/*
 * ====================================================================
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 */

package org.apache.ogt.http.impl.io;

import java.io.IOException;
import java.io.InterruptedIOException;
import java.net.Socket;

import org.apache.ogt.http.io.EofSensor;
import org.apache.ogt.http.io.SessionInputBuffer;
import org.apache.ogt.http.params.HttpParams;

/**
 * {@link SessionInputBuffer} implementation bound to a {@link Socket}.
 * <p>
 * The following parameters can be used to customize the behavior of this
 * class:
 * <ul>
 *  <li>{@link org.apache.ogt.http.params.CoreProtocolPNames#HTTP_ELEMENT_CHARSET}</li>
 *  <li>{@link org.apache.ogt.http.params.CoreConnectionPNames#MAX_LINE_LENGTH}</li>
 * </ul>
 *
 * @since 4.0
 */
public class SocketInputBuffer extends AbstractSessionInputBuffer implements EofSensor {

    static private final Class SOCKET_TIMEOUT_CLASS = SocketTimeoutExceptionClass();

    /**
     * Returns <code>SocketTimeoutExceptionClass<code> or <code>null</code> if the class
     * does not exist.
     *
     * @return <code>SocketTimeoutExceptionClass<code>, or <code>null</code> if unavailable.
     */
    static private Class SocketTimeoutExceptionClass() {
        try {
            return Class.forName("java.net.SocketTimeoutException");
        } catch (ClassNotFoundException e) {
            return null;
        }
    }

    private static boolean isSocketTimeoutException(final InterruptedIOException e) {
        if (SOCKET_TIMEOUT_CLASS != null) {
            return SOCKET_TIMEOUT_CLASS.isInstance(e);
        } else {
            return true;
        }
    }

    private final Socket socket;

    private boolean eof;

    /**
     * Creates an instance of this class.
     *
     * @param socket the socket to read data from.
     * @param buffersize the size of the internal buffer. If this number is less
     *   than <code>0</code> it is set to the value of
     *   {@link Socket#getReceiveBufferSize()}. If resultant number is less
     *   than <code>1024</code> it is set to <code>1024</code>.
     * @param params HTTP parameters.
     */
    public SocketInputBuffer(
            final Socket socket,
            int buffersize,
            final HttpParams params) throws IOException {
        super();
        if (socket == null) {
            throw new IllegalArgumentException("Socket may not be null");
        }
        this.socket = socket;
        this.eof = false;
        if (buffersize < 0) {
            buffersize = socket.getReceiveBufferSize();
        }
        if (buffersize < 1024) {
            buffersize = 1024;
        }
        init(socket.getInputStream(), buffersize, params);
    }

    protected int fillBuffer() throws IOException {
        int i = super.fillBuffer();
        this.eof = i == -1;
        return i;
    }

    public boolean isDataAvailable(int timeout) throws IOException {
        boolean result = hasBufferedData();
        if (!result) {
            int oldtimeout = this.socket.getSoTimeout();
            try {
                this.socket.setSoTimeout(timeout);
                fillBuffer();
                result = hasBufferedData();
            } catch (InterruptedIOException e) {
                if (!isSocketTimeoutException(e)) {
                    throw e;
                }
            } finally {
                socket.setSoTimeout(oldtimeout);
            }
        }
        return result;
    }

    public boolean isEof() {
        return this.eof;
    }

}