/*

* Copyright (c) 2006, 2008 Nokia Corporation and/or its subsidiary(-ies).

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of the License "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description: 

*

*/

package com.nokia.carbide.internal.api.template.engine;

import com.nokia.carbide.internal.api.templatewizard.ui.IExtraPagesProvider;

import com.nokia.carbide.internal.template.gen.Template.TemplateType;

import com.nokia.carbide.template.engine.ILoadedTemplate;

import com.nokia.carbide.template.engine.ITemplate;

import com.nokia.carbide.templatewizard.Messages;

import com.nokia.carbide.templatewizard.TemplateWizardPlugin;

import com.nokia.cpp.internal.api.utils.core.Logging;

import org.eclipse.core.runtime.*;

import org.eclipse.jface.resource.ImageDescriptor;

import org.eclipse.ui.PlatformUI;

import org.eclipse.ui.activities.IActivityManager;

import org.osgi.framework.Bundle;

import java.net.URL;

import java.text.MessageFormat;

import java.util.*;

/**

 * Singleton class that reads wizard template extensions and maintains list of available templates

 * for use by the templates wizard.

 */

public class TemplateEngine {

	private static final String EXTENSION_ID = TemplateWizardPlugin.ID + ".wizardTemplate"; //$NON-NLS-1$

	private static final String TEMPLATE_ID = "templateId"; //$NON-NLS-1$

	private static final String LOCATION = "location"; //$NON-NLS-1$

	private static final String WIZARD_ID = "wizardId"; //$NON-NLS-1$

	private static final String GROUP_LABEL = "groupLabel"; //$NON-NLS-1$

	private static final String FILTER_ARGS = "filterArguments"; //$NON-NLS-1$

	private static final String EXTRA_PAGES_PROVIDER = "extraPagesProvider"; //$NON-NLS-1$

	private static final String IMAGE = "image"; //$NON-NLS-1$

	private static final String DISPLAY_NAME = "displayName"; //$NON-NLS-1$

	private static TemplateEngine instance;

	private List<ITemplate> templates;

	public static TemplateEngine getInstance() {

		if (instance == null) {

			instance = new TemplateEngine();

		}

		return instance;

	}

	public static boolean isLoaded() {

		return instance != null;

	}

	private TemplateEngine() {

		templates = readTemplates(true);

	}

	public static List<ITemplate> readTemplates(boolean validate) {

		List<ITemplate> templates = new ArrayList<ITemplate>();

		IExtensionRegistry extensionRegistry = Platform.getExtensionRegistry();

		IExtensionPoint extensionPoint = extensionRegistry.getExtensionPoint(EXTENSION_ID);

		IExtension[] extensions = extensionPoint.getExtensions();

		for (int i = 0; i < extensions.length; i++) {

			IExtension extension = extensions[i];

			String pluginId = extension.getNamespaceIdentifier();

			IConfigurationElement[] elements = extension.getConfigurationElements();

			for (int j = 0; j < elements.length; j++) {

				IConfigurationElement element = elements[j];

				String templateId = element.getAttribute(TEMPLATE_ID);

				String location = element.getAttribute(LOCATION);

				String wizardId = element.getAttribute(WIZARD_ID);

				String name = element.getAttribute(DISPLAY_NAME);

				String groupLabel = element.getAttribute(GROUP_LABEL);

				String filterArgs = element.getAttribute(FILTER_ARGS);

				String imageAttribute = element.getAttribute(IMAGE);

				Bundle bundle = Platform.getBundle(pluginId);

				URL templateUrl = bundle.getEntry(location);

				Map<String, String> metadata =	new LinkedHashMap<String, String>();

				IConfigurationElement[] metadatas = element.getChildren("metadata");

				for (IConfigurationElement meta : metadatas) {

					metadata.put(meta.getAttribute("name"), meta.getValue());

