/*******************************************************************************
 * Copyright (c) 2010- Association for Decentralized Information Management in
 * Industry THTH ry.
 * 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:
 *    VTT Technical Research Centre of Finland - initial API and implementation
 *******************************************************************************/
package org.simantics.databoard.binding.util;

import java.util.IdentityHashMap;

import org.simantics.databoard.type.ArrayType;
import org.simantics.databoard.type.BooleanType;
import org.simantics.databoard.type.ByteType;
import org.simantics.databoard.type.Component;
import org.simantics.databoard.type.Datatype;
import org.simantics.databoard.type.Datatype.Visitor;
import org.simantics.databoard.type.DoubleType;
import org.simantics.databoard.type.FloatType;
import org.simantics.databoard.type.IntegerType;
import org.simantics.databoard.type.LongType;
import org.simantics.databoard.type.MapType;
import org.simantics.databoard.type.OptionalType;
import org.simantics.databoard.type.RecordType;
import org.simantics.databoard.type.StringType;
import org.simantics.databoard.type.UnionType;
import org.simantics.databoard.type.VariantType;

public class IsReferableQuery implements Visitor<Result> {
	
	public static Result isReferable(Datatype type) {
		IsReferableQuery query = new IsReferableQuery();
		Result result = type.accept(query);
		return result;
	}
	
	IdentityHashMap<Datatype, Result> visited = new IdentityHashMap<Datatype, Result>();	
	
	@Override
	public Result visit(ArrayType b) {
		visited.put(b, Result.No);
		Datatype ct = b.componentType();
		Result cr = visited.get(ct);
		if (cr!=null) return cr;		
		cr = ct.accept(this);
		if (cr!=Result.No) visited.put(b, cr);		
		return cr; 
	}

	@Override
	public Result visit(BooleanType b) {
		return null;
	}

	@Override
	public Result visit(DoubleType b) {
		return null;
	}

	@Override
	public Result visit(FloatType b) {
		return null;
	}

	@Override
	public Result visit(IntegerType b) {
		return null;
	}

	@Override
	public Result visit(ByteType b) {
		return null;
	}

	@Override
	public Result visit(LongType b) {
		return null;
	}

	@Override
	public Result visit(OptionalType b) {
		visited.put(b, Result.No);
		Datatype ct = b.getComponentType();
		Result cr = visited.get(ct);
		if (cr!=null) return cr;		
		cr = ct.accept(this);
		if (cr!=Result.No) visited.put(b, cr);		
		return cr; 
	}

	@Override
	public Result visit(RecordType b) {		
		if (b.isReferable()) {
			visited.put(b, Result.Yes);
			return Result.Yes;
		}
				
		Result result = Result.No;
		visited.put(b, result);
		
		for (Component c : b.getComponents()) {
			Datatype ct = c.type;
			
			Result cr = visited.get(ct);
			if (cr==null) cr = ct.accept(this);
			if (cr!=null) {
				if (cr == Result.Yes) {
					result = cr;
					break;
				}
				if (cr == Result.Possible) {
					result = cr;					
				}
			}			
		}
		
		if (result!=Result.No) visited.put(b, result);		
		return result;
	}

	@Override
	public Result visit(StringType b) {
		return Result.No;
	}

	@Override
	public Result visit(UnionType b) {
		Result result = Result.No;
		visited.put(b, result);
		
		for (Component c : b.getComponents()) {
			Datatype ct = c.type;
			
			Result cr = visited.get(ct);
			if (cr==null) cr = ct.accept(this);
			if (cr!=null) {
				if (cr == Result.Yes) {
					result = cr;
					break;
				}
				if (cr == Result.Possible) {
					result = cr;					
				}
			}			
		}
		
		if (result!=Result.No) visited.put(b, result);		
		return result;
	}

	@Override
	public Result visit(VariantType b) {
		return Result.Possible;
	}

	@Override
	public Result visit(MapType b) {
		visited.put(b, Result.No);
		Datatype kt = b.keyType;
		Result kr = visited.get(kt);
		if (kr == null) kr = kt.accept(this);
		
		Datatype vt = b.valueType;
		Result vr = visited.get(vt);
		if (vr == null) vr = vt.accept(this);
		
		Result result = Result.No;
		if (kr==Result.Yes || vr==Result.Yes) result = Result.Yes;
		else if (kr==Result.Possible || vr==Result.Possible) result = Result.Possible;

		if (result!=Result.No) 
			visited.put(b, Result.No);
		
		return result; 
	}
	
}