//
//  angle_test.cxx
//  math-test
//
//  Created by Sam Jaffe on 6/1/19.
//  Copyright © 2019 Sam Jaffe. All rights reserved.
//

#include "game/math/angle.hpp"

#include <testing/xcode_gtest_helper.h>

using testing::DoubleNear;
using testing::Eq;

TEST(RadianTest, Negation) {
  math::radian radians{M_PI};
  EXPECT_THAT((-radians).value, -M_PI);
  EXPECT_THAT((-(-radians)).value, radians.value);
}

TEST(DegreeTest, Negation) {
  math::degree degrees{180.0};
  EXPECT_THAT((-degrees).value, -180.0);
  EXPECT_THAT((-(-degrees)).value, degrees.value);
}

// Degree -> Radian
TEST(RadianTest, ZeroDegreeIsZeroRadian) {
  math::degree degrees{0};
  EXPECT_THAT(math::radian{degrees}.value, Eq(0.0));
}

TEST(RadianTest, OneRadianIsAbout57Degrees) {
  math::degree degrees{57.2957795131};
  EXPECT_THAT(math::radian{degrees}.value, DoubleNear(1, 1E-10));
}

TEST(RadianTest, OneEightyDegreeIsPiRadians) {
  math::degree degrees{180};
  EXPECT_THAT(math::radian{degrees}.value, DoubleNear(M_PI, 1E-12));
}

TEST(RadianTest, NinetyDegreeIsHalfPiRadians) {
  math::degree degrees{90};
  EXPECT_THAT(math::radian{degrees}.value, DoubleNear(M_PI_2, 1E-12));
}

// Radian -> Degree
TEST(DegreeTest, ZeroDegreeIsZeroRadian) {
  math::radian radians{0};
  EXPECT_THAT(math::degree{radians}.value, Eq(0.0));
}

TEST(DegreeTest, OneRadianIsAbout57Degrees) {
  math::radian radians{1.0};
  // 1E-10 because that's how many digits I wrote down
  EXPECT_THAT(math::degree{radians}.value, DoubleNear(57.2957795131, 1E-10));
}

TEST(DegreeTest, OneEightyDegreeIsPiRadians) {
  math::radian radians{M_PI};
  EXPECT_THAT(math::degree{radians}.value, DoubleNear(180.0, 1E-12));
}

TEST(DegreeTest, NinetyDegreeIsHalfPiRadians) {
  math::radian radians{M_PI_2};
  EXPECT_THAT(math::degree{radians}.value, DoubleNear(90, 1E-12));
}

// Trigonometry
struct TrigonometryTest : testing::TestWithParam<double> {};

TEST_P(TrigonometryTest, SinRadianIsSinDouble) {
  double const angle = GetParam();
  math::radian rad{angle};
  EXPECT_THAT(sin(rad), sin(angle));
}

TEST_P(TrigonometryTest, CosRadianIsCosDouble) {
  double const angle = GetParam();
  math::radian rad{angle};
  EXPECT_THAT(cos(rad), cos(angle));
}

TEST_P(TrigonometryTest, TanRadianIsTanDouble) {
  double const angle = GetParam();
  math::radian rad{angle};
  EXPECT_THAT(tan(rad), tan(angle));
}

using testing::Values;
INSTANTIATE_TEST_SUITE_P(MapsToRawValue, TrigonometryTest,
                         Values(0.0, M_PI_4, M_PI_2, 3 * M_PI_4, M_PI,
                                5 * M_PI_4, 3 * M_PI_2, 7 * M_PI_4, 2 * M_PI));