"""Generate golden fixtures capturing PRE-REFACTOR behavior (Phase 0).

Run once against the un-refactored sc3_aui_app.py; the outputs are committed
under tests/golden/.  After the refactor, tests compare the new
implementations against these committed files — do NOT regenerate them
against refactored code, that would defeat the purpose.

Usage:  .venv/bin/python tests/gen_goldens.py
"""
import json
import shutil
import sys
from pathlib import Path

sys.path.insert(0, str(Path(__file__).resolve().parent.parent))
import conftest  # noqa: F401  (pyueye stub + offscreen)

import sc3_aui_app as app

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

# ── Geometry fixtures ────────────────────────────────────────────────────────

GEOMETRY_CASES = [
    # label, XS, YS, XD, YD, num_angles, row_spacing
    ("single_angle_square",   "10.0", "10.0", "10.0",  "10.0",  "1", "0.25"),
    ("single_angle_rect",     "10.0", "10.0", "80.0",  "50.0",  "1", "0.25"),
    ("three_angles",          "5.0",  "5.0",  "20.0",  "12.0",  "3", "0.1"),
    ("five_angles",           "0.0",  "0.0",  "30.0",  "30.0",  "5", "0.5"),
    ("seven_angles_asym",     "12.5", "7.5",  "42.0",  "17.0",  "7", "0.05"),
    ("two_angles_tiny",       "1.0",  "1.0",  "0.02",  "0.02",  "2", "0.01"),
    ("flat_line_ydelta_zero", "10.0", "10.0", "5.0",   "0.0",   "1", "0.25"),
    ("fine_spacing",          "3.0",  "4.0",  "2.5",   "1.5",   "4", "0.025"),
]

GEOMETRY_ERROR_CASES = [
    ("xd_zero",       "10.0", "10.0", "0.0",  "10.0", "1", "0.25"),
    ("xd_negative",   "10.0", "10.0", "-5.0", "10.0", "1", "0.25"),
    ("spacing_zero",  "10.0", "10.0", "10.0", "10.0", "1", "0.0"),
    ("angles_zero",   "10.0", "10.0", "10.0", "10.0", "0", "0.25"),
    ("xs_not_number", "abc",  "10.0", "10.0", "10.0", "1", "0.25"),
]


class _W:
    """Stands in for a QLineEdit: _build_scan_params only calls .text()."""
    def __init__(self, text):
        self._text = text

    def text(self):
        return self._text


def _fake_window(xs, ys, xd, yd, na, rs):
    fs = type("FakeMainWindow", (), {})()
    fs.x_start_edit      = _W(xs)
    fs.y_start_edit      = _W(ys)
    fs.x_delta_edit      = _W(xd)
    fs.y_delta_edit      = _W(yd)
    fs.num_angles_edit   = _W(na)
    fs.row_spacing_edit  = _W(rs)
    fs.scan_prefix_edit  = _W("golden")
    fs.scan_save_dir_edit = _W("/tmp/golden-scans")
    return fs


def build_geometry_fixtures():
    out = {"constants": {
        "LASER_FREQ_HZ": app.LASER_FREQ_HZ,
        "SCAN_VELOCITY_MM_S": app.SCAN_VELOCITY_MM_S,
        "GR_ROTATION_SIGN": app.GR_ROTATION_SIGN,
    }, "cases": {}, "error_cases": {}}

    for label, *inputs in GEOMETRY_CASES:
        params = app.MainWindow._build_scan_params(_fake_window(*inputs))
        out["cases"][label] = {
            "inputs": dict(zip(("XS", "YS", "XD", "YD", "num_angles", "row_spacing"), inputs)),
            "params": params,
        }

    for label, *inputs in GEOMETRY_ERROR_CASES:
        try:
            app.MainWindow._build_scan_params(_fake_window(*inputs))
            raise AssertionError(f"error case {label} did not raise")
        except ValueError as e:
            out["error_cases"][label] = {
                "inputs": dict(zip(("XS", "YS", "XD", "YD", "num_angles", "row_spacing"), inputs)),
                "message": str(e),
            }

    with open(GOLDEN / "geometry.json", "w") as f:
        json.dump(out, f, indent=2)
    print(f"geometry.json: {len(out['cases'])} cases, {len(out['error_cases'])} error cases")


# ── SRAS v6 file fixtures ────────────────────────────────────────────────────

SPF = 8            # samples per frame (synthetic, tiny)
SAMPLE_RATE = 6.25e9
PREAMBLES = [f"WFMOUTPRE:CH{ch};SYNTHETIC;PT_FMT Y;XINCR 1.6E-10" for ch in app.SCAN_CHANNELS]
BACKGROUND = bytes(range(SPF))


def _synthetic_frame(ai, ri, ci, fi):
    return bytes((ai * 7 + ri * 5 + ci * 3 + fi + s) % 256 for s in range(SPF))


def build_sras_fixtures():
    # Geometry via the real pre-refactor code path: 2 angles, 3 rows, 4 frames.
    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]

    complete = GOLDEN / "complete.sras"
    f = app._open_scan_file(
        complete, 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:
        data_start = f.tell()
        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()

    info = app._read_sras_header(complete)
    assert info["data_start_offset"] == data_start
    row_bytes = info["n_channels"] * per_angle[0]["n_frames"] * SPF * info["bytes_per_sample"]
    angle_bytes = [row_bytes * pa["n_rows"] for pa in per_angle]

    def _truncate(name, size):
        dst = GOLDEN / name
        shutil.copyfile(complete, dst)
        with open(dst, "r+b") as g:
            g.truncate(data_start + size)
        return dst

    variants = {
        "complete.sras": complete,
        "trunc_midrow_a1.sras": _truncate(
            "trunc_midrow_a1.sras", angle_bytes[0] + row_bytes + row_bytes // 2),
        "trunc_rowboundary_a1.sras": _truncate(
            "trunc_rowboundary_a1.sras", angle_bytes[0] + 2 * row_bytes),
        "trunc_angleboundary.sras": _truncate(
            "trunc_angleboundary.sras", angle_bytes[0]),
        "trunc_midrow_a0.sras": _truncate(
            "trunc_midrow_a0.sras", row_bytes + row_bytes // 2),
        "header_only.sras": _truncate("header_only.sras", 0),
    }

    expected = {"header": info, "statuses": {}}
    for name, path in variants.items():
        expected["statuses"][name] = app._compute_angle_status(path, info)

    with open(GOLDEN / "sras_expected.json", "w") as f_json:
        json.dump(expected, f_json, indent=2)
    print(f"sras fixtures: {len(variants)} files, "
          f"data block {sum(angle_bytes)} bytes, row_bytes={row_bytes}")


if __name__ == "__main__":
    GOLDEN.mkdir(exist_ok=True)
    build_geometry_fixtures()
    build_sras_fixtures()
    print("done")