/*******************************************************************************
 * Copyright (c) 2000, 2005 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.ui.internal.ide;

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

import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.jface.resource.ImageDescriptor;
import org.eclipse.ui.ISharedImages;
import org.eclipse.ui.PlatformUI;
import org.eclipse.ui.WorkbenchException;
import org.eclipse.ui.model.IWorkbenchAdapter;
import org.eclipse.ui.model.WorkbenchAdapter;

/**
 * Category provides for hierarchical grouping of elements
 * registered in the registry. One extension normally defines
 * a category, and other reference it via its ID.
 * <p>
 * A category may specify its parent category in order to
 * achieve hierarchy.
 * </p>
 */
public class Category extends WorkbenchAdapter {
    /**
     * Name of the miscellaneous category
     */
    public final static String MISC_NAME = IDEWorkbenchMessages.ICategory_other;

    /**
     * Identifier of the miscellaneous category
     */
    public final static String MISC_ID = "org.eclipse.ui.internal.otherCategory"; //$NON-NLS-1$

    private static final String ATT_ID = "id"; //$NON-NLS-1$

    private static final String ATT_PARENT = "parentCategory"; //$NON-NLS-1$

    private static final String ATT_NAME = "name"; //$NON-NLS-1$

    private String id;

    private String name;

    private String[] parentPath;

    private String unparsedPath;

    private ArrayList elements;

    /**
     * Creates an instance of <code>Category</code> as a
     * miscellaneous category.
     */
    public Category() {
        this.id = MISC_ID;
        this.name = MISC_NAME;
    }

    /**
     * Creates an instance of <code>Category</code> with
     * an ID and label.
     * 
     * @param id the unique identifier for the category
     * @param label the presentation label for this category
     */
    public Category(String id, String label) {
        this.id = id;
        this.name = label;
    }

    /**
     * Creates an instance of <code>Category</code> using the
     * information from the specified configuration element.
     * 
     * @param configElement the <code>IConfigurationElement<code> containing
     * 		the ID, label, and optional parent category path.
     * @throws WorkbenchException if the ID or label is <code>null</code
     */
    public Category(IConfigurationElement configElement)
            throws WorkbenchException {
        id = configElement.getAttribute(ATT_ID);
        name = configElement.getAttribute(ATT_NAME);
        unparsedPath = configElement.getAttribute(ATT_PARENT);

        if (id == null || name == null)
            throw new WorkbenchException("Invalid category: " + id); //$NON-NLS-1$
    }

    /* (non-Javadoc)
     * Method declared on ICategory.
     */
    public void addElement(Object element) {
        if (elements == null)
            elements = new ArrayList(5);
        elements.add(element);
    }

    /* (non-Javadoc)
     * Method declared on IAdaptable.
     */
    public Object getAdapter(Class adapter) {
        if (adapter == IWorkbenchAdapter.class)
            return this;
        else
            return null;
    }

    /* (non-Javadoc)
     * Method declared on IWorkbenchAdapter.
     */
    public Object[] getChildren(Object o) {
        return getElements().toArray();
    }

    /* (non-Javadoc)
     * Method declared on IWorkbenchAdapter.
     */
    public ImageDescriptor getImageDescriptor(Object object) {
        return PlatformUI.getWorkbench().getSharedImages().getImageDescriptor(
                ISharedImages.IMG_OBJ_FOLDER);
    }

    /* (non-Javadoc)
     * Method declared on IWorkbenchAdapter.
     */
    public String getLabel(Object o) {
        return getLabel();
    }

    /* (non-Javadoc)
     * Method declared on ICategory.
     */
    public String getId() {
        return id;
    }

    /* (non-Javadoc)
     * Method declared on ICategory.
     */
    public String getLabel() {
        return name;
    }

    /* (non-Javadoc)
     * Method declared on ICategory.
     */
    public String[] getParentPath() {
        if (unparsedPath != null) {
            StringTokenizer stok = new StringTokenizer(unparsedPath, "/"); //$NON-NLS-1$
            parentPath = new String[stok.countTokens()];
            for (int i = 0; stok.hasMoreTokens(); i++) {
                parentPath[i] = stok.nextToken();
            }
            unparsedPath = null;
        }

        return parentPath;
    }

    /* (non-Javadoc)
     * Method declared on ICategory.
     */
    public String getRootPath() {
        String[] path = getParentPath();
        if (path != null && path.length > 0)
            return path[0];
        else
            return id;
    }

    /* (non-Javadoc)
     * Method declared on ICategory.
     */
    public ArrayList getElements() {
        return elements;
    }

    /* (non-Javadoc)
     * Method declared on ICategory.
     */
    public boolean hasElements() {
        if (elements != null)
            return !elements.isEmpty();
        else
            return false;
    }
}