package main

import (
	"context"
	"log"
	"matrix-bot/bot"
	"os"
	"path/filepath"
	"sync"

	"maunium.net/go/mautrix"
	"maunium.net/go/mautrix/crypto"
	"maunium.net/go/mautrix/crypto/cryptohelper"
	"maunium.net/go/mautrix/event"
	"maunium.net/go/mautrix/id"
)

var homeserver string
var username string
var password string
var roomID string
var userId string
var accessToken string
var deviceId string
var pickleKeyString string
var recoveryKey string
var cryptoDBPath string

func setupCryptoHelper(cli *mautrix.Client) (*cryptohelper.CryptoHelper, error) {
	// remember to use a secure key for the pickle key in production
	pickleKey := []byte(pickleKeyString)

	if cryptoDBPath != "" {
		dir := filepath.Dir(cryptoDBPath)
		if dir != "." {
			if err := os.MkdirAll(dir, 0o755); err != nil {
				return nil, err
			}
		}
	}

	helper, err := cryptohelper.NewCryptoHelper(cli, pickleKey, cryptoDBPath)
	if err != nil {
		return nil, err
	}

	err = helper.Init(context.Background())
	if err != nil {
		return nil, err
	}

	return helper, nil
}

func verifyWithRecoveryKey(machine *crypto.OlmMachine) (err error) {
	ctx := context.Background()

	keyId, keyData, err := machine.SSSS.GetDefaultKeyData(ctx)
	if err != nil {
		return
	}
	key, err := keyData.VerifyRecoveryKey(keyId, recoveryKey)
	if err != nil {
		return
	}
	err = machine.FetchCrossSigningKeysFromSSSS(ctx, key)
	if err != nil {
		return
	}
	err = machine.SignOwnDevice(ctx, machine.OwnIdentity())
	if err != nil {
		return
	}
	err = machine.SignOwnMasterKey(ctx)

	return
}

func envOrFatal(key string) string {
	val := os.Getenv(key)
	if val == "" {
		log.Fatalf("missing required env var: %s", key)
	}
	return val
}

func envOrDefault(key string, def string) string {
	val := os.Getenv(key)
	if val == "" {
		return def
	}
	return val
}

func loadConfig() {
	homeserver = envOrFatal("MATRIX_HOMESERVER")
	username = envOrDefault("MATRIX_USERNAME", "")
	password = envOrDefault("MATRIX_PASSWORD", "")
	roomID = envOrDefault("MATRIX_ROOM_ID", "")
	userId = envOrFatal("MATRIX_USER_ID")
	accessToken = envOrFatal("MATRIX_ACCESS_TOKEN")
	deviceId = envOrFatal("MATRIX_DEVICE_ID")
	pickleKeyString = envOrFatal("MATRIX_PICKLE_KEY")
	recoveryKey = envOrFatal("MATRIX_RECOVERY_KEY")
	cryptoDBPath = envOrDefault("MATRIX_CRYPTO_DB", "crypto.db")
}

func main() {
	var err error
	loadConfig()
	bot.Load()

	client, err := mautrix.NewClient(homeserver, id.UserID(userId), accessToken)
	if err != nil {
		log.Fatal(err)
	}
	client.DeviceID = id.DeviceID(deviceId)

	syncer := mautrix.NewDefaultSyncer()
	client.Syncer = syncer

	cryptoHelper, err := setupCryptoHelper(client)
	if err != nil {
		log.Fatal(err)
	}
	client.Crypto = cryptoHelper

	syncer.OnEventType(event.EventMessage, func(ctx context.Context, evt *event.Event) {
		// Ignore our own messages
		if evt.Sender.String() == userId {
			return
		}

		content := evt.Content.AsMessage()
		if content.MsgType != event.MsgText {
			return
		}

		log.Printf("Message from %s: %s\n", evt.Sender, content.Body)

		response := bot.HandleCommand(content.Body, evt.Sender.String(), evt.RoomID.String(),
			ctx, client, evt, &event.RelatesTo{
				InReplyTo: &event.InReplyTo{EventID: evt.ID},
			})
		if response == nil {
			return
		}

		for _, resp := range response {
			switch r := resp.(type) {
			case event.MessageEventContent:
				_, err := client.SendMessageEvent(ctx, evt.RoomID, event.EventMessage, r)
				if err != nil {
					log.Println("Send error:", err)
				}
			default:
				log.Println("Unknown response type")
			}
		}
	})
	ready := make(chan struct{})
	var once sync.Once
	syncer.OnSync(func(ctx context.Context, resp *mautrix.RespSync, since string) bool {
		once.Do(func() { close(ready) })
		return true
	})

	go func() {
		if err := client.Sync(); err != nil {
			log.Fatal(err)
		}
	}()

	log.Println("Waiting for initial sync...")
	<-ready
	log.Println("Sync complete")

	if err := verifyWithRecoveryKey(cryptoHelper.Machine()); err != nil {
		log.Fatal(err)
	}

	log.Println("Bot is running...")
	select {}
}