/*******************************************************************************
 * 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.core;

import net.sourceforge.phpdt.core.ICompilationUnit;
import net.sourceforge.phpdt.core.IJavaElement;
import net.sourceforge.phpdt.core.IJavaModelStatus;
import net.sourceforge.phpdt.core.IPackageDeclaration;
import net.sourceforge.phpdt.core.IType;
import net.sourceforge.phpdt.core.JavaConventions;
import net.sourceforge.phpdt.core.JavaModelException;
import net.sourceforge.phpdt.core.jdom.DOMFactory;
import net.sourceforge.phpdt.core.jdom.IDOMNode;
import net.sourceforge.phpdt.core.jdom.IDOMPackage;
import net.sourceforge.phpdt.internal.core.jdom.DOMNode;
import net.sourceforge.phpdt.internal.core.util.Util;

/**
 * <p>
 * This operation adds/replaces a package declaration in an existing compilation
 * unit. If the compilation unit already includes the specified package
 * declaration, it is not generated (it does not generate duplicates).
 * 
 * <p>
 * Required Attributes:
 * <ul>
 * <li>Compilation unit element
 * <li>Package name
 * </ul>
 */
public class CreatePackageDeclarationOperation extends
		CreateElementInCUOperation {
	/**
	 * The name of the package declaration being created
	 */
	protected String fName = null;

	/**
	 * When executed, this operation will add a package declaration to the given
	 * compilation unit.
	 */
	public CreatePackageDeclarationOperation(String name,
			ICompilationUnit parentElement) {
		super(parentElement);
		fName = name;
	}

	/**
	 * @see CreateTypeMemberOperation#generateElementDOM
	 */
	protected IDOMNode generateElementDOM() throws JavaModelException {
		IJavaElement[] children = getCompilationUnit().getChildren();
		// look for an existing package declaration
		for (int i = 0; i < children.length; i++) {
			if (children[i].getElementType() == IJavaElement.PACKAGE_DECLARATION) {
				IPackageDeclaration pck = (IPackageDeclaration) children[i];
				IDOMPackage pack = (IDOMPackage) ((JavaElement) pck)
						.findNode(fCUDOM);
				if (!pack.getName().equals(fName)) {
					// get the insertion position before setting the name, as
					// this makes it a detailed node
					// thus the start position is always 0
					DOMNode node = (DOMNode) pack;
					fInsertionPosition = node.getStartPosition();
					fReplacementLength = node.getEndPosition()
							- fInsertionPosition + 1;
					pack.setName(fName);
					fCreatedElement = (net.sourceforge.phpdt.internal.core.jdom.DOMNode) pack;
				} else {
					// equivalent package declaration already exists
					fCreationOccurred = false;
				}

				return null;
			}
		}
		IDOMPackage pack = (new DOMFactory()).createPackage();
		pack.setName(fName);
		return pack;
	}

	/**
	 * Creates and returns the handle for the element this operation created.
	 */
	protected IJavaElement generateResultHandle() {
		return getCompilationUnit().getPackageDeclaration(fName);
	}

	/**
	 * @see CreateElementInCUOperation#getMainTaskName()
	 */
	public String getMainTaskName() {
		return Util.bind("operation.createPackageProgress"); //$NON-NLS-1$
	}

	/**
	 * Sets the correct position for new package declaration:
	 * <ul>
	 * <li> before the first import
	 * <li> if no imports, before the first type
	 * <li> if no type - first thing in the CU
	 * <li>
	 */
	protected void initializeDefaultPosition() {
		try {
			ICompilationUnit cu = getCompilationUnit();
			// IImportDeclaration[] imports = cu.getImports();
			// if (imports.length > 0) {
			// createBefore(imports[0]);
			// return;
			// }
			IType[] types = cu.getTypes();
			if (types.length > 0) {
				createBefore(types[0]);
				return;
			}
		} catch (JavaModelException npe) {
		}
	}

	/**
	 * Possible failures:
	 * <ul>
	 * <li>NO_ELEMENTS_TO_PROCESS - no compilation unit was supplied to the
	 * operation
	 * <li>INVALID_NAME - a name supplied to the operation was not a valid
	 * package declaration name.
	 * </ul>
	 * 
	 * @see IJavaModelStatus
	 * @see JavaConventions
	 */
	public IJavaModelStatus verify() {
		IJavaModelStatus status = super.verify();
		if (!status.isOK()) {
			return status;
		}
		// if (JavaConventions.validatePackageName(fName).getSeverity() ==
		// IStatus.ERROR) {
		// return new JavaModelStatus(IJavaModelStatusConstants.INVALID_NAME,
		// fName);
		// }
		return JavaModelStatus.VERIFIED_OK;
	}
}