package org.helioviewer.jhv.io;

import java.io.IOException;
import java.io.InputStream;
import java.security.GeneralSecurityException;
import java.security.KeyStore;
import java.security.cert.Certificate;
import java.security.cert.CertificateFactory;
import java.util.Arrays;
import java.util.Collection;

import javax.net.ssl.KeyManagerFactory;
import javax.net.ssl.HttpsURLConnection;
import javax.net.ssl.SSLContext;
import javax.net.ssl.TrustManager;
import javax.net.ssl.TrustManagerFactory;
import javax.net.ssl.X509TrustManager;

import org.helioviewer.jhv.base.FileUtils;

class SSLCert {

    static void addRootCA(String cert) {
        try {
            X509TrustManager trustManager = trustManagerForCertificates(FileUtils.getResourceInputStream("/cert/" + cert));
            SSLContext sslContext = SSLContext.getInstance("TLS");
            sslContext.init(null, new TrustManager[]{ trustManager }, null);
            HttpsURLConnection.setDefaultSSLSocketFactory(sslContext.getSocketFactory());
        } catch (GeneralSecurityException e) {
            throw new RuntimeException(e);
        }
    }

    private static X509TrustManager trustManagerForCertificates(InputStream in) throws GeneralSecurityException {
        CertificateFactory certificateFactory = CertificateFactory.getInstance("X.509");
        Collection<? extends Certificate> certificates = certificateFactory.generateCertificates(in);
        if (certificates.isEmpty()) {
            throw new IllegalArgumentException("expected non-empty set of trusted certificates");
        }

        // Put the certificates a key store
        char[] password = "password".toCharArray(); // Any password will work
        KeyStore keyStore = newEmptyKeyStore(password);
        int index = 0;
        for (Certificate certificate : certificates) {
            String certificateAlias = Integer.toString(index++);
            keyStore.setCertificateEntry(certificateAlias, certificate);
        }

        // Use it to build an X509 trust manager
        KeyManagerFactory keyManagerFactory = KeyManagerFactory.getInstance(KeyManagerFactory.getDefaultAlgorithm());
        keyManagerFactory.init(keyStore, password);
        TrustManagerFactory trustManagerFactory = TrustManagerFactory.getInstance(TrustManagerFactory.getDefaultAlgorithm());
        trustManagerFactory.init(keyStore);
        TrustManager[] trustManagers = trustManagerFactory.getTrustManagers();
        if (trustManagers.length != 1 || !(trustManagers[0] instanceof X509TrustManager)) {
            throw new IllegalStateException("Unexpected default trust managers:" + Arrays.toString(trustManagers));
        }
        return (X509TrustManager) trustManagers[0];
    }

    private static KeyStore newEmptyKeyStore(char[] password) throws GeneralSecurityException {
        try {
            KeyStore keyStore = KeyStore.getInstance(KeyStore.getDefaultType());
            InputStream in = null; // By convention, 'null' creates an empty key store
            keyStore.load(in, password);
            return keyStore;
        } catch (IOException e) {
            throw new AssertionError(e);
        }
    }

}

Add root certificate without destroying system ones
Add root certificate without destroying system ones
