from dataclasses import replace

import pytest

from he11lib.deconvolution import DiffusionDeconvolver
from he11lib.fitting import ModalFitter
from he11lib.modes import LGBasis
from he11lib.reconstruct import BeamReconstructor
from he11lib.synthetic import SyntheticBeamGenerator

W0 = 5e-3
Z0 = 0.5
WAVELENGTH = 1.76e-3
PIXEL_SCALE = 4e-4
IMAGE_SHAPE = (61, 61)
Z_LIST = [0.35, 0.5, 0.65, 0.8]


def make_basis():
    return LGBasis(w0=W0, z0=Z0, wavelength=WAVELENGTH)


def make_generator(basis):
    return SyntheticBeamGenerator(basis=basis, image_shape=IMAGE_SHAPE, pixel_scale=PIXEL_SCALE)


def test_reconstruct_recovers_pure_mode_purity():
    basis = make_basis()
    gen = make_generator(basis)
    planes = gen.generate(coefficients={(0, 0): 1.0 + 0j}, z_list=Z_LIST, noise_std=1e-4, seed=0)

    reconstructor = BeamReconstructor(w0=W0, z0=Z0, wavelength=WAVELENGTH, max_order=2)
    result = reconstructor.reconstruct(planes)

    power_fraction, _ = result.purity[(0, 0)]
    assert power_fraction == pytest.approx(1.0, abs=1e-3)
    assert result.used_phase_retrieval is False


def test_reconstruct_recovers_center_offset():
    basis = make_basis()
    gen = make_generator(basis)
    true_center = (10 * PIXEL_SCALE, -5 * PIXEL_SCALE)
    planes = gen.generate(
        coefficients={(0, 0): 1.0 + 0j}, z_list=Z_LIST, center=true_center, noise_std=1e-4, seed=1
    )

    reconstructor = BeamReconstructor(w0=W0, z0=Z0, wavelength=WAVELENGTH, max_order=2)
    result = reconstructor.reconstruct(planes)

    for cx, cy in result.centers:
        assert cx == pytest.approx(true_center[0], abs=2 * PIXEL_SCALE)
        assert cy == pytest.approx(true_center[1], abs=2 * PIXEL_SCALE)


def test_reconstruct_with_deconvolution_corrects_blur():
    basis = make_basis()
    gen = make_generator(basis)
    planes = gen.generate(coefficients={(0, 0): 1.0 + 0j}, z_list=Z_LIST, noise_std=1e-4, seed=2)

    deconvolver = DiffusionDeconvolver(thermal_diffusivity=1e-6, dwell_time=30.0)
    blurred_planes = [
        replace(p, flux=deconvolver.blur(p.flux, p.pixel_scale)) for p in planes
    ]

    # Without deconvolution, blur should measurably hurt purity recovery.
    fitter = ModalFitter(basis)
    result_no_deconv = fitter.fit(blurred_planes, modes=[(0, 0), (1, 0), (0, 1)])
    purity_no_deconv, _ = result_no_deconv.purity[(0, 0)]

    reconstructor = BeamReconstructor(
        w0=W0, z0=Z0, wavelength=WAVELENGTH, max_order=2, deconvolver=deconvolver
    )
    result = reconstructor.reconstruct(blurred_planes)
    purity_with_deconv, _ = result.purity[(0, 0)]

    assert purity_with_deconv > purity_no_deconv
    assert purity_with_deconv > 0.9


def test_reconstruct_forces_phase_retrieval_fallback():
    basis = make_basis()
    gen = SyntheticBeamGenerator(basis=basis, image_shape=(121, 121), pixel_scale=3e-4)
    z_list = [0.47, 0.5, 0.53]
    planes = gen.generate(coefficients={(0, 0): 1.0 + 0j}, z_list=z_list, noise_std=1e-5, seed=3)

    reconstructor = BeamReconstructor(
        w0=W0, z0=Z0, wavelength=WAVELENGTH, max_order=2, force_phase_retrieval=True
    )
    result = reconstructor.reconstruct(planes)

    assert result.used_phase_retrieval is True
    power_fraction, _ = result.purity[(0, 0)]
    assert power_fraction > 0.9


def test_reconstruct_falls_back_automatically_on_high_residual():
    basis = make_basis()
    gen = SyntheticBeamGenerator(basis=basis, image_shape=(121, 121), pixel_scale=3e-4)
    z_list = [0.47, 0.5, 0.53]
    planes = gen.generate(coefficients={(0, 0): 1.0 + 0j}, z_list=z_list, noise_std=1e-5, seed=4)

    reconstructor = BeamReconstructor(
        w0=W0,
        z0=Z0,
        wavelength=WAVELENGTH,
        max_order=2,
        phase_retrieval_residual_threshold=1e-8,
    )
    result = reconstructor.reconstruct(planes)

    assert result.used_phase_retrieval is True