				}

				Template template = new Template(templateUrl, bundle, name, groupLabel, 

												filterArgs, templateId, wizardId,

												metadata,

												element);

				if (imageAttribute != null) {

					URL iconUrl = template.getBundle().getEntry(imageAttribute);

					if (iconUrl == null) {

						Logging.log(TemplateWizardPlugin.getDefault(), 

								Logging.newStatus(TemplateWizardPlugin.getDefault(), IStatus.ERROR, 

										MessageFormat.format(Messages.getString("TemplateEngine.ImageNotFoundError"),  //$NON-NLS-1$

												new Object[] { imageAttribute, template.getBundle().getSymbolicName() })));

					}

					ImageDescriptor imageDescriptor = ImageDescriptor.createFromURL(iconUrl);

					template.setImageDescriptor(imageDescriptor);

				}

				templates.add(template);

			}

		}

		return templates;

	}

	private boolean isEnabledActivity(String templateId) {

		try {

			IActivityManager activityManager = PlatformUI.getWorkbench().getActivitySupport().getActivityManager();

			Set definedActivityIds = activityManager.getDefinedActivityIds();

			Set enabledActivityIds = activityManager.getEnabledActivityIds();

			return !definedActivityIds.contains(templateId) || enabledActivityIds.contains(templateId);

		} catch (IllegalStateException e) {

			// PlatformUI.getWorkbench() throws if running headless: assume everything's enabled

			return true;

		}

	}

	/**

	 * Get all the templates for a given wizard registered with the template engine.

	 * @param wizardId the "new project" wizard identifier, or <code>null</code> for all

	 * @return non-<code>null</code> list of templates

	 */

	public List<ITemplate> getTemplates(String wizardId) {

		List<ITemplate> filteredTemplates = new ArrayList<ITemplate>();

		for (Iterator<ITemplate> iter = templates.iterator(); iter.hasNext();) {

			ITemplate template = iter.next();

			if (isEnabledActivity(template.getTemplateId()) &&

					(wizardId == null || wizardId.equals(template.getWizardId())))

				filteredTemplates.add(template);

		}

		return filteredTemplates;

	}

	/**

	 * Get all the templates registered with the template engine passing a given filter

	 * @param filter the filter to apply, or <code>null</code> for all

	 * @return non-<code>null</code> list of templates

	 */

	public List<ITemplate> getFilteredTemplates(ITemplateFilter filter) {

		List<ITemplate> filteredTemplates = new ArrayList<ITemplate>();

		for (Iterator<ITemplate> iter = templates.iterator(); iter.hasNext();) {

			ITemplate template = iter.next();

			if (isEnabledActivity(template.getTemplateId()) &&

				filteredTemplates.add(template);

			}

		}

		return filteredTemplates;

	}

	public static void logError(String message, Throwable t) {

		Logging.log(TemplateWizardPlugin.getDefault(), Logging.newSimpleStatus(IStatus.ERROR, t));

	}

	public static IStatus runProcesses(ITemplate template, IProgressMonitor monitor) {

		try {

			ILoadedTemplate loadedTemplate = template.getLoadedTemplate();

			return loadedTemplate.runProcesses(monitor);

		} catch (CoreException e) {

			return e.getStatus();

		}

	}

	static ILoadedTemplate loadTemplate(ITemplate template, IConfigurationElement element) throws CoreException {

		TemplateType templateType = TemplateLoader.loadTemplate(template.getBundle(), template.getTemplateUrl(), true);

		LoadedTemplate loadedTemplate = new LoadedTemplate(template, templateType);

		String providerAttribute = element != null ? element.getAttribute(EXTRA_PAGES_PROVIDER) : null;

		if (providerAttribute != null) {

			try {

				IExtraPagesProvider extraPagesProvider = 

					(IExtraPagesProvider) element.createExecutableExtension(TemplateEngine.EXTRA_PAGES_PROVIDER);

				loadedTemplate.setExtraPagesProvider(extraPagesProvider);

			} 

			catch (InvalidRegistryObjectException e) {

				// if the configuration element is out of date

				throw new CoreException(Logging.newStatus(TemplateWizardPlugin.getDefault(), e));

			}

		}		

		return loadedTemplate;

	}

}