/*

 * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.

 * 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.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

import java.io.BufferedReader;

import java.io.File;

import java.io.FileInputStream;

import java.io.IOException;

import java.io.InputStreamReader;

import java.math.BigInteger;

import java.security.*;

import java.security.spec.*;

import java.util.ArrayList;

import java.util.List;

public final class SigRecord {

    static final String TEST_SRC = System.getProperty("test.src", ".");

    // utility method for converting byte array to hex string

    static String toHexString(byte[] array) {

        StringBuilder sb = new StringBuilder(array.length * 2);

        for (byte b : array) {

            // The single digits 0123456789abcdef get a leading 0

            if ((b >= 0x00) && (b < 0x10)) {

                sb.append('0');

            }

            sb.append(Integer.toHexString(b & 0xff));

        }

        return sb.toString();

    }

    // utility method for converting hex string to byte array

    static byte[] toByteArray(String s) {

        byte[] bytes = new byte[s.length() / 2];

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

            int index = i * 2;

            int v = Integer.parseInt(s.substring(index, index + 2), 16);

            bytes[i] = (byte) v;

        }

        return bytes;

    }

    public static final class SigVector {

        // digest algorithm to use

        final String mdAlg;

        // message to test

        final String msg;

        // expected signature

        final String sig;

        // optional PSS-only salt value, maybe null

        final String salt;

        public SigVector(String mdAlg, String msg, String sig, String salt) {

            if (mdAlg == null || mdAlg.isEmpty()) {

                throw new IllegalArgumentException("Digest algo must be specified");

            }

            if (msg == null || mdAlg.isEmpty()) {

                throw new IllegalArgumentException("Message must be specified");

            }

            if (sig == null || mdAlg.isEmpty()) {

                throw new IllegalArgumentException("Signature must be specified");

            }

            this.mdAlg = mdAlg;

            this.msg = msg;

            this.sig = sig;

            this.salt = salt;

        }

        @Override

        public String toString() {

            return mdAlg + ": msg=" + msg + ": sig=" + sig +

                (salt != null? (": salt=" + salt) : "");

        }

    }

    final String id;

    // RSA private key value associated with the corresponding test vectors

    final RSAPrivateKeySpec privKeySpec;

    // RSA public key value associated with the corresponding test vectors

    final RSAPublicKeySpec pubKeySpec;

    // set of test vectors

    final List<SigVector> testVectors;

    SigRecord(String mod, String pubExp, String privExp, List<SigVector> testVectors) {

        if (mod == null || mod.isEmpty()) {

            throw new IllegalArgumentException("Modulus n must be specified");

        }

        if (pubExp == null || pubExp.isEmpty()) {

            throw new IllegalArgumentException("Public Exponent e must be specified");

        }

        if (privExp == null || privExp.isEmpty()) {

            throw new IllegalArgumentException("Private Exponent d must be specified");

        }

        if (testVectors == null || (testVectors.size() == 0)) {

            throw new IllegalArgumentException("One or more test vectors must be specified");

        }

        BigInteger n = new BigInteger(1, toByteArray(mod));

        BigInteger e = new BigInteger(1, toByteArray(pubExp));

        BigInteger d = new BigInteger(1, toByteArray(privExp));

        this.id = ("n=" + mod + ", e=" + pubExp);

        this.pubKeySpec = new RSAPublicKeySpec(n, e);

        this.privKeySpec = new RSAPrivateKeySpec(n, d);

        this.testVectors = testVectors;

    }

    /*

     * Read a data file into an ArrayList.

     * This function will exit the program if reading the file fails

     * or if the file is not in the expected format.

     */

    public static List<SigRecord> read(String filename)

            throws IOException {

        List<SigRecord> data = new ArrayList<>();

        try (BufferedReader br = new BufferedReader(

                new InputStreamReader(new FileInputStream(

                        TEST_SRC + File.separator + filename)))) {

            String line;

            String mod = null;

            String pubExp = null;

            String privExp = null;

            List<SigVector> testVectors = new ArrayList<>();

            while ((line = br.readLine()) != null) {

                if (line.startsWith("n =")) {

                    mod = line.split("=")[1].trim();

                } else if (line.startsWith("e =")) {

                    pubExp = line.split("=")[1].trim();

                } else if (line.startsWith("d =")) {

                    privExp = line.split("=")[1].trim();

                    // now should start parsing for test vectors

                    String mdAlg = null;

                    String msg = null;

                    String sig = null;

                    String salt = null;

                    boolean sigVectorDone = false;

                    while ((line = br.readLine()) != null) {

                        // we only care for lines starting with

                        // SHAALG, Msg, S, and Salt

                        if (line.startsWith("SHAAlg =")) {

                            mdAlg = line.split(" = ")[1].trim();

                        } else if (line.startsWith("Msg =")) {

                            msg = line.split(" = ")[1].trim();

                        } else if (line.startsWith("S =")) {

                            sig = line.split(" = ")[1].trim();

                        } else if (line.startsWith("SaltVal =")) {

                            salt = line.split(" = ")[1].trim();

                            if (salt.equals("00")) {

                                salt = "";

                            }

                        } else if (line.startsWith("[mod")) {

                            sigVectorDone = true;

                        }

                        if ((mdAlg != null) && (msg != null) && (sig != null) &&

                            (salt != null)) {

                            // finish off current SigVector

                            testVectors.add(new SigVector(mdAlg, msg, sig, salt));

                            mdAlg = msg = sig = salt = null;

                        }

                        if (sigVectorDone) {

                            break;

                        }

                    }

                    // finish off current SigRecord and clear data for next SigRecord

                    data.add(new SigRecord(mod, pubExp, privExp, testVectors));

                    mod = pubExp = privExp = null;

                    testVectors = new ArrayList<>();

                }

            }

            if (data.isEmpty()) {

                throw new RuntimeException("Nothing read from file "

                        + filename);

            }

        }

        return data;

    }

    @Override

    public String toString() {

        return (id + ", " + testVectors.size() + " test vectors");

    }

}