/*******************************************************************************
 * Copyright (c) 2004, 2007 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.intro.impl.model.loader;

import org.eclipse.ui.internal.intro.impl.model.ExtensionMap;
import org.eclipse.ui.internal.intro.impl.model.IntroModelRoot;
import org.eclipse.ui.internal.intro.impl.util.Log;

/**
 * Manages all Intro plugin extension points. Currently, there are two:
 * org.eclipse.ui.intro.config & org.eclipse.ui.intro.configExtension. <br>
 * The model is lazily loaded on per need basis. This happens when a page is
 * asked for its children, or when the model is trying to resolve includes or
 * extensions. <br>
 */

public class ExtensionPointManager extends BaseExtensionPointManager {

    // singleton instance. Can be retrieved from here or from the Intro Plugin.
    private static ExtensionPointManager inst = new ExtensionPointManager();

    // The root model class that represents a full/combined OOBBE config. This
    // model is loaded based on an introId when the customizableIntroPart tries
    // to load a model based on introId. This is different when includes and
    // extension aer resolved because in tnose cases models are being loaded
    // given an id and not an introId.
    private IntroModelRoot currentModel;

    // the id of the intro part contribution who's model (config) we are trying
    // to load. The customizableIntroPart loads this id and loads the model that
    // is bound to this intro id (ie: has this id as an introId).
    private String introId;

    /*
     * Prevent creation.
     */
    private ExtensionPointManager() {
        super();
    }

    /**
     * @return Returns the inst.
     */
    public static ExtensionPointManager getInst() {
        return inst;
    }

    /**
     * Load the intro model given the current intro id.
     */
    private void loadCurrentModel() {
        currentModel = loadModel(ATT_CONFIG_INTRO_ID, this.introId);
    }

    /**
     * @return Returns the Intro Model root. Note: Prefereed way of getting to
     *         the intro model root is throught the intro plugin.
     */
    public IntroModelRoot getCurrentModel() {
        if (currentModel == null)
            // we never loaded this model before, or we tried before and we
            // failed. Load it. Get the correct config element based on
            // config introId, and log any extra contributions.
            loadCurrentModel();
        return currentModel;
    }

    /**
     * Load an intro model given a config id.
     *
     * @param configId
     * @return
     */
    public IntroModelRoot getModel(String configId) {
        IntroModelRoot model = getCachedModel(configId);
        if (model == null) {
            // we never loaded this model before, or we tried before and we
            // failed. Load it. Get the correct config element based on
            // config id, and log any extra contributions.
            model = loadModel(ATT_ID, configId);
        }
        return model;
    }

    /**
     * @param introPartId
     *            The introPartId to set.
     */
    public void setIntroId(String introId) {
        this.introId = introId;
        // we do not have to clean model here. remove cached model, if it
        // exists.
        this.currentModel = null;
    }

    public void clear() {
        currentModel = null;
        sharedConfigExtensionsManager = null;
        introModels.clear();
        ExtensionMap.getInstance().clear();
        if (Log.logInfo)
            Log.info("Cleared Intro model"); //$NON-NLS-1$
    }


}