/*******************************************************************************
 * Copyright (c) 2000, 2001, 2002 International Business Machines Corp. and others.
 * All rights reserved. This program and the accompanying materials 
 * are made available under the terms of the Common Public License v0.5 
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v05.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 ******************************************************************************/
package net.sourceforge.phpdt.internal.compiler.ast;

import net.sourceforge.phpdt.internal.compiler.IAbstractSyntaxTreeVisitor;
import net.sourceforge.phpdt.internal.compiler.codegen.CaseLabel;
import net.sourceforge.phpdt.internal.compiler.codegen.CodeStream;
import net.sourceforge.phpdt.internal.compiler.flow.FlowContext;
import net.sourceforge.phpdt.internal.compiler.flow.FlowInfo;
import net.sourceforge.phpdt.internal.compiler.impl.Constant;
import net.sourceforge.phpdt.internal.compiler.lookup.BlockScope;
import net.sourceforge.phpdt.internal.compiler.lookup.TypeBinding;

public class Case extends Statement {
	
	public Expression constantExpression;
	public CaseLabel targetLabel;
	public Case(int sourceStart, Expression constantExpression) {
		this.constantExpression = constantExpression;
		this.sourceEnd = constantExpression.sourceEnd;
		this.sourceStart = sourceStart;
	}

	public FlowInfo analyseCode(
		BlockScope currentScope,
		FlowContext flowContext,
		FlowInfo flowInfo) {

		if (constantExpression.constant == NotAConstant)
			currentScope.problemReporter().caseExpressionMustBeConstant(constantExpression);

		this.constantExpression.analyseCode(currentScope, flowContext, flowInfo);
		return flowInfo;
	}

	/**
	 * Case code generation
	 *
	 */
	public void generateCode(BlockScope currentScope, CodeStream codeStream) {

		if ((bits & IsReachableMASK) == 0) {
			return;
		}
		int pc = codeStream.position;
		targetLabel.place();
		codeStream.recordPositionsFrom(pc, this.sourceStart);
	}

	public void resolve(BlockScope scope) {

		// error....use resolveCase....
		throw new NullPointerException();
	}

	public Constant resolveCase(
		BlockScope scope,
		TypeBinding testTb,
		SwitchStatement switchStatement) {

		// add into the collection of cases of the associated switch statement
		switchStatement.cases[switchStatement.caseCount++] = this;
		TypeBinding caseTb = constantExpression.resolveType(scope);
		if (caseTb == null || testTb == null)
			return null;
		if (constantExpression.isConstantValueOfTypeAssignableToType(caseTb, testTb))
			return constantExpression.constant;
		if (BlockScope.areTypesCompatible(caseTb, testTb))
			return constantExpression.constant;
		scope.problemReporter().typeMismatchErrorActualTypeExpectedType(
			constantExpression,
			caseTb,
			testTb);
		return null;
	}

	public String toString(int tab) {

		String s = tabString(tab);
		s = s + "case " + constantExpression.toStringExpression() + " : "; //$NON-NLS-1$ //$NON-NLS-2$
		return s;
	}

	public void traverse(
		IAbstractSyntaxTreeVisitor visitor,
		BlockScope blockScope) {

		if (visitor.visit(this, blockScope)) {
			constantExpression.traverse(visitor, blockScope);
		}
		visitor.endVisit(this, blockScope);
	}
}