//+build darwin

package passgo

import (
	"bufio"
	"bytes"
	"encoding/hex"
	"fmt"
	"os"
	"os/exec"
	"os/user"
	"path"
	"strings"
	"strconv"
	"sync"

	"golang.org/x/crypto/openpgp"

	"github.com/jcmdev0/gpgagent"
	"github.com/fsnotify/fsnotify"
)

func (s *Store) nativeDecrypt(name string) (string, error) {
	fmt.Println("calling gpg -d")
	file := path.Join(s.Dir, strings.Join([]string{name, ".gpg"}, ""))
	if _, err := os.Stat(file); os.IsNotExist(err) {
		return "", fmt.Errorf("Not in password store.")
	}
	output, err := exec.Command("gpg", "-d", file).Output()
	if err != nil {
		return "", fmt.Errorf("Error running gpg: %s", err)
	}
	return string(output[:len(output)-1]), nil
}

func (s *Store) nativeEncrypt(pw string) ([]byte, error) {
	if s.Id == "" {
		return nil, fmt.Errorf("No ID")
	}
	fmt.Printf("Calling gpg -e -r %s\n", s.Id)
	cmd := exec.Command("gpg", "-e", "-r", s.Id)
	cmd.Stdin = strings.NewReader(pw + "\n")
	output, err := cmd.Output()
	if err != nil {
		fmt.Printf("Error running GPG: %s\n", err)
		return nil, err
	}
	fmt.Println("success")
	return output, nil
}

var (
	idMux sync.Mutex
	cachedIdentities []string
)

func nativeIdentities() ([]string, error) {
	idMux.Lock()
	defer idMux.Unlock()
	if cachedIdentities != nil {
		ret := make([]string,len(cachedIdentities))
		copy(ret, cachedIdentities)
		return ret, nil
	}
	ret := make([]string,0)
	fmt.Println("calling gpg")
	output, err := exec.Command("gpg", "--list-secret-keys", "--with-colons").Output()
	if err != nil {
		return nil, fmt.Errorf("Error running gpg: %s", err)
	}
	scanner := bufio.NewScanner(bytes.NewBuffer(output))
	for scanner.Scan() {
		fs := strings.Split(scanner.Text(),":")
		if fs[0] == "uid" {
			fmt.Printf("%s: %s\n",fs[0], fs[9])
			ret = append(ret, fs[9])
		}
	}
	if len(ret) > 0 {
		cachedIdentities = ret
	}
	return ret, nil
}

func setAgentInfo() {
	// get UID of current user
	usr, err := user.Current()
	if err != nil {
		fmt.Printf("Error: cannot get user ID: %s\n", err)
		return
	}
	uid := usr.Uid

	// get GPG Agent PID
	// look for gpg-agent running as the current user:
	output, err := exec.Command("pgrep", "-U", uid, "gpg-agent").Output()
	if err != nil {
		fmt.Printf("Error: %s\n", err)
		return
	} else {
		fmt.Printf("gpg-agent process number is %s\n", output)
	}
	// trim trailing /n and convert to int
	pid, err := strconv.Atoi(string(output[:len(output)-1]))
	if err != nil {
		fmt.Printf("Integer conversion failed: %s\n", err)
		return
	}

	// find agent socket file
	// find unix domain sockets opened by the current user's gpg-agent
	cmd := exec.Command("lsof", "-w", "-Fn", "-u", uid, "-baUcgpg-agent")
	stdout, err := cmd.StdoutPipe()
	if err != nil {
		fmt.Printf("Error: connect stdout to lsof: %s\n", err)
		return
	}
	scanner := bufio.NewScanner(stdout)
	err = cmd.Start()
	if err != nil {
		fmt.Printf("Error: cannot run lsof: %s\n", err)
	}

	// look for a socket named "S.gpg-agent"
	filename := ""
	for scanner.Scan() {
		x := scanner.Text()
		if x[0] != 'n' {
			continue
		}
		x = x[1:]
		if path.Base(x) == "S.gpg-agent" {
			fmt.Println(x)
			filename = x
		}
	}
	cmd.Wait()

	if filename == "" {
		fmt.Printf("Error: gpg-agent socket file not found\n")
		return
	}
	s := fmt.Sprintf("%s:%d:1", filename, pid)
	fmt.Printf("GPG_AGENT_INFO = %s\n", s)
	os.Setenv("GPG_AGENT_INFO", s)

	// gpg-agent is running, so use GPGPrompt as password prompt
	ask = GPGPrompt

}

func GPGPrompt(keys []openpgp.Key, symmetric bool) ([]byte, error) {
       conn, err := gpgagent.NewGpgAgentConn()
       if err != nil {
	       return nil, err
       }
       defer conn.Close()

       for _, key := range keys {
	       cacheId := strings.ToUpper(hex.EncodeToString(key.PublicKey.Fingerprint[:]))
	       request := gpgagent.PassphraseRequest{CacheKey: cacheId}
	       for i := 0; i < 3; i++ {
		       var passphrase string
		       passphrase, err = conn.GetPassphrase(&request)
		       if err != nil {
			       continue
		       }
		       err = key.PrivateKey.Decrypt([]byte(passphrase))
		       if err != nil {
			       conn.RemoveFromCache(cacheId)
			       continue
		       }
		       return []byte(passphrase), nil
	       }
	       return nil, err
       }
       return nil, fmt.Errorf("Unable to find key")
}

func init() {
	setAgentInfo()
	go func() {
		watcher, err := fsnotify.NewWatcher()
		if err != nil {
			fmt.Printf("Cannot create filesystem watcher: %s\n", err)
			return
		}
		u, err := user.Current()
		if err != nil {
			fmt.Printf("Cannot get current user: %s\n", err)
			return
		}
		watcher.Add(path.Join(u.HomeDir, ".gnupg"))
		fmt.Println("Watching ", path.Join(u.HomeDir, ".gnupg"))
		for {
			select {
			case <-watcher.Events:
				idMux.Lock()
				cachedIdentities = nil
				idMux.Unlock()
			}
		}
	}()
}

//Clip copies a string to the clipboard
func Clip(x string) {
	b := bytes.NewBuffer([]byte(x))
	cmd := exec.Command("pbcopy")
	cmd.Stdin = b
	cmd.Run()
}