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#include <gtest/gtest.h>
#include "StickYaw.hpp"

#include <px4_platform_common/defines.h>

TEST(StickYawTest, UnaidedYawNanTransitionNoYawJump)
{
	// When unaided_yaw transitions from finite to NAN mid-flight,
	// the yaw setpoint must not jump discontinuously.
	// See: https://github.com/PX4/PX4-Autopilot/pull/25710

	param_control_autosave(false);

	StickYaw stick_yaw{nullptr};
	float yawspeed_sp = 0.f;
	float yaw_sp = NAN;
	const float dt = 0.01f;

	// Phase 1: Establish yaw lock at yaw=0 with unaided_yaw=0
	stick_yaw.reset(0.f, 0.f);

	for (int i = 0; i < 10; i++) {
		stick_yaw.generateYawSetpoint(yawspeed_sp, yaw_sp, 0.f, 0.f, dt, 0.f);
	}

	EXPECT_NEAR(yaw_sp, 0.f, 0.01f);

	// Phase 2: Simulate EKF yaw correction — yaw jumps to 0.3 rad while
	// unaided_yaw stays at 0. This creates a yaw_error of 0.3 and triggers
	// the convergence detector, building up _yaw_correction ≈ 0.3.
	for (int i = 0; i < 5; i++) {
		stick_yaw.generateYawSetpoint(yawspeed_sp, yaw_sp, 0.f, 0.3f, dt, 0.f);
	}

	const float yaw_sp_before = yaw_sp;
	ASSERT_TRUE(PX4_ISFINITE(yaw_sp_before));

	// Phase 3: unaided_yaw becomes NAN — yaw setpoint must not jump.
	stick_yaw.generateYawSetpoint(yawspeed_sp, yaw_sp, 0.f, 0.3f, dt, NAN);

	EXPECT_NEAR(yaw_sp, yaw_sp_before, 0.01f)
			<< "Yaw setpoint jumped from " << yaw_sp_before << " to " << yaw_sp
			<< " when unaided_yaw became NAN";
}