/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at legal-notices/CDDLv1_0.txt
 * or http://forgerock.org/license/CDDLv1.0.html.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at legal-notices/CDDLv1_0.txt.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information:
 *      Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 *
 *
 *      Copyright 2010 Sun Microsystems, Inc.
 *      Portions copyright 2012 ForgeRock AS.
 */

package org.forgerock.opendj.ldap.requests;

import java.util.Collections;
import java.util.List;

import org.forgerock.opendj.ldap.DecodeException;
import org.forgerock.opendj.ldap.DecodeOptions;
import org.forgerock.opendj.ldap.Function;
import org.forgerock.opendj.ldap.Functions;
import org.forgerock.opendj.ldap.controls.Control;
import org.forgerock.opendj.ldap.controls.ControlDecoder;
import org.forgerock.opendj.ldap.controls.GenericControl;

import com.forgerock.opendj.util.Collections2;
import com.forgerock.opendj.util.Validator;

/**
 * Unmodifiable request implementation.
 *
 * @param <R>
 *            The type of request.
 */
abstract class AbstractUnmodifiableRequest<R extends Request> implements Request {

    protected final R impl;

    /**
     * Creates a new unmodifiable request implementation.
     *
     * @param impl
     *            The underlying request implementation to be made unmodifiable.
     */
    AbstractUnmodifiableRequest(final R impl) {
        this.impl = impl;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public final R addControl(final Control control) {
        throw new UnsupportedOperationException();
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public final <C extends Control> C getControl(final ControlDecoder<C> decoder,
            final DecodeOptions options) throws DecodeException {
        Validator.ensureNotNull(decoder, options);

        final List<Control> controls = impl.getControls();

        // Avoid creating an iterator if possible.
        if (controls.isEmpty()) {
            return null;
        }

        for (final Control control : controls) {
            if (control.getOID().equals(decoder.getOID())) {
                // Got a match. Return a defensive copy only if necessary.
                final C decodedControl = decoder.decodeControl(control, options);

                if (decodedControl != control) {
                    // This was not the original control so return it
                    // immediately.
                    return decodedControl;
                } else if (decodedControl instanceof GenericControl) {
                    // Generic controls are immutable, so return it immediately.
                    return decodedControl;
                } else {
                    // Re-decode to get defensive copy.
                    final GenericControl genericControl = GenericControl.newControl(control);
                    return decoder.decodeControl(genericControl, options);
                }
            }
        }

        return null;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public final List<Control> getControls() {
        // We need to make all controls unmodifiable as well, which implies
        // making
        // defensive copies where necessary.
        final Function<Control, Control, Void> function = new Function<Control, Control, Void>() {

            @Override
            public Control apply(final Control value, final Void p) {
                // Return defensive copy.
                return GenericControl.newControl(value);
            }

        };

        final List<Control> unmodifiableControls =
                Collections2.transformedList(impl.getControls(), function, Functions
                        .<Control> identityFunction());
        return Collections.unmodifiableList(unmodifiableControls);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public final String toString() {
        return impl.toString();
    }

}