/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

package org.mozilla.jss.crypto;

import java.security.NoSuchAlgorithmException;
import java.util.Hashtable;

import org.mozilla.jss.asn1.OBJECT_IDENTIFIER;

/**
 * Algorithms that can be used for generating symmetric keys.
 */
public class KeyGenAlgorithm extends Algorithm {

    protected static interface KeyStrengthValidator {
        public boolean isValidKeyStrength(int strength);
    }

    protected static class FixedKeyStrengthValidator
            implements KeyStrengthValidator {
        private int strength;

        public FixedKeyStrengthValidator(int strength) {
            this.strength = strength;
        }

        @Override
        public boolean isValidKeyStrength(int strength) {
            return this.strength == strength;
        }
    }

    protected static class AnyKeyStrengthValidator
            implements KeyStrengthValidator {
        @Override
        public boolean isValidKeyStrength(int strength) {
            return true;
        }
    }

    protected KeyGenAlgorithm(int oidTag, String name,
            KeyStrengthValidator keyStrengthValidator,
            OBJECT_IDENTIFIER oid, Class<?> paramClass) {
        super(oidTag, name, oid, paramClass);
        this.keyStrengthValidator = keyStrengthValidator;
        if (oid != null) {
            oidMap.put(oid, this);
        }
    }

    ///////////////////////////////////////////////////////////////////////
    // OIDs
    ///////////////////////////////////////////////////////////////////////
    private static final OBJECT_IDENTIFIER PKCS5 = OBJECT_IDENTIFIER.PKCS5;
    private static final OBJECT_IDENTIFIER PKCS12_PBE = OBJECT_IDENTIFIER.PKCS12.subBranch(1);

    ///////////////////////////////////////////////////////////////////////
    // OID mapping
    ///////////////////////////////////////////////////////////////////////
    private static Hashtable<OBJECT_IDENTIFIER, KeyGenAlgorithm> oidMap = new Hashtable<>();

    public static KeyGenAlgorithm fromOID(OBJECT_IDENTIFIER oid)
            throws NoSuchAlgorithmException {
        Object alg = oidMap.get(oid);
        if (alg == null) {
            throw new NoSuchAlgorithmException(oid.toString());
        } else {
            return (KeyGenAlgorithm) alg;
        }
    }

    private KeyStrengthValidator keyStrengthValidator;

    /**
     * @param strength Key strength.
     * @return <code>true</code> if the given strength is valid for this
     *         key generation algorithm. Note that PBE algorithms require
     *         PBEParameterSpecs rather than strengths. It is the responsibility
     *         of the caller to verify this.
     */
    public boolean isValidStrength(int strength) {
        return keyStrengthValidator.isValidKeyStrength(strength);
    }

    //////////////////////////////////////////////////////////////
    public static final KeyGenAlgorithm GENERIC_SECRET = new KeyGenAlgorithm(
            CKM_GENERIC_SECRET_KEY_GEN,
            "GenericSecret",
            new AnyKeyStrengthValidator(),
            null,
            null);

    //////////////////////////////////////////////////////////////
    public static final KeyGenAlgorithm DES = new KeyGenAlgorithm(
            CKM_DES_KEY_GEN,
            "DES",
            new FixedKeyStrengthValidator(56),
            null,
            null);

    //////////////////////////////////////////////////////////////
    public static final KeyGenAlgorithm DES3 = new KeyGenAlgorithm(
            CKM_DES3_KEY_GEN,
            "DESede",
            new FixedKeyStrengthValidator(168),
            null,
            null);

    public static final KeyGenAlgorithm DESede = DES3;

    //////////////////////////////////////////////////////////////
    public static final KeyGenAlgorithm RC4 = new KeyGenAlgorithm(
            CKM_RC4_KEY_GEN,
            "RC4",
            new AnyKeyStrengthValidator(),
            null,
            null);

