package main

import (
	"bufio"
	"fmt"
	"io/ioutil"
	"log"
	"net/http"
	"net/url"
	"os"
	"time"

	"golang.org/x/sys/windows/registry"
)

func main() {

	ex, err := os.Executable()
	if err != nil {
		log.Fatalf("failed to get executable path: %v", err)
	}
	programFullPath := fmt.Sprintf("\"%s\"", ex)

	ruTorrentURL, err := getRUTorrentURL()
	if err != nil {
		log.Fatalf("failed to get ruTorrent URL: %v", err)
	}

	if len(os.Args[1:]) < 1 {
		err := registerProtocolHandler(programFullPath)
		if err != nil {
			log.Fatalf("failed to register protocol handler for magnet URLs: %v", err)
		}
		log.Printf("successfully set registry handler for magnet links")
		return
	}

	magnetLink := os.Args[1]

	if len(magnetLink) > 7 {
		if magnetLink[:7] != "magnet:" {
			log.Fatalf("unexpected argument '%s', expected a magnet link", os.Args[1:])
		}
	}

	err = addRuTorrent(ruTorrentURL, magnetLink)
	if err != nil {
		log.Printf("failed to add magnet link to rutorrent: %v", err)

		fmt.Println(ruTorrentURL)
		fmt.Println(magnetLink)
		time.Sleep(time.Minute)
	}
}

func addRuTorrent(ruTorrentURL, magnetLink string) error {

	addTorrentEndpoint := fmt.Sprintf("%s/php/addtorrent.php", ruTorrentURL)

	/*
		magnetLink, err := url.QueryUnescape(magnetLink)
		if err != nil {
			return fmt.Errorf("failed to URL decode magnet link: %v", err)
		}*/

	form := url.Values{}
	form.Add("url", magnetLink)

	client := http.Client{}

	resp, err := client.PostForm(addTorrentEndpoint, form)
	if err != nil {
		return fmt.Errorf("failed to do POST request to '%s': %v", addTorrentEndpoint, err)
	}

	if resp.StatusCode != http.StatusOK {
		body, _ := ioutil.ReadAll(resp.Body)
		defer resp.Body.Close()
		fmt.Println(string(body))
		return fmt.Errorf("unexpected HTTP status code '%d', expected '%d'", resp.StatusCode, http.StatusOK)
	}

	return nil
}

func getRUTorrentURL() (string, error) {

	userConfigDir, err := os.UserConfigDir()
	if err != nil {
		return "", fmt.Errorf("failed to get user config dir: %v", err)
	}

	configDir := fmt.Sprintf("%s/dipole", userConfigDir)
	configFile := fmt.Sprintf("%s/dipole.conf", configDir)

	if _, err := os.Stat(configDir); os.IsNotExist(err) {
		if err := os.Mkdir(configDir, 0700); err != nil {
			return "", fmt.Errorf("failed to make config dir '%s': %v", configDir, err)
		}
	}

	var ruTorrentURL string
	if _, err := os.Stat(configFile); os.IsNotExist(err) {
		// collect
		fmt.Println("Enter your rutorrent instance URL: ")
		_, err = fmt.Scanln(&ruTorrentURL)
		if err != nil {
			return "", fmt.Errorf("failed to scan line while collecting rutorrent URL: %v", err)
		}

		f, err := os.OpenFile(configFile, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0755)
		if err != nil {
			return "", fmt.Errorf("failed to open config file '%s' for writing: %v", configFile, err)
		}

		_, err = f.Write([]byte(ruTorrentURL))
		if err != nil {
			return "", fmt.Errorf("failed to write ruTorrentURL to config file '%s': %v", configFile, err)
		}
		if err := f.Close(); err != nil {
			return "", fmt.Errorf("failed to close config file '%s': %v", configFile, err)
		}
	} else {
		f, err := os.Open(configFile)
		if err != nil {
			return "", fmt.Errorf("failed to open config file '%s': %v", configFile, err)
		}

		scanner := bufio.NewScanner(f)
		for scanner.Scan() {
			ruTorrentURL = scanner.Text()
		}
		if err := scanner.Err(); err != nil {
			return "", fmt.Errorf("failed to scan config file: %v", err)
		}

		if err := f.Close(); err != nil {
			return "", fmt.Errorf("failed to close config file '%s': %v", configFile, err)
		}
	}

	return ruTorrentURL, err
}

func registerProtocolHandler(programFullPath string) error {

	prefix := "SOFTWARE\\Classes\\"
	urlScheme := "magnet"
	basePath := prefix + urlScheme
	permission := uint32(registry.QUERY_VALUE | registry.SET_VALUE)
	baseKey := registry.CURRENT_USER

	// create key
	k, _, err := registry.CreateKey(baseKey, basePath, permission)
	if err != nil {
		return fmt.Errorf("failed to create base key: %v", err)
	}

	// set description
	err = k.SetStringValue("", "Dipole Magnet Link Handler")
	if err != nil {
		return fmt.Errorf("failed to set description string value: %v", err)
	}
	err = k.SetStringValue("URL Protocol", "")
	if err != nil {
		return fmt.Errorf("failed to set description url protocol value: %v", err)
	}

	// set icon
	k, _, err = registry.CreateKey(registry.CURRENT_USER, "lumiere\\DefaultIcon", registry.ALL_ACCESS)
	if err != nil {
		return fmt.Errorf("failed to set icon key: %v", err)
	}
	err = k.SetStringValue("", programFullPath+",1")
	if err != nil {
		return fmt.Errorf("failed to set programFullPath value for icon: %v", err)
	}

	// create tree
	_, _, err = registry.CreateKey(baseKey, basePath+"\\shell", permission)
	if err != nil {
		return fmt.Errorf("failed to create shell key: %v", err)
	}
	_, _, err = registry.CreateKey(baseKey, basePath+"\\shell\\open", permission)
	if err != nil {
		return fmt.Errorf("failed to create shell/open key: %v", err)
	}
	k, _, err = registry.CreateKey(baseKey, basePath+"\\shell\\open\\command", permission)
	if err != nil {
		return fmt.Errorf("failed to create shell/open/command key: %v", err)
	}

	// set open command
	err = k.SetStringValue("", programFullPath+" \"%1\"")
	if err != nil {
		return fmt.Errorf("failed to set programFullPath for open command: %v", err)
	}
	return nil
}