package main

import (
	"fmt"
	"log"
	"os"
	"strings"
	"time"

	"github.com/anacrolix/torrent"
)

func main() {
	if len(os.Args) < 2 {
		fmt.Println("Usage: ./magnet-to-torrent \"magnet_link\" [output.torrent]")
		os.Exit(1)
	}

	magnetLink := os.Args[1]
	outputFile := ""

	if len(os.Args) == 3 {
		outputFile = os.Args[2]
	}

	clientConfig := torrent.NewDefaultClientConfig()
	clientConfig.DataDir = os.TempDir()
	clientConfig.NoUpload = true

	client, err := torrent.NewClient(clientConfig)
	if err != nil {
		log.Fatalf("Error creating torrent client: %v", err)
	}
	defer client.Close()

	t, err := client.AddMagnet(magnetLink)
	if err != nil {
		log.Fatalf("Error adding magnet link: %v", err)
	}

	<-t.GotInfo()
	info := t.Metainfo()

	if outputFile == "" {
		outputFile = strings.ReplaceAll(t.Name(), " ", "_") + ".torrent"
	}

	f, err := os.Create(outputFile)
	if err != nil {
		log.Fatalf("Error creating file: %v", err)
	}
	defer f.Close()

	err = info.Write(f)
	if err != nil {
		log.Fatalf("Error writing torrent file: %v", err)
	}

	fmt.Printf("Torrent metadata saved to %s\n", outputFile)

	t.Drop()
	client.Close()

	// Give client some time to gracefully close
	time.Sleep(2 * time.Second)
}