/**
 * Copyright (C) 2010-14 diirt developers. See COPYRIGHT.TXT
 * All rights reserved. Use is subject to license terms. See LICENSE.TXT
 */
package org.diirt.datasource.sim;

import org.diirt.vtype.VDouble;
import static org.diirt.vtype.ValueFactory.*;
import java.time.Instant;

/**
 * Function to simulate a signal shaped like a sine. The warning
 * limits are set at 80% of the range and the alarm at 90% the range.
 * All values are going to have no alarm status, with the timestamp set at the
 * moment the sample was generated.
 *
 * @author carcassi
 */
public class Sine extends SimFunction<VDouble> {

    private double min;
    private double max;
    private long currentValue;
    private double samplesPerCycle;
    private double range;
    private VDouble lastValue;

    /**
     * Creates a sine shaped signal between min and max, updating
     * every interval seconds with samplesPerCycles samples every full sine cycle.
     *
     * @param min minimum value
     * @param max maximum value
     * @param samplesPerCycle number of samples for each full cycle (each 2 Pi)
     * @param secondsBeetwenSamples interval between samples in seconds
     */
    public Sine(Double min, Double max, Double samplesPerCycle, Double secondsBeetwenSamples) {
        super(secondsBeetwenSamples, VDouble.class);
        this.min = min;
        this.max = max;
        this.currentValue = 0;
        this.samplesPerCycle = samplesPerCycle;
        range = this.max - this.min;
        lastValue = newVDouble(0.0, alarmNone(), timeNow(),
                newDisplay(min, min + range * 0.1, min + range * 0.2, "x", Constants.DOUBLE_FORMAT,
                min + range * 0.8, min + range * 0.9, max, min, max));
    }

    /**
     * Creates a sine shaped signal between min and max, updating
     * every interval seconds with 10 samples every full sine cycle.
     *
     * @param min minimum value
     * @param max maximum value
     * @param secondsBeetwenSamples interval between samples in seconds
     */
    public Sine(Double min, Double max, Double secondsBeetwenSamples) {
        this(min, max, 10.0, secondsBeetwenSamples);
    }

    /**
     * Creates a sine shaped signal between -5 and 5, updating
     * every second with 10 samples every full sine cycle.
     */
    public Sine() {
        this(-5.0, 5.0, 1.0);
    }

    @Override
    VDouble nextValue() {
        double value = Math.sin(currentValue * 2 * Math.PI /samplesPerCycle) * range / 2 + min + (range / 2);
        currentValue++;

        return newValue(value, lastValue);
    }
}