/*******************************************************************************
 * Copyright (c) 2009 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *     Zend Technologies
 *******************************************************************************/
/**
 * 
 */
package org2.eclipse.php.internal.core.search;

import org2.eclipse.php.internal.core.CoreMessages;
import org2.eclipse.php.internal.core.ast.nodes.*;

/**
 * A local variable occurrence finder.
 * 
 * @author shalom
 */
public class LocalVariableOccurrencesFinder extends AbstractOccurrencesFinder {

	public static final String ID = "LocalVariableOccurrencesFinder"; //$NON-NLS-1$

	private Identifier fIdentifier;
	private FunctionDeclaration fFunctionDeclaration;

	/**
	 * @param root
	 *            the AST root
	 * @param node
	 *            the selected node (must be an {@link Identifier} instance)
	 * @return returns a message if there is a problem
	 */
	public String initialize(Program root, ASTNode node) {
		fASTRoot = root;
		if (isIdendifier(node)) {
			fIdentifier = (Identifier) node;
			ASTNode parent = node.getParent();
			while (parent != null && fFunctionDeclaration == null) {
				final int type = parent.getType();
				if (type == ASTNode.FUNCTION_DECLARATION) {
					fFunctionDeclaration = (FunctionDeclaration) parent;
				}
				parent = parent.getParent();
			}
			return null;
		}
		// return "OccurrencesFinder_no_occurrence";
		fDescription = "OccurrencesFinder_occurrence_description"; //$NON-NLS-1$
		return fDescription;
	}

	/*
	 * Check if the node is an identifier node.
	 */
	private final boolean isIdendifier(ASTNode node) {
		return node != null && node.getType() == ASTNode.IDENTIFIER;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org2.eclipse.php.internal.ui.search.AbstractOccurrencesFinder#findOccurrences
	 * ()
	 */
	protected void findOccurrences() {
		fDescription = Messages
				.format(
						CoreMessages
								.getString("LocalVariableOccurrencesFinder.1"), fIdentifier.getName()); //$NON-NLS-1$
		fFunctionDeclaration.accept(this);
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org2.eclipse.php.internal.core.ast.visitor.AbstractVisitor#visit(org.eclipse
	 * .php.internal.core.ast.nodes.Variable)
	 */
	public boolean visit(Variable variable) {
		Expression name = variable.getName();
		if (name.getType() == ASTNode.IDENTIFIER
				&& variable.isDollared()
				&& variable.getParent().getType() != ASTNode.STATIC_FIELD_ACCESS) {
			if (((Identifier) name).getName()
					.equals(this.fIdentifier.getName())) {
				addOccurrence(variable);
			}
		}
		return true;
	}

	private void addOccurrence(ASTNode node) {
		int readWriteType = getOccurrenceType(node);
		String desc = fDescription;
		if (readWriteType == IOccurrencesFinder.F_WRITE_OCCURRENCE) {
			desc = Messages.format(BASE_WRITE_DESCRIPTION, '$' + fIdentifier
					.getName());
		}
		fResult.add(new OccurrenceLocation(node.getStart(), node.getLength(),
				readWriteType, desc));
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org2.eclipse.php.internal.ui.search.AbstractOccurrencesFinder#
	 * getOccurrenceReadWriteType
	 * (org2.eclipse.php.internal.core.ast.nodes.ASTNode)
	 */
	protected int getOccurrenceType(ASTNode node) {
		Variable variable = (Variable) node;
		ASTNode parent = variable.getParent();
		boolean isArrayAccess = false;
		int parentType = parent.getType();
		if (parentType == ASTNode.ARRAY_ACCESS) {
			parent = parent.getParent();
			parentType = parent.getType();
			isArrayAccess = true;
		}
		if (parentType == ASTNode.ASSIGNMENT) {
			Assignment assignment = (Assignment) parent;
			VariableBase leftHandSide = assignment.getLeftHandSide();
			if (!isArrayAccess) {
				if (leftHandSide == node) {
					return IOccurrencesFinder.F_WRITE_OCCURRENCE;
				}
			} else {
				if (leftHandSide.getType() == ASTNode.ARRAY_ACCESS) {
					if (((ArrayAccess) leftHandSide).getName() == node) {
						return IOccurrencesFinder.F_WRITE_OCCURRENCE;
					}
				}
			}
		}

		if ((parentType == ASTNode.FOR_EACH_STATEMENT && node
				.getLocationInParent() != ForEachStatement.EXPRESSION_PROPERTY)
				|| parentType == ASTNode.FORMAL_PARAMETER
				|| parentType == ASTNode.CATCH_CLAUSE
				|| parentType == ASTNode.PREFIX_EXPRESSION
				|| parentType == ASTNode.REFERENCE
				&& parent.getParent().getType() == ASTNode.FORMAL_PARAMETER
				|| parentType == ASTNode.POSTFIX_EXPRESSION) {
			return IOccurrencesFinder.F_WRITE_OCCURRENCE;
		}

		return IOccurrencesFinder.F_READ_OCCURRENCE;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org2.eclipse.php.internal.ui.search.IOccurrencesFinder#getElementName()
	 */
	public String getElementName() {
		return fIdentifier.getName();
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org2.eclipse.php.internal.ui.search.IOccurrencesFinder#getID()
	 */
	public String getID() {
		return ID;
	}
}