package keys

import (
	"bytes"
	"crypto/aes"
	"crypto/ed25519"
	"crypto/rand"
	"crypto/sha256"
	"encoding/base64"
	"fmt"
	"github.com/matchsystems/werr"
	"os"
)

// TODO:
// default path is $HOME/.config/micw/keys
// ./micw-util keys regen
// -p | --path ./path
// ./micw-util keys get-pub
// -p | --path
// ./micw-util keys get
// -p | --path

func NewKeyFile(path string, password string) error {
	// TODO: Check if file already exists

	fmt.Printf("Generating new keys by path %s\n", path)
	public, private, err := ed25519.GenerateKey(rand.Reader)
	if err != nil {
		return err
	}

	fmt.Printf("Enter password (empty for no password):")
	var password string
	if _, err := fmt.Scanln(&password); err != nil {
		return err
	}

	buf := bytes.NewBuffer(public)
	if password != "" {
		encryptedPrivate := make([]byte, 0)
		passwordHash := sha256.Sum256([]byte(password))
		cypher, err := aes.NewCipher(passwordHash[:])
		if err != nil {
			return err
		}
		cypher.Encrypt(encryptedPrivate, private)
		// Separator
		// Byte between means if private key was encrypted
		buf.Write([]byte{'\n', 1, '\n'})
		buf.Write(encryptedPrivate)
	} else {
		buf.Write([]byte{'\n', 0, '\n'})
		buf.Write(private)
	}

	err = os.WriteFile(path, buf.Bytes(), 0600)
	return err
}

func ReadKeyFile(path string) ([][]byte, error) {
	data, err := os.ReadFile(path)
	if err != nil {
		return nil, err
	}
	dataSplited := bytes.Split(data, []byte("\n"))
	if len(dataSplited) != 3 {
		return nil, fmt.Errorf("invalid keys file. Expected 3 parts "+
			"(pub key, isEncrypted byte, encrypted private key), but got %d", len(dataSplited))
	}
	return dataSplited, nil
}

func GetPub(path string) (err error) {
	keyFileData, err := ReadKeyFile(path)
	if err != nil {
		return werr.Wrapf(err, "reading keys file %s", path)
	}
	fmt.Printf(base64.StdEncoding.EncodeToString(keyFileData[1]))
	return nil
}

func Get(path string) error {
	keyFileData, err := ReadKeyFile(path)
	if err != nil {
		return "", werr.Wrapf(err, "reading keys file %s", path)
	}
	publicKey := base64.StdEncoding.EncodeToString(keyFileData[1])
	// Split public and private
	// Return private
	return nil
}