/*******************************************************************************
 * Copyright (c) 2000, 2003 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials 
 * are made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package net.sourceforge.phpeclipse.internal.compiler.ast;

import net.sourceforge.phpdt.internal.compiler.IAbstractSyntaxTreeVisitor;
import net.sourceforge.phpdt.internal.compiler.codegen.Label;
import net.sourceforge.phpdt.internal.compiler.flow.FlowContext;
import net.sourceforge.phpdt.internal.compiler.flow.FlowInfo;
import net.sourceforge.phpdt.internal.compiler.flow.SwitchFlowContext;
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 SwitchStatement extends Statement {
	public Expression testExpression;
	public Statement[] statements;
	public BlockScope scope;
	public int explicitDeclarations;
	public Label breakLabel;
	public Case[] cases;
	public DefaultCase defaultCase;
	public int caseCount = 0;

	// for local variables table attributes
	int preSwitchInitStateIndex = -1;
	int mergedInitStateIndex = -1;
	/**
	 * SwitchStatement constructor comment.
	 */
	public SwitchStatement() {
		super();
	}
	public FlowInfo analyseCode(
		BlockScope currentScope,
		FlowContext flowContext,
		FlowInfo flowInfo) {
		flowInfo = testExpression.analyseCode(currentScope, flowContext, flowInfo);
		SwitchFlowContext switchContext =
			new SwitchFlowContext(flowContext, this, (breakLabel = new Label()));

		// analyse the block by considering specially the case/default statements (need to bind them 
		// to the entry point)
		FlowInfo caseInits = FlowInfo.DEAD_END;
		// in case of statements before the first case
		preSwitchInitStateIndex =
			currentScope.methodScope().recordInitializationStates(flowInfo);
		int caseIndex = 0;
		if (statements != null) {
			boolean didAlreadyComplain = false;
			for (int i = 0, max = statements.length; i < max; i++) {
				Statement statement = statements[i];
				if ((caseIndex < caseCount) && (statement == cases[caseIndex])) { // statement is a case
					caseIndex++;
					caseInits = caseInits.mergedWith(flowInfo.copy().unconditionalInits());
					didAlreadyComplain = false; // reset complaint
				} else if (statement == defaultCase) { // statement is the default case
					caseInits = caseInits.mergedWith(flowInfo.copy().unconditionalInits());
					didAlreadyComplain = false; // reset complaint
				}
				if (!caseInits.complainIfUnreachable(statement, scope, didAlreadyComplain)) {
					caseInits = statement.analyseCode(scope, switchContext, caseInits);
				} else {
					didAlreadyComplain = true;
				}
			}
		}

		// if no default case, then record it may jump over the block directly to the end
		if (defaultCase == null) {
			// only retain the potential initializations
			flowInfo.addPotentialInitializationsFrom(
				caseInits.mergedWith(switchContext.initsOnBreak));
			mergedInitStateIndex =
				currentScope.methodScope().recordInitializationStates(flowInfo);
			return flowInfo;
		}

