/*******************************************************************************
 * Copyright (c) 2000, 2005 IBM Corporation and others.
 * Copyright (c) 2005 Red Hat, Inc.
 * 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 implementation
 *     Red Hat, Inc - Extracted methods from WizardArchiveFileResourceImportPage1
 *******************************************************************************/

package org.eclipse.ui.internal.wizards.datatransfer;

import java.io.IOException;
import java.util.zip.ZipFile;

import org.eclipse.jface.dialogs.MessageDialog;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.ui.internal.ide.IDEWorkbenchMessages;

/**
 * @since 3.1
 */
public class ArchiveFileManipulations {

	private static ZipLeveledStructureProvider zipProviderCache;

	private static TarLeveledStructureProvider tarProviderCache;

	/**
	 * Determine whether the file with the given filename is in .tar.gz or .tar
	 * format.
	 * 
	 * @param fileName
	 *            file to test
	 * @return true if the file is in tar format
	 */
	public static boolean isTarFile(String fileName) {
		if (fileName.length() == 0)
			return false;

		try {
			new TarFile(fileName);
		} catch (TarException tarException) {
			return false;
		} catch (IOException ioException) {
			return false;
		}

		return true;
	}

	/**
	 * Determine whether the file with the given filename is in .zip or .jar
	 * format.
	 * 
	 * @param fileName
	 *            file to test
	 * @return true if the file is in tar format
	 */
	public static boolean isZipFile(String fileName) {
		if (fileName.length() == 0)
			return false;

		try {
			new ZipFile(fileName);
		} catch (IOException ioException) {
			return false;
		}

		return true;
	}

	/**
	 * Clears the cached structure provider after first finalizing it properly.
	 * 
	 * @param shell
	 *            The shell to display any possible Dialogs in
	 */
	public static void clearProviderCache(Shell shell) {
		if (zipProviderCache != null) {
			closeZipFile(zipProviderCache.getZipFile(), shell);
			zipProviderCache = null;
		}
		tarProviderCache = null;
	}

	/**
	 * @param targetZip
	 * @param shell
	 * @return the structure provider
	 */
	public static ZipLeveledStructureProvider getZipStructureProvider(
			ZipFile targetZip, Shell shell) {
		if (zipProviderCache == null)
			zipProviderCache = new ZipLeveledStructureProvider(targetZip);
		else if (!zipProviderCache.getZipFile().getName().equals(
				targetZip.getName())) {
			clearProviderCache(shell);
			// ie.- new value, so finalize&remove old value
			zipProviderCache = new ZipLeveledStructureProvider(targetZip);
		} else if (!zipProviderCache.getZipFile().equals(targetZip))
			closeZipFile(targetZip, shell); // ie.- duplicate handle to same
		// .zip

		return zipProviderCache;
	}

	/**
	 * Attempts to close the passed zip file, and answers a boolean indicating
	 * success.
	 * 
	 * @param file
	 *            The zip file to attempt to close
	 * @param shell
	 *            The shell to display error dialogs in
	 * @return Returns true if the operation was successful
	 */
	public static boolean closeZipFile(ZipFile file, Shell shell) {
		try {
			file.close();
		} catch (IOException e) {
			displayErrorDialog(DataTransferMessages.ZipImport_couldNotClose,
					shell);
			return false;
		}

		return true;
	}

	/**
	 * Returns a structure provider for the specified tar file.
	 * 
	 * @param targetTar
	 *            The specified tar file
	 * @param shell
	 *            The shell to display dialogs in
	 * @return the structure provider
	 */
	public static TarLeveledStructureProvider getTarStructureProvider(
			TarFile targetTar, Shell shell) {
		if (tarProviderCache == null)
			tarProviderCache = new TarLeveledStructureProvider(targetTar);
		else if (!tarProviderCache.getTarFile().getName().equals(
				targetTar.getName())) {
			ArchiveFileManipulations.clearProviderCache(shell);
			// ie.- new value, so finalize&remove old value
			tarProviderCache = new TarLeveledStructureProvider(targetTar);
		}

		return tarProviderCache;
	}

	/**
	 * Display an error dialog with the specified message.
	 * 
	 * @param message
	 *            the error message
	 */
	protected static void displayErrorDialog(String message, Shell shell) {
		MessageDialog.openError(shell, getErrorDialogTitle(), message);
	}

	/**
	 * Get the title for an error dialog. Subclasses should override.
	 */
	protected static String getErrorDialogTitle() {
		return IDEWorkbenchMessages.WizardExportPage_internalErrorTitle;
	}
}