/*******************************************************************************
 * Copyright (c) 2005, 2009 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
 *     Wind River Systems - added support for IToggleBreakpointsTargetFactory
 *******************************************************************************/
package org.eclipse.debug.ui.actions;

import org.eclipse.core.runtime.CoreException;
import org.eclipse.debug.internal.ui.DebugUIPlugin;
import org.eclipse.debug.internal.ui.actions.ActionMessages;
import org.eclipse.debug.internal.ui.actions.IToggleBreakpointsTargetManagerListener;
import org.eclipse.debug.internal.ui.actions.ToggleBreakpointsTargetManager;
import org.eclipse.jface.action.Action;
import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.IDocument;
import org.eclipse.jface.text.IRegion;
import org.eclipse.jface.text.ITextSelection;
import org.eclipse.jface.text.TextSelection;
import org.eclipse.jface.text.source.IVerticalRulerInfo;
import org.eclipse.jface.viewers.ISelection;
import org.eclipse.jface.viewers.ISelectionProvider;
import org.eclipse.ui.IWorkbenchPart;
import org.eclipse.ui.texteditor.IDocumentProvider;
import org.eclipse.ui.texteditor.ITextEditor;
import org.eclipse.ui.texteditor.IUpdate;

/**
 * Action to toggle a breakpoint in a vertical ruler of a workbench part
 * containing a document. The part must provide an <code>IToggleBreakpointsTarget</code>
 * adapter which may optionally be an instance of an
 * <code>IToggleBreakpointsTargetExtension</code>.
 * <p>
 * Clients may instantiate this class. 
 * </p>
 * @since 3.1
 * @see org.eclipse.debug.ui.actions.RulerToggleBreakpointActionDelegate
 * @noextend This class is not intended to be subclassed by clients.
 */
public class ToggleBreakpointAction extends Action implements IUpdate {
	
	private IWorkbenchPart fPart;
	private IDocument fDocument;
	private IVerticalRulerInfo fRulerInfo;
	private IToggleBreakpointsTargetManagerListener fListener = new IToggleBreakpointsTargetManagerListener() {
	    public void preferredTargetsChanged() {
	        update();	        
	    }
	};

	/**
	 * Constructs a new action to toggle a breakpoint in the given
	 * part containing the given document and ruler.
	 * 
	 * @param part the part in which to toggle the breakpoint - provides
	 *  an <code>IToggleBreakpointsTarget</code> adapter
	 * @param document the document breakpoints are being set in or
	 * <code>null</code> when the document should be derived from the
	 * given part
	 * @param rulerInfo specifies location the user has double-clicked
	 */
	public ToggleBreakpointAction(IWorkbenchPart part, IDocument document, IVerticalRulerInfo rulerInfo) {
		super(ActionMessages.ToggleBreakpointAction_0);
		fPart = part;
		fDocument = document;
		fRulerInfo = rulerInfo;
		ToggleBreakpointsTargetManager.getDefault().addChangedListener(fListener);
	}
	/*
	 *  (non-Javadoc)
	 * @see org.eclipse.jface.action.IAction#run()
	 */
	public void run() {
		IDocument document= getDocument();
		if (document == null) {
			return;
		}

		int line = fRulerInfo.getLineOfLastMouseButtonActivity();
		
		// Test if line is valid
		if (line == -1)
			return;

		try {
			ITextSelection selection = getTextSelection(document, line);
			IToggleBreakpointsTarget toggleTarget = 
			    ToggleBreakpointsTargetManager.getDefault().getToggleBreakpointsTarget(fPart, selection);
			if (toggleTarget == null) {
			    return;
			}

			if (toggleTarget instanceof IToggleBreakpointsTargetExtension) {
			    IToggleBreakpointsTargetExtension extension = (IToggleBreakpointsTargetExtension) toggleTarget;
				if (extension.canToggleBreakpoints(fPart, selection)) {
					extension.toggleBreakpoints(fPart, selection);
					return;
				}
			}
			if (toggleTarget.canToggleLineBreakpoints(fPart, selection)) {
			    toggleTarget.toggleLineBreakpoints(fPart, selection);
			} else if (toggleTarget.canToggleWatchpoints(fPart, selection)) {
			    toggleTarget.toggleWatchpoints(fPart, selection);
			} else if (toggleTarget.canToggleMethodBreakpoints(fPart, selection)) {
			    toggleTarget.toggleMethodBreakpoints(fPart, selection);
			}
		} catch (BadLocationException e) {
			reportException(e);
		} catch (CoreException e) {
			reportException(e);
		}
	}
	
