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/*******************************************************************************
 * Copyright (c) 2008, 2019 SWTChart project.
 *
 * This program and the accompanying materials are made
 * available under the terms of the Eclipse Public License 2.0
 * which is available at https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 * 
 * Contributors:
 * yoshitaka - initial API and implementation
 *******************************************************************************/
package org.eclipse.swtchart.internal.compress;

import java.util.ArrayList;

/**
 * A compressor for scatter series data
 */
public class CompressScatterSeries extends Compress {

	/** the state indicating if line is visible */
	private boolean isLineVisible;
	/** flag indicating whether the grid is occupied */
	private boolean occupied[][];

	@Override
	protected void addNecessaryPlots(ArrayList xList, ArrayList yList, ArrayList indexList) {

		if(isLineVisible) {
			for(int i = 0; i < xSeries.length && i < ySeries.length; i++) {
				if(!isInSameGridAsPrevious(xSeries[i], ySeries[i])) {
					addToList(xList, yList, indexList, xSeries[i], ySeries[i], i);
				}
			}
		} else {
			int width = (int)config.getWidthInPixel();
			int height = (int)config.getHeightInPixel();
			if(width <= 0 || height <= 0) {
				return;
			}
			// initialize flag
			occupied = new boolean[width][height];
			for(int i = 0; i < xSeries.length && i < ySeries.length; i++) {
				if(xSeries[i] >= xLower && xSeries[i] <= xUpper && ySeries[i] >= yLower && ySeries[i] <= yUpper && !isOccupied(xSeries[i], ySeries[i])) {
					addToList(xList, yList, indexList, xSeries[i], ySeries[i], i);
				}
			}
		}
	}

	/**
	 * check if the grid is already occupied
	 * 
	 * @param x
	 *            the X coordinate
	 * @param y
	 *            the Y coordinate
	 * @return true if the grid is already occupied
	 */
	private boolean isOccupied(double x, double y) {

		int xGridIndex;
		int yGridIndex;
		// calculate the X grid index
		if(config.isXLogScale()) {
			double lower = Math.log10(config.getXLowerValue());
			double upper = Math.log10(config.getXUpperValue());
			xGridIndex = (int)((Math.log10(x) - lower) / (upper - lower) * config.getWidthInPixel());
		} else {
			xGridIndex = (int)((x - config.getXLowerValue()) / (config.getXUpperValue() - config.getXLowerValue()) * config.getWidthInPixel());
		}
		// calculate the Y grid index
		if(config.isYLogScale()) {
			double lower = Math.log10(config.getYLowerValue());
			double upper = Math.log10(config.getYUpperValue());
			yGridIndex = (int)((Math.log10(y) - lower) / (upper - lower) * config.getHeightInPixel());
		} else {
			yGridIndex = (int)((y - config.getYLowerValue()) / (config.getYUpperValue() - config.getYLowerValue()) * config.getHeightInPixel());
		}
		boolean isOccupied = occupied[xGridIndex][yGridIndex];
		occupied[xGridIndex][yGridIndex] = true;
		return isOccupied;
	}

	/**
	 * Sets the state indicating if the line is visible.
	 * 
	 * @param visible
	 *            the state indicating if the line is visible
	 */
	public void setLineVisible(boolean visible) {

		isLineVisible = visible;
	}
}