/**
 * Copyright 2005 JBoss Inc
 *
 * 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.drools;

import java.util.Map;

import org.drools.common.InternalFactHandle;
import org.drools.common.InternalWorkingMemory;
import org.drools.rule.Declaration;

public class QueryResult {

    protected FactHandle[] factHandles;
    private WorkingMemory workingMemory;
    private QueryResults  queryResults;

    public QueryResult(final FactHandle[] factHandles,
                       final WorkingMemory workingMemory,
                       final QueryResults queryResults) {
        this.factHandles = factHandles;
        this.workingMemory = workingMemory;
        this.queryResults = queryResults;
    }

    /**
     * Return a map of Declarations where the key is the identifier and the value
     * is the Declaration.
     * 
     * @return
     *      The Map of Declarations.
     */    
    public Map getDeclarations() {
        return this.queryResults.getDeclarations();
    }

    /**
     * Returns the Object for int position in the Tuple
     * 
     * @param i
     * @return
     *     The Object
     */
    public Object get(final int i) {
        return getObject( this.factHandles[ i + 1]); // Add one, as we hide root DroolsQuery
    }

    /** 
     * Return the Object for the given Declaration identifier.
     * @param identifier
     * @return
     *      The Object
     */
    public Object get(final String identifier) {
        return get( this.queryResults.getDeclarations().get( identifier ) );
    }

    /** 
     * Return the Object for the given Declaration.
     * @param identifier
     * @return
     *      The Object
     */    
    public Object get(final Declaration declaration) {
        return declaration.getValue( (InternalWorkingMemory) workingMemory, getObject( getFactHandle( declaration ) ) );
    }
    
    public FactHandle getFactHandle(String identifier) {
        return getFactHandle( this.queryResults.getDeclarations().get( identifier ) );
    }
    
    public FactHandle getFactHandle(Declaration declr) {
        return this.factHandles[  declr.getPattern().getOffset() ]; // -1 because we shifted the array left
                                                                       // when removing the query object
    }     
    
    public FactHandle getFactHandle(int i) {
        return this.factHandles[ i + 1 ];
    }    

    /**
     * Return the FactHandles for the Tuple.
     * @return
     */
    public FactHandle[] getFactHandles() {
        int size = size();
        FactHandle[] subArray = new FactHandle[ size];
        
        System.arraycopy( this.factHandles, 1, subArray, 0, size );
        return subArray;
    }

    /**
     * The size of the Tuple; i.e. the number of columns (FactHandles) in this row result.
     * @return
     */
    public int size() {
        return this.factHandles.length -1;
    }
    
    /**
     * Get the Object for the given FactHandle
     * @param handle
     * @return
     */
    private Object getObject(FactHandle factHandle) {
        return (( InternalFactHandle ) factHandle).getObject(); 
    }
}