/**
 *
 * Copyright the original author or authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.jivesoftware.smackx.bytestreams.ibb;

import org.jivesoftware.smack.iqrequest.AbstractIqRequestHandler;
import org.jivesoftware.smack.packet.IQ;
import org.jivesoftware.smack.packet.StanzaError;

import org.jivesoftware.smackx.bytestreams.BytestreamListener;
import org.jivesoftware.smackx.bytestreams.ibb.packet.Open;
import org.jivesoftware.smackx.filetransfer.StreamNegotiator;


/**
 * InitiationListener handles all incoming In-Band Bytestream open requests. If there are no
 * listeners for a In-Band Bytestream request InitiationListener will always refuse the request and
 * reply with a &lt;not-acceptable/&gt; error (<a
 * href="http://xmpp.org/extensions/xep-0047.html#example-5" >XEP-0047</a> Section 2.1).
 * <p>
 * All In-Band Bytestream request having a block size greater than the maximum allowed block size
 * for this connection are rejected with an &lt;resource-constraint/&gt; error. The maximum block
 * size can be set by invoking {@link InBandBytestreamManager#setMaximumBlockSize(int)}.
 *
 * @author Henning Staib
 */
class InitiationListener extends AbstractIqRequestHandler {

    /* manager containing the listeners and the XMPP connection */
    private final InBandBytestreamManager manager;

    /**
     * Constructor.
     *
     * @param manager the In-Band Bytestream manager
     */
    protected InitiationListener(InBandBytestreamManager manager) {
        super(Open.ELEMENT, Open.NAMESPACE, IQ.Type.set, Mode.async);
        this.manager = manager;
     }

    @Override
    public IQ handleIQRequest(final IQ iqRequest) {
        Open ibbRequest = (Open) iqRequest;

        int blockSize = ibbRequest.getBlockSize();
        int maximumBlockSize = manager.getMaximumBlockSize();
        // validate that block size is within allowed range
        if (blockSize > maximumBlockSize) {
            StanzaError error = StanzaError.getBuilder().setCondition(StanzaError.Condition.resource_constraint)
                            .setDescriptiveEnText("Requests block size of " + blockSize + " exceeds maximum block size of "
                                                            + maximumBlockSize)
                            .build();
            return IQ.createErrorResponse(iqRequest, error);
        }

        StreamNegotiator.signal(ibbRequest.getFrom().toString() + '\t' + ibbRequest.getSessionID(), ibbRequest);

        // ignore request if in ignore list
        if (this.manager.getIgnoredBytestreamRequests().remove(ibbRequest.getSessionID())) {
            return null;
        }

        // build bytestream request from packet
        InBandBytestreamRequest request = new InBandBytestreamRequest(this.manager, ibbRequest);

        // notify listeners for bytestream initiation from a specific user
        BytestreamListener userListener = this.manager.getUserListener(ibbRequest.getFrom());
        if (userListener != null) {
            userListener.incomingBytestreamRequest(request);
        }
        else if (!this.manager.getAllRequestListeners().isEmpty()) {
            /*
             * if there is no user specific listener inform listeners for all initiation requests
             */
            for (BytestreamListener listener : this.manager.getAllRequestListeners()) {
                listener.incomingBytestreamRequest(request);
            }
        }
        else {
            StanzaError error = StanzaError.getBuilder()
                            .setCondition(StanzaError.Condition.not_acceptable)
                            .setDescriptiveEnText("No file-transfer listeners registered")
                            .build();
            return IQ.createErrorResponse(iqRequest, error);
        }

        return null;
    }

}