from __future__ import annotations

import unittest

from PythonModels.components.amesim_pneumatic_line import AmesimPnl0001Pipe


class AmesimPnl0001PipeTests(unittest.TestCase):
    def setUp(self) -> None:
        self.pipe = AmesimPnl0001Pipe(
            name="pneumatic_96",
            diameter_mm=14.0,
            length_m=1.0,
            relative_roughness=0.045 / 14.0,
            p0=15.3e6,
            T0=293.15,
        )

    def test_initial_state_uses_real_pipe_volume_and_two_states(self) -> None:
        properties = self.pipe.properties()

        self.assertAlmostEqual(self.pipe.volume, 1.539380400258999e-4)
        self.assertEqual(len(self.pipe.get_state_vector()), 2)
        self.assertAlmostEqual(properties.p, 15.3e6, delta=1.0e-5)
        self.assertAlmostEqual(properties.T, 293.15)
        self.assertAlmostEqual(self.pipe.gas_mass_g(), 3.716965219188, places=10)

    def test_resistance_flow_follows_pressure_gradient(self) -> None:
        forward = self.pipe.resistance_mass_flow(
            port_1_pressure_pa=15.31e6,
            port_1_temperature_k=293.15,
        )
        reverse = self.pipe.resistance_mass_flow(
            port_1_pressure_pa=15.29e6,
            port_1_temperature_k=293.15,
        )

        self.assertGreater(forward, 0.0)
        self.assertLess(reverse, 0.0)
        self.assertAlmostEqual(abs(forward), abs(reverse), delta=abs(forward) * 0.01)

    def test_diagnostics_reproduce_laminar_friction_contract(self) -> None:
        diagnostics = self.pipe.diagnostics(mass_flow_kg_s=8.90603914774626e-6)

        self.assertGreater(diagnostics.reynolds_number, 40.0)
        self.assertLess(diagnostics.reynolds_number, 45.0)
        self.assertAlmostEqual(
            diagnostics.friction_factor,
            64.0 / diagnostics.reynolds_number,
        )
        self.assertGreater(diagnostics.gas_velocity_m_s, 0.0)
        self.assertGreater(diagnostics.pressure_drop_pa, 0.0)

    def test_connection_derivative_preserves_mass_and_stream_direction(self) -> None:
        internal = self.pipe.properties()
        derivative = self.pipe.derivatives_from_connections(
            port_1_m_flow=0.2,
            connected_h_1=internal.h + 1000.0,
            port_2_m_flow=-0.1,
            connected_h_2=internal.h - 1000.0,
        )

        self.assertAlmostEqual(derivative.m, 0.1)
        self.assertAlmostEqual(
            derivative.U,
            0.2 * (internal.h + 1000.0) - 0.1 * internal.h,
        )


if __name__ == "__main__":
    unittest.main()