package org.openstreetmap.josm.actions.mapmode;

import java.awt.Rectangle;
import java.awt.event.KeyEvent;
import java.util.Collection;

import org.openstreetmap.josm.data.osm.OsmPrimitive;
import org.openstreetmap.josm.gui.MapFrame;
import org.openstreetmap.josm.gui.SelectionManager;
import org.openstreetmap.josm.gui.SelectionManager.SelectionEnded;

/**
 * This MapMode enables the user to easy make a selection of different objects.
 * 
 * The selected objects are drawn in a different style.
 * 
 * Holding and dragging the left mouse button draws an selection rectangle. 
 * When releasing the left mouse button, all objects within the rectangle get 
 * selected. 
 * 
 * When releasing the left mouse button while the right mouse button pressed,
 * nothing happens (the selection rectangle will be cleared, however).
 *
 * When releasing the mouse button and one of the following keys was hold:
 *
 * If Alt key was hold, select all objects that are touched by the 
 * selection rectangle. If the Alt key was not hold, select only those objects 
 * completly within (e.g. for tracks mean: only if all nodes of the track are 
 * within).  
 *
 * If Shift key was hold, the objects are added to the current selection. If
 * Shift key wasn't hold, the current selection get replaced.
 * 
 * If Ctrl key was hold, remove all objects under the current rectangle from
 * the active selection (if there were any). Nothing is added to the current
 * selection.
 *
 * Alt can be combined with Ctrl or Shift. Ctrl and Shift cannot be combined.
 * If both are pressed, nothing happens when releasing the mouse button.
 *
 * The user can also only click on the map. All total movements of 2 or less 
 * pixel are considered "only click". If that happens, the nearest Node will
 * be selected if there is any within 10 pixel range. If there is no Node within
 * 10 pixel, the nearest LineSegment (or Street, if user hold down the Alt-Key)
 * within 10 pixel range is selected. If there is no LineSegment within 10 pixel
 * and the user clicked in or 10 pixel away from an area, this area is selected. 
 * If there is even no area, nothing is selected. Shift and Ctrl key applies to 
 * this as usual. For more, @see MapView#getNearest(Point, boolean)
 *
 * @author imi
 */
public class SelectionAction extends MapMode implements SelectionEnded {

	/**
	 * The SelectionManager that manages the selection rectangle.
	 */
	private SelectionManager selectionManager;

	/**
	 * Create a new SelectionAction in the given frame.
	 * @param mapFrame The frame this action belongs to
	 */
	public SelectionAction(MapFrame mapFrame) {
		super("Selection", "selection", "Select objects by dragging or clicking", KeyEvent.VK_S, mapFrame);
		this.selectionManager = new SelectionManager(this, false, mv);
	}

	@Override
	public void registerListener() {
		super.registerListener();
		selectionManager.register(mv);
	}

	@Override
	public void unregisterListener() {
		super.unregisterListener();
		selectionManager.unregister(mv);
	}


	/**
	 * Check the state of the keys and buttons and set the selection accordingly.
	 */
	public void selectionEnded(Rectangle r, boolean alt, boolean shift, boolean ctrl) {
		if (shift && ctrl)
			return; // not allowed together

		if (!ctrl && !shift)
			ds.clearSelection(); // new selection will replace the old.

		Collection<OsmPrimitive> selectionList = selectionManager.getObjectsInRectangle(r,alt);
		for (OsmPrimitive osm : selectionList)
			osm.setSelected(!ctrl, ds);
		mv.repaint();
	}
}