/*
 * 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.usergrid.mongo.protocol;


import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.charset.Charset;
import java.util.ArrayList;
import java.util.List;

import org.bson.BSONObject;
import org.jboss.netty.buffer.ChannelBuffer;
import org.jboss.netty.buffer.ChannelBuffers;
import org.apache.usergrid.mongo.utils.BSONUtils;
import org.apache.usergrid.utils.StringUtils;


public class Message {

    public static final int OP_REPLY = 1; // Reply to a client request
    public static final int OP_MSG = 1000; // generic msg command
    public static final int OP_UPDATE = 2001; // update document
    public static final int OP_INSERT = 2002; // insert new document
    public static final int RESERVED = 2003; // formerly used for OP_GET_BY_OID
    public static final int OP_QUERY = 2004; // query a collection
    public static final int OP_GET_MORE = 2005; // Get more data from a query
    public static final int OP_DELETE = 2006; // Delete documents
    public static final int OP_KILL_CURSORS = 2007; // Client done with cursor

    protected int messageLength;
    protected int requestID;
    protected int responseTo;
    protected int opCode;


    public Message() {

    }


    public int getMessageLength() {
        return messageLength;
    }


    public void setMessageLength( int messageLength ) {
        this.messageLength = messageLength;
    }


    public int getRequestID() {
        return requestID;
    }


    public void setRequestID( int requestID ) {
        this.requestID = requestID;
    }


    public int getResponseTo() {
        return responseTo;
    }


    public void setResponseTo( int responseTo ) {
        this.responseTo = responseTo;
    }


    public int getOpCode() {
        return opCode;
    }


    public void setOpCode( int opCode ) {
        this.opCode = opCode;
    }


    public void decode( ChannelBuffer buffer ) throws IOException {
        messageLength = buffer.readInt();
        requestID = buffer.readInt();
        responseTo = buffer.readInt();
        opCode = buffer.readInt();
    }


    public ChannelBuffer encode( ChannelBuffer buffer ) {
        if ( buffer == null ) {
            buffer = ChannelBuffers.buffer( ByteOrder.LITTLE_ENDIAN, messageLength );
        }
        buffer.writeInt( messageLength );
        buffer.writeInt( requestID );
        buffer.writeInt( responseTo );
        buffer.writeInt( opCode );
        return buffer;
    }


    public String readCString( ChannelBuffer buffer ) {
        int i = buffer.bytesBefore( ( byte ) 0 );
        if ( i < 0 ) {
            return null;
        }
        String s = buffer.toString( buffer.readerIndex(), i, Charset.forName( "UTF-8" ) );
        buffer.skipBytes( i + 1 );
        return s;
    }


    public void writeCString( String str, ChannelBuffer buffer ) {
        if ( str != null ) {
            buffer.writeBytes( str.getBytes( Charset.forName( "UTF-8" ) ) );
        }
        buffer.writeByte( 0 );
    }


    public ByteBuffer getCString( String str ) {
        byte[] bytes = new byte[0];
        if ( str != null ) {
            bytes = str.getBytes( Charset.forName( "UTF-8" ) );
        }
        ByteBuffer buffer = ByteBuffer.allocate( bytes.length + 1 );
        buffer.put( bytes );
        buffer.rewind();
        return buffer;
    }


    public static List<ByteBuffer> encodeDocuments( List<BSONObject> documents ) {
        List<ByteBuffer> encodedDocuments = new ArrayList<ByteBuffer>();
        if ( documents != null ) {
            for ( BSONObject d : documents ) {
                byte[] encoded = BSONUtils.encoder().encode( d );
                encodedDocuments.add( ByteBuffer.wrap( encoded ) );
            }
        }
        return encodedDocuments;
    }


    public static int buffersSize( List<ByteBuffer> buffers ) {
        int l = 0;
        for ( ByteBuffer b : buffers ) {
            l += b.capacity();
        }
        return l;
    }


    public static ByteBuffer encodeDocument( BSONObject document ) {
        if ( document == null ) {
            return ByteBuffer.allocate( 0 );
        }
        return ByteBuffer.wrap( BSONUtils.encoder().encode( document ) );
    }


    public static String getDatabaseName( String fullCollectionName ) {
        return StringUtils.stringOrSubstringBeforeFirst( fullCollectionName, '.' );
    }


    public static String getCollectionName( String fullCollectionName ) {
        return StringUtils.stringOrSubstringAfterFirst( fullCollectionName, '.' );
    }


    @Override
    public String toString() {
        return "Message [messageLength=" + messageLength + ", requestID=" + requestID + ", responseTo=" + responseTo
                + ", opCode=" + opCode + "]";
    }
}