/*******************************************************************************
 * 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.lookup;

import net.sourceforge.phpdt.internal.compiler.ast.AbstractMethodDeclaration;
import net.sourceforge.phpdt.internal.compiler.ast.ConstructorDeclaration;
import net.sourceforge.phpdt.internal.compiler.ast.QualifiedNameReference;
import net.sourceforge.phpdt.internal.compiler.ast.SingleNameReference;
import net.sourceforge.phpdt.internal.compiler.ast.TypeDeclaration;
import net.sourceforge.phpdt.internal.compiler.flow.FlowInfo;
import net.sourceforge.phpdt.internal.compiler.flow.UnconditionalFlowInfo;
import net.sourceforge.phpdt.internal.compiler.impl.ReferenceContext;
import net.sourceforge.phpdt.internal.compiler.problem.ProblemReporter;

/**
 * Particular block scope used for methods, constructors or clinits,
 * representing its outermost blockscope. Note also that such a scope will be
 * provided to enclose field initializers subscopes as well.
 */
public class MethodScope extends BlockScope {

	public ReferenceContext referenceContext;

	public boolean isStatic; // method modifier or initializer one

	// fields used during name resolution
	public static final int NotInFieldDecl = -1; // must be a negative value

	public boolean isConstructorCall = false;

	public FieldBinding initializedField; // the field being initialized

	public int fieldDeclarationIndex = NotInFieldDecl;

	// flow analysis
	public int analysisIndex; // for setting flow-analysis id

	public boolean isPropagatingInnerClassEmulation;

	// for local variables table attributes
	public int lastIndex = 0;

	public long[] definiteInits = new long[4];

	public long[][] extraDefiniteInits = new long[4][];

	// inner-emulation
	public SyntheticArgumentBinding[] extraSyntheticArguments;

	public MethodScope(ClassScope parent, ReferenceContext context,
			boolean isStatic) {

		super(METHOD_SCOPE, parent);
		locals = new LocalVariableBinding[5];
		this.referenceContext = context;
		this.isStatic = isStatic;
		this.startIndex = 0;
	}

	/*
	 * Spec : 8.4.3 & 9.4
	 */
	private void checkAndSetModifiersForConstructor(MethodBinding methodBinding) {

		int modifiers = methodBinding.modifiers;
		if ((modifiers & AccAlternateModifierProblem) != 0)
			problemReporter().duplicateModifierForMethod(
					methodBinding.declaringClass,
					(AbstractMethodDeclaration) referenceContext);

		if (((ConstructorDeclaration) referenceContext).isDefaultConstructor) {
			if (methodBinding.declaringClass.isPublic())
				modifiers |= AccPublic;
			else if (methodBinding.declaringClass.isProtected())
				modifiers |= AccProtected;
		}

		// after this point, tests on the 16 bits reserved.
		int realModifiers = modifiers & AccJustFlag;

		// check for abnormal modifiers
		int unexpectedModifiers = ~(AccPublic | AccPrivate | AccProtected);// |
																			// AccStrictfp);
		if ((realModifiers & unexpectedModifiers) != 0)
			problemReporter().illegalModifierForMethod(
					methodBinding.declaringClass,
					(AbstractMethodDeclaration) referenceContext);
		// else if (
		// (((AbstractMethodDeclaration) referenceContext).modifiers &
		// AccStrictfp) != 0)
		// // must check the parse node explicitly
		// problemReporter().illegalModifierForMethod(
		// methodBinding.declaringClass,
		// (AbstractMethodDeclaration) referenceContext);

		// check for incompatible modifiers in the visibility bits, isolate the
		// visibility bits
		int accessorBits = realModifiers
				& (AccPublic | AccProtected | AccPrivate);
		if ((accessorBits & (accessorBits - 1)) != 0) {
			problemReporter().illegalVisibilityModifierCombinationForMethod(
					methodBinding.declaringClass,
					(AbstractMethodDeclaration) referenceContext);

			// need to keep the less restrictive
			if ((accessorBits & AccPublic) != 0) {
				if ((accessorBits & AccProtected) != 0)
					modifiers ^= AccProtected;
				if ((accessorBits & AccPrivate) != 0)
					modifiers ^= AccPrivate;
			}
			if ((accessorBits & AccProtected) != 0)
				if ((accessorBits & AccPrivate) != 0)
					modifiers ^= AccPrivate;
		}

