package java2.koz01.lab13;

import java.io.BufferedReader;
import java.io.IOException;
import java.math.BigInteger;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.NoSuchAlgorithmException;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.RSAPrivateKeySpec;
import java.security.spec.RSAPublicKeySpec;

public class KeyPairLoader {

	private KeyFactory kf;

	public KeyPairLoader() throws NoSuchAlgorithmException {
		kf = KeyFactory.getInstance("RSA");
	}

	public KeyPair load(String file) throws IOException, InvalidKeySpecException {
		try (BufferedReader br = Files.newBufferedReader(Paths.get(file))) {
			BigInteger modulus = new BigInteger(br.readLine());
			BigInteger pubExp = new BigInteger(br.readLine());
			BigInteger privExp = new BigInteger(br.readLine());
			RSAPrivateKeySpec priv = new RSAPrivateKeySpec(modulus, privExp);
			RSAPublicKeySpec pub = new RSAPublicKeySpec(modulus, pubExp);
			return new KeyPair(kf.generatePublic(pub), kf.generatePrivate(priv));
		}
	}
}