/*

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code 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 General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 */

/**

 *

 * @author Sean Mullan

 * @author Steve Hanna

 *

 */

import java.io.ByteArrayOutputStream;

import java.io.File;

import java.io.FileInputStream;

import java.io.InputStream;

import java.io.IOException;

import java.security.cert.CertificateFactory;

import java.security.cert.CertPath;

import java.security.cert.CertPathBuilder;

import java.security.cert.CertPathValidator;

import java.security.cert.CertStore;

import java.security.cert.CollectionCertStoreParameters;

import java.security.cert.PKIXBuilderParameters;

import java.security.cert.PKIXCertPathBuilderResult;

import java.security.cert.PKIXCertPathValidatorResult;

import java.security.cert.PKIXParameters;

import java.security.cert.X509Certificate;

import java.security.cert.X509CRL;

import java.util.ArrayList;

import java.util.HashSet;

import java.util.List;

import java.util.Set;

/**

 * Static utility methods useful for testing certificate/certpath APIs.

 */

public class CertUtils {

    private CertUtils() {}

    /**

     * Get a DER-encoded X.509 certificate from a file.

     *

     * @param certFilePath path to file containing DER-encoded certificate

     * @return X509Certificate

     * @throws IOException on error

     */

    public static X509Certificate getCertFromFile(String certFilePath)

        throws IOException {

            X509Certificate cert = null;

            try {

                File certFile = new File(System.getProperty("test.src", "."),

                    certFilePath);

                if (!certFile.canRead())

                    throw new IOException("File " +

                                          certFile.toString() +

                                          " is not a readable file.");

                FileInputStream certFileInputStream =

                    new FileInputStream(certFile);

                CertificateFactory cf = CertificateFactory.getInstance("X509");

                cert = (X509Certificate)

                    cf.generateCertificate(certFileInputStream);

            } catch (Exception e) {

                e.printStackTrace();

                throw new IOException("Can't construct X509Certificate: " +

                                      e.getMessage());

            }

            return cert;

    }

    /**

     * Get a DER-encoded X.509 CRL from a file.

     *

     * @param crlFilePath path to file containing DER-encoded CRL

     * @return X509CRL

     * @throws IOException on error

     */

    public static X509CRL getCRLFromFile(String crlFilePath)

        throws IOException {

            X509CRL crl = null;

            try {

                File crlFile = new File(System.getProperty("test.src", "."),

                    crlFilePath);

                if (!crlFile.canRead())

                    throw new IOException("File " +

                                          crlFile.toString() +

                                          " is not a readable file.");

                FileInputStream crlFileInputStream =

                    new FileInputStream(crlFile);

                CertificateFactory cf = CertificateFactory.getInstance("X509");

                crl = (X509CRL) cf.generateCRL(crlFileInputStream);

            } catch (Exception e) {

                e.printStackTrace();

                throw new IOException("Can't construct X509CRL: " +

                                      e.getMessage());

            }

            return crl;

    }

    /**

     * Read a bunch of certs from files and create a CertPath from them.

     *

     * @param fileNames an array of <code>String</code>s that are file names

     * @throws Exception on error

     */

    public static CertPath buildPath(String [] fileNames) throws Exception {

        return buildPath("", fileNames);

    }

    /**

     * Read a bunch of certs from files and create a CertPath from them.

     *

     * @param relPath relative path containing certs (must end in

     *    file.separator)

     * @param fileNames an array of <code>String</code>s that are file names

     * @throws Exception on error

     */

    public static CertPath buildPath(String relPath, String [] fileNames)

        throws Exception {

        List<X509Certificate> list = new ArrayList<X509Certificate>();

        for (int i = 0; i < fileNames.length; i++) {

            list.add(0, getCertFromFile(relPath + fileNames[i]));

        }

        CertificateFactory cf = CertificateFactory.getInstance("X509");

        return(cf.generateCertPath(list));

    }

    /**

     * Read a bunch of certs from files and create a CertStore from them.

     *

     * @param fileNames an array of <code>String</code>s that are file names

     * @return the <code>CertStore</code> created

     * @throws Exception on error

     */

    public static CertStore createStore(String [] fileNames) throws Exception {

        return createStore("", fileNames);

    }

    /**

     * Read a bunch of certs from files and create a CertStore from them.

     *

     * @param relPath relative path containing certs (must end in

     *    file.separator)

     * @param fileNames an array of <code>String</code>s that are file names

     * @return the <code>CertStore</code> created

     * @throws Exception on error

     */

    public static CertStore createStore(String relPath, String [] fileNames)

        throws Exception {

        Set<X509Certificate> certs = new HashSet<X509Certificate>();

        for (int i = 0; i < fileNames.length; i++) {

            certs.add(getCertFromFile(relPath + fileNames[i]));

        }

        return CertStore.getInstance("Collection",

            new CollectionCertStoreParameters(certs));

    }

    /**

     * Read a bunch of CRLs from files and create a CertStore from them.

     *

     * @param fileNames an array of <code>String</code>s that are file names

     * @return the <code>CertStore</code> created

     * @throws Exception on error

     */

    public static CertStore createCRLStore(String [] fileNames)

        throws Exception {

        return createCRLStore("", fileNames);

    }

    /**

     * Read a bunch of CRLs from files and create a CertStore from them.

     *

     * @param relPath relative path containing CRLs (must end in file.separator)

     * @param fileNames an array of <code>String</code>s that are file names

     * @return the <code>CertStore</code> created

     * @throws Exception on error

     */

    public static CertStore createCRLStore(String relPath, String [] fileNames)

        throws Exception {

        Set<X509CRL> crls = new HashSet<X509CRL>();

        for (int i = 0; i < fileNames.length; i++) {

            crls.add(getCRLFromFile(relPath + fileNames[i]));

        }

        return CertStore.getInstance("Collection",

            new CollectionCertStoreParameters(crls));

    }

    /**

     * Perform a PKIX path build. On failure, throw an exception.

     *

     * @param params PKIXBuilderParameters to use in validation

     * @throws Exception on error

     */

    public static PKIXCertPathBuilderResult build(PKIXBuilderParameters params)

        throws Exception {

        CertPathBuilder builder =

            CertPathBuilder.getInstance("PKIX");

        return (PKIXCertPathBuilderResult) builder.build(params);

    }

    /**

     * Perform a PKIX validation. On failure, throw an exception.

     *

     * @param path CertPath to validate

     * @param params PKIXParameters to use in validation

     * @throws Exception on error

     */

    public static PKIXCertPathValidatorResult validate

        (CertPath path, PKIXParameters params) throws Exception {

        CertPathValidator validator =

            CertPathValidator.getInstance("PKIX");

        return (PKIXCertPathValidatorResult) validator.validate(path, params);

    }

    /*

     * Reads the entire input stream into a byte array.

     */

    private static byte[] getTotalBytes(InputStream is) throws IOException {

           byte[] buffer = new byte[8192];

        ByteArrayOutputStream baos = new ByteArrayOutputStream(2048);

        int n;

        baos.reset();

        while ((n = is.read(buffer, 0, buffer.length)) != -1) {

            baos.write(buffer, 0, n);

        }

        return baos.toByteArray();

    }

}