content: /*******************************************************************************
   * Copyright (c) 2000, 2008 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.jsdt.ui.actions;
  
  import org.eclipse.jface.dialogs.MessageDialog;
  import org.eclipse.jface.text.ITextSelection;
  import org.eclipse.jface.viewers.IStructuredSelection;
  import org.eclipse.ui.IWorkbenchSite;
  import org.eclipse.ui.PlatformUI;
  import org.eclipse.wst.jsdt.core.IJavaScriptElement;
  import org.eclipse.wst.jsdt.core.IFunction;
  import org.eclipse.wst.jsdt.core.JavaScriptModelException;
  import org.eclipse.wst.jsdt.internal.corext.refactoring.RefactoringAvailabilityTester;
  import org.eclipse.wst.jsdt.internal.corext.refactoring.RefactoringExecutionStarter;
  import org.eclipse.wst.jsdt.internal.corext.util.JavaModelUtil;
  import org.eclipse.wst.jsdt.internal.ui.IJavaHelpContextIds;
  import org.eclipse.wst.jsdt.internal.ui.JavaScriptPlugin;
  import org.eclipse.wst.jsdt.internal.ui.actions.ActionUtil;
  import org.eclipse.wst.jsdt.internal.ui.actions.SelectionConverter;
  import org.eclipse.wst.jsdt.internal.ui.javaeditor.JavaEditor;
  import org.eclipse.wst.jsdt.internal.ui.javaeditor.JavaTextSelection;
  import org.eclipse.wst.jsdt.internal.ui.refactoring.RefactoringMessages;
  import org.eclipse.wst.jsdt.internal.ui.util.ExceptionHandler;
  
  /**
   * Action to start the modify parameters refactoring. The refactoring supports 
   * swapping and renaming of arguments.
   * <p>
   * This action is applicable to selections containing a method with one or
   * more arguments.
   * 
   * <p>
   * This class may be instantiated; it is not intended to be subclassed.
   * </p>
   * 
   *
   * Provisional API: This class/interface is part of an interim API that is still under development and expected to
   * change significantly before reaching stability. It is being made available at this early stage to solicit feedback
   * from pioneering adopters on the understanding that any code that uses this API will almost certainly be broken
   * (repeatedly) as the API evolves.
   */
  public class ModifyParametersAction extends SelectionDispatchAction {
  	
  	private JavaEditor fEditor;
  	
  	/**
  	 * Note: This constructor is for internal use only. Clients should not call this constructor.
  	 * @param editor the JavaScript editor
  	 */
  	public ModifyParametersAction(JavaEditor editor) {
  		this(editor.getEditorSite());
  		fEditor= editor;
  		setEnabled(SelectionConverter.canOperateOn(fEditor));
  	}
  
  	/**
  	 * Creates a new <code>ModifyParametersAction</code>. The action requires
  	 * that the selection provided by the site's selection provider is of type <code>
  	 * org.eclipse.jface.viewers.IStructuredSelection</code>.
  	 * 
  	 * @param site the site providing context information for this action
  	 */
  	public ModifyParametersAction(IWorkbenchSite site) {
  		super(site);
  		setText(RefactoringMessages.RefactoringGroup_modify_Parameters_label);
  		PlatformUI.getWorkbench().getHelpSystem().setHelp(this, IJavaHelpContextIds.MODIFY_PARAMETERS_ACTION);
  	}
  	
  	/*
  	 * @see SelectionDispatchAction#selectionChanged(IStructuredSelection)
  	 */
  	public void selectionChanged(IStructuredSelection selection) {
  		try {
  			setEnabled(RefactoringAvailabilityTester.isChangeSignatureAvailable(selection));
  		} catch (JavaScriptModelException e) {
  			// http://bugs.eclipse.org/bugs/show_bug.cgi?id=19253
  			if (JavaModelUtil.isExceptionToBeLogged(e))
  				JavaScriptPlugin.log(e);
  			setEnabled(false);//no UI here - happens on selection changes
  		}
  	}
  
      /*
       * @see SelectionDispatchAction#selectionChanged(ITextSelection)
       */
  	public void selectionChanged(ITextSelection selection) {
  		setEnabled(true);
  	}
  
  	/**
  	 * Note: This method is for internal use only. Clients should not call this method.
  	 */
  	public void selectionChanged(JavaTextSelection selection) {
  		try {
  			setEnabled(RefactoringAvailabilityTester.isChangeSignatureAvailable(selection));
  		} catch (JavaScriptModelException e) {
  			setEnabled(false);
  		}
  	}
  
  	/*
  	 * @see SelectionDispatchAction#run(IStructuredSelection)
  	 */
  	public void run(IStructuredSelection selection) {
  		try {
  			// we have to call this here - no selection changed event is sent after a refactoring but it may still invalidate enablement
  			if (RefactoringAvailabilityTester.isChangeSignatureAvailable(selection)) {
  				IFunction method= getSingleSelectedMethod(selection);
  				if (! ActionUtil.isEditable(getShell(), method))
  					return;
  				RefactoringExecutionStarter.startChangeSignatureRefactoring(method, this, getShell());
  			}
  		} catch (JavaScriptModelException e) {
  			ExceptionHandler.handle(e, RefactoringMessages.OpenRefactoringWizardAction_refactoring, RefactoringMessages.OpenRefactoringWizardAction_exception); 
  		}
  	}
  
      /*
       * @see SelectionDispatchAction#run(ITextSelection)
       */
  	public void run(ITextSelection selection) {
  		try {
  			if (! ActionUtil.isEditable(fEditor))
  				return;
  			IFunction method= getSingleSelectedMethod(selection);
  			if (RefactoringAvailabilityTester.isChangeSignatureAvailable(method)){
  				RefactoringExecutionStarter.startChangeSignatureRefactoring(method, this, getShell());
  			} else {
  				MessageDialog.openInformation(getShell(), RefactoringMessages.OpenRefactoringWizardAction_unavailable, RefactoringMessages.ModifyParametersAction_unavailable); 
  			}
  		} catch (JavaScriptModelException e) {
  			ExceptionHandler.handle(e, RefactoringMessages.OpenRefactoringWizardAction_refactoring, RefactoringMessages.OpenRefactoringWizardAction_exception); 
  		}
  	}
  
  	private static IFunction getSingleSelectedMethod(IStructuredSelection selection){
  		if (selection.isEmpty() || selection.size() != 1) 
  			return null;
  		if (selection.getFirstElement() instanceof IFunction)
  			return (IFunction)selection.getFirstElement();
  		return null;
  	}
  
  	private IFunction getSingleSelectedMethod(ITextSelection selection) throws JavaScriptModelException{
  		//- when caret/selection on method name (call or declaration) -> that method
  		//- otherwise: caret position's enclosing method declaration
  		//  - when caret inside argument list of method declaration -> enclosing method declaration
  		//  - when caret inside argument list of method call -> enclosing method declaration (and NOT method call)
  		IJavaScriptElement[] elements= SelectionConverter.codeResolve(fEditor); 
  		if (elements.length > 1)
  			return null;
  		if (elements.length == 1 && elements[0] instanceof IFunction)
  			return (IFunction)elements[0];
  		IJavaScriptElement elementAt= SelectionConverter.getInputAsCompilationUnit(fEditor).getElementAt(selection.getOffset());
  		if (elementAt instanceof IFunction)
  			return (IFunction)elementAt;
  		return null;
  	}
  }
  