/*******************************************************************************
 * Copyright (c) 2000, 2008 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
 *******************************************************************************/
package org.eclipse.jface.text.templates.persistence;

import org.eclipse.core.runtime.Assert;

import org.eclipse.jface.text.templates.Template;


/**
 * TemplatePersistenceData stores information about a template. It uniquely
 * references contributed templates via their id. Contributed templates may be
 * deleted or modified. All template may be enabled or not.
 * <p>
 * Clients may use this class, although this is not usually needed except when
 * implementing a custom template preference page or template store. This class
 * is not intended to be subclassed.
 * </p>
 *
 * @since 3.0
 * @noextend This class is not intended to be subclassed by clients.
 */
public class TemplatePersistenceData {
	private final Template fOriginalTemplate;
	private final String fId;
	private final boolean fOriginalIsEnabled;

	private Template fCustomTemplate= null;
	private boolean fIsDeleted= false;
	private boolean fCustomIsEnabled= true;

	/**
	 * Creates a new, user-added instance that is not linked to a contributed
	 * template.
	 *
	 * @param template the template which is stored by the new instance
	 * @param enabled whether the template is enabled
	 */
	public TemplatePersistenceData(Template template, boolean enabled) {
		this(template, enabled, null);
	}

	/**
	 * Creates a new instance. If <code>id</code> is not <code>null</code>,
	 * the instance is represents a template that is contributed and can be
	 * identified via its id.
	 *
	 * @param template the template which is stored by the new instance
	 * @param enabled whether the template is enabled
	 * @param id the id of the template, or <code>null</code> if a user-added
	 *        instance should be created
	 */
	public TemplatePersistenceData(Template template, boolean enabled, String id) {
		Assert.isNotNull(template);
		fOriginalTemplate= template;
		fCustomTemplate= template;
		fOriginalIsEnabled= enabled;
		fCustomIsEnabled= enabled;
		fId= id;
	}

	/**
	 * Returns the id of this template store, or <code>null</code> if there is none.
	 *
	 * @return the id of this template store
	 */
	public String getId() {
		return fId;
	}

	/**
	 * Returns the deletion state of the stored template. This is only relevant
	 * of contributed templates.
	 *
	 * @return the deletion state of the stored template
	 */
	public boolean isDeleted() {
		return fIsDeleted;
	}

	/**
	 * Sets the deletion state of the stored template.
	 *
	 * @param isDeleted the deletion state of the stored template
	 */
	public void setDeleted(boolean isDeleted) {
		fIsDeleted= isDeleted;
	}

	/**
	 * Returns the template encapsulated by the receiver.
	 *
	 * @return the template encapsulated by the receiver
	 */
	public Template getTemplate() {
		return fCustomTemplate;
	}


	/**
	 * Sets the template encapsulated by the receiver.
	 *
	 * @param template the new template
	 */
	public void setTemplate(Template template) {
		fCustomTemplate= template;
	}

	/**
	 * Returns whether the receiver represents a custom template, i.e. is either
	 * a user-added template or a contributed template that has been modified.
	 *
	 * @return <code>true</code> if the contained template is a custom
	 *         template and cannot be reconstructed from the contributed
	 *         templates
	 */
	public boolean isCustom() {
		return fId == null
				|| fIsDeleted
				|| fOriginalIsEnabled != fCustomIsEnabled
				|| !fOriginalTemplate.equals(fCustomTemplate);
	}

	/**
	 * Returns whether the receiver represents a modified template, i.e. a
	 * contributed template that has been changed.
	 *
	 * @return <code>true</code> if the contained template is contributed but has been modified, <code>false</code> otherwise
	 */
	public boolean isModified() {
		return isCustom() && !isUserAdded();
	}

	/**
	 * Returns <code>true</code> if the contained template was added by a
	 * user, i.e. does not reference a contributed template.
	 *
	 * @return <code>true</code> if the contained template was added by a user, <code>false</code> otherwise
	 */
	public boolean isUserAdded() {
		return fId == null;
	}


	/**
	 * Reverts the template to its original setting.
	 */
	public void revert() {
		fCustomTemplate= fOriginalTemplate;
		fCustomIsEnabled= fOriginalIsEnabled;
		fIsDeleted= false;
	}


	/**
	 * Returns the enablement state of the contained template.
	 *
	 * @return the enablement state of the contained template
	 */
	public boolean isEnabled() {
		return fCustomIsEnabled;
	}

	/**
	 * Sets the enablement state of the contained template.
	 *
	 * @param isEnabled the new enablement state of the contained template
	 */
	public void setEnabled(boolean isEnabled) {
		fCustomIsEnabled= isEnabled;
	}
}
