/*******************************************************************************
 * 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.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.BindingIds;
import net.sourceforge.phpdt.internal.compiler.lookup.BlockScope;
import net.sourceforge.phpdt.internal.compiler.lookup.FieldBinding;
import net.sourceforge.phpdt.internal.compiler.lookup.InvocationSite;
import net.sourceforge.phpdt.internal.compiler.lookup.MethodBinding;
import net.sourceforge.phpdt.internal.compiler.lookup.ReferenceBinding;
import net.sourceforge.phpdt.internal.compiler.lookup.Scope;
import net.sourceforge.phpdt.internal.compiler.lookup.SourceTypeBinding;
import net.sourceforge.phpdt.internal.compiler.lookup.TypeBinding;

public class FieldReference extends Reference implements InvocationSite {

	public Expression receiver;

	public char[] token;

	public FieldBinding binding, codegenBinding;

	public long nameSourcePosition; // (start<<32)+end

	MethodBinding syntheticReadAccessor, syntheticWriteAccessor;

	public TypeBinding receiverType;

	public FieldReference(char[] source, long pos) {

		token = source;
		nameSourcePosition = pos;
		// by default the position are the one of the field (not true for super
		// access)
		// sourceStart = (int) (pos >>> 32);
		// sourceEnd = (int) (pos & 0x00000000FFFFFFFFL);
		sourceStart = (int) pos;
		sourceEnd = sourceStart + source.length;
		bits |= BindingIds.FIELD;

	}

	public FlowInfo analyseAssignment(BlockScope currentScope,
			FlowContext flowContext, FlowInfo flowInfo, Assignment assignment,
			boolean isCompound) {

		// compound assignment extra work
		if (isCompound) { // check the variable part is initialized if blank
							// final
			if (binding.isBlankFinal() && receiver.isThis()
					&& currentScope.allowBlankFinalFieldAssignment(binding)
					&& (!flowInfo.isDefinitelyAssigned(binding))) {
				currentScope.problemReporter().uninitializedBlankFinalField(
						binding, this);
				// we could improve error msg here telling "cannot use compound
				// assignment on final blank field"
			}
			manageSyntheticReadAccessIfNecessary(currentScope);
		}
		flowInfo = receiver.analyseCode(currentScope, flowContext, flowInfo,
				!binding.isStatic()).unconditionalInits();
		if (assignment.expression != null) {
			flowInfo = assignment.expression.analyseCode(currentScope,
					flowContext, flowInfo).unconditionalInits();
		}
		manageSyntheticWriteAccessIfNecessary(currentScope);

		// check if assigning a final field
		if (binding.isFinal()) {
			// in a context where it can be assigned?
			if (binding.isBlankFinal() && !isCompound && receiver.isThis()
					&& !(receiver instanceof QualifiedThisReference)
					&& ((receiver.bits & ParenthesizedMASK) == 0) // (this).x
																	// is
																	// forbidden
					&& currentScope.allowBlankFinalFieldAssignment(binding)) {
				if (flowInfo.isPotentiallyAssigned(binding)) {
					currentScope.problemReporter()
							.duplicateInitializationOfBlankFinalField(binding,
									this);
				} else {
					flowContext.recordSettingFinal(binding, this);
				}
				flowInfo.markAsDefinitelyAssigned(binding);
			} else {
				// assigning a final field outside an initializer or constructor
				// or wrong reference
				currentScope.problemReporter().cannotAssignToFinalField(
						binding, this);
			}
		}
		return flowInfo;
	}

