/*******************************************************************************
 * 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.phpdt.internal.compiler.ast;

import net.sourceforge.phpdt.internal.compiler.ASTVisitor;
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.LoopingFlowContext;
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 ForStatement extends Statement {

	public Statement[] initializations;

	public Expression condition;

	public Statement[] increments;

	public Statement action;

	// when there is no local declaration, there is no need of a new scope
	// scope is positionned either to a new scope, or to the "upper"scope (see
	// resolveType)
	public boolean neededScope;

	public BlockScope scope;

	private Label breakLabel, continueLabel;

	// for local variables table attributes
	int preCondInitStateIndex = -1;

	int condIfTrueInitStateIndex = -1;

	int mergedInitStateIndex = -1;

	public ForStatement(Statement[] initializations, Expression condition,
			Statement[] increments, Statement action, boolean neededScope,
			int s, int e) {

		this.sourceStart = s;
		this.sourceEnd = e;
		this.initializations = initializations;
		this.condition = condition;
		this.increments = increments;
		this.action = action;
		this.neededScope = neededScope;
	}

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

		breakLabel = new Label();
		continueLabel = new Label();

		// process the initializations
		if (initializations != null) {
			int count = initializations.length, i = 0;
			while (i < count) {
				flowInfo = initializations[i++].analyseCode(scope, flowContext,
						flowInfo);
			}
		}
		preCondInitStateIndex = currentScope.methodScope()
				.recordInitializationStates(flowInfo);

		Constant cst = this.condition == null ? null : this.condition.constant;
		boolean isConditionTrue = cst == null
				|| (cst != NotAConstant && cst.booleanValue() == true);
		boolean isConditionFalse = cst != null
				&& (cst != NotAConstant && cst.booleanValue() == false);

		cst = this.condition == null ? null : this.condition
				.optimizedBooleanConstant();
		boolean isConditionOptimizedTrue = cst == null
				|| (cst != NotAConstant && cst.booleanValue() == true);
		boolean isConditionOptimizedFalse = cst != null
				&& (cst != NotAConstant && cst.booleanValue() == false);

		// process the condition
		LoopingFlowContext condLoopContext = null;
		if (condition != null) {
			if (!isConditionTrue) {
				flowInfo = condition.analyseCode(scope,
						(condLoopContext = new LoopingFlowContext(flowContext,
								this, null, null, scope)), flowInfo);
			}
		}

		// process the action
		LoopingFlowContext loopingContext;
		FlowInfo actionInfo;
		if (action == null) {
			// || (action.isEmptyBlock() &&
			// currentScope.environment().options.complianceLevel <=
			// CompilerOptions.JDK1_3)) {
			if (condLoopContext != null)
				condLoopContext.complainOnFinalAssignmentsInLoop(scope,
						flowInfo);
			if (isConditionTrue) {
				return FlowInfo.DEAD_END;
			} else {
				if (isConditionFalse) {
					continueLabel = null; // for(;false;p());
				}
				actionInfo = flowInfo.initsWhenTrue().copy();
				loopingContext = new LoopingFlowContext(flowContext, this,
						breakLabel, continueLabel, scope);
			}
		} else {
			loopingContext = new LoopingFlowContext(flowContext, this,
					breakLabel, continueLabel, scope);
			FlowInfo initsWhenTrue = flowInfo.initsWhenTrue();
			condIfTrueInitStateIndex = currentScope.methodScope()
					.recordInitializationStates(initsWhenTrue);

			if (isConditionFalse) {
				actionInfo = FlowInfo.DEAD_END;
			} else {
				actionInfo = initsWhenTrue.copy();
				if (isConditionOptimizedFalse) {
					actionInfo.setReachMode(FlowInfo.UNREACHABLE);
				}
			}
			if (!actionInfo.complainIfUnreachable(action, scope, false)) {
				actionInfo = action.analyseCode(scope, loopingContext,
						actionInfo);
			}

