/**
 *        CloudGraph Community Edition (CE) License
 * 
 * This is a community release of CloudGraph, a dual-license suite of
 * Service Data Object (SDO) 2.1 services designed for relational and 
 * big-table style "cloud" databases, such as HBase and others. 
 * This particular copy of the software is released under the 
 * version 2 of the GNU General Public License. CloudGraph was developed by 
 * TerraMeta Software, Inc.
 * 
 * Copyright (c) 2013, TerraMeta Software, Inc. All rights reserved.
 * 
 * General License information can be found below.
 * 
 * This distribution may include materials developed by third
 * parties. For license and attribution notices for these
 * materials, please refer to the documentation that accompanies
 * this distribution (see the "Licenses for Third-Party Components"
 * appendix) or view the online documentation at 
 * <http://cloudgraph.org/licenses/>. 
 */
package org.cloudgraph.hbase.key;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.cloudgraph.config.ColumnKeyFieldConfig;
import org.cloudgraph.config.DataGraphConfig;
import org.cloudgraph.config.KeyFieldConfig;
import org.cloudgraph.config.PreDefinedFieldName;
import org.cloudgraph.config.PreDefinedKeyFieldConfig;
import org.cloudgraph.store.key.GraphColumnKeyFactory;
import org.plasma.sdo.PlasmaProperty;
import org.plasma.sdo.PlasmaType;


/**
 * Creates an HBase column key based on the configured CloudGraph column key {@link org.cloudgraph.config.ColumnKeyModel
 * model} for a specific HTable {@link org.cloudgraph.config.Table configuration}. 
 * <p>
 * The initial creation and subsequent reconstitution for query retrieval
 * purposes of both row and column keys in CloudGraph™ is efficient, 
 * as it leverages byte array level API in both Java and the current 
 * underlying SDO 2.1 implementation, <a target="#" href="http://plasma-sdo.org">PlasmaSDO™</a>. Both composite row and 
 * column keys are composed in part of structural metadata, and the 
 * lightweight metadata API within <a target="#" href="http://plasma-sdo.org">PlasmaSDO™</a> contains byte-array level, 
 * cached lookup of all basic metadata elements including logical and 
 * physical type and property names.  
 * </p>
 * @see org.cloudgraph.config.ColumnKeyModel
 * @see org.cloudgraph.config.Table
 * @author Scott Cinnamond
 * @since 0.5
 */
public class CompositeColumnKeyFactory extends ByteBufferKeyFactory  
    implements GraphColumnKeyFactory 
{
	private static final Log log = LogFactory.getLog(CompositeColumnKeyFactory.class);
		
	public CompositeColumnKeyFactory(PlasmaType rootType) {
		super(rootType);
	}

	@Override
	public byte[] createColumnKey( 
		PlasmaType type, PlasmaProperty property) {
		
		this.buf.clear();
		
		int i = 0;
		for (KeyFieldConfig fieldConfig : this.graph.getColumnKeyFields()) {
    		if (i > 0)
        	    this.buf.put(graph.getColumnKeyFieldDelimiterBytes());
			
    		PreDefinedKeyFieldConfig predefinedFieldCOnfig = (PreDefinedKeyFieldConfig)fieldConfig;
    		byte[] keyValue = predefinedFieldCOnfig.getKeyBytes(type, property);
    		if (fieldConfig.isHash()) {
				keyValue = this.hashing.toStringBytes(keyValue);
			}
			
		    this.buf.put(keyValue);
				
			i++;
		}

		// ByteBuffer.array() returns unsized array so don't sent that back to clients
		// to misuse. 
		// Use native arraycopy() method as it uses native memcopy to create result array
		// and because and
		// ByteBuffer.get(byte[] dst,int offset, int length) is not native
	    byte [] result = new byte[this.buf.position()];
	    System.arraycopy(this.buf.array(), this.buf.arrayOffset(), result, 0, this.buf.position()); 

		return result;
	}		

	protected byte[] configureTokenBytes(byte[] token, 
			DataGraphConfig graph, Hashing hashing, 
			PreDefinedFieldName tokenName)
	{
		byte[] result = token;
		ColumnKeyFieldConfig tokenConfig = graph.getColumnKeyField(tokenName);
		if (tokenConfig != null) {
			if (tokenConfig.isHash()) {
				result = hashing.toStringBytes(result);
			}
		}
		return result;
	}

}