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

		return analyseCode(currentScope, flowContext, flowInfo, true);
	}

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

		receiver.analyseCode(currentScope, flowContext, flowInfo, !binding
				.isStatic());
		if (valueRequired) {
			manageSyntheticReadAccessIfNecessary(currentScope);
		}
		return flowInfo;
	}

	public FieldBinding fieldBinding() {

		return binding;
	}

	// public void generateAssignment(
	// BlockScope currentScope,
	// CodeStream codeStream,
	// Assignment assignment,
	// boolean valueRequired) {
	//
	// receiver.generateCode(
	// currentScope,
	// codeStream,
	// !this.codegenBinding.isStatic());
	// assignment.expression.generateCode(currentScope, codeStream, true);
	// fieldStore(
	// codeStream,
	// this.codegenBinding,
	// syntheticWriteAccessor,
	// valueRequired);
	// if (valueRequired) {
	// codeStream.generateImplicitConversion(assignment.implicitConversion);
	// }
	// }

	/**
	 * Field reference code generation
	 * 
	 * @param currentScope
	 *            net.sourceforge.phpdt.internal.compiler.lookup.BlockScope
	 * @param codeStream
	 *            net.sourceforge.phpdt.internal.compiler.codegen.CodeStream
	 * @param valueRequired
	 *            boolean
	 */
	// public void generateCode(
	// BlockScope currentScope,
	// CodeStream codeStream,
	// boolean valueRequired) {
	//
	// int pc = codeStream.position;
	// if (constant != NotAConstant) {
	// if (valueRequired) {
	// codeStream.generateConstant(constant, implicitConversion);
	// }
	// } else {
	// boolean isStatic = this.codegenBinding.isStatic();
	// receiver.generateCode(currentScope, codeStream, !isStatic);
	// if (valueRequired) {
	// if (this.codegenBinding.constant == NotAConstant) {
	// if (this.codegenBinding.declaringClass == null) { // array length
	// codeStream.arraylength();
	// } else {
	// if (syntheticReadAccessor == null) {
	// if (isStatic) {
	// codeStream.getstatic(this.codegenBinding);
	// } else {
	// codeStream.getfield(this.codegenBinding);
	// }
	// } else {
	// codeStream.invokestatic(syntheticReadAccessor);
	// }
	// }
	// codeStream.generateImplicitConversion(implicitConversion);
	// } else {
	// if (!isStatic) {
	// codeStream.invokeObjectGetClass(); // perform null check
	// codeStream.pop();
	// }
	// codeStream.generateConstant(this.codegenBinding.constant,
	// implicitConversion);
	// }
	// } else {
	// if (!isStatic){
	// codeStream.invokeObjectGetClass(); // perform null check
	// codeStream.pop();
	// }
	// }
	// }
	// codeStream.recordPositionsFrom(pc, this.sourceStart);
	// }
	//
	// public void generateCompoundAssignment(
	// BlockScope currentScope,
	// CodeStream codeStream,
	// Expression expression,
	// int operator,
	// int assignmentImplicitConversion,
	// boolean valueRequired) {
	//
	// boolean isStatic;
	// receiver.generateCode(
	// currentScope,
	// codeStream,
	// !(isStatic = this.codegenBinding.isStatic()));
	// if (isStatic) {
	// if (syntheticReadAccessor == null) {
	// codeStream.getstatic(this.codegenBinding);
	// } else {
	// codeStream.invokestatic(syntheticReadAccessor);
	// }
	// } else {
	// codeStream.dup();
	// if (syntheticReadAccessor == null) {
	// codeStream.getfield(this.codegenBinding);
	// } else {
	// codeStream.invokestatic(syntheticReadAccessor);
	// }
	// }
	// int operationTypeID;
	// if ((operationTypeID = implicitConversion >> 4) == T_String) {
	// codeStream.generateStringAppend(currentScope, null, expression);
	// } else {
	// // promote the array reference to the suitable operation type
	// codeStream.generateImplicitConversion(implicitConversion);
	// // generate the increment value (will by itself be promoted to the
	// operation value)
	// if (expression == IntLiteral.One) { // prefix operation
	// codeStream.generateConstant(expression.constant, implicitConversion);
	// } else {
	// expression.generateCode(currentScope, codeStream, true);
	// }
	// // perform the operation
	// codeStream.sendOperator(operator, operationTypeID);
	// // cast the value back to the array reference type
	// codeStream.generateImplicitConversion(assignmentImplicitConversion);
	// }
	// fieldStore(
	// codeStream,
	// this.codegenBinding,
	// syntheticWriteAccessor,
	// valueRequired);
	// }
	//
	// public void generatePostIncrement(
	// BlockScope currentScope,
	// CodeStream codeStream,
	// CompoundAssignment postIncrement,
	// boolean valueRequired) {
	//
	// boolean isStatic;
	// receiver.generateCode(
	// currentScope,
	// codeStream,
	// !(isStatic = this.codegenBinding.isStatic()));
	// if (isStatic) {
	// if (syntheticReadAccessor == null) {
	// codeStream.getstatic(this.codegenBinding);
	// } else {
	// codeStream.invokestatic(syntheticReadAccessor);
	// }
	// } else {
	// codeStream.dup();
	// if (syntheticReadAccessor == null) {
	// codeStream.getfield(this.codegenBinding);
	// } else {
	// codeStream.invokestatic(syntheticReadAccessor);
	// }
	// }
	// if (valueRequired) {
	// if (isStatic) {
	// if ((this.codegenBinding.type == LongBinding)
	// || (this.codegenBinding.type == DoubleBinding)) {
	// codeStream.dup2();
	// } else {
	// codeStream.dup();
	// }
	// } else { // Stack: [owner][old field value] ---> [old field
	// value][owner][old field value]
	// if ((this.codegenBinding.type == LongBinding)
	// || (this.codegenBinding.type == DoubleBinding)) {
	// codeStream.dup2_x1();
	// } else {
	// codeStream.dup_x1();
	// }
	// }
	// }
	// codeStream.generateConstant(
	// postIncrement.expression.constant,
	// implicitConversion);
	// codeStream.sendOperator(postIncrement.operator,
	// this.codegenBinding.type.id);
	// codeStream.generateImplicitConversion(
	// postIncrement.assignmentImplicitConversion);
	// fieldStore(codeStream, this.codegenBinding, syntheticWriteAccessor,
	// false);
	// }
	public static final Constant getConstantFor(FieldBinding binding,
			Reference reference, boolean isImplicit, Scope referenceScope) {

