/*
 *  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.
 */

package org.apache.jk.common;

import java.io.IOException;

import org.apache.coyote.OutputBuffer;
import org.apache.coyote.InputBuffer;
import org.apache.coyote.Request;
import org.apache.coyote.Response;

import org.apache.jk.core.Msg;
import org.apache.jk.core.MsgContext;

import org.apache.tomcat.util.buf.ByteChunk;
import org.apache.tomcat.util.buf.MessageBytes;
import org.apache.tomcat.util.buf.C2BConverter;
import org.apache.tomcat.util.http.HttpMessages;
import org.apache.tomcat.util.http.MimeHeaders;

/** Generic input stream impl on top of ajp
 */
public class JkInputStream implements InputBuffer, OutputBuffer {
    private static org.apache.juli.logging.Log log=
        org.apache.juli.logging.LogFactory.getLog( JkInputStream.class );

    private Msg bodyMsg;
    private Msg outputMsg;
    private MsgContext mc;

    
    // Holds incoming chunks of request body data
    private MessageBytes bodyBuff = MessageBytes.newInstance();
    private MessageBytes tempMB = MessageBytes.newInstance();
    private boolean end_of_stream=false; 
    private boolean isEmpty = true;
    private boolean isFirst = true;
    private boolean isReplay = false;
    private boolean isReadRequired = false;
    private int packetSize = AjpConstants.MAX_PACKET_SIZE;

    static {
        // Make certain HttpMessages is loaded for SecurityManager
        try {
            Class.forName("org.apache.tomcat.util.http.HttpMessages");
        } catch(Exception ex) {
            // ignore
        }
    }

    public JkInputStream(MsgContext context, int bsize) {
        mc = context;
        // Never use less than the default maximum packet size.
        if (bsize < AjpConstants.MAX_PACKET_SIZE)
            this.packetSize = AjpConstants.MAX_PACKET_SIZE;
        else
            this.packetSize = bsize;
        bodyMsg = new MsgAjp(this.packetSize);
        outputMsg = new MsgAjp(this.packetSize);
    }
    /**
     * @deprecated
     */
    public JkInputStream(MsgContext context) {
        this(context, AjpConstants.MAX_PACKET_SIZE);
    }

    // -------------------- Jk specific methods --------------------


    /**
     * Set the flag saying that the server is sending a body
     */
    public void setIsReadRequired(boolean irr) {
        isReadRequired = irr;
    }

    /**
     * Return the flag saying that the server is sending a body
     */
    public boolean isReadRequired() {
        return isReadRequired;
    }

    
    /** Must be called before or after each request
     */
    public void recycle() {
        if(isReadRequired && isFirst) {
            // The Servlet never read the request body, so we need to junk it
            try {
              receive();
            } catch(IOException iex) {
              log.debug("Error consuming request body",iex);
            }
        }

        end_of_stream = false;
        isEmpty = true;
        isFirst = true;
        isReplay = false;
        isReadRequired = false;
        bodyBuff.recycle();
        tempMB.recycle();
    }


    public void endMessage() throws IOException {
        outputMsg.reset();
        outputMsg.appendByte(AjpConstants.JK_AJP13_END_RESPONSE);
        outputMsg.appendByte(1);
        mc.getSource().send(outputMsg, mc);
        mc.getSource().flush(outputMsg, mc);
    }


    // -------------------- OutputBuffer implementation --------------------

        
    public int doWrite(ByteChunk chunk, Response res) 
        throws IOException    {
        if (!res.isCommitted()) {
            // Send the connector a request for commit. The connector should
            // then validate the headers, send them (using sendHeader) and 
            // set the filters accordingly.
            res.sendHeaders();
        }

        int len=chunk.getLength();
        byte buf[]=outputMsg.getBuffer();
        // 4 - hardcoded, byte[] marshalling overhead 
        int chunkSize=buf.length - outputMsg.getHeaderLength() - 4;
        int off=0;
        while( len > 0 ) {
            int thisTime=len;
            if( thisTime > chunkSize ) {
                thisTime=chunkSize;
            }
            len-=thisTime;
            
            outputMsg.reset();
            outputMsg.appendByte( AjpConstants.JK_AJP13_SEND_BODY_CHUNK);
            if( log.isTraceEnabled() ) 
                log.trace("doWrite " + off + " " + thisTime + " " + len );
            outputMsg.appendBytes( chunk.getBytes(), chunk.getOffset() + off, thisTime );
            off+=thisTime;
            mc.getSource().send( outputMsg, mc );
        }
        return 0;
    }

    public int doRead(ByteChunk responseChunk, Request req) 
        throws IOException {

        if( log.isDebugEnabled())
            log.debug( "doRead "  + end_of_stream+
                       " " + responseChunk.getOffset()+ " " + responseChunk.getLength());
        if( end_of_stream ) {
            return -1;
        }

        if( isFirst && isReadRequired ) {
            // Handle special first-body-chunk, but only if httpd expects it.
            if( !receive() ) {
                return 0;
            }
        } else if(isEmpty) {
            if ( !refillReadBuffer() ){
                return -1;
            }
        }
        ByteChunk bc = bodyBuff.getByteChunk();
        responseChunk.setBytes( bc.getBuffer(), bc.getStart(), bc.getLength() );
        isEmpty = true;
        return responseChunk.getLength();
    }
    
