package encrypt

import (
	"crypto/rand"
	"crypto/rsa"
	"crypto/x509"
	"encoding/pem"
	"errors"
)

type Encrypt struct {
	PubKey  string `env:"ENCRYPT_PUBLIC_KEY"`
	PrivKey string `env:"ENCRYPT_PRIVATE_KEY"`
}

func (e *Encrypt) EncryptStr(str string) ([]byte, error) {
	block, _ := pem.Decode([]byte(e.PubKey))
	if block == nil {
		return nil, errors.New("failed to parse PEM block containing the public key")
	}
	pub, err := x509.ParsePKIXPublicKey(block.Bytes)
	if err != nil {
		return nil, err
	}
	rsaPubKey, ok := pub.(*rsa.PublicKey)
	if !ok {
		return nil, errors.New("failed to parse RSA public key")
	}

	shifr, err := rsa.EncryptPKCS1v15(rand.Reader, rsaPubKey, []byte(str))
	if err != nil {
		return nil, err
	}
	return shifr, nil
}

func (e *Encrypt) DecryptStr(shifr []byte) (string, error) {
	block, _ := pem.Decode([]byte(e.PrivKey))
	if block == nil {
		return "", errors.New("failed to parse PEM block containing the private key")
	}

	priv, err := x509.ParsePKCS1PrivateKey(block.Bytes)
	if err != nil {
		return "", err
	}

	res, err := rsa.DecryptPKCS1v15(rand.Reader, priv, shifr)
	if err != nil {
		return "", err
	}
	return string(res), nil
}