		// propagation of the constant.

		// ref can be a FieldReference, a SingleNameReference or a
		// QualifiedNameReference
		// indexInQualification may have a value greater than zero only for
		// QualifiednameReference
		// if ref==null then indexInQualification==0 AND implicitReceiver ==
		// false. This case is a
		// degenerated case where a fake reference field (null)
		// is associted to a real FieldBinding in order
		// to allow its constant computation using the regular path (in other
		// words, find the fieldDeclaration
		// and proceed to its type resolution). As implicitReceiver is false, no
		// error reporting
		// against ref will be used ==> no nullPointerException risk ....

		// special treatment for langage-built-in field (their declaring class
		// is null)
		if (binding.declaringClass == null) {
			// currently only one field "length" : the constant computation is
			// never done
			return NotAConstant;
		}
		if (!binding.isFinal()) {
			return binding.constant = NotAConstant;
		}
		if (binding.constant != null) {
			if (isImplicit
					|| (reference instanceof QualifiedNameReference && binding == ((QualifiedNameReference) reference).binding)) {
				return binding.constant;
			}
			return NotAConstant;
		}

		// The field has not been yet type checked.
		// It also means that the field is not coming from a class that
		// has already been compiled. It can only be from a class within
		// compilation units to process. Thus the field is NOT from a
		// BinaryTypeBinbing

