/*******************************************************************************
 * 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.subscribers;

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

import org.eclipse.core.resources.IResource;
import org.eclipse.core.resources.IWorkspaceRoot;
import org.eclipse.core.resources.ResourcesPlugin;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IPath;
import org.eclipse.core.runtime.Path;
import org.eclipse.team.core.diff.IDiff;
import org.eclipse.team.core.mapping.provider.ResourceDiffTree;
import org.eclipse.team.internal.core.TeamPlugin;
import org.osgi.service.prefs.Preferences;

/**
 * An active change set represents a set of local resource changes
 * that are grouped together as a single logical change.
 * @since 3.1
 */
public class ActiveChangeSet extends DiffChangeSet {

	private static final String CTX_TITLE = "title"; //$NON-NLS-1$
	private static final String CTX_COMMENT = "comment"; //$NON-NLS-1$
	private static final String CTX_RESOURCES = "resources"; //$NON-NLS-1$
	private static final String CTX_USER_CREATED = "userCreated"; //$NON-NLS-1$

	private final ActiveChangeSetManager manager;
	private String comment;
	private boolean userCreated = true;

	/**
	 * Create a change set with the given title
	 * @param manager the manager that owns this set
	 * @param title the title of the set
	 */
	public ActiveChangeSet(ActiveChangeSetManager manager, String title) {
		super(title);
		this.manager = manager;
	}

	/**
	 * Get the title of the change set. The title is used
	 * as the comment when the set is checking in if no comment
	 * has been explicitly set using <code>setComment</code>.
	 * @return the title of the set
	 */
	public String getTitle() {
		return getName();
	}

	/**
	 * Set the title of the set. The title is used
	 * as the comment when the set is committed if no comment
	 * has been explicitly set using <code>setComment</code>.
	 * @param title the title of the set
	 */
	public void setTitle(String title) {
		setName(title);
		getManager().fireNameChangedEvent(this);
	}

	/**
	 * Get the comment of this change set. If the comment
	 * as never been set, the title is returned as the comment
	 * @return the comment to be used when the set is committed
	 */
	@Override
	public String getComment() {
		if (comment == null) {
			return getTitle();
		}
		return comment;
	}

	/**
	 * Set the comment to be used when the change set is committed.
	 * If <code>null</code> is passed, the title of the set
	 * will be used as the comment.
	 * @param comment the comment for the set or <code>null</code>
	 * if the title should be the comment
	 */
	public void setComment(String comment) {
		if (comment != null && comment.equals(getTitle())) {
			this.comment = null;
		} else {
			this.comment = comment;
		}
	}

	/*
	 * Override inherited method to only include outgoing changes
	 */
	@Override
	protected boolean isValidChange(IDiff diff) {
		return getManager().isModified(diff);
	}

	private void addResource(IResource resource) throws CoreException {
		IDiff diff = getManager().getDiff(resource);
		if (diff != null) {
			add(diff);
		}
	}

	private ActiveChangeSetManager getManager() {
		return manager;
	}

	/**
	 * Return whether the set has a comment that differs from the title.
	 * @return whether the set has a comment that differs from the title
	 */
	public boolean hasComment() {
		return comment != null;
	}

	public void save(Preferences prefs) {
		prefs.put(CTX_TITLE, getTitle());
		if (comment != null) {
			prefs.put(CTX_COMMENT, comment);
		}
		if (!isEmpty()) {
			StringBuilder buffer = new StringBuilder();
			IResource[] resources = getResources();
			for (int i = 0; i < resources.length; i++) {
				IResource resource = resources[i];
				buffer.append(resource.getFullPath().toString());
				buffer.append('\n');
			}
			prefs.put(CTX_RESOURCES, buffer.toString());
		}
		prefs.putBoolean(CTX_USER_CREATED, isUserCreated());
	}

	public void init(Preferences prefs) {
		setName(prefs.get(CTX_TITLE, "")); //$NON-NLS-1$
		comment = prefs.get(CTX_COMMENT, null);
		String resourcePaths = prefs.get(CTX_RESOURCES, null);
		if (resourcePaths != null) {
			ResourceDiffTree tree = internalGetDiffTree();
			try {
				tree.beginInput();
				IWorkspaceRoot root = ResourcesPlugin.getWorkspace().getRoot();
				StringTokenizer tokenizer = new StringTokenizer(resourcePaths, "\n"); //$NON-NLS-1$
				while (tokenizer.hasMoreTokens()) {
					String next = tokenizer.nextToken();
					if (next.trim().length() > 0) {
						IResource resource = getResource(root, next);
						// Only include the resource if it is out-of-sync
						try {
							if (resource != null && getManager().getDiff(resource) != null) {
								addResource(resource);
							}
						} catch (CoreException e) {
							TeamPlugin.log(e);
						}
					}
				}
			} finally {
				tree.endInput(null);
			}
		}
		userCreated = prefs.getBoolean(CTX_USER_CREATED, true);
	}

	private IResource getResource(IWorkspaceRoot root, String next) {
		IResource resource = root.findMember(next);
		if (resource == null) {
			// May be an outgoing deletion
			Path path = new Path(null, next);
			if (next.charAt(next.length()-1) == IPath.SEPARATOR) {
				if (path.segmentCount() == 1) {
					// resource is a project
					resource = root.getProject(path.lastSegment());
				} else {
					// resource is a folder
					resource = root.getFolder(path);
				}
			} else {
				// resource is a file
				resource = root.getFile(path);
			}
		}
		return resource;
	}

	/**
	 * Add the resources to the change set if they are outgoing changes.
	 * @param resources the resources to add.
	 * @throws CoreException
	 */
	public void add(IResource[] resources) throws CoreException {
		List<IDiff> toAdd = new ArrayList<>();
		for (int i = 0; i < resources.length; i++) {
			IResource resource = resources[i];
			IDiff diff = getManager().getDiff(resource);
			if (diff != null) {
				toAdd.add(diff);
			}
		}
		if (!toAdd.isEmpty()) {
			add(toAdd.toArray(new IDiff[toAdd.size()]));
		}
	}

	/**
	 * Set whether this set was created by the user.
	 * @param userCreated whether this set was created by the user
	 */
	public void setUserCreated(boolean userCreated) {
		this.userCreated = userCreated;
	}

	/**
	 * Return whether this set was created by the user.
	 * @return whether this set was created by the user
	 */
	public boolean isUserCreated() {
		return userCreated;
	}
}