		// if the receiver's declaring class is a private nested type, then make
		// sure the receiver is not private (causes problems for inner type
		// emulation)
		if (methodBinding.declaringClass.isPrivate())
			if ((modifiers & AccPrivate) != 0)
				modifiers ^= AccPrivate;

		methodBinding.modifiers = modifiers;
	}

	/*
	 * Spec : 8.4.3 & 9.4
	 */
	private void checkAndSetModifiersForMethod(MethodBinding methodBinding) {

		int modifiers = methodBinding.modifiers;
		if ((modifiers & AccAlternateModifierProblem) != 0)
			problemReporter().duplicateModifierForMethod(
					methodBinding.declaringClass,
					(AbstractMethodDeclaration) referenceContext);

		// after this point, tests on the 16 bits reserved.
		int realModifiers = modifiers & AccJustFlag;

		// set the requested modifiers for a method in an interface
		if (methodBinding.declaringClass.isInterface()) {
			if ((realModifiers & ~(AccPublic | AccAbstract)) != 0)
				problemReporter().illegalModifierForInterfaceMethod(
						methodBinding.declaringClass,
						(AbstractMethodDeclaration) referenceContext);
			return;
		}

		// check for abnormal modifiers
		int unexpectedModifiers = ~(AccPublic | AccPrivate | AccProtected
				| AccAbstract | AccStatic | AccFinal);
		// | AccSynchronized
		// | AccNative
		// | AccStrictfp);
		if ((realModifiers & unexpectedModifiers) != 0)
			problemReporter().illegalModifierForMethod(
					methodBinding.declaringClass,
					(AbstractMethodDeclaration) referenceContext);

		// check for incompatible modifiers in the visibility bits, isolate the
		// visibility bits
		int accessorBits = realModifiers
				& (AccPublic | AccProtected | AccPrivate);
		if ((accessorBits & (accessorBits - 1)) != 0) {
			problemReporter().illegalVisibilityModifierCombinationForMethod(
					methodBinding.declaringClass,
					(AbstractMethodDeclaration) referenceContext);

			// need to keep the less restrictive
			if ((accessorBits & AccPublic) != 0) {
				if ((accessorBits & AccProtected) != 0)
					modifiers ^= AccProtected;
				if ((accessorBits & AccPrivate) != 0)
					modifiers ^= AccPrivate;
			}
			if ((accessorBits & AccProtected) != 0)
				if ((accessorBits & AccPrivate) != 0)
					modifiers ^= AccPrivate;
		}

		// check for modifiers incompatible with abstract modifier
		if ((modifiers & AccAbstract) != 0) {
			int incompatibleWithAbstract = AccPrivate | AccStatic | AccFinal;// |
																				// AccSynchronized
																				// |
																				// AccNative
																				// |
																				// AccStrictfp;
			if ((modifiers & incompatibleWithAbstract) != 0)
				problemReporter().illegalAbstractModifierCombinationForMethod(
						methodBinding.declaringClass,
						(AbstractMethodDeclaration) referenceContext);
			if (!methodBinding.declaringClass.isAbstract())
				problemReporter().abstractMethodInAbstractClass(
						(SourceTypeBinding) methodBinding.declaringClass,
						(AbstractMethodDeclaration) referenceContext);
		}

		/*
		 * DISABLED for backward compatibility with javac (if enabled should
		 * also mark private methods as final) // methods from a final class are
		 * final : 8.4.3.3 if (methodBinding.declaringClass.isFinal()) modifiers |=
		 * AccFinal;
		 */
		// native methods cannot also be tagged as strictfp
		// if ((modifiers & AccNative) != 0 && (modifiers & AccStrictfp) != 0)
		// problemReporter().nativeMethodsCannotBeStrictfp(
		// methodBinding.declaringClass,
		// (AbstractMethodDeclaration) referenceContext);
		// static members are only authorized in a static member or top level
		// type
		if (((realModifiers & AccStatic) != 0)
				&& methodBinding.declaringClass.isNestedType()
				&& !methodBinding.declaringClass.isStatic())
			problemReporter().unexpectedStaticModifierForMethod(
					methodBinding.declaringClass,
					(AbstractMethodDeclaration) referenceContext);