		// merge all branches inits
		FlowInfo mergedInfo = caseInits.mergedWith(switchContext.initsOnBreak);
		mergedInitStateIndex =
			currentScope.methodScope().recordInitializationStates(mergedInfo);
		return mergedInfo;
	}
	/**
	 * Switch code generation
	 *
	 * @param currentScope org.eclipse.jdt.internal.compiler.lookup.BlockScope
	 * @param codeStream org.eclipse.jdt.internal.compiler.codegen.CodeStream
	 */
//	public void generateCode(BlockScope currentScope, CodeStream codeStream) {
//		int[] sortedIndexes = new int[caseCount];
//		int[] localKeysCopy;
//		if ((bits & IsReachableMASK) == 0) {
//			return;
//		}
//		int pc = codeStream.position;
//
//		// prepare the labels and constants
//		breakLabel.codeStream = codeStream;
//		CaseLabel[] caseLabels = new CaseLabel[caseCount];
//		int[] constants = new int[caseCount];
//		boolean needSwitch = caseCount != 0;
//		for (int i = 0; i < caseCount; i++) {
//			constants[i] = cases[i].constantExpression.constant.intValue();
//			cases[i].targetLabel = (caseLabels[i] = new CaseLabel(codeStream));
//		}
//
//		// we sort the keys to be able to generate the code for tableswitch or lookupswitch
//		for (int i = 0; i < caseCount; i++) {
//			sortedIndexes[i] = i;
//		}
//		System.arraycopy(
//			constants,
//			0,
//			(localKeysCopy = new int[caseCount]),
//			0,
//			caseCount);
//		CodeStream.sort(localKeysCopy, 0, caseCount - 1, sortedIndexes);
//		CaseLabel defaultLabel = new CaseLabel(codeStream);
//		if (defaultCase != null) {
//			defaultCase.targetLabel = defaultLabel;
//		}
//		// generate expression testes
//		testExpression.generateCode(currentScope, codeStream, needSwitch);
//
//		// generate the appropriate switch table/lookup bytecode
//		if (needSwitch) {
//			int max = localKeysCopy[caseCount - 1];
//			int min = localKeysCopy[0];
//			if ((long) (caseCount * 2.5) > ((long) max - (long) min)) {
//				
//				// work-around 1.3 VM bug, if max>0x7FFF0000, must use lookup bytecode
//				// see http://dev.eclipse.org/bugs/show_bug.cgi?id=21557
//				if (max > 0x7FFF0000 && currentScope.environment().options.complianceLevel < CompilerOptions.JDK1_4) {
//					codeStream.lookupswitch(defaultLabel, constants, sortedIndexes, caseLabels);
//
//				} else {
//					codeStream.tableswitch(
//						defaultLabel,
//						min,
//						max,
//						constants,
//						sortedIndexes,
//						caseLabels);
//				}
//			} else {
//				codeStream.lookupswitch(defaultLabel, constants, sortedIndexes, caseLabels);
//			}
//			codeStream.updateLastRecordedEndPC(codeStream.position);
//		}
//		
//		// generate the switch block statements
//		int caseIndex = 0;
//		if (statements != null) {
//			for (int i = 0, maxCases = statements.length; i < maxCases; i++) {
//				Statement statement = statements[i];
//				if ((caseIndex < caseCount)
//					&& (statement == cases[caseIndex])) { // statements[i] is a case
//					if (preSwitchInitStateIndex != -1) {
//						codeStream.removeNotDefinitelyAssignedVariables(
//							currentScope,
//							preSwitchInitStateIndex);
//						caseIndex++;
//					}
//				} else {
//					if (statement == defaultCase) { // statements[i] is a case or a default case
//						if (preSwitchInitStateIndex != -1) {
//							codeStream.removeNotDefinitelyAssignedVariables(
//								currentScope,
//								preSwitchInitStateIndex);
//						}
//					}
//				}
//				statement.generateCode(scope, codeStream);
//			}
//		}
//		// place the trailing labels (for break and default case)
//		breakLabel.place();
//		if (defaultCase == null) {
//			defaultLabel.place();
//		}
//		// May loose some local variable initializations : affecting the local variable attributes
//		if (mergedInitStateIndex != -1) {
//			codeStream.removeNotDefinitelyAssignedVariables(
//				currentScope,
//				mergedInitStateIndex);
//			codeStream.addDefinitelyAssignedVariables(currentScope, mergedInitStateIndex);
//		}
//		if (scope != currentScope) {
//			codeStream.exitUserScope(scope);
//		}
//		codeStream.recordPositionsFrom(pc, this.sourceStart);
//	}


	public void resetStateForCodeGeneration() {
		if (this.breakLabel != null) {
			this.breakLabel.resetStateForCodeGeneration();
		}
	}

