/*
 * Copyright (C) 2008-2020, Juick
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package com.juick;

import com.juick.www.api.activity.model.objects.Person;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.core.io.Resource;
import org.springframework.util.Base64Utils;

import javax.net.ssl.KeyManagerFactory;
import java.io.IOException;
import java.io.InputStream;
import java.security.*;
import java.security.cert.Certificate;
import java.security.cert.CertificateException;
import java.security.spec.X509EncodedKeySpec;
import java.util.Arrays;

public class KeystoreManager {
    private static final Logger logger = LoggerFactory.getLogger("ActivityPub");

    private String keystorePassword;

    private KeyStore ks;

    public KeystoreManager(Resource keystore, String keystorePassword) {
        this.keystorePassword = keystorePassword;
        try (InputStream ksIs = keystore.getInputStream()) {
            ks = KeyStore.getInstance("PKCS12");
            ks.load(ksIs, keystorePassword.toCharArray());
            KeyManagerFactory kmf = KeyManagerFactory.getInstance(KeyManagerFactory
                    .getDefaultAlgorithm());
            kmf.init(ks, keystorePassword.toCharArray());
        } catch (IOException | KeyStoreException | NoSuchAlgorithmException | UnrecoverableKeyException | CertificateException e) {
            logger.error("Keystore error", e);
        }
    }

    private KeyPair getKeyPair() {
        Key privateKey;
        try {
            privateKey = ks.getKey("1", keystorePassword.toCharArray());
            Certificate certificate = ks.getCertificate("1");
            return new KeyPair(certificate.getPublicKey(), (PrivateKey) privateKey);
        } catch (KeyStoreException | NoSuchAlgorithmException | UnrecoverableKeyException e) {
            e.printStackTrace();
        }
        return null;
    }
    public PrivateKey getPrivateKey() {
        return getKeyPair().getPrivate();
    }
    public PublicKey getPublicKey() {
        return getKeyPair().getPublic();
    }
    public String getPublicKeyPem() {
        String[] key = Base64Utils.encodeToString(getKeyPair().getPublic().getEncoded()).split("(?<=\\G.{64})");
        return String.format("-----BEGIN PUBLIC KEY-----\n%s\n-----END PUBLIC KEY-----\n",
                String.join("\n", key));
    }
    public static PublicKey publicKeyOf(Person person) {
        String pubkeyPem = person.getPublicKey().getPublicKeyPem();
        String[] rawKey = pubkeyPem.split("\\n");
        String pubkeyData = String.join("", Arrays.asList(rawKey).subList(1, rawKey.length - 1));
        try{
            byte[] byteKey = Base64Utils.decodeFromString(pubkeyData);
            X509EncodedKeySpec X509publicKey = new X509EncodedKeySpec(byteKey);
            KeyFactory kf = KeyFactory.getInstance("RSA");
            return kf.generatePublic(X509publicKey);
        }
        catch(Exception e){
            e.printStackTrace();
        }
        return null;
    }
}