// Command verify sets up cross-signing keys for a Matrix bot user.
// This eliminates the "Encrypted by a device not verified by its owner" warning.
//
// Usage:
//
//	go run -tags goolm ./cmd/verify --homeserver https://... --username asistente-2 --password <pass> --token <access_token>
package main

import (
	"context"
	"crypto/sha256"
	"fmt"
	"os"
	"path/filepath"
	"strings"

	"github.com/spf13/cobra"
	"maunium.net/go/mautrix"
	"maunium.net/go/mautrix/crypto"
	"maunium.net/go/mautrix/crypto/cryptohelper"
	"maunium.net/go/mautrix/id"
)

func main() {
	var (
		homeserver string
		username   string
		password   string
		token      string
		storePath  string
	)

	root := &cobra.Command{
		Use:   "verify",
		Short: "Set up cross-signing keys for a Matrix bot",
		Long: `Generates and uploads cross-signing keys so the bot's device is verified.
This removes the "Encrypted by a device not verified by its owner" warning.

Requires the bot's access token and password (for UIA during key upload).`,
		RunE: func(cmd *cobra.Command, args []string) error {
			homeserver = strings.TrimRight(homeserver, "/")
			serverName := homeserver
			serverName = strings.TrimPrefix(serverName, "https://")
			serverName = strings.TrimPrefix(serverName, "http://")

			userID := id.UserID(fmt.Sprintf("@%s:%s", username, serverName))
			fmt.Printf("→ Setting up cross-signing for %s\n", userID)

			// Create mautrix client
			client, err := mautrix.NewClient(homeserver, userID, token)
			if err != nil {
				return fmt.Errorf("create client: %w", err)
			}

			ctx := context.Background()

			// Resolve device ID
			whoami, err := client.Whoami(ctx)
			if err != nil {
				return fmt.Errorf("whoami: %w", err)
			}
			client.DeviceID = whoami.DeviceID
			fmt.Printf("→ Device ID: %s\n", client.DeviceID)

			// Initialize crypto
			sum := sha256.Sum256([]byte(token))
			pickleKey := sum[:]

			dbPath := filepath.Join(storePath, "crypto.db")
			if err := os.MkdirAll(filepath.Dir(dbPath), 0700); err != nil {
				return fmt.Errorf("create store dir: %w", err)
			}

			helper, err := cryptohelper.NewCryptoHelper(client, pickleKey, dbPath)
			if err != nil {
				return fmt.Errorf("create crypto helper: %w", err)
			}
			helper.DBAccountID = username

			if err := helper.Init(ctx); err != nil {
				return fmt.Errorf("init crypto: %w", err)
			}
			defer helper.Close()

			client.Crypto = helper

			// Get the OlmMachine to generate cross-signing keys
			olmMachine := helper.Machine()
			if olmMachine == nil {
				return fmt.Errorf("olm machine not available")
			}

			fmt.Println("→ Generating and uploading cross-signing keys...")
			_, _, err = olmMachine.GenerateAndUploadCrossSigningKeysWithPassword(ctx, password, "")
			if err != nil {
				// If keys already exist, try to just sign our device
				fmt.Printf("  Note: %v\n", err)
				fmt.Println("→ Attempting to sign own device with existing keys...")
				return signOwnDevice(ctx, olmMachine, client)
			}

			fmt.Println("✓ Cross-signing keys uploaded successfully")
			fmt.Printf("✓ Device %s is now verified by %s\n", client.DeviceID, userID)
			return nil
		},
	}

	root.Flags().StringVar(&homeserver, "homeserver", "", "Matrix homeserver URL")
	root.Flags().StringVar(&username, "username", "", "Bot username (without @ or server)")
	root.Flags().StringVar(&password, "password", "", "Bot password (for UIA auth)")
	root.Flags().StringVar(&token, "token", "", "Bot access token")
	root.Flags().StringVar(&storePath, "store", "./data/verify-crypto/", "Crypto store path")
	_ = root.MarkFlagRequired("homeserver")
	_ = root.MarkFlagRequired("username")
	_ = root.MarkFlagRequired("password")
	_ = root.MarkFlagRequired("token")

	if err := root.Execute(); err != nil {
		os.Exit(1)
	}
}

func signOwnDevice(ctx context.Context, mach *crypto.OlmMachine, client *mautrix.Client) error {
	device := &id.Device{
		UserID:   client.UserID,
		DeviceID: client.DeviceID,
	}
	err := mach.SignOwnDevice(ctx, device)
	if err != nil {
		return fmt.Errorf("sign own device: %w", err)
	}
	fmt.Printf("✓ Device %s signed with cross-signing key\n", client.DeviceID)
	return nil
}