		SourceTypeBinding typeBinding = (SourceTypeBinding) binding.declaringClass;
		TypeDeclaration typeDecl = typeBinding.scope.referenceContext;
		FieldDeclaration fieldDecl = typeDecl.declarationOf(binding);

		fieldDecl.resolve(binding.isStatic() // side effect on binding
		? typeDecl.staticInitializerScope
				: typeDecl.initializerScope);

		if (isImplicit
				|| (reference instanceof QualifiedNameReference && binding == ((QualifiedNameReference) reference).binding)) {
			return binding.constant;
		}
		return NotAConstant;
	}

	public boolean isSuperAccess() {

		return receiver.isSuper();
	}

	public boolean isTypeAccess() {

		return receiver != null && receiver.isTypeReference();
	}

	/*
	 * No need to emulate access to protected fields since not implicitly
	 * accessed
	 */
	public void manageSyntheticReadAccessIfNecessary(BlockScope currentScope) {

		if (binding.isPrivate()) {
			if ((currentScope.enclosingSourceType() != binding.declaringClass)
					&& (binding.constant == NotAConstant)) {
				syntheticReadAccessor = ((SourceTypeBinding) binding.declaringClass)
						.addSyntheticMethod(binding, true);
				currentScope.problemReporter().needToEmulateFieldReadAccess(
						binding, this);
				return;
			}

		} else if (receiver instanceof QualifiedSuperReference) { // qualified
																	// super

			// qualified super need emulation always
			SourceTypeBinding destinationType = (SourceTypeBinding) (((QualifiedSuperReference) receiver).currentCompatibleType);
			syntheticReadAccessor = destinationType.addSyntheticMethod(binding,
					true);
			currentScope.problemReporter().needToEmulateFieldReadAccess(
					binding, this);
			return;

		} else if (binding.isProtected()) {

			SourceTypeBinding enclosingSourceType;
			if (((bits & DepthMASK) != 0)
					&& binding.declaringClass.getPackage() != (enclosingSourceType = currentScope
							.enclosingSourceType()).getPackage()) {

				SourceTypeBinding currentCompatibleType = (SourceTypeBinding) enclosingSourceType
						.enclosingTypeAt((bits & DepthMASK) >> DepthSHIFT);
				syntheticReadAccessor = currentCompatibleType
						.addSyntheticMethod(binding, true);
				currentScope.problemReporter().needToEmulateFieldReadAccess(
						binding, this);
				return;
			}
		}
		// if the binding declaring class is not visible, need special action
		// for runtime compatibility on 1.2 VMs : change the declaring class of
		// the binding
		// NOTE: from target 1.2 on, field's declaring class is touched if any
		// different from receiver type
		// if (binding.declaringClass != this.receiverType
		// && !this.receiverType.isArrayType()
		// && binding.declaringClass != null // array.length
		// && binding.constant == NotAConstant
		// && ((currentScope.environment().options.targetJDK >=
		// CompilerOptions.JDK1_2
		// && binding.declaringClass.id != T_Object)
		// //no change for Object fields (in case there was)
		// || !binding.declaringClass.canBeSeenBy(currentScope))) {
		// this.codegenBinding =
		// currentScope.enclosingSourceType().getUpdatedFieldBinding(
		// binding,
		// (ReferenceBinding) this.receiverType);
		// }
	}

	/*
	 * No need to emulate access to protected fields since not implicitly
	 * accessed
	 */
	public void manageSyntheticWriteAccessIfNecessary(BlockScope currentScope) {

		if (binding.isPrivate()) {
			if (currentScope.enclosingSourceType() != binding.declaringClass) {
				syntheticWriteAccessor = ((SourceTypeBinding) binding.declaringClass)
						.addSyntheticMethod(binding, false);
				currentScope.problemReporter().needToEmulateFieldWriteAccess(
						binding, this);
				return;
			}

		} else if (receiver instanceof QualifiedSuperReference) { // qualified
																	// super

			// qualified super need emulation always
			SourceTypeBinding destinationType = (SourceTypeBinding) (((QualifiedSuperReference) receiver).currentCompatibleType);
			syntheticWriteAccessor = destinationType.addSyntheticMethod(
					binding, false);
			currentScope.problemReporter().needToEmulateFieldWriteAccess(
					binding, this);
			return;

