"""Golden-fixture consistency tests.

Phase 0: assert the pre-refactor implementations reproduce the committed
fixtures.  Phase 2 migrates these assertions onto core.sras_format /
core.scan_geometry; the fixtures themselves never change.
"""
import json
from pathlib import Path

import pytest

import sc3_aui_app as app
from gen_goldens import (
    BACKGROUND, PREAMBLES, SAMPLE_RATE, SPF, _fake_window, _synthetic_frame,
)

GOLDEN = Path(__file__).parent / "golden"


@pytest.fixture(scope="module")
def geometry():
    with open(GOLDEN / "geometry.json") as f:
        return json.load(f)


@pytest.fixture(scope="module")
def sras_expected():
    with open(GOLDEN / "sras_expected.json") as f:
        return json.load(f)


def test_geometry_cases_match(geometry):
    for label, case in geometry["cases"].items():
        inputs = case["inputs"]
        params = app.MainWindow._build_scan_params(_fake_window(*inputs.values()))
        assert params == case["params"], f"geometry mismatch for case {label}"


def test_geometry_error_cases_raise(geometry):
    for label, case in geometry["error_cases"].items():
        with pytest.raises(ValueError):
            app.MainWindow._build_scan_params(_fake_window(*case["inputs"].values()))


def test_writer_output_byte_identical(tmp_path, sras_expected):
    params = app.MainWindow._build_scan_params(
        _fake_window("1.0", "1.0", "0.02", "0.02", "2", "0.01"))
    per_angle = params["per_angle"]
    angles = [pa["angle"] for pa in per_angle]

    out = tmp_path / "rewrite.sras"
    f = app._open_scan_file(
        out, angles, per_angle,
        params["x_start_nominal"], params["y_start_nominal"],
        params["x_delta_nominal"], params["y_delta_nominal"],
        params["row_spacing"],
        app.SCAN_VELOCITY_MM_S, app.LASER_FREQ_HZ,
        SPF, SAMPLE_RATE, PREAMBLES, BACKGROUND,
    )
    try:
        for ai, pa in enumerate(per_angle):
            for ri in range(pa["n_rows"]):
                for ci in range(len(app.SCAN_CHANNELS)):
                    for fi in range(pa["n_frames"]):
                        f.write(_synthetic_frame(ai, ri, ci, fi))
    finally:
        f.close()

    assert out.read_bytes() == (GOLDEN / "complete.sras").read_bytes()


def test_header_parse_matches(sras_expected):
    info = app._read_sras_header(GOLDEN / "complete.sras")
    assert info == sras_expected["header"]


def test_angle_status_all_variants(sras_expected):
    info = app._read_sras_header(GOLDEN / "complete.sras")
    for name, expected in sras_expected["statuses"].items():
        statuses = app._compute_angle_status(GOLDEN / name, info)
        assert statuses == expected, f"status mismatch for {name}"