/*
 * Copyright (c) 2008 Stiftung Deutsches Elektronen-Synchrotron,
 * Member of the Helmholtz Association, (DESY), HAMBURG, GERMANY.
 *
 * THIS SOFTWARE IS PROVIDED UNDER THIS LICENSE ON AN "../AS IS" BASIS.
 * WITHOUT WARRANTY OF ANY KIND, EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED
 * TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR PARTICULAR PURPOSE AND
 * NON-INFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
 * FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR
 * THE USE OR OTHER DEALINGS IN THE SOFTWARE. SHOULD THE SOFTWARE PROVE DEFECTIVE
 * IN ANY RESPECT, THE USER ASSUMES THE COST OF ANY NECESSARY SERVICING, REPAIR OR
 * CORRECTION. THIS DISCLAIMER OF WARRANTY CONSTITUTES AN ESSENTIAL PART OF THIS LICENSE.
 * NO USE OF ANY SOFTWARE IS AUTHORIZED HEREUNDER EXCEPT UNDER THIS DISCLAIMER.
 * DESY HAS NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS,
 * OR MODIFICATIONS.
 * THE FULL LICENSE SPECIFYING FOR THE SOFTWARE THE REDISTRIBUTION, MODIFICATION,
 * USAGE AND OTHER RIGHTS AND OBLIGATIONS IS INCLUDED WITH THE DISTRIBUTION OF THIS
 * PROJECT IN THE FILE LICENSE.HTML. IF THE LICENSE IS NOT INCLUDED YOU MAY FIND A COPY
 * AT HTTP://WWW.DESY.DE/LEGAL/LICENSE.HTM
 */

package org.csstudio.sds.components.ui.internal.figures;

import java.util.List;

/**
 * Maps data values to display coordinates.
 * 
 * @author Joerg Rathlev
 */
final class LinearAxis implements IAxis {

	/**
	 * The lower bound of the data range of this axis.
	 */
	private double _dataLower;
	
	/**
	 * The upper bound of the data range of this axis.
	 */
	private double _dataUpper;
	
	/**
	 * The size of this axis in display units. 
	 */
	private int _displaySize;

	/**
	 * Creates a new axis.
	 * 
	 * @param dataLower
	 *            the lower bound of the data range.
	 * @param dataUpper
	 *            the upper bound of the data range.
	 * @param displaySize
	 *            the size of the display.
	 */
	LinearAxis(final double dataLower, final double dataUpper,
			final int displaySize) {
		if (displaySize < 0) {
			throw new IllegalArgumentException("Invalid display size");
		}

		_dataLower = dataLower;
		_dataUpper = dataUpper;
		_displaySize = displaySize;
	}

	/**
	 * {@inheritDoc}
	 */
	@Override
	public int valueToCoordinate(final double value) {
		double dataRange = _dataUpper - _dataLower;
		double scaling = (_displaySize - 1) / dataRange;

		long intermediate = Math.round((value - _dataLower) * scaling);
		// constrain the value to an integer value
		return intermediate > Integer.MAX_VALUE ? Integer.MAX_VALUE
				: (intermediate < Integer.MIN_VALUE ? Integer.MIN_VALUE
						: (int) intermediate);
	}
	
	/**
	 * Checks whether the specified value is a legal value for this axis. For
	 * a linear axis, all values except NaN are legal.
	 * 
	 * @param value
	 *            the data value to check.
	 * @return <code>true</code> if the value is legal, <code>false</code>
	 *         otherwise.
	 */
	@Override
	public boolean isLegalValue(final double value) {
		// Note: cannot use == or != operator here because NaN != NaN.
		return !Double.isNaN(value);
	}
	
	/**
	 * {@inheritDoc}
	 */
	@Override
	public List<Tick> calculateTicks(final int minMajorDistance,
			final int minMinorDistance) {
		
		// TODO: calculate minor tickmarks. TickCalculator calculates only
		// major tickmarks.
		
		TickCalculator calc = new TickCalculator();
		if (_dataLower < _dataUpper) {
			calc.setMinimumValue(_dataLower);
			calc.setMaximumValue(_dataUpper);
		} else {
			calc.setMinimumValue(_dataUpper);
			calc.setMaximumValue(_dataLower);
		}
		calc.setMaximumTickCount(_displaySize / minMajorDistance);
		return calc.calculateTicks();
	}
	
	/**
	 * {@inheritDoc}
	 */
	@Override
	public List<Tick> calculateIntegerTicks(final int minMajorDistance,
			final int minMinorDistance) {
		
		// TODO: calculate minor tickmarks. TickCalculator calculates only
		// major tickmarks.
		
		TickCalculator calc = new TickCalculator();
		if (_dataLower < _dataUpper) {
			calc.setMinimumValue(_dataLower);
			calc.setMaximumValue(_dataUpper);
		} else {
			calc.setMinimumValue(_dataUpper);
			calc.setMaximumValue(_dataLower);
		}
		calc.setMaximumTickCount(_displaySize / minMajorDistance);
		calc.setIntegerOnly(true);
		return calc.calculateTicks();
	}

	/**
	 * {@inheritDoc}
	 */
	@Override
	public void setDataRange(final double lower, final double upper) {
		_dataLower = lower;
		_dataUpper = upper;
	}

	/**
	 * {@inheritDoc}
	 */
	@Override
	public void setDisplaySize(final int size) {
		if (size < 0) {
			throw new IllegalArgumentException("Invalid display size");
		}

		_displaySize = size;
	}

}