    //////////////////////////////////////////////////////////////
    public static final KeyGenAlgorithm PBA_SHA1_HMAC = new KeyGenAlgorithm(
            CKM_PBA_SHA1_WITH_SHA1_HMAC,
            "PBA/SHA1/HMAC",
            new FixedKeyStrengthValidator(160),
            null,
            PBEKeyGenParams.class);

    public static final KeyGenAlgorithm SHA1_HMAC = new KeyGenAlgorithm(
            CKM_SHA_1_HMAC,
            "SHA1/HMAC",
            new FixedKeyStrengthValidator(160),
            null,
            null);

    public static final KeyGenAlgorithm SHA256_HMAC = new KeyGenAlgorithm(
            CKM_SHA256_HMAC,
            "SHA256/HMAC",
            new FixedKeyStrengthValidator(256),
            null,
            null);

    public static final KeyGenAlgorithm SHA384_HMAC = new KeyGenAlgorithm(
            CKM_SHA384_HMAC,
            "SHA384/HMAC",
            new FixedKeyStrengthValidator(384),
            null,
            null);

    public static final KeyGenAlgorithm SHA512_HMAC = new KeyGenAlgorithm(
            CKM_SHA512_HMAC,
            "SHA512/HMAC",
            new FixedKeyStrengthValidator(512),
            null,
            null);

    //////////////////////////////////////////////////////////////
    public static final KeyGenAlgorithm AES = new KeyGenAlgorithm(
            CKM_AES_KEY_GEN,
            "AES",
            new KeyStrengthValidator() {
                @Override
                public boolean isValidKeyStrength(int strength) {
                    return strength == 128 || strength == 192 || strength == 256;
                }
            },
            null,
            null);
    //////////////////////////////////////////////////////////////
    public static final KeyGenAlgorithm RC2 = new KeyGenAlgorithm(
            CKM_RC2_KEY_GEN,
            "RC2",
            new KeyStrengthValidator() {
                @Override
                public boolean isValidKeyStrength(int strength) {
                    // Allow any key of size between 1 byte and 128 bytes
                    return strength >= 8 && strength <= (128 * 8);
                }
            },
            null,
            null);
    //////////////////////////////////////////////////////////////
    /////////////// GENERIC KBKDFs: NIST SP800-108 ///////////////
    //////////////////////////////////////////////////////////////
    public static final KeyGenAlgorithm SP800_108_COUNTER_KDF = new KeyGenAlgorithm(
            CKM_SP800_108_COUNTER_KDF,
            "SP800_108_COUNTER_KDF",
            new AnyKeyStrengthValidator(),
            null,
            KBKDFCounterParams.class);

    public static final KeyGenAlgorithm SP800_108_FEEDBACK_KDF = new KeyGenAlgorithm(
            CKM_SP800_108_FEEDBACK_KDF,
            "SP800_108_FEEDBACK_KDF",
            new AnyKeyStrengthValidator(),
            null,
            KBKDFFeedbackParams.class);

    public static final KeyGenAlgorithm SP800_108_DOUBLE_PIPELINE_KDF = new KeyGenAlgorithm(
            CKM_SP800_108_DOUBLE_PIPELINE_KDF,
            "SP800_108_DOUBLE_PIPELINE_KDF",
            new AnyKeyStrengthValidator(),
            null,
            KBKDFPipelineParams.class);
    //////////////////////////////////////////////////////////////
    //////////// Data KBKDFs: NSS-only NIST SP800-108 ////////////
    //////////////////////////////////////////////////////////////
    public static final KeyGenAlgorithm NSS_SP800_108_COUNTER_KDF_DERIVE_DATA = new KeyGenAlgorithm(
            CKM_NSS_SP800_108_COUNTER_KDF_DERIVE_DATA,
            "NSS_SP800_108_COUNTER_KDF_DERIVE_DATA",
            new AnyKeyStrengthValidator(),
            null,
            KBKDFCounterParams.class);

    public static final KeyGenAlgorithm NSS_SP800_108_FEEDBACK_KDF_DERIVE_DATA = new KeyGenAlgorithm(
            CKM_NSS_SP800_108_FEEDBACK_KDF_DERIVE_DATA,
            "NSS_SP800_108_FEEDBACK_KDF_DERIVE_DATA",
            new AnyKeyStrengthValidator(),
            null,
            KBKDFFeedbackParams.class);

    public static final KeyGenAlgorithm NSS_SP800_108_DOUBLE_PIPELINE_KDF_DERIVE_DATA = new KeyGenAlgorithm(
            CKM_NSS_SP800_108_DOUBLE_PIPELINE_KDF_DERIVE_DATA,
            "NSS_SP800_108_DOUBLE_PIPELINE_KDF_DERIVE_DATA",
            new AnyKeyStrengthValidator(),
            null,
            KBKDFPipelineParams.class);
}