		methodBinding.modifiers = modifiers;
	}

	/*
	 * Compute variable positions in scopes given an initial position offset
	 * ignoring unused local variables.
	 * 
	 * Deal with arguments here, locals and subscopes are processed in
	 * BlockScope method
	 */
	// public void computeLocalVariablePositions(int initOffset, CodeStream
	// codeStream) {
	//
	// boolean isReportingUnusedArgument = false;
	//
	// if (referenceContext instanceof AbstractMethodDeclaration) {
	// AbstractMethodDeclaration methodDecl =
	// (AbstractMethodDeclaration)referenceContext;
	// MethodBinding method = methodDecl.binding;
	// CompilerOptions options = compilationUnitScope().environment.options;
	// if (!(method.isAbstract()
	// || (method.isImplementing() &&
	// !options.reportUnusedParameterWhenImplementingAbstract)
	// || (method.isOverriding() && !method.isImplementing() &&
	// !options.reportUnusedParameterWhenOverridingConcrete)
	// || method.isMain())) {
	// isReportingUnusedArgument = true;
	// }
	// }
	// this.offset = initOffset;
	// this.maxOffset = initOffset;
	//
	// // manage arguments
	// int ilocal = 0, maxLocals = this.localIndex;
	// while (ilocal < maxLocals) {
	// LocalVariableBinding local = locals[ilocal];
	// if (local == null || !local.isArgument) break; // done with arguments
	//
	// // do not report fake used variable
	// if (isReportingUnusedArgument
	// && local.useFlag == LocalVariableBinding.UNUSED
	// && ((local.declaration.bits & ASTNode.IsLocalDeclarationReachableMASK) !=
	// 0)) { // declaration is reachable
	// this.problemReporter().unusedArgument(local.declaration);
	// }
	//
	// // record user-defined argument for attribute generation
	// codeStream.record(local);
	//
	// // assign variable position
	// local.resolvedPosition = this.offset;
	//
	// if ((local.type == LongBinding) || (local.type == DoubleBinding)) {
	// this.offset += 2;
	// } else {
	// this.offset++;
	// }
	// // check for too many arguments/local variables
	// if (this.offset > 0xFF) { // no more than 255 words of arguments
	// this.problemReporter().noMoreAvailableSpaceForArgument(local,
	// local.declaration);
	// }
	// ilocal++;
	// }
	//		
	// // sneak in extra argument before other local variables
	// if (extraSyntheticArguments != null) {
	// for (int iarg = 0, maxArguments = extraSyntheticArguments.length; iarg <
	// maxArguments; iarg++){
	// SyntheticArgumentBinding argument = extraSyntheticArguments[iarg];
	// argument.resolvedPosition = this.offset;
	// if ((argument.type == LongBinding) || (argument.type == DoubleBinding)){
	// this.offset += 2;
	// } else {
	// this.offset++;
	// }
	// if (this.offset > 0xFF) { // no more than 255 words of arguments
	// this.problemReporter().noMoreAvailableSpaceForArgument(argument,
	// (ASTNode)this.referenceContext);
	// }
	// }
	// }
	// this.computeLocalVariablePositions(ilocal, this.offset, codeStream);
	// }
	/*
	 * Error management: keep null for all the errors that prevent the method to
	 * be created otherwise return a correct method binding (but without the
	 * element that caused the problem) : ie : Incorrect thrown exception
	 */
	MethodBinding createMethod(AbstractMethodDeclaration method) {

		// is necessary to ensure error reporting
		this.referenceContext = method;
		method.scope = this;
		SourceTypeBinding declaringClass = referenceType().binding;
		int modifiers = method.modifiers | AccUnresolved;
		if (method.isConstructor()) {
			method.binding = new MethodBinding(modifiers, null, null,
					declaringClass);
			checkAndSetModifiersForConstructor(method.binding);
		} else {
			if (declaringClass.isInterface())
				modifiers |= AccPublic | AccAbstract;
			method.binding = new MethodBinding(modifiers, method.selector,
					null, null, null, declaringClass);
			checkAndSetModifiersForMethod(method.binding);
		}

		this.isStatic = method.binding.isStatic();
		return method.binding;
	}

	/*
	 * Overridden to detect the error case inside an explicit constructor call:
	 * 
	 * class X { int i; X myX; X(X x) { this(i, myX.i, x.i); // same for super
	 * calls... only the first 2 field accesses are errors } }
	 */
	public FieldBinding findField(TypeBinding receiverType, char[] fieldName,
			InvocationSite invocationSite) {