    /** Receive a chunk of data. Called to implement the
     *  'special' packet in ajp13 and to receive the data
     *  after we send a GET_BODY packet
     */
    public boolean receive() throws IOException {
        isFirst = false;
        bodyMsg.reset();
        int err = mc.getSource().receive(bodyMsg, mc);
        if( log.isDebugEnabled() )
            log.info( "Receiving: getting request body chunk " + err + " " + bodyMsg.getLen() );
        
        if(err < 0) {
            throw new IOException();
        }

        // No data received.
        if( bodyMsg.getLen() == 0 ) { // just the header
            // Don't mark 'end of stream' for the first chunk.
            // end_of_stream = true;
            return false;
        }
        int blen = bodyMsg.peekInt();

        if( blen == 0 ) {
            return false;
        }

        if( log.isTraceEnabled() ) {
            bodyMsg.dump("Body buffer");
        }
        
        bodyMsg.getBytes(bodyBuff);
        if( log.isTraceEnabled() )
            log.trace( "Data:\n" + bodyBuff);
        isEmpty = false;
        return true;
    }
    
    /**
     * Get more request body data from the web server and store it in the 
     * internal buffer.
     *
     * @return true if there is more data, false if not.    
     */
    private boolean refillReadBuffer() throws IOException 
    {
        // If the server returns an empty packet, assume that that end of
        // the stream has been reached (yuck -- fix protocol??).
        if(isReplay) {
            end_of_stream = true; // we've read everything there is
        }
        if (end_of_stream) {
            if( log.isDebugEnabled() ) 
                log.debug("refillReadBuffer: end of stream " );
            return false;
        }

        // Why not use outBuf??
        bodyMsg.reset();
        bodyMsg.appendByte(AjpConstants.JK_AJP13_GET_BODY_CHUNK);
        // Adjust allowed size if packetSize != default (AjpConstants.MAX_PACKET_SIZE)
        bodyMsg.appendInt(AjpConstants.MAX_READ_SIZE + packetSize - AjpConstants.MAX_PACKET_SIZE);
        
        if( log.isDebugEnabled() )
            log.debug("refillReadBuffer " + Thread.currentThread());

        mc.getSource().send(bodyMsg, mc);
        mc.getSource().flush(bodyMsg, mc); // Server needs to get it

        // In JNI mode, response will be in bodyMsg. In TCP mode, response need to be
        // read

        boolean moreData=receive();
        if( !moreData ) {
            end_of_stream=true;
        }
        return moreData;
    }

    public void appendHead(Response res) throws IOException {
        if( log.isDebugEnabled() )
            log.debug("COMMIT sending headers " + res + " " + res.getMimeHeaders() );
        
        C2BConverter c2b=mc.getConverter();
        
        outputMsg.reset();
        outputMsg.appendByte(AjpConstants.JK_AJP13_SEND_HEADERS);
        outputMsg.appendInt( res.getStatus() );
        
        String message = null;
        if (org.apache.coyote.Constants.USE_CUSTOM_STATUS_MSG_IN_HEADER &&
                HttpMessages.isSafeInHttpHeader(res.getMessage())) {
            message = res.getMessage();
        } 
        if (message == null) {
            message= HttpMessages.getMessage(res.getStatus());
        }
        if (message == null) {
            // mod_jk + httpd 2.x fails with a null status message - bug 45026
            message = Integer.toString(res.getStatus());
        }
        tempMB.setString( message );
        c2b.convert( tempMB );
        outputMsg.appendBytes(tempMB);

        // XXX add headers
        
        MimeHeaders headers=res.getMimeHeaders();
        String contentType = res.getContentType();
        if( contentType != null ) {
            headers.setValue("Content-Type").setString(contentType);
        }
        String contentLanguage = res.getContentLanguage();
        if( contentLanguage != null ) {
            headers.setValue("Content-Language").setString(contentLanguage);
        }
        long contentLength = res.getContentLengthLong();
        if( contentLength >= 0 ) {
            headers.setValue("Content-Length").setLong(contentLength);
        }
        int numHeaders = headers.size();
        outputMsg.appendInt(numHeaders);
        for( int i=0; i<numHeaders; i++ ) {
            MessageBytes hN=headers.getName(i);
            // no header to sc conversion - there's little benefit
            // on this direction
            c2b.convert ( hN );
            outputMsg.appendBytes( hN );
                        
            MessageBytes hV=headers.getValue(i);
            c2b.convert( hV );
            outputMsg.appendBytes( hV );
        }
        mc.getSource().send( outputMsg, mc );
    }

    /**
     * Set the replay buffer for Form auth
     */
    public void setReplay(ByteChunk replay) {
        isFirst = false;
        isEmpty = false;
        isReplay = true;
        bodyBuff.setBytes(replay.getBytes(), replay.getStart(), replay.getLength());
    }


}