	public void resolve(BlockScope upperScope) {

		TypeBinding testType = testExpression.resolveType(upperScope);
		if (testType == null)
			return;
		testExpression.implicitWidening(testType, testType);
		if (!(testExpression.isConstantValueOfTypeAssignableToType(testType, IntBinding))) {
			if (!testType.isCompatibleWith(IntBinding)) {
				upperScope.problemReporter().incorrectSwitchType(testExpression, testType);
				return;
			}
		}
		if (statements != null) {
			scope = explicitDeclarations == 0 ? upperScope : new BlockScope(upperScope);
			int length;
			// collection of cases is too big but we will only iterate until caseCount
			cases = new Case[length = statements.length];
			int[] casesValues = new int[length];
			int counter = 0;
			for (int i = 0; i < length; i++) {
				Constant cst;
				if ((cst = statements[i].resolveCase(scope, testType, this)) != null) {
					//----check for duplicate case statement------------
					if (cst != NotAConstant) {
						int key = cst.intValue();
						for (int j = 0; j < counter; j++) {
							if (casesValues[j] == key) {
								scope.problemReporter().duplicateCase((Case) statements[i], cst); //TODO: (philippe) could improve diagnosis to indicate colliding case
							}
						}
						casesValues[counter++] = key;
					}
				}
			}
		}
	}
	public String toString(int tab) {

		String inFront, s = tabString(tab);
		inFront = s;
		s = s + "switch (" + testExpression.toStringExpression() + ") "; //$NON-NLS-1$ //$NON-NLS-2$
		if (statements == null) {
			s = s + "{}"; //$NON-NLS-1$
			return s;
		} else
			s = s + "{"; //$NON-NLS-1$
			s = s
					+ (explicitDeclarations != 0
						? "// ---scope needed for " //$NON-NLS-1$
							+ String.valueOf(explicitDeclarations)
							+ " locals------------ \n"//$NON-NLS-1$
						: "// ---NO scope needed------ \n"); //$NON-NLS-1$

		int i = 0;
		String tabulation = "  "; //$NON-NLS-1$
		try {
			while (true) {
				//use instanceof in order not to polluate classes with behavior only needed for printing purpose.
				if (statements[i] instanceof Expression)
					s = s + "\n" + inFront + tabulation; //$NON-NLS-1$
				if (statements[i] instanceof Break)
					s = s + statements[i].toString(0);
				else
					s = s + "\n" + statements[i].toString(tab + 2); //$NON-NLS-1$
				//=============	
				if ((statements[i] instanceof Case)
					|| (statements[i] instanceof DefaultCase)) {
					i++;
					while (!((statements[i] instanceof Case)
						|| (statements[i] instanceof DefaultCase))) {
						if ((statements[i] instanceof Expression) || (statements[i] instanceof Break))
							s = s + statements[i].toString(0) + " ; "; //$NON-NLS-1$
						else
							s = s + "\n" + statements[i].toString(tab + 6) + " ; "; //$NON-NLS-1$ //$NON-NLS-2$
						i++;
					}
				} else {
					s = s + " ;"; //$NON-NLS-1$
					i++;
				}
			}
		} catch (IndexOutOfBoundsException e) {
		};
		s = s + "}"; //$NON-NLS-1$
		return s;
	}

	public void traverse(
		IAbstractSyntaxTreeVisitor visitor,
		BlockScope blockScope) {

		if (visitor.visit(this, blockScope)) {
			testExpression.traverse(visitor, scope);
			if (statements != null) {
				int statementsLength = statements.length;
				for (int i = 0; i < statementsLength; i++)
					statements[i].traverse(visitor, scope);
			}
		}
		visitor.endVisit(this, blockScope);
	}
	
	/**
	 * Dispatch the call on its last statement.
	 */
	public void branchChainTo(Label label) {
		
		// in order to improve debug attributes for stepping (11431)
		// we want to inline the jumps to #breakLabel which already got
		// generated (if any), and have them directly branch to a better
		// location (the argument label).
		// we know at this point that the breakLabel already got placed
		if (this.breakLabel.hasForwardReferences()) {
			label.appendForwardReferencesFrom(this.breakLabel);
		}
	}
}