		FieldBinding field = super.findField(receiverType, fieldName,
				invocationSite);
		if (field == null)
			return null;
		if (!field.isValidBinding())
			return field; // answer the error field
		if (field.isStatic())
			return field; // static fields are always accessible

		if (!isConstructorCall || receiverType != enclosingSourceType())
			return field;

		if (invocationSite instanceof SingleNameReference)
			return new ProblemFieldBinding(field.declaringClass, fieldName,
					NonStaticReferenceInConstructorInvocation);
		if (invocationSite instanceof QualifiedNameReference) {
			// look to see if the field is the first binding
			QualifiedNameReference name = (QualifiedNameReference) invocationSite;
			if (name.binding == null)
				// only true when the field is the fieldbinding at the beginning
				// of name's tokens
				return new ProblemFieldBinding(field.declaringClass, fieldName,
						NonStaticReferenceInConstructorInvocation);
		}
		return field;
	}

	public boolean isInsideInitializer() {

		return (referenceContext instanceof TypeDeclaration);
	}

	public boolean isInsideInitializerOrConstructor() {

		return (referenceContext instanceof TypeDeclaration)
				|| (referenceContext instanceof ConstructorDeclaration);
	}

	/*
	 * Answer the problem reporter to use for raising new problems.
	 * 
	 * Note that as a side-effect, this updates the current reference context
	 * (unit, type or method) in case the problem handler decides it is
	 * necessary to abort.
	 */
	public ProblemReporter problemReporter() {

		MethodScope outerMethodScope;
		if ((outerMethodScope = outerMostMethodScope()) == this) {
			ProblemReporter problemReporter = referenceCompilationUnit().problemReporter;
			problemReporter.referenceContext = referenceContext;
			return problemReporter;
		} else {
			return outerMethodScope.problemReporter();
		}
	}

	public final int recordInitializationStates(FlowInfo flowInfo) {

		if (!flowInfo.isReachable())
			return -1;

		UnconditionalFlowInfo unconditionalFlowInfo = flowInfo
				.unconditionalInits();
		long[] extraInits = unconditionalFlowInfo.extraDefiniteInits;
		long inits = unconditionalFlowInfo.definiteInits;
		checkNextEntry: for (int i = lastIndex; --i >= 0;) {
			if (definiteInits[i] == inits) {
				long[] otherInits = extraDefiniteInits[i];
				if ((extraInits != null) && (otherInits != null)) {
					if (extraInits.length == otherInits.length) {
						int j, max;
						for (j = 0, max = extraInits.length; j < max; j++) {
							if (extraInits[j] != otherInits[j]) {
								continue checkNextEntry;
							}
						}
						return i;
					}
				} else {
					if ((extraInits == null) && (otherInits == null)) {
						return i;
					}
				}
			}
		}

		// add a new entry
		if (definiteInits.length == lastIndex) {
			// need a resize
			System.arraycopy(definiteInits, 0,
					(definiteInits = new long[lastIndex + 20]), 0, lastIndex);
			System.arraycopy(extraDefiniteInits, 0,
					(extraDefiniteInits = new long[lastIndex + 20][]), 0,
					lastIndex);
		}
		definiteInits[lastIndex] = inits;
		if (extraInits != null) {
			extraDefiniteInits[lastIndex] = new long[extraInits.length];
			System.arraycopy(extraInits, 0, extraDefiniteInits[lastIndex], 0,
					extraInits.length);
		}
		return lastIndex++;
	}

	/*
	 * Answer the reference type of this scope.
	 * 
	 * It is the nearest enclosing type of this scope.
	 */
	public TypeDeclaration referenceType() {

		return (TypeDeclaration) ((ClassScope) parent).referenceContext;
	}

	String basicToString(int tab) {

		String newLine = "\n"; //$NON-NLS-1$
		for (int i = tab; --i >= 0;)
			newLine += "\t"; //$NON-NLS-1$

		String s = newLine + "--- Method Scope ---"; //$NON-NLS-1$
		newLine += "\t"; //$NON-NLS-1$
		s += newLine + "locals:"; //$NON-NLS-1$
		for (int i = 0; i < localIndex; i++)
			s += newLine + "\t" + locals[i].toString(); //$NON-NLS-1$
		s += newLine + "startIndex = " + startIndex; //$NON-NLS-1$
		s += newLine + "isConstructorCall = " + isConstructorCall; //$NON-NLS-1$
		s += newLine + "initializedField = " + initializedField; //$NON-NLS-1$
		s += newLine + "fieldDeclarationIndex = " + fieldDeclarationIndex; //$NON-NLS-1$
		s += newLine + "referenceContext = " + referenceContext; //$NON-NLS-1$
		return s;
	}

}