/**
 * 
 */
package com.topsun.posclient.application;

import java.util.ArrayList;
import java.util.List;

import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.core.runtime.IExtension;
import org.eclipse.core.runtime.IExtensionPoint;
import org.eclipse.core.runtime.Platform;

public class ApplicationCustomizationsRegistry {

	public static final String EXTENSION_ID = "com.topsun.posclient.application.customizations";

	private static ApplicationCustomizationsRegistry instance = null;

	public static ApplicationCustomizationsRegistry getInstance() {
		if (instance == null) {
			synchronized (ApplicationCustomizationsRegistry.class) {
				if (instance == null) {
					instance = new ApplicationCustomizationsRegistry();
				}
			}
		}
		return instance;
	}

	public ApplicationCustomizationsRegistry() {
		init();
	}

	private List<ApplicationCustomizationDescriptor> descriptorList = new ArrayList<ApplicationCustomizationDescriptor>();

	private void init() {
		IExtensionPoint extensionPoint = Platform.getExtensionRegistry().getExtensionPoint(EXTENSION_ID);
		IExtension[] extensions = extensionPoint.getExtensions();
		for (IExtension extension : extensions) {
			IConfigurationElement[] elements = extension.getConfigurationElements();
			for (IConfigurationElement element : elements) {
				ApplicationCustomizationDescriptor descriptor = new ApplicationCustomizationDescriptor();
				descriptor.init(element);
				descriptorList.add(descriptor);
			}
		}
		if (descriptorList.size() == 0) {
			descriptorList.add(new ApplicationCustomizationDescriptor());
		}
	}

	public ApplicationCustomizationDescriptor[] getDescriptors() {
		return descriptorList.toArray(new ApplicationCustomizationDescriptor[descriptorList.size()]);
	}

	public ApplicationCustomizationDescriptor getDefaultDescriptor() {
		ApplicationCustomizationDescriptor descriptor = getDescriptor(ApplicationCustomizationDescriptor.DEFAULT_ID);
		
		return descriptor != null ? descriptor : (descriptorList.size() != 0
				? descriptorList.get(0) : null);
	}
	
	public ApplicationCustomizationDescriptor getDescriptor(String id) {
		if (id == null || id.trim().length() == 0) {
			return null;
		}
		for (ApplicationCustomizationDescriptor descriptor : descriptorList) {
			if (id.equals(descriptor.getId())) {
				return descriptor;
			}
		}
		return null;
	}
}