/*******************************************************************************
 * 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 v2.0
 * 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 java.lang.reflect.InvocationTargetException;
import java.net.URL;

import org.eclipse.core.runtime.CoreException;
import org.eclipse.jface.dialogs.MessageDialog;
import org.eclipse.jface.text.ITextSelection;
import org.eclipse.jface.viewers.IStructuredSelection;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.ui.IWorkbenchSite;
import org.eclipse.ui.PlatformUI;
import org.eclipse.wst.jsdt.core.IJavaScriptElement;
import org.eclipse.wst.jsdt.core.IPackageFragmentRoot;
import org.eclipse.wst.jsdt.internal.corext.util.JavaModelUtil;
import org.eclipse.wst.jsdt.internal.corext.util.Messages;
import org.eclipse.wst.jsdt.internal.ui.IJavaHelpContextIds;
import org.eclipse.wst.jsdt.internal.ui.JavaScriptPlugin;
import org.eclipse.wst.jsdt.internal.ui.actions.ActionMessages;
import org.eclipse.wst.jsdt.internal.ui.actions.ActionUtil;
import org.eclipse.wst.jsdt.internal.ui.actions.OpenBrowserUtil;
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.util.ExceptionHandler;
import org.eclipse.wst.jsdt.ui.JavaScriptElementLabels;
import org.eclipse.wst.jsdt.ui.JavaScriptUI;

/**
 * This action opens the selected element's Javadoc in an external 
 * browser. 
 * <p>
 * The action is applicable to selections containing elements of 
 * type <code>IJavaScriptElement</code>.
 * 
 * <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 OpenExternalJavadocAction extends SelectionDispatchAction {
		
	private JavaEditor fEditor;
	
	/**
	 * Creates a new <code>OpenExternalJavadocAction</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 additional context information for this action
	 */ 
	public OpenExternalJavadocAction(IWorkbenchSite site) {
		super(site);
		setText(ActionMessages.OpenExternalJavadocAction_label); 
		setDescription(ActionMessages.OpenExternalJavadocAction_description); 
		setToolTipText(ActionMessages.OpenExternalJavadocAction_tooltip); 
		PlatformUI.getWorkbench().getHelpSystem().setHelp(this, IJavaHelpContextIds.OPEN_EXTERNAL_JAVADOC_ACTION);
	}
	

	
	/**
	 * Note: This constructor is for internal use only. Clients should not call this constructor.
	 * @param editor the JavaScript editor
	 */
	public OpenExternalJavadocAction(JavaEditor editor) {
		this(editor.getEditorSite());
		fEditor= editor;
		setEnabled(SelectionConverter.canOperateOn(fEditor));
	}
	
	/* (non-Javadoc)
	 * Method declared on SelectionDispatchAction.
	 */
	public void selectionChanged(ITextSelection selection) {
	}

	/* (non-Javadoc)
	 * Method declared on SelectionDispatchAction.
	 */
	public void selectionChanged(IStructuredSelection selection) {
		setEnabled(checkEnabled(selection));
	}
	
	private boolean checkEnabled(IStructuredSelection selection) {
		if (selection.size() != 1)
			return false;
		return selection.getFirstElement() instanceof IJavaScriptElement;
	}
	
	/* (non-Javadoc)
	 * Method declared on SelectionDispatchAction.
	 */
	public void run(ITextSelection selection) {
		IJavaScriptElement element= SelectionConverter.getInput(fEditor);
		if (!ActionUtil.isProcessable(getShell(), element))
			return;
		
		try {
			IJavaScriptElement[] elements= SelectionConverter.codeResolveOrInputForked(fEditor);
			if (elements == null || elements.length == 0)
				return;
			IJavaScriptElement candidate= elements[0];
			if (elements.length > 1) {
				candidate= SelectionConverter.selectJavaElement(elements, getShell(), getDialogTitle(), ActionMessages.OpenExternalJavadocAction_select_element);
			}
			if (candidate != null) {
				run(candidate);
			}
		} catch (InvocationTargetException e) {
			ExceptionHandler.handle(e, getShell(), getDialogTitle(), ActionMessages.OpenExternalJavadocAction_code_resolve_failed); 
		} catch (InterruptedException e) {
			// cancelled
		}
	}
	
	/* (non-Javadoc)
	 * Method declared on SelectionDispatchAction.
	 */
	public void run(IStructuredSelection selection) {
		if (!checkEnabled(selection))
			return;
		IJavaScriptElement element= (IJavaScriptElement)selection.getFirstElement();
		if (!ActionUtil.isProcessable(getShell(), element))
			return;			
		run(element);
	}
	
	/*
	 * No Javadoc since the method isn't meant to be public but is
	 * since the beginning
	 */
	public void run(IJavaScriptElement element) {
		if (element == null)
			return;
		Shell shell= getShell();
		try {
			String labelName= JavaScriptElementLabels.getElementLabel(element, JavaScriptElementLabels.ALL_DEFAULT);
			
			URL baseURL= JavaScriptUI.getJSdocBaseLocation(element);
			if (baseURL == null) {
				IPackageFragmentRoot root= JavaModelUtil.getPackageFragmentRoot(element);
				if (root != null && root.getKind() == IPackageFragmentRoot.K_BINARY) {
					String message= ActionMessages.OpenExternalJavadocAction_libraries_no_location;	 
					showMessage(shell, Messages.format(message, new String[] { labelName, root.getElementName() }), false);
				} else {
					IJavaScriptElement annotatedElement= element.getJavaScriptProject();
					String message= ActionMessages.OpenExternalJavadocAction_source_no_location;	 
					showMessage(shell, Messages.format(message, new String[] { labelName, annotatedElement.getElementName() }), false);
				}
				return;
			}		
			URL url= JavaScriptUI.getJSdocLocation(element, true);
			if (url != null) {
				OpenBrowserUtil.open(url, shell.getDisplay(), getTitle());
			} 		
		} catch (CoreException e) {
			JavaScriptPlugin.log(e);
			showMessage(shell, ActionMessages.OpenExternalJavadocAction_opening_failed, true); 
		}
	}
	
	private static void showMessage(final Shell shell, final String message, final boolean isError) {
		Display.getDefault().asyncExec(new Runnable() {
			public void run() {
				if (isError) {
					MessageDialog.openError(shell, getTitle(), message); 
				} else {
					MessageDialog.openInformation(shell, getTitle(), message); 
				}
			}
		});
	}
	
	private static String getTitle() {
		return ActionMessages.OpenExternalJavadocAction_dialog_title; 
	}
	
	/**
	 * Note: this method is for internal use only. Clients should not call this method.
	 * 
	 * @return the dialog default title
	 */
	protected String getDialogTitle() {
		return getTitle();
	}	
}