/*----------------------------------------------------------------------------*/
/* Copyright (c) 2019-2020 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 <functional>
#include <initializer_list>

#include <frc/trajectory/TrapezoidProfile.h>
#include <wpi/ArrayRef.h>

#include "frc2/Timer.h"
#include "frc2/command/CommandBase.h"
#include "frc2/command/CommandHelper.h"

namespace frc2 {
/**
 * A command that runs a TrapezoidProfile.  Useful for smoothly controlling
 * mechanism motion.
 *
 * @see TrapezoidProfile
 */
template <class Distance>
class TrapezoidProfileCommand
    : public CommandHelper<CommandBase, TrapezoidProfileCommand<Distance>> {
  using Distance_t = units::unit_t<Distance>;
  using Velocity =
      units::compound_unit<Distance, units::inverse<units::seconds>>;
  using Velocity_t = units::unit_t<Velocity>;
  using State = typename frc::TrapezoidProfile<Distance>::State;

 public:
  /**
   * Creates a new TrapezoidProfileCommand that will execute the given
   * TrapezoidalProfile. Output will be piped to the provided consumer function.
   *
   * @param profile The motion profile to execute.
   * @param output  The consumer for the profile output.
   */
  TrapezoidProfileCommand(frc::TrapezoidProfile<Distance> profile,
                          std::function<void(State)> output,
                          std::initializer_list<Subsystem*> requirements)
      : m_profile(profile), m_output(output) {
    this->AddRequirements(requirements);
  }

  /**
   * Creates a new TrapezoidProfileCommand that will execute the given
   * TrapezoidalProfile. Output will be piped to the provided consumer function.
   *
   * @param profile The motion profile to execute.
   * @param output  The consumer for the profile output.
   */
  TrapezoidProfileCommand(frc::TrapezoidProfile<Distance> profile,
                          std::function<void(State)> output,
                          wpi::ArrayRef<Subsystem*> requirements = {})
      : m_profile(profile), m_output(output) {
    this->AddRequirements(requirements);
  }

  void Initialize() override {
    m_timer.Reset();
    m_timer.Start();
  }

  void Execute() override { m_output(m_profile.Calculate(m_timer.Get())); }

  void End(bool interrupted) override { m_timer.Stop(); }

  bool IsFinished() override {
    return m_timer.HasElapsed(m_profile.TotalTime());
  }

 private:
  frc::TrapezoidProfile<Distance> m_profile;
  std::function<void(State)> m_output;

  Timer m_timer;
};

}  // namespace frc2