			// code generation can be optimized when no need to continue in the
			// loop
			if (!actionInfo.isReachable()
					&& !loopingContext.initsOnContinue.isReachable()) {
				continueLabel = null;
			} else {
				if (condLoopContext != null)
					condLoopContext.complainOnFinalAssignmentsInLoop(scope,
							flowInfo);
				loopingContext.complainOnFinalAssignmentsInLoop(scope,
						actionInfo);
				actionInfo = actionInfo
						.mergedWith(loopingContext.initsOnContinue
								.unconditionalInits());
				// for increments
			}
		}
		if ((continueLabel != null) && (increments != null)) {
			LoopingFlowContext loopContext = new LoopingFlowContext(
					flowContext, this, null, null, scope);
			int i = 0, count = increments.length;
			while (i < count)
				actionInfo = increments[i++].analyseCode(scope, loopContext,
						actionInfo);
			loopContext.complainOnFinalAssignmentsInLoop(scope, actionInfo);
		}

		// infinite loop
		FlowInfo mergedInfo;
		if (isConditionOptimizedTrue) {
			mergedInitStateIndex = currentScope.methodScope()
					.recordInitializationStates(
							mergedInfo = loopingContext.initsOnBreak);
			return mergedInfo;
		}

		// end of loop: either condition false or break
		mergedInfo = flowInfo.initsWhenFalse().unconditionalInits().mergedWith(
				loopingContext.initsOnBreak.unconditionalInits());
		if (isConditionOptimizedTrue && continueLabel == null) {
			mergedInfo.setReachMode(FlowInfo.UNREACHABLE);
		}
		mergedInitStateIndex = currentScope.methodScope()
				.recordInitializationStates(mergedInfo);
		return mergedInfo;
	}

	/**
	 * For statement code generation
	 * 
	 * @param currentScope
	 *            net.sourceforge.phpdt.internal.compiler.lookup.BlockScope
	 * @param codeStream
	 *            net.sourceforge.phpdt.internal.compiler.codegen.CodeStream
	 */
	// public void generateCode(BlockScope currentScope, CodeStream codeStream)
	// {
	//
	// if ((bits & IsReachableMASK) == 0) {
	// return;
	// }
	// int pc = codeStream.position;
	//
	// // generate the initializations
	// if (initializations != null) {
	// for (int i = 0, max = initializations.length; i < max; i++) {
	// initializations[i].generateCode(scope, codeStream);
	// }
	// }
	//
	// // label management
	// Label actionLabel = new Label(codeStream);
	// Label conditionLabel = new Label(codeStream);
	// breakLabel.codeStream = codeStream;
	// if (continueLabel != null) {
	// continueLabel.codeStream = codeStream;
	// }
	// // jump over the actionBlock
	// if ((condition != null)
	// && (condition.constant == NotAConstant)
	// && !((action == null || action.isEmptyBlock()) && (increments == null)))
	// {
	// int jumpPC = codeStream.position;
	// codeStream.goto_(conditionLabel);
	// codeStream.recordPositionsFrom(jumpPC, condition.sourceStart);
	// }
	// // generate the loop action
	// actionLabel.place();
	// if (action != null) {
	// // Required to fix 1PR0XVS: LFRE:WINNT - Compiler: variable table for
	// method appears incorrect
	// if (condIfTrueInitStateIndex != -1) {
	// // insert all locals initialized inside the condition into the action
	// generated prior to the condition
	// codeStream.addDefinitelyAssignedVariables(
	// currentScope,
	// condIfTrueInitStateIndex);
	// }
	// action.generateCode(scope, codeStream);
	// }
	// // continuation point
	// if (continueLabel != null) {
	// continueLabel.place();
	// // generate the increments for next iteration
	// if (increments != null) {
	// for (int i = 0, max = increments.length; i < max; i++) {
	// increments[i].generateCode(scope, codeStream);
	// }
	// }
	// }
	//
	// // May loose some local variable initializations : affecting the local
	// variable attributes
	// if (preCondInitStateIndex != -1) {
	// codeStream.removeNotDefinitelyAssignedVariables(
	// currentScope,
	// preCondInitStateIndex);
	// }
	//
	// // generate the condition
	// conditionLabel.place();
	// if ((condition != null) && (condition.constant == NotAConstant)) {
	// condition.generateOptimizedBoolean(scope, codeStream, actionLabel, null,
	// true);
	// } else {
	// if (continueLabel != null) {
	// codeStream.goto_(actionLabel);
	// }
	// }
	// breakLabel.place();
	//
	// // May loose some local variable initializations : affecting the local
	// variable attributes
	// if (neededScope) {
	// codeStream.exitUserScope(scope);
	// }
	// if (mergedInitStateIndex != -1) {
	// codeStream.removeNotDefinitelyAssignedVariables(
	// currentScope,
	// mergedInitStateIndex);
	// }
	// codeStream.recordPositionsFrom(pc, this.sourceStart);
	// }
	public void resetStateForCodeGeneration() {
		if (this.breakLabel != null) {
			this.breakLabel.resetStateForCodeGeneration();
		}
		if (this.continueLabel != null) {
			this.continueLabel.resetStateForCodeGeneration();
		}
	}

