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#include <gtest/gtest.h>

#include "AttitudeControlMath.hpp"

using namespace matrix;
using namespace AttitudeControlMath;

static const Vector3f z_unit(0.f, 0.f, 1.f);

TEST(AttitudeControlMath, tiltCorrectionNoError)
{
	// GIVEN: some desired (non yaw-rotated) tilt setpoint
	Quatf q_tilt_sp_ne(z_unit, Vector3f(-0.3, 0.1, 0.7));

	// AND: a desired yaw setpoint
	const Quatf q_sp_yaw = AxisAnglef(z_unit, -1.23f);

	// WHEN: the current yaw error is zero (regardless of the tilt)
	const Quatf q = q_sp_yaw * Quatf(z_unit, Vector3f(0.1f, -0.2f, 1.f));
	const Quatf q_tilt_sp_ne_before = q_tilt_sp_ne;
	correctTiltSetpointForYawError(q_tilt_sp_ne, q, q_sp_yaw);

	// THEN: the tilt setpoint is unchanged
	EXPECT_TRUE(isEqual(q_tilt_sp_ne_before, q_tilt_sp_ne));
}

TEST(AttitudeControlMath, tiltCorrectionYaw180)
{
	// GIVEN: some desired (non yaw-rotated) tilt setpoint and a desired yaw setpoint
	Quatf q_tilt_sp_ne(z_unit, Vector3f(-0.3, 0.1, 0.7));
	const Quatf q_sp_yaw = AxisAnglef(z_unit, -M_PI_F / 2.f);

	// WHEN: there is a yaw error of 180 degrees
	const Quatf q_yaw = Quatf(AxisAnglef(z_unit, M_PI_F / 2.f));
	const Quatf q = q_yaw * Quatf(z_unit, Vector3f(0.1f, -0.2f, 1.f));
	const Quatf q_tilt_sp_ne_before = q_tilt_sp_ne;
	correctTiltSetpointForYawError(q_tilt_sp_ne, q, q_sp_yaw);

	// THEN: the tilt is reversed (the corrected tilt angle is the same but the axis of rotation is opposite)
	EXPECT_FLOAT_EQ(AxisAnglef(q_tilt_sp_ne_before).angle(), AxisAnglef(q_tilt_sp_ne).angle());
	EXPECT_TRUE(isEqual(AxisAnglef(q_tilt_sp_ne_before).axis(), -AxisAnglef(q_tilt_sp_ne).axis()));
}

TEST(AttitudeControlMath, tiltCorrection)
{
	// GIVEN: some desired (non yaw-rotated) tilt setpoint and a desired yaw setpoint
	Quatf q_tilt_sp_ne(z_unit, Vector3f(0.5, -0.1, 0.7));
	const Quatf q_sp_yaw = AxisAnglef(z_unit, -1.23f);

	// WHEN: there is a some yaw error
	const Quatf q_yaw = Quatf(AxisAnglef(z_unit, 3.1f));
	const Quatf q = q_yaw * Quatf(z_unit, Vector3f(0.1f, -0.2f, 1.f));
	const Quatf q_tilt_sp_ne_before = q_tilt_sp_ne;
	correctTiltSetpointForYawError(q_tilt_sp_ne, q, q_sp_yaw);

	// THEN: the tilt vector obtained by rotating the corrected tilt by the yaw setpoint is the same as
	// the one obtained by rotating the initial tilt by the current yaw of the vehicle
	EXPECT_TRUE(isEqual((q_sp_yaw * q_tilt_sp_ne).dcm_z(), (q_yaw * q_tilt_sp_ne_before).dcm_z()));
}