		} else if (binding.isProtected()) {

			SourceTypeBinding enclosingSourceType;
			if (((bits & DepthMASK) != 0)
					&& binding.declaringClass.getPackage() != (enclosingSourceType = currentScope
							.enclosingSourceType()).getPackage()) {

				SourceTypeBinding currentCompatibleType = (SourceTypeBinding) enclosingSourceType
						.enclosingTypeAt((bits & DepthMASK) >> DepthSHIFT);
				syntheticWriteAccessor = currentCompatibleType
						.addSyntheticMethod(binding, false);
				currentScope.problemReporter().needToEmulateFieldWriteAccess(
						binding, this);
				return;
			}
		}
		// if the binding declaring class is not visible, need special action
		// for runtime compatibility on 1.2 VMs : change the declaring class of
		// the binding
		// NOTE: from target 1.2 on, field's declaring class is touched if any
		// different from receiver type
		// if (binding.declaringClass != this.receiverType
		// && !this.receiverType.isArrayType()
		// && binding.declaringClass != null // array.length
		// && binding.constant == NotAConstant
		// && ((currentScope.environment().options.targetJDK >=
		// CompilerOptions.JDK1_2
		// && binding.declaringClass.id != T_Object)
		// //no change for Object fields (in case there was)
		// || !binding.declaringClass.canBeSeenBy(currentScope))) {
		// this.codegenBinding =
		// currentScope.enclosingSourceType().getUpdatedFieldBinding(
		// binding,
		// (ReferenceBinding) this.receiverType);
		// }
	}

	public TypeBinding resolveType(BlockScope scope) {

		// Answer the signature type of the field.
		// constants are propaged when the field is final
		// and initialized with a (compile time) constant

		// regular receiver reference
		this.receiverType = receiver.resolveType(scope);
		if (this.receiverType == null) {
			constant = NotAConstant;
			return null;
		}
		// the case receiverType.isArrayType and token = 'length' is handled by
		// the scope API
		this.codegenBinding = this.binding = scope.getField(this.receiverType,
				token, this);
		if (!binding.isValidBinding()) {
			constant = NotAConstant;
			scope.problemReporter().invalidField(this, this.receiverType);
			return null;
		}

		if (isFieldUseDeprecated(binding, scope))
			scope.problemReporter().deprecatedField(binding, this);

		boolean isImplicitThisRcv = receiver.isImplicitThis();
		constant = FieldReference.getConstantFor(binding, this,
				isImplicitThisRcv, scope);
		if (!isImplicitThisRcv) {
			constant = NotAConstant;
		}
		if (binding.isStatic()) {
			// static field accessed through receiver? legal but unoptimal
			// (optional warning)
			if (!(isImplicitThisRcv || receiver.isSuper() || (receiver instanceof NameReference && (((NameReference) receiver).bits & BindingIds.TYPE) != 0))) {
				scope.problemReporter().unnecessaryReceiverForStaticField(this,
						binding);
			}
		}
		return this.resolvedType = binding.type;
	}

	public void setActualReceiverType(ReferenceBinding receiverType) {
		// ignored
	}

	public void setDepth(int depth) {

		bits &= ~DepthMASK; // flush previous depth if any
		if (depth > 0) {
			bits |= (depth & 0xFF) << DepthSHIFT; // encoded on 8 bits
		}
	}

	public void setFieldIndex(int index) {
		// ignored
	}

	public StringBuffer printExpression(int indent, StringBuffer output) {

		return receiver.printExpression(0, output).append('.').append(token);
	}

	public String toStringExpression() {

		return receiver.toString() + "." //$NON-NLS-1$
				+ new String(token);
	}

	public void traverse(ASTVisitor visitor, BlockScope scope) {

		if (visitor.visit(this, scope)) {
			receiver.traverse(visitor, scope);
		}
		visitor.endVisit(this, scope);
	}
}