/*----------------------------------------------------------------------------*/
/* Copyright (c) 2014-2019 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.                                                               */
/*----------------------------------------------------------------------------*/

#include "frc/Timer.h"
#include "frc/controller/PIDController.h"
#include "gtest/gtest.h"

using namespace frc;

class PIDToleranceTest : public testing::Test {
 protected:
  const double setpoint = 50.0;
  const double range = 200;
  const double tolerance = 10.0;

  class FakeInput {
   public:
    double val = 0;

    double Get() { return val; }
  };

  class FakeOutput {
   public:
    void Set(double output) {}
  };

  FakeInput inp;
  FakeOutput out;
  frc2::PIDController* pidController;

  void SetUp() override {
    pidController = new frc2::PIDController(0.5, 0.0, 0.0);
    pidController->SetInputRange(-range / 2, range / 2);
  }

  void TearDown() override { delete pidController; }

  void Reset() { inp.val = 0; }
};

TEST_F(PIDToleranceTest, Initial) { EXPECT_FALSE(pidController->AtSetpoint()); }

TEST_F(PIDToleranceTest, Absolute) {
  Reset();

  pidController->SetAbsoluteTolerance(tolerance);
  pidController->SetSetpoint(setpoint);

  EXPECT_FALSE(pidController->AtSetpoint())
      << "Error was in tolerance when it should not have been. Error was "
      << pidController->GetError();

  inp.val = setpoint + tolerance / 2;
  for (int i = 0; i <= 50; i++) {
    pidController->Calculate(inp.Get());
  }

  EXPECT_TRUE(pidController->AtSetpoint())
      << "Error was not in tolerance when it should have been. Error was "
      << pidController->GetError();

  inp.val = setpoint + 10 * tolerance;
  for (int i = 0; i <= 50; i++) {
    pidController->Calculate(inp.Get());
  }

  EXPECT_FALSE(pidController->AtSetpoint())
      << "Error was in tolerance when it should not have been. Error was "
      << pidController->GetError();
}

TEST_F(PIDToleranceTest, Percent) {
  Reset();

  pidController->SetPercentTolerance(tolerance);
  pidController->SetSetpoint(setpoint);

  EXPECT_FALSE(pidController->AtSetpoint())
      << "Error was in tolerance when it should not have been. Error was "
      << pidController->GetError();

  inp.val =
      setpoint + (tolerance) / 200 *
                     range;  // half of percent tolerance away from setpoint
  for (int i = 0; i <= 50; i++) {
    pidController->Calculate(inp.Get());
  }

  EXPECT_TRUE(pidController->AtSetpoint())
      << "Error was not in tolerance when it should have been. Error was "
      << pidController->GetError();

  inp.val =
      setpoint +
      (tolerance) / 50 * range;  // double percent tolerance away from setPoint

  for (int i = 0; i <= 50; i++) {
    pidController->Calculate(inp.Get());
  }

  EXPECT_FALSE(pidController->AtSetpoint())
      << "Error was in tolerance when it should not have been. Error was "
      << pidController->GetError();
}