"""
Tests for neutrino mass functionality in CLI and configuration.
"""

import numpy as np
from beta_spectrum.spectrum import SpectrumConfig
from beta_spectrum.components.phase_space import PhaseSpace


class TestNeutrinoMassConfig:
    """Test neutrino mass parameter in SpectrumConfig."""

    def test_neutrino_mass_default_value(self):
        """Test that neutrino_mass_MeV defaults to 0.0 in SpectrumConfig."""
        config = SpectrumConfig(
            Z_parent=43,
            Z_daughter=44,
            A_number=99,
            endpoint_MeV=0.2111,
            transition_type="F2",
            e_step_MeV=0.001,
        )
        assert config.neutrino_mass_MeV == 0.0, "Default neutrino mass should be 0.0"

    def test_neutrino_mass_custom_value(self):
        """Test that neutrino_mass_MeV can be set to a custom value."""
        config = SpectrumConfig(
            Z_parent=43,
            Z_daughter=44,
            A_number=99,
            endpoint_MeV=0.2111,
            transition_type="F2",
            e_step_MeV=0.001,
            neutrino_mass_MeV=0.01,
        )
        assert config.neutrino_mass_MeV == 0.01, "Neutrino mass should be 0.01 MeV"


class TestNeutrinoMassPhaseSpace:
    """Test neutrino mass parameter in PhaseSpace component."""

    def test_phase_space_neutrino_mass_parameter(self):
        """Test that PhaseSpace accepts and uses neutrino mass parameter."""
        ps = PhaseSpace(W0=5.0, transition_type="A", m_nu=0.01)
        assert ps.m_nu == 0.01, "PhaseSpace should store neutrino mass parameter"

    def test_phase_space_neutrino_mass_effect(self):
        """Test that neutrino mass affects the phase space calculation."""
        ps_zero = PhaseSpace(W0=5.0, transition_type="A", m_nu=0.0)
        ps_massive = PhaseSpace(W0=5.0, transition_type="A", m_nu=0.1)

        # Test near endpoint where neutrino mass effect should be visible
        W_near_endpoint = np.array([4.8])  # W₀−W = 0.2 > m_nu=0.1

        val_zero = ps_zero(W_near_endpoint)[0]
        val_massive = ps_massive(W_near_endpoint)[0]

        assert not np.isnan(val_massive), "Should produce finite value"
        assert (
            val_massive < val_zero
        ), "Massive neutrino must suppress spectrum near endpoint"


class TestCLIArguments:
    """Test CLI argument parsing for neutrino mass."""

    def test_neutrino_mass_cli_argument_exists(self):
        """Test that --neutrino-mass argument is available in CLI parser."""
        from beta_spectrum.cli import _build_parser

        parser = _build_parser()

        # Check that the argument is in the parser
        args = parser.parse_args(["--nuclide", "Tc99", "--neutrino-mass", "0.01"])
        assert hasattr(args, "neutrino_mass"), "CLI should have neutrino_mass argument"
        assert args.neutrino_mass == 0.01, "CLI neutrino_mass should be 0.01"

    def test_neutrino_mass_cli_default_value(self):
        """Test that --neutrino-mass defaults to 0.0 in CLI."""
        from beta_spectrum.cli import _build_parser

        parser = _build_parser()

        args = parser.parse_args(["--nuclide", "Tc99"])
        assert args.neutrino_mass == 0.0, "CLI neutrino_mass default should be 0.0"