//+build darwin

package passgo

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

	"git.wow.st/gmp/clip"

	"golang.org/x/crypto/openpgp"

	"github.com/jcmdev0/gpgagent"
)

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()
}

//Clip copies a string to the clipboard
func Clip(x string) {
	clip.Set(x)
}