	/**
	 * Report an error to the user.
	 * 
	 * @param e underlying exception
	 */
	private void reportException(Exception e) {
		DebugUIPlugin.errorDialog(fPart.getSite().getShell(), ActionMessages.ToggleBreakpointAction_1, ActionMessages.ToggleBreakpointAction_2, e); //
	}
	
	/**
	 * Disposes this action. Clients must call this method when
	 * this action is no longer needed.
	 */
	public void dispose() {
		fDocument = null;
		fPart = null;
		fRulerInfo = null;
	    ToggleBreakpointsTargetManager.getDefault().removeChangedListener(fListener);
	}

	/**
	 * Returns the document on which this action operates.
	 * 
	 * @return the document or <code>null</code> if none
	 */
	private IDocument getDocument() {
		if (fDocument != null)
			return fDocument;
		
		if (fPart instanceof ITextEditor) {
			ITextEditor editor= (ITextEditor)fPart;
			IDocumentProvider provider = editor.getDocumentProvider();
			if (provider != null)
				return provider.getDocument(editor.getEditorInput());
		}
		
		IDocument doc = (IDocument) fPart.getAdapter(IDocument.class);
		if (doc != null) {
			return doc;
		}
		
		return null;
	}
	
	/* (non-Javadoc)
	 * @see org.eclipse.ui.texteditor.IUpdate#update()
	 */
	public void update() {
		IDocument document= getDocument();
		if (document != null) {
		    int line = fRulerInfo.getLineOfLastMouseButtonActivity();
		    if (line > -1) {
		        try {
		            ITextSelection selection = getTextSelection(document, line);
                   
                    IToggleBreakpointsTarget adapter = 
                        ToggleBreakpointsTargetManager.getDefault().getToggleBreakpointsTarget(fPart, selection);
                    if (adapter == null) {
                        setEnabled(false);
                        return;
                    }
                    if (adapter instanceof IToggleBreakpointsTargetExtension) {
                        IToggleBreakpointsTargetExtension extension = (IToggleBreakpointsTargetExtension) adapter;
                        if (extension.canToggleBreakpoints(fPart, selection)) {
                            setEnabled(true);
                            return;
                        }
                    }
                    if (adapter.canToggleLineBreakpoints(fPart, selection) ||
                        adapter.canToggleWatchpoints(fPart, selection) ||
                        adapter.canToggleMethodBreakpoints(fPart, selection)) 
                    {
                        setEnabled(true);
                        return;
                    }
                } catch (BadLocationException e) {
                    reportException(e);
                }
			}
		}
		setEnabled(false);
	}

	/**
	 * Determines the text selection for the breakpoint action.  If clicking on the ruler inside
	 * the highlighted text, return the text selection for the highlighted text.  Otherwise, 
	 * return a text selection representing the start of the line.
	 * 
	 * @param document	The IDocument backing the Editor.
	 * @param line	The line clicked on in the ruler.
	 * @return	An ITextSelection as described.
	 * @throws BadLocationException	If underlying operations throw.
	 */
	private ITextSelection getTextSelection(IDocument document, int line) throws BadLocationException {
		IRegion region = document.getLineInformation(line);
		ITextSelection textSelection = new TextSelection(document, region.getOffset(), 0);
		ISelectionProvider provider = fPart.getSite().getSelectionProvider();
		if (provider != null){
			ISelection selection = provider.getSelection();
			if (selection instanceof ITextSelection
					&& ((ITextSelection) selection).getStartLine() <= line
					&& ((ITextSelection) selection).getEndLine() >= line) {
				textSelection = (ITextSelection) selection;
			} 
		}
		return textSelection;
	}

}