/*******************************************************************************
 * Copyright (c) 2011 Bruno Medeiros and other Contributors.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     Bruno Medeiros - initial API and implementation
 *******************************************************************************/
package dtool.ast.references;

import melnorme.lang.tooling.context.ISemanticContext;
import melnorme.lang.tooling.engine.PickedElement;
import melnorme.lang.tooling.engine.resolver.IReference;
import melnorme.lang.tooling.engine.resolver.ReferenceSemantics;
import melnorme.lang.tooling.engine.scoping.ResolutionLookup;
import melnorme.lang.tooling.symbols.INamedElement;

/** 
 * A reference based on an identifier. These references also 
 * allow doing a search based on their lookup rules.
 */
public abstract class NamedReference extends Reference implements IQualifierNode {
	
	/** @return the central/primary name of this reference. 
	 * (that usually means the rightmost identifier without qualifiers).
	 * Can be null. */
	public abstract String getCoreReferenceName();
	
	/** @return whether the core reference is missing or not (it can be missing on syntax errors). */
	public boolean isMissingCoreReference() {
		return getCoreReferenceName() == null || getCoreReferenceName().isEmpty();
	}
	
	
	/* -----------------  ----------------- */
	
	@Override
	public NamedReferenceSemantics getSemantics(ISemanticContext parentContext) {
		return (NamedReferenceSemantics) super.getSemantics(parentContext);
	}
	@Override
	protected NamedReferenceSemantics doCreateSemantics(PickedElement<?> pickedElement) {
		return new NamedReferenceSemantics(this, pickedElement);
	}
	
	public class NamedReferenceSemantics extends ReferenceSemantics {
		
		protected NamedReferenceSemantics(IReference reference, PickedElement<?> pickedElement) {
			super(reference, pickedElement);
		}
		
		@Override
		protected INamedElement doResolveTargetElement() {
			if(isMissingCoreReference()) {
				return null;
			}
			ResolutionLookup search = doResolutionLookup();
			return search.getMatchedElement();
		}
		
		public ResolutionLookup doResolutionLookup() {
			if(isMissingCoreReference()) {
				return null;
			}
			
			int startPos = hasSourceRangeInfo() ? getStartPos() : -1;
			ResolutionLookup search = new ResolutionLookup(getCoreReferenceName(), startPos, context);
			performNameLookup(search);
			search.completeSearchMatches();
			return search;
		}
	}
	
	/** Return wheter this reference can match the given defunit.
	 * This is a very lightweight method that only compares the defunit's name 
	 * with the core identifier of this reference.
	 */
	public final boolean canMatch(String simpleName) {
		return getCoreReferenceName().equals(simpleName);
	}
	
}