/*******************************************************************************
 * Copyright (c) 2010 Attila Kovacs <attila_kovacs@post.harvard.edu>.
 * All rights reserved. 
 * 
 * This file is part of crush.
 * 
 *     crush is free software: you can redistribute it and/or modify
 *     it under the terms of the GNU General Public License as published by
 *     the Free Software Foundation, either version 3 of the License, or
 *     (at your option) any later version.
 * 
 *     crush is distributed in the hope that it will be useful,
 *     but WITHOUT ANY WARRANTY; without even the implied warranty of
 *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *     GNU General Public License for more details.
 * 
 *     You should have received a copy of the GNU General Public License
 *     along with crush.  If not, see <http://www.gnu.org/licenses/>.
 * 
 * Contributors:
 *     Attila Kovacs <attila_kovacs@post.harvard.edu> - initial API and implementation
 ******************************************************************************/
// Copyright (c) 2009 Attila Kovacs 

package crush.array;


import crush.*;
import util.*;

public abstract class RotatingArray<PixelType extends SimplePixel> extends MonoArray<PixelType> {
	/**
	 * 
	 */
	private static final long serialVersionUID = 2271933035438315377L;
	
	public RotatingArray(String name, int size) {
		super(name, size);
	}

	public RotatingArray(String name) {
		super(name);
	}
	
	public abstract Vector2D getPointingCenterOffset();
	
	public abstract double getRotation();
	
	@Override
	public void loadChannelData() {
		super.loadChannelData();
		
		if(hasOption("rotation")) {
			double rotation = option("rotation").getDouble() * Unit.deg;
			for(PixelType pixel : this) pixel.position.rotate(rotation);
		}
	}
	
	@Override
	public void setReferencePosition(Vector2D position) {
		super.setReferencePosition(position);
		appliedRotation = 0.0;
		rotate(getRotation());
	}
	
	// Returns the offset of the pointing center from the the rotation center for a given rotation...
	private Vector2D getPointingOffset(double rotationAngle) {
		Vector2D offset = new Vector2D();
		
		final double sinA = Math.sin(rotationAngle);
		final double cosA = Math.cos(rotationAngle);
		
		if(mount == Mount.CASSEGRAIN) {
			Vector2D dP = getPointingCenterOffset();	
			offset.x = dP.x * (1.0 - cosA) + dP.y * sinA;
			offset.y += dP.x * sinA + dP.y * (1.0 - cosA);
		}
		return offset;
	}
	
	
	// How about different pointing and rotation centers?...
	// If assuming that pointed at rotation a0 and observing at a
	// then the pointing center will rotate by (a-a0) on the array rel. to the rotation
	// center... (dP is the pointing rel. to rotation vector)
	// i.e. the effective array offsets change by:
	//	dP - dP.rotate(a-a0)

	// For Cassegrain assume pointing at zero rotation (a0 = 0.0)
	// For Nasmyth assume pointing at same elevation (a = a0)
	protected double appliedRotation = 0.0;
	
	protected void rotate(double angle) {
		// Undo the prior rotation...
		Vector2D priorOffset = getPointingOffset(appliedRotation);
		Vector2D newOffset = getPointingOffset(angle);
		
		for(SimplePixel pixel : this) {
			// Center positions on the rotation center...
			pixel.position.subtract(priorOffset);
			// Do the rotation...
			pixel.position.rotate(angle - appliedRotation);
			// Re-center on the pointing center...
			pixel.position.add(newOffset);
		}
		
		appliedRotation = angle;
	}

}
