/*----------------------------------------------------------------------------*/
/* Copyright (c) 2008-2018 FIRST. All Rights Reserved.                        */
/* Open Source Software - may be modified and shared by FRC teams. The code   */
/* must be accompanied by the FIRST BSD license file in the root directory of */
/* the project.                                                               */
/*----------------------------------------------------------------------------*/

#pragma once

#include <memory>

#include <HAL/Types.h>
#include <wpi/raw_ostream.h>

#include "ErrorBase.h"
#include "MotorSafety.h"
#include "SmartDashboard/SendableBase.h"

namespace frc {

class MotorSafetyHelper;

/**
 * Class for Spike style relay outputs.
 *
 * Relays are intended to be connected to spikes or similar relays. The relay
 * channels controls a pair of pins that are either both off, one on, the other
 * on, or both on. This translates into two spike outputs at 0v, one at 12v and
 * one at 0v, one at 0v and the other at 12v, or two spike outputs at 12V. This
 * allows off, full forward, or full reverse control of motors without variable
 * speed. It also allows the two channels (forward and reverse) to be used
 * independently for something that does not care about voltage polarity (like
 * a solenoid).
 */
class Relay : public MotorSafety, public ErrorBase, public SendableBase {
 public:
  enum Value { kOff, kOn, kForward, kReverse };
  enum Direction { kBothDirections, kForwardOnly, kReverseOnly };

  /**
   * Relay constructor given a channel.
   *
   * This code initializes the relay and reserves all resources that need to be
   * locked. Initially the relay is set to both lines at 0v.
   *
   * @param channel   The channel number (0-3).
   * @param direction The direction that the Relay object will control.
   */
  explicit Relay(int channel, Direction direction = kBothDirections);

  /**
   * Free the resource associated with a relay.
   *
   * The relay channels are set to free and the relay output is turned off.
   */
  ~Relay() override;

  /**
   * Set the relay state.
   *
   * Valid values depend on which directions of the relay are controlled by the
   * object.
   *
   * When set to kBothDirections, the relay can be any of the four states:
   * 0v-0v, 0v-12v, 12v-0v, 12v-12v
   *
   * When set to kForwardOnly or kReverseOnly, you can specify the constant for
   * the direction or you can simply specify kOff and kOn.  Using only kOff and
   * kOn is recommended.
   *
   * @param value The state to set the relay.
   */
  void Set(Value value);

  /**
   * Get the Relay State
   *
   * Gets the current state of the relay.
   *
   * When set to kForwardOnly or kReverseOnly, value is returned as kOn/kOff not
   * kForward/kReverse (per the recommendation in Set).
   *
   * @return The current state of the relay as a Relay::Value
   */
  Value Get() const;

  int GetChannel() const;

  /**
   * Set the expiration time for the Relay object.
   *
   * @param timeout The timeout (in seconds) for this relay object
   */
  void SetExpiration(double timeout) override;

  /**
   * Return the expiration time for the relay object.
   *
   * @return The expiration time value.
   */
  double GetExpiration() const override;

  /**
   * Check if the relay object is currently alive or stopped due to a timeout.
   *
   * @return a bool value that is true if the motor has NOT timed out and should
   *         still be running.
   */
  bool IsAlive() const override;

  /**
   * Stop the motor associated with this PWM object.
   *
   * This is called by the MotorSafetyHelper object when it has a timeout for
   * this relay and needs to stop it from running.
   */
  void StopMotor() override;

  /**
   * Enable/disable motor safety for this device.
   *
   * Turn on and off the motor safety option for this relay object.
   *
   * @param enabled True if motor safety is enforced for this object
   */
  void SetSafetyEnabled(bool enabled) override;

  /**
   * Check if motor safety is enabled for this object.
   *
   * @returns True if motor safety is enforced for this object
   */
  bool IsSafetyEnabled() const override;

  void GetDescription(wpi::raw_ostream& desc) const override;

  void InitSendable(SendableBuilder& builder) override;

 private:
  int m_channel;
  Direction m_direction;

  HAL_RelayHandle m_forwardHandle = HAL_kInvalidHandle;
  HAL_RelayHandle m_reverseHandle = HAL_kInvalidHandle;

  std::unique_ptr<MotorSafetyHelper> m_safetyHelper;
};

}  // namespace frc