/*
 * %W% %E% Dymik739
 * Email: dymik739@109.86.70.81
 *
 * Copyright (C) 2023 FIOT Dev Team
 *
 * This program 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.
 *
 * This program 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 this program.  If not, see <https://www.gnu.org/licenses/>.
 */

/**
 * Class which represents a server rack.
 *
 * @author Dymik739
 * @since 0.3
 */
public class ServerRack extends Appliance {
    /** Defines power used by the rack at lowest temperature. */
    private float basePower = 160.0f;

    /** Defines power limit for this rack */
    private float maxPower = 350.0f;

    /** Contains the inner temperature of this rack */
    private float temperature = 20f;

    /** Defines current usage of this device */
    private float currentLoad = 0.2f;

    /** Predicts the future change of the load */
    private float loadVector = +1f;

    /**
     * Constructor for this class.
     *
     * @param plugged defines if the device is plugged in at the start
     */
    public ServerRack(boolean plugged) {
        super(plugged);
        super.setType("ServerRack");
    }

    /**
     * Method for simulating this device behaviour.
     * This rack processes video segments for the streaming platform and
     * serves them to the public in different qualities. Every device requires
     * the fragments to be encoded in it's respective format in order to play
     * the stream. As such, the load rises when new fragment arrives and falls
     * as it converts it into all the formats required.
     *
     * Temperature depends on many factors. Firstly, the device heats up while
     * performing tasks and the rate is affected by:
     * - current temperature (hotter = more power drawn);
     * - load on the CPU (more load = more heat);
     *
     * Of course, the temperature can be reduced using the vent installed in
     * the house. The rate of reduction is calculated using:
     * - current temperature (the bigger the difference compared to the outside
     *   temperature, the larger impact the vent has on it);
     * - air flow, created by the vent (the faster the air moves, the more
     *   heat it takes away from the system);
     *
     * This device can also cool itself down while standing still as the heat
     * slowly transfers to the air even when the vent doesn't force it.
     * The rate is calculated by only the temperature difference between inner
     * and outer temperatures.
     *
     * @param seconds delta time to simulate for
     * @param ventRPM air flow created by the vent
     */
    public void step(float seconds, float ventRPM) {
        currentLoad += loadVector/10 * seconds;

        if (currentLoad >= 1) {
            loadVector = -1f;
        } else if (currentLoad <= 0.2) {
            loadVector = +1f;
        }

        if (super.getPowerState()) {
            temperature += min(basePower + (temperature - 20f) * 1.8f
                    * max(min(currentLoad, 1), 0), maxPower) * seconds
                    * 0.024f;
        }

        temperature -= (temperature - 20f) * ventRPM * 0.00013f * seconds;
        temperature -= 0.002f * (temperature - 20f) * seconds;
    }

    /**
     * Method which calculates power consumption if this device.
     *
     * @return power consumption of this device
     */
    public float getPowerConsumption() {
        if (super.getPowerState()) {
            return min(basePower + (temperature - 20f) * 1.8f * max(min(currentLoad, 1), 0), maxPower);
        } else {
            return 0f;
        }
    }

    /**
     * Overridden toString() method for printing the state of this device.
     *
     * @return String representing current state of this device
     */
    @Override
    public String toString() {
        return String.format("ServerRack(%s, %4.1fW, %3.1f℃C, %3.1f%%)",
                super.getPowerState() ? "on" : "off", getPowerConsumption(),
                temperature, currentLoad * 100);
    }
}