/*
* Copyright (c) 2002 IBM Corporation and others.
* All rights reserved.   This program and the accompanying materials
* are made available under the terms of the Common Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/cpl-v10.html
* 
* Contributors:
*   IBM - Initial API and implementation
*   Jens Lukowski/Innoopract - initial renaming/restructuring
* 
*/
package org.eclipse.wst.xml.core.internal.contentmodel.internal.annotation;

import java.net.URL;

import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.core.runtime.IExtensionPoint;
import org.eclipse.core.runtime.IPluginRegistry;
import org.eclipse.core.runtime.Platform;
import org.eclipse.wst.xml.core.internal.Logger;


/**
* This class reads the plugin manifests and adds each specified gramamr annotation file with the AnnotationProvider
*/
public class AnnotationFileRegistryReader
{
  protected static final String EXTENSION_POINT_ID = "annotationFiles"; //$NON-NLS-1$
  protected static final String TAG_NAME = "annotationFile"; //$NON-NLS-1$
  protected static final String ATT_PUBLIC_ID = "publicId"; //$NON-NLS-1$
  protected static final String ATT_LOCATION = "location"; //$NON-NLS-1$

  private AnnotationFileRegistry annotationFileRegistry;

  public AnnotationFileRegistryReader(AnnotationFileRegistry annotationFileRegistry)
  {
    this.annotationFileRegistry = annotationFileRegistry;
  }

  /**
   * read from plugin registry and parse it.
   */
  public void readRegistry()
  {
    IPluginRegistry pluginRegistry = Platform.getPluginRegistry();
	String pluginId = "org.eclipse.wst.xml.core";     //$NON-NLS-1$
    IExtensionPoint point = pluginRegistry.getExtensionPoint(pluginId, EXTENSION_POINT_ID);
    if (point != null)
    {
      IConfigurationElement[] elements = point.getConfigurationElements();
      for (int i = 0; i < elements.length; i++)
      {
        readElement(elements[i]);
      }
    }
  }

  /**
   * readElement() - parse and deal with an extension like:
   *
   * <extension point="org.eclipse.wst.xml.core.internal.contentmodel.util_implementation">
   *    <util_implementation class = corg.eclipse.wst.baseutil.CMUtilImplementationImpl  />
   * </extension>
   */
  protected void readElement(IConfigurationElement element)
  {
    if (element.getName().equals(TAG_NAME))
    {
      String publicId = element.getAttribute(ATT_PUBLIC_ID);
      String location = element.getAttribute(ATT_LOCATION);
      if (publicId != null && location != null)
      {
        try
        {
          URL installURL = element.getDeclaringExtension().getDeclaringPluginDescriptor().getInstallURL();
          String qualifiedLocation = resolve(installURL, location);
          annotationFileRegistry.addAnnotationFile(publicId, qualifiedLocation);
        }
        catch (Exception e)
        {
          Logger.logException("problem adding annotation file " + location, e); //$NON-NLS-1$
        }
      }
    }
  }

  public String resolve(URL platformURL, String relativePath) throws Exception
  {
    URL resolvedURL = Platform.resolve(platformURL);
    return resolvedURL.toString() + relativePath;
  }
}