/*******************************************************************************
 * Copyright (c) 2012 xored software, Inc. 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:
 * xored software, Inc. - initial API and implementation (Yuri Strot)
 ******************************************************************************/
package com.xored.glance.ui.controls.text.styled;

import com.xored.glance.ui.sources.Match;

import org.eclipse.jface.text.Region;
import org.eclipse.swt.events.FocusEvent;
import org.eclipse.swt.events.FocusListener;
import org.eclipse.swt.widgets.Control;

/**
 * For all rich text components we remove native selection (make it empty) to draw our own colorful
 * current match. However if focus was moved back to text component, selection should be drawn as
 * usually. TextSelector manages this behavior.
 * 
 * @author Yuri Strot
 */
public abstract class TextSelector implements FocusListener {

  private Match match;

  public void dispose() {
    getControl().removeFocusListener(this);
    showSelection();
  }

  @Override
  public void focusGained(FocusEvent e) {
//    showSelection();
  }

  @Override
  public void focusLost(FocusEvent e) {
//    hideSelection();
  }

  public void setMatch(Match match) {
    this.match = match;
    if (match != null) {
      reveal(match.getOffset(), match.getLength());
    }
  }

  protected abstract Control getControl();

  protected abstract Region getSelection();

  protected void init() {
    getControl().addFocusListener(this);
    hideSelection();
  }

  protected abstract void reveal(int offset, int length);

  protected abstract void setSelection(int offset, int length);

  private void hideSelection() {
    Region region = getSelection();
    setSelection(region.getOffset() + region.getLength(), 0);
  }

  private void showSelection() {
    if (match != null) {
      setSelection(match.getOffset(), match.getLength());
    }
  }

}