/*
 *    Copyright (c) 2013, Will Szumski
 *    Copyright (c) 2013, Doug Szumski
 *
 *    This file is part of Cyclismo.
 *
 *    Cyclismo 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.
 *
 *    Cyclismo 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 Cyclismo.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.cowboycoders.turbotrainers.bushido.headunit;

import org.cowboycoders.turbotrainers.DataPacketProvider;
import org.cowboycoders.turbotrainers.Parameters;
import org.cowboycoders.turbotrainers.Parameters.CommonParametersInterface;
import org.cowboycoders.turbotrainers.bushido.BushidoUtils;


/**
 * Provides data packets for setting the slope and weight on the Bushido Head unit
 *
 * Slope and weight are sent to the Bushido head unit via the PC interface in the
 * same data packet. This data packet starts with DC01.
 *
 * @author will
 */
public class BushidoTargetSlopeModel extends AbstractBushidoModel {

  //The slope is set in the following bytes of the DC01 packet:
  private static final int SLOPE_BYTE_1 = 3;
  private static final int SLOPE_BYTE_2 = 4;
  //The slope is sent in the format percentage * 10
  private static final int SLOPE_MULTIPLIER = 10;
  // The slope is bounded within this range:
  private static final double SLOPE_MAX = 20.0;
  private static final double SLOPE_MIN = -5.0;
  //The weight is set in this byte of the DC01 packet
  private static final int WEIGHT_BYTE = 5;

  /**
   * Provides a data packet into which the current slope and weight are injected
   */
  DataPacketProvider slopeProvider = new DataPacketProvider() {

    @Override
    public byte[] getDataPacket() {
      byte[] dc01Packet = BushidoUtils.getDc01Prototype();
      dc01Packet = injectSlope(dc01Packet);
      dc01Packet = injectWeight(dc01Packet);
      return dc01Packet;
    }

  };

  private double slope;

  // Packets are to be sent in this sequence
  {
    addPacketProvider(slopeProvider);
    addPacketProvider(keepAliveProvider);
  }

  // Set slope bits in the packet
  private byte[] injectSlope(byte[] dc01Packet) {
    double slope = getSlope();
    if (slope < 0) {
      dc01Packet[SLOPE_BYTE_1] = (byte) 0xFF;
      dc01Packet[SLOPE_BYTE_2] = (byte) (256 + slope * SLOPE_MULTIPLIER);
    } else {
      dc01Packet[SLOPE_BYTE_2] = (byte) (slope * SLOPE_MULTIPLIER);
    }

    return dc01Packet;
  }

  // Sets weight bits in a packet
  private byte[] injectWeight(byte[] dc01Packet) {
    dc01Packet[WEIGHT_BYTE] = (byte) getTotalWeight();
    return dc01Packet;
  }


  @Override
  public void setParameters(CommonParametersInterface parameters)
      throws IllegalArgumentException {
    Parameters.TargetSlope castParameters = null;
    try {
      castParameters = (Parameters.TargetSlope) parameters;
    } catch (ClassCastException e) {
      throw new IllegalArgumentException("Expecting target slope", e);
    }
    setTotalWeight(castParameters.getTotalWeight());
    setSlope(castParameters.getSlope());

  }

  public double getSlope() {
    return slope;
  }

  public void setSlope(double slope) {
    slope = getBoundedSlope(slope);
    this.slope = slope;
  }

  private double getBoundedSlope(double slope) {
    if (slope > SLOPE_MAX) {
      return SLOPE_MAX;
    }
    if (slope < -SLOPE_MIN) {
      return -SLOPE_MIN;
    }
    return slope;
  }

}