package localconfig

import (
	"bufio"
	"encoding/json"
	"errors"
	"fmt"
	"math/rand"
	"os"
	"strings"
	"time"

	"github.com/ProtonMail/gopenpgp/v2/helper"
	"github.com/howeyc/gopass"
)

// Creds is user credentials
type Creds struct {
	Login    string
	Password string
}

func randomString(n int) string {
	rand.Seed(time.Now().UnixNano())
	var letters = []rune("яшертёыуиопющэъасдфгчйкльжзхцвбнмabéàèùàçïôÖcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789&([-|_@])=+§!:;,*%$£µ")
	s := make([]rune, n)
	for i := range s {
		s[i] = letters[rand.Intn(len(letters))]
	}
	return string(s)
}

func loadRootKey() []byte {
	rkpath := getConfig("rk")
	rk, err := os.ReadFile(rkpath)
	if err != nil {
		rk = []byte(randomString(64))
		os.WriteFile(rkpath, rk, 0600)
	}
	return rk
}

func (creds *Creds) Exists(filename string) bool {
	if _, err := os.Stat(getConfig(filename)); err == nil {
		return true
	} else if errors.Is(err, os.ErrNotExist) {
		return false
	} else {
		return false
	}
}

// Init will initalize login/password
func (creds *Creds) Init(filename string) {
	fmt.Print("Enter login: ")
	var login string
	reader := bufio.NewReader(os.Stdin)
	login, _ = reader.ReadString('\n')
	creds.Login = strings.Trim(login, "\r\n")
	if login != "" {
		fmt.Print("Enter password:")
		bytePassword, _ := gopass.GetPasswd()
		silentPassword := string(bytePassword)
		if silentPassword != "" {
			creds.Password = silentPassword
			b, _ := json.Marshal(creds)
			fmt.Println("Writing credentials to : " + getConfig(filename))
			armor, _ := helper.EncryptMessageWithPassword(loadRootKey(), string(b))
			os.WriteFile(getConfig(filename), []byte(armor), 0600)
		}
	}
}

// Pw : update password
func (creds *Creds) NewPw(filename string) {
	fmt.Print("Enter new password:")
	bytePassword, _ := gopass.GetPasswd()
	silentPassword := string(bytePassword)
	if silentPassword != "" {
		creds.Password = silentPassword
		b, _ := json.Marshal(creds)
		armor, _ := helper.EncryptMessageWithPassword(loadRootKey(), string(b))
		os.WriteFile(getConfig(filename), []byte(armor), 0600)
	}
}

// Load credentials if available or creates them
func (creds *Creds) Load(filename string) error {
	indata, err := os.ReadFile(getConfig(filename))
	if err != nil {
		creds.Init(filename)
		return nil
	}
	pass, err := helper.DecryptMessageWithPassword(loadRootKey(), string(indata))
	if err != nil {
		creds.Init(filename)
		return nil
	}
	err = json.Unmarshal([]byte(pass), &creds)
	if err != nil {
		creds.Init(filename)
		return nil
	}
	return nil
}