/*******************************************************************************
 * Copyright (c) 2007, 2008 Symbian Software Limited 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:
 * Bala Torati (Symbian) - Initial API and implementation
 *******************************************************************************/
package org.eclipse.cdt.core.templateengine.process;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.eclipse.cdt.core.CCorePlugin;
import org.eclipse.cdt.core.templateengine.TemplateEngineUtil;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.core.runtime.IExtension;
import org.eclipse.core.runtime.IExtensionPoint;
import org.eclipse.core.runtime.Platform;

/**
 * Factory class for creating the Process Runners.
 */
public class ProcessRunnerFactory {
	private static final String EXTENSION_POINT_PROCESSES = CCorePlugin.PLUGIN_ID + ".templateProcessTypes"; //$NON-NLS-1$
	private static final String ELEM_NAME = "name"; //$NON-NLS-1$
	private static final String ELEM_PROCESS_RUNNER = "processRunner"; //$NON-NLS-1$
	private static ProcessRunnerFactory instance;
	
	static {
		instance = new ProcessRunnerFactory();
	}
	
	private Map<String, ProcessRunner> processRunnerMap;
	
	private ProcessRunnerFactory() {
		initializeProcessRunners();
	}
	
	/**
	 * Initialises the process runners.
	 *
	 */
	private synchronized void initializeProcessRunners() {
		processRunnerMap = new HashMap<String, ProcessRunner>();
		IExtensionPoint point = Platform.getExtensionRegistry().getExtensionPoint(EXTENSION_POINT_PROCESSES);
		IExtension[] extensions = point.getExtensions();
		for(int i=0; i<extensions.length; i++) {
			IExtension extension = extensions[i];
			String prefix = extension.getNamespaceIdentifier() + "."; //$NON-NLS-1$
			IConfigurationElement[] configurationElements = extension.getConfigurationElements();
			for(int j=0; j<configurationElements.length; j++) {
				IConfigurationElement element = configurationElements[j];
				String processType = element.getAttribute(ELEM_NAME);
				if (processType != null) {
					try {
						ProcessRunner runner = (ProcessRunner) element.createExecutableExtension(ELEM_PROCESS_RUNNER);
						List<ProcessParameter> params = null;
						IConfigurationElement[] elementChildren = element.getChildren();
						for (int k=0; k<elementChildren.length; k++) {
							if (params == null) {
								params = new ArrayList<ProcessParameter>();
							}
							params.add(new ProcessParameter(elementChildren[k]));
						}
						if (params != null) {
							runner.setProcessParameters(params.toArray(new ProcessParameter[params.size()]));
						}
						processRunnerMap.put(prefix + processType, runner);
					} catch (CoreException e) {
						TemplateEngineUtil.log(e);
					}
				}
			}
		}
	}
	
	/**
	 * @return the singleton {@link ProcessRunnerFactory}
	 */
	public static ProcessRunnerFactory getDefault() {
		return instance;
	}

	/**
	 * @param processType
	 * @return the ProcessRunner based on the ProcessType.
	 */
	public ProcessRunner getProcessRunner(String processType) {
		return processRunnerMap.get(processType);
	}
}