	public StringBuffer printStatement(int tab, StringBuffer output) {

		printIndent(tab, output).append("for ("); //$NON-NLS-1$
		// inits
		if (initializations != null) {
			for (int i = 0; i < initializations.length; i++) {
				// nice only with expressions
				if (i > 0)
					output.append(", "); //$NON-NLS-1$
				initializations[i].print(0, output);
			}
		}
		output.append("; "); //$NON-NLS-1$
		// cond
		if (condition != null)
			condition.printExpression(0, output);
		output.append("; "); //$NON-NLS-1$
		// updates
		if (increments != null) {
			for (int i = 0; i < increments.length; i++) {
				if (i > 0)
					output.append(", "); //$NON-NLS-1$
				increments[i].print(0, output);
			}
		}
		output.append(") "); //$NON-NLS-1$
		// block
		if (action == null)
			output.append(';');
		else {
			output.append('\n');
			action.printStatement(tab + 1, output); //$NON-NLS-1$
		}
		return output.append(';');
	}

	public void resolve(BlockScope upperScope) {

		// use the scope that will hold the init declarations
		scope = neededScope ? new BlockScope(upperScope) : upperScope;
		if (initializations != null)
			for (int i = 0, length = initializations.length; i < length; i++)
				initializations[i].resolve(scope);
		if (condition != null) {
			TypeBinding type = condition.resolveTypeExpecting(scope,
					BooleanBinding);
			condition.implicitWidening(type, type);
		}
		if (increments != null)
			for (int i = 0, length = increments.length; i < length; i++)
				increments[i].resolve(scope);
		if (action != null)
			action.resolve(scope);
	}

	public String toString(int tab) {

		String s = tabString(tab) + "for ("; //$NON-NLS-1$
		if (!neededScope)
			s = s
					+ " //--NO upperscope scope needed\n" + tabString(tab) + "     "; //$NON-NLS-2$ //$NON-NLS-1$
		// inits
		if (initializations != null) {
			for (int i = 0; i < initializations.length; i++) {
				// nice only with expressions
				s = s + initializations[i].toString(0);
				if (i != (initializations.length - 1))
					s = s + " , "; //$NON-NLS-1$
			}
		}
		;
		s = s + "; "; //$NON-NLS-1$
		// cond
		if (condition != null)
			s = s + condition.toStringExpression();
		s = s + "; "; //$NON-NLS-1$
		// updates
		if (increments != null) {
			for (int i = 0; i < increments.length; i++) {
				// nice only with expressions
				s = s + increments[i].toString(0);
				if (i != (increments.length - 1))
					s = s + " , "; //$NON-NLS-1$
			}
		}
		;
		s = s + ") "; //$NON-NLS-1$
		// block
		if (action == null)
			s = s + "{}"; //$NON-NLS-1$
		else
			s = s + "\n" + action.toString(tab + 1); //$NON-NLS-1$
		return s;
	}

	public void traverse(ASTVisitor visitor, BlockScope blockScope) {

		if (visitor.visit(this, blockScope)) {
			if (initializations != null) {
				int initializationsLength = initializations.length;
				for (int i = 0; i < initializationsLength; i++)
					initializations[i].traverse(visitor, scope);
			}

			if (condition != null)
				condition.traverse(visitor, scope);

			if (increments != null) {
				int incrementsLength = increments.length;
				for (int i = 0; i < incrementsLength; i++)
					increments[i].traverse(visitor, scope);
			}

			if (action != null)
				action.traverse(visitor, scope);
		}
		visitor.endVisit(this, blockScope);
	}
}