/*******************************************************************************
 * Copyright (c) 2000, 2017 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.team.internal.core;

import java.util.ArrayList;
import java.util.List;

import org.eclipse.core.resources.IFile;
import org.eclipse.core.resources.team.FileModificationValidationContext;
import org.eclipse.core.resources.team.FileModificationValidator;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.core.runtime.IExtension;
import org.eclipse.core.runtime.IExtensionPoint;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.MultiStatus;
import org.eclipse.core.runtime.Platform;
import org.eclipse.core.runtime.Status;
import org.eclipse.osgi.util.NLS;
import org.eclipse.team.core.ITeamStatus;
import org.eclipse.team.core.TeamStatus;

public class DefaultFileModificationValidator extends FileModificationValidator {

	/*
	 * A validator plugged in the the Team UI that will prompt
	 * the user to make read-only files writable. In the absence of
	 * this validator, edit/save fail on read-only files.
	 */
	private FileModificationValidator uiValidator;

	protected IStatus getDefaultStatus(IFile file) {
		return
			file.isReadOnly()
			? new TeamStatus(IStatus.ERROR, TeamPlugin.ID, ITeamStatus.READ_ONLY_LOCAL, NLS.bind(Messages.FileModificationValidator_fileIsReadOnly, new String[] { file.getFullPath().toString() }), null, file)
				: Status.OK_STATUS;
	}

	@Override
	public IStatus validateEdit(IFile[] files, FileModificationValidationContext context) {
		IFile[] readOnlyFiles = getReadOnly(files);
		if (readOnlyFiles.length == 0)
			return Status.OK_STATUS;
		synchronized (this) {
			if (uiValidator == null)
				uiValidator = loadUIValidator();
		}
		if (uiValidator != null) {
			return uiValidator.validateEdit(files, context);
		}
		// There was no plugged in validator so fail gracefully
		return getStatus(files);
	}

	protected IStatus getStatus(IFile[] files) {
		if (files.length == 1) {
			return getDefaultStatus(files[0]);
		}

		IStatus[] stati = new Status[files.length];
		boolean allOK = true;

		for (int i = 0; i < files.length; i++) {
			stati[i] = getDefaultStatus(files[i]);
			if(! stati[i].isOK())
				allOK = false;
		}

		return new MultiStatus(TeamPlugin.ID,
			0, stati,
			allOK
					? Messages.ok
					: Messages.FileModificationValidator_someReadOnly,
			null);
	}

	private IFile[] getReadOnly(IFile[] files) {
		List<IFile> result = new ArrayList<>(files.length);
		for (IFile file : files) {
			if (file.isReadOnly()) {
				result.add(file);
			}
		}
		return result.toArray(new IFile[result.size()]);
	}

	@Override
	public IStatus validateSave(IFile file) {
		if (!file.isReadOnly())
			return Status.OK_STATUS;
		synchronized (this) {
			if (uiValidator == null)
				uiValidator = loadUIValidator();
		}
		if (uiValidator != null) {
			return uiValidator.validateSave(file);
		}
		return getDefaultStatus(file);
	}

	private FileModificationValidator loadUIValidator() {
		IExtensionPoint extension = Platform.getExtensionRegistry().getExtensionPoint(TeamPlugin.ID, TeamPlugin.DEFAULT_FILE_MODIFICATION_VALIDATOR_EXTENSION);
		if (extension != null) {
			IExtension[] extensions =  extension.getExtensions();
			if (extensions.length > 0) {
				IConfigurationElement[] configElements = extensions[0].getConfigurationElements();
				if (configElements.length > 0) {
					try {
						Object o = configElements[0].createExecutableExtension("class"); //$NON-NLS-1$
						if (o instanceof FileModificationValidator) {
							return (FileModificationValidator)o;
						}
					} catch (CoreException e) {
						TeamPlugin.log(e);
					}
				}
			}
		}
		return null;
	}
}