/*******************************************************************************
 * Copyright (c) 2000, 2003 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 Corporation - initial API and implementation
 *******************************************************************************/

package org.eclipse.jface.text.contentassist;


import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.events.SelectionListener;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Table;
import org.eclipse.swt.widgets.TableItem;

import org.eclipse.jface.text.AbstractInformationControlManager;
import org.eclipse.jface.text.Assert;
import org.eclipse.jface.text.IInformationControl;
import org.eclipse.jface.text.IInformationControlCreator;


/**
 * Displays the additional information available for a completion proposal.
 * 
 * @since 2.0
 */
class AdditionalInfoController extends AbstractInformationControlManager implements Runnable {
	
	/**
	 * Internal table selection listener.
	 */
	private class TableSelectionListener implements SelectionListener {
		
		/*
		 * @see SelectionListener#widgetSelected(SelectionEvent)
		 */
		public void widgetSelected(SelectionEvent e) {
			handleTableSelectionChanged();
		}
		
		/*
		 * @see SelectionListener#widgetDefaultSelected(SelectionEvent)
		 */
		public void widgetDefaultSelected(SelectionEvent e) {
		}
	};
	
	
	/** The proposal table */
	private Table fProposalTable;
	/** The thread controlling the delayed display of the additional info */
	private Thread fThread;
	/** Indicates whether the display delay has been reset */
	private boolean fIsReset= false;
	/** Object to synchronize display thread and table selection changes */
	private Object fMutex= new Object();
	/** Object to synchronize initial display of additonal info */
	private Object fStartSignal;
	/** The table selection listener */
	private SelectionListener fSelectionListener= new TableSelectionListener();
	/** The delay after which additional information is displayed */
	private int fDelay;
	
	
	/**
	 * Creates a new additional information controller.
	 * 
	 * @param creator the information control creator to be used by this controller
	 * @param delay time in milliseconds after which additional info should be displayed
	 */
	AdditionalInfoController(IInformationControlCreator creator, int delay) {
		super(creator);
		fDelay= delay;
		setAnchor(ANCHOR_RIGHT);
		setFallbackAnchors(new Anchor[] { ANCHOR_LEFT, ANCHOR_BOTTOM, ANCHOR_RIGHT });
	}
	
	/*
	 * @see AbstractInformationControlManager#install(Control)
	 */
	public void install(Control control) {

		if (fProposalTable == control) {
			// already installed
			return;
		}
		
		super.install(control);
		
		Assert.isTrue(control instanceof Table);
		fProposalTable= (Table) control;
		fProposalTable.addSelectionListener(fSelectionListener);
		fThread= new Thread(this, JFaceTextMessages.getString("InfoPopup.info_delay_timer_name")); //$NON-NLS-1$
		
		fStartSignal= new Object();
		synchronized (fStartSignal) {
			fThread.start();
			try {
				// wait until thread is ready
				fStartSignal.wait();
			} catch (InterruptedException x) {
			}
		}
	}
	
	/*
	 * @see AbstractInformationControlManager#disposeInformationControl()
	 */	
	 public void disposeInformationControl() {
		
		if (fThread != null) {
			fThread.interrupt();
			fThread= null;
		}
		
		if (fProposalTable != null && !fProposalTable.isDisposed()) {
			fProposalTable.removeSelectionListener(fSelectionListener);
			fProposalTable= null;
		}
		
		super.disposeInformationControl();
	}
	
	/*
	 * @see java.lang.Runnable#run()
	 */
	public void run() {
		try {
			while (true) {
				
				synchronized (fMutex) {
					
					if (fStartSignal != null) {
						synchronized (fStartSignal) {
							fStartSignal.notifyAll();
							fStartSignal= null;
						}
					}
					
					// Wait for a selection event to occur.
					fMutex.wait();
					
					while (true) {
						fIsReset= false;
						// Delay before showing the popup.
						fMutex.wait(fDelay);
						if (!fIsReset)
							break;
					}
				}
				
				if (fProposalTable != null && !fProposalTable.isDisposed()) {
					fProposalTable.getDisplay().asyncExec(new Runnable() {
						public void run() {
							if (!fIsReset)
								showInformation();
						}
					});
				}
				
			}
		} catch (InterruptedException e) {
		}
		
		fThread= null;
	}
	
	/**
	 *Handles a change of the line selected in the associated selector.
	 */
	public void handleTableSelectionChanged() {
		
		if (fProposalTable != null && !fProposalTable.isDisposed() && fProposalTable.isVisible()) {
			synchronized (fMutex) {
				fIsReset= true;
				fMutex.notifyAll();
			}
		}
	}
			
	/*
	 * @see AbstractInformationControlManager#computeInformation()
	 */
	protected void computeInformation() {
		
		if (fProposalTable == null || fProposalTable.isDisposed())
			return;
			
		TableItem[] selection= fProposalTable.getSelection();
		if (selection != null && selection.length > 0) {
			
			TableItem item= selection[0];
			
			// compute information
			String information= null;
			Object d= item.getData();
			if (d instanceof ICompletionProposal) {
				ICompletionProposal p= (ICompletionProposal) d;
				information= p.getAdditionalProposalInfo();
			}
			
			// compute subject area
			setMargins(4, -1);
			Rectangle area= fProposalTable.getBounds();
			area.x= 0; // subject area is the whole subject control
			area.y= 0;
			
			// set information & subject area
			setInformation(information, area);
		}
	}
	
	/*
	 * @see org.eclipse.jface.text.AbstractInformationControlManager#computeSizeConstraints(Control, IInformationControl)
	 */
	protected Point computeSizeConstraints(Control subjectControl, IInformationControl informationControl) {
		Point sizeConstraint= super.computeSizeConstraints(subjectControl, informationControl);
		Point size= subjectControl.getSize();
		if (sizeConstraint.x < size.x)
			sizeConstraint.x= size.x;
		if (sizeConstraint.y < size.y)
			sizeConstraint.y= size.y;
		return sizeConstraint;
	}
}