/*******************************************************************************
 * Copyright (c) 2001, 2006 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.wst.xsd.ui.internal.common.commands;
import org.eclipse.core.resources.IFile;
import org.eclipse.emf.common.util.URI;
import org.eclipse.emf.ecore.resource.Resource;
import org.eclipse.gef.commands.Command;
import org.eclipse.xsd.XSDComponent;
import org.eclipse.xsd.XSDConcreteComponent;
import org.eclipse.xsd.XSDFactory;
import org.eclipse.xsd.XSDImport;
import org.eclipse.xsd.XSDSchema;
import org.eclipse.xsd.XSDSchemaDirective;
import org.eclipse.xsd.util.XSDResourceImpl;
public abstract class UpdateComponentReferenceAndManageDirectivesCommand extends Command
{
  protected XSDConcreteComponent concreteComponent;
  protected String componentName;
  protected String componentNamespace;
  protected IFile file;

  public UpdateComponentReferenceAndManageDirectivesCommand(XSDConcreteComponent concreteComponent, String componentName, String componentNamespace, IFile file)
  {
    this.concreteComponent = concreteComponent;
    this.componentName = componentName;
    this.componentNamespace = componentNamespace;
    this.file = file;
  }

  protected XSDComponent computeComponent()
  {
    XSDComponent result = null;
    XSDSchema schema = concreteComponent.getSchema();
    XSDSchemaDirective directive = null;
    // TODO (cs) handle case where namespace==null
    //
    if (componentNamespace != null)
    {
      // lets see if the element is already visible to our schema
      result = getDefinedComponent(schema, componentName, componentNamespace);
      if (result == null)
      {
        // TODO (cs) we need to provide a separate command to do this part
        //
        // apparently the element is not yet visible, we need to add
        // includes/imports to get to it
        if (componentNamespace.equals(schema.getTargetNamespace()))
        {
          // we need to add an include
          directive = XSDFactory.eINSTANCE.createXSDInclude();
        }
        else
        {
          // we need to add an import
          XSDImport xsdImport = XSDFactory.eINSTANCE.createXSDImport();
          xsdImport.setNamespace(componentNamespace);
          directive = xsdImport;
        }
     
        String location = computeNiceLocation(schema.getSchemaLocation(), file);       
        directive.setSchemaLocation(location);
        // TODO (cs) we should at the directive 'next' in the list of directives
        // for now I'm just adding as the first thing in the schema :-(
        //
        schema.getContents().add(0, directive);
        XSDSchema resolvedSchema = directive.getResolvedSchema();
        if (resolvedSchema == null)
        {
          String platformLocation = "platform:/resource" + file.getFullPath();
          Resource resource = concreteComponent.eResource().getResourceSet().createResource(URI.createURI(platformLocation));
          if (resource instanceof XSDResourceImpl)
          {
            try
            {
              resource.load(null);
              XSDResourceImpl resourceImpl = (XSDResourceImpl) resource;
              resolvedSchema = resourceImpl.getSchema();
              if (resolvedSchema != null)
              {
                directive.setResolvedSchema(resolvedSchema);
              }
            }
            catch (Exception e)
            {
            }
          }
        }
        if (resolvedSchema != null)
        {
          result = getDefinedComponent(resolvedSchema, componentName, componentNamespace);
        }
        else
        {
          // TODO (cs) consider setting some error state so that the client can
          // provide a pop-dialog error
          // we should also remove the import/include so save from cluttering
          // the file with bogus directives
        }
      }
    }
    return result;
  }
  
  private final static String PLATFORM_RESOURCE_PREFIX = "platform:/resource";
  private String computeNiceLocation(String baseLocation, IFile file)
  {     
    if (baseLocation.startsWith(PLATFORM_RESOURCE_PREFIX))
    {
      URI baseURI = URI.createURI(baseLocation);
      URI fileURI = URI.createPlatformResourceURI(file.getFullPath().toString());
      URI relative = fileURI.deresolve(baseURI);     
      return relative.toString();
    }
    else
    {
      URI baseURI = URI.createURI(baseLocation);          
      URI fileURI = URI.createFileURI(file.getLocation().toOSString());
      URI relative = fileURI.deresolve(baseURI);     
      return relative.toString();    
    } 
  }

  protected abstract XSDComponent getDefinedComponent(XSDSchema schema, String componentName, String componentNamespace);

  public abstract void execute();
}