) {
	botUser = r.User
	fmt.Printf("✅ Eingeloggt als %s#%s\n", r.User.Username, r.User.Discriminator)
}

func registerCommands() {
	guildID := config.Cfg.Discord.GuildID
	registered, err := dg.ApplicationCommandBulkOverwrite(dg.State.User.ID, guildID, commands)
	if err != nil {
		log.Fatalf("❌ Slash-Commands konnten nicht registriert werden: %v", err)
	}
	scope := "global"
	if guildID != "" {
		scope = "guild " + guildID
	}
	for _, cmd := range registered {
		fmt.Printf("📝 Slash-Command /%s registriert (%s)\n", cmd.Name, scope)
	}
}

func onInteraction(s *discordgo.Session, i *discordgo.InteractionCreate) {
	if i.Type != discordgo.InteractionApplicationCommand {
		return
	}

	switch i.ApplicationCommandData().Name {
	case "ask":
		handleAsk(s, i, i.ApplicationCommandData().Options[0].StringValue(), true)
	case "asknobrain":
		handleAsk(s, i, i.ApplicationCommandData().Options[0].StringValue(), false)
	case "ingest":
		handleIngest(s, i)
	case "remember":
		handleRemember(s, i)
	}
}

func onMessage(s *discordgo.Session, m *discordgo.MessageCreate) {
	if m.Author.Bot {
		return
	}
	if botUser == nil {
		return
	}

	mentioned := false
	for _, u := range m.Mentions {
		if u.ID == botUser.ID {
			mentioned = true
			break
		}
	}
	if !mentioned {
		return
	}

	// Mention aus der Nachricht entfernen
	question := strings.TrimSpace(
		strings.ReplaceAll(m.Content, "<@"+botUser.ID+">", ""),
	)
	if question == "" {
		s.ChannelMessageSend(m.ChannelID, "Stell mir eine Frage! Beispiel: @Brain Was sind meine TODOs?")
		return
	}

	s.ChannelTyping(m.ChannelID)
	reply := queryAndFormat(question)
	s.ChannelMessageSendReply(m.ChannelID, reply, m.Reference())
}

func handleAsk(s *discordgo.Session, i *discordgo.InteractionCreate, question string, useBrain bool) {
	s.InteractionRespond(i.Interaction, &discordgo.InteractionResponse{
		Type: discordgo.InteractionResponseDeferredChannelMessageWithSource,
	})

	var reply string
	if useBrain {
		reply = queryAndFormat(question)
	} else {
		answer, err := brain.ChatDirect(question)
		if err != nil {
			reply = fmt.Sprintf("❌ Fehler: %v", err)
		} else {
			reply = fmt.Sprintf("💬 **Antwort:** _%s_\n\n%s", question, answer)
		}
	}

	s.InteractionResponseEdit(i.Interaction, &discordgo.WebhookEdit{
		Content: &reply,
	})
}

func handleIngest(s *discordgo.Session, i *discordgo.InteractionCreate) {
	s.InteractionRespond(i.Interaction, &discordgo.InteractionResponse{
		Type: discordgo.InteractionResponseDeferredChannelMessageWithSource,
	})

	fmt.Println("📥 Ingest gestartet via Discord...")
	brain.RunIngest(config.Cfg.BrainRoot)

	msg := fmt.Sprintf("✅ Ingest abgeschlossen! Quelle: `%s`", config.Cfg.BrainRoot)
	s.InteractionResponseEdit(i.Interaction, &discordgo.WebhookEdit{
		Content: &msg,
	})
}

func handleRemember(s *discordgo.Session, i *discordgo.InteractionCreate) {
	s.InteractionRespond(i.Interaction, &discordgo.InteractionResponse{
		Type: discordgo.InteractionResponseDeferredChannelMessageWithSource,
	})

	text := i.ApplicationCommandData().Options[0].StringValue()
	var author string
	if i.Member != nil {
		author = i.Member.User.Username
	} else if i.User != nil {
		author = i.User.Username
	} else {
		author = "unknown"
	}
	source := fmt.Sprintf("discord/#%s", i.ChannelID)

	err := brain.IngestChatMessage(text, author, source)
	var msg string
	if err != nil {
		msg = fmt.Sprintf("❌ Fehler beim Speichern: %v", err)
	} else {
		msg = fmt.Sprintf("✅ Gespeichert: _%s_", text)
	}
	s.InteractionResponseEdit(i.Interaction, &discordgo.WebhookEdit{Content: &msg})
}

func queryAndFormat(question string) string {
	answer, chunks, err := brain.AskQuery(question)
	if err != nil {
		return fmt.Sprintf("❌ Fehler: %v", err)
	}
	if len(chunks) == 0 {
		return "❌ Keine relevanten Informationen in der Datenbank gefunden.\nFüge mehr Daten mit `/ingest` hinzu."
	}

	var sb strings.Builder
	fmt.Fprintf(&sb, "💬 **Antwort auf:** _%s_\n\n", question)
	sb.WriteString(answer)
	sb.WriteString("\n\n📚 **Quellen:**\n")
	for _, chunk := range chunks {
		fmt.Fprintf(&sb, "• %.1f%% – %s\n", chunk.Score*100, chunk.Source)
	}
	return sb.String()
}