"""Tests for Qt viewer backend force history and aspect-aware display helpers."""

from __future__ import annotations

import sys
import types
from pathlib import Path
from unittest.mock import MagicMock

import numpy as np
import pytest

_REPO_ROOT = Path(__file__).resolve().parents[1]
_EXAMPLES_DIR = _REPO_ROOT / "examples"
if str(_EXAMPLES_DIR) not in sys.path:
    sys.path.insert(0, str(_EXAMPLES_DIR))

from gui.viewer2d.backend import (  # noqa: E402
    QtViewerBackend,
    image_shape_meta,
    panel_width_for_aspect,
    scale_bgr_to_fit,
    select_display_image,
)
from gui.sensors import (  # noqa: E402
    FrameSnapshot,
    _snapshot_from_sensor,
    calibrate_normal_force,
)


class FakeForceAdapter:
    """Minimal adapter that emits changing FN/FX/FY without a real sensor."""

    def __init__(self):
        self._i = 0

    def read(self):
        i = self._i
        self._i += 1
        return FrameSnapshot(
            image=np.zeros((100, 200, 3), dtype=np.uint8),
            normal_force=1000.0 + 50.0 * i,
            shear_x=-200.0 + 10.0 * i,
            shear_y=300.0 - 5.0 * i,
            normal_force_calibrated=calibrate_normal_force(1000.0 + 50.0 * i),
            fps=30.0,
            timestamp=float(i) / 30.0,
            flow_overlay=np.zeros((100, 200, 3), dtype=np.uint8),
            record_frame=np.zeros((100, 200, 3), dtype=np.uint8),
        )


def test_backend_force_history_tracks_all_channels():
    adapter = FakeForceAdapter()
    backend = QtViewerBackend(npoints=32, lowpass_cutoff_hz=0.0)

    for _ in range(8):
        snap = adapter.read()
        backend.ingest(snap, now=snap.timestamp)

    state = backend.plot_state()
    assert state is not None
    assert state.sample_count == 8
    assert state.values.shape == (8, 3)

    # All three channels must change across frames (not stay flat).
    fn_span = float(state.values[:, 0].max() - state.values[:, 0].min())
    fx_span = float(state.values[:, 1].max() - state.values[:, 1].min())
    fy_span = float(state.values[:, 2].max() - state.values[:, 2].min())
    assert fn_span > 100.0
    assert fx_span > 20.0
    assert fy_span > 10.0

    # Raw FN is used for curves, not the tiny calibrated Newton scale.
    assert float(state.values[-1, 0]) == pytest.approx(1000.0 + 50.0 * 7)


@pytest.mark.parametrize(
    "shape,expected_aspect",
    [
        ((100, 200, 3), 2.0),  # wide
        ((120, 120, 3), 1.0),  # square
        ((200, 100, 3), 0.5),  # portrait
    ],
)
def test_backend_image_aspect_metadata(shape, expected_aspect):
    img = np.zeros(shape, dtype=np.uint8)
    h, w, aspect = image_shape_meta(img)
    assert (h, w) == (shape[0], shape[1])
    assert aspect == pytest.approx(expected_aspect)

    snap = FrameSnapshot(flow_overlay=img, normal_force=1.0, shear_x=2.0, shear_y=3.0)
    backend = QtViewerBackend(lowpass_cutoff_hz=0.0)
    frame = backend.ingest(snap, now=0.0)
    assert frame.image_height == shape[0]
    assert frame.image_width == shape[1]
    assert frame.aspect_ratio == pytest.approx(expected_aspect)

    fitted = scale_bgr_to_fit(img, max_w=80, max_h=80)
    fh, fw = fitted.shape[:2]
    assert fw <= 80 and fh <= 80
    assert abs((fw / fh) - expected_aspect) < 0.05

    panel_w = panel_width_for_aspect(200, expected_aspect, min_size=160)
    assert panel_w >= 160
    assert panel_w == pytest.approx(max(160, int(round(200 * expected_aspect))))


def test_select_display_image_prefers_flow_overlay():
    overlay = np.full((10, 20, 3), 7, dtype=np.uint8)
    processed = np.full((10, 20, 3), 3, dtype=np.uint8)
    snap = FrameSnapshot(flow_overlay=overlay, processed_image=processed, image=processed)
    out = select_display_image(snap)
    assert np.array_equal(out, overlay)


def test_snapshot_requests_hhd_every_frame_without_motion_gate():
    """Regression: force refresh must not use check_motion=True gating."""
    sensor = MagicMock()
    sensor.img = np.zeros((32, 32), dtype=np.uint8)
    sensor.frame = np.zeros((32, 32), dtype=np.uint8)
    sensor.info = types.SimpleNamespace(
        FPS="FPS",
        VRAW="VRAW",
        VNORMAL="VNORMAL",
        IMG="IMG",
        CONTOUR="CONTOUR",
        CENTROID="CENTROID",
        DEPTH="DEPTH",
        FNORMAL="FNORMAL",
        FSHEARX="FSHEARX",
        FSHEARY="FSHEARY",
    )
    sensor.read_info.return_value = (
        30.0,
        np.zeros((32, 32, 2), dtype=np.float32),
        np.zeros((32, 32), dtype=np.float32),
        sensor.img,
        None,
        None,
        np.zeros((32, 32), dtype=np.float32),
        12345.0,
        -100.0,
        50.0,
    )

    # Avoid depending on orisys.util.draw_arrows implementation details.
    import gui.sensors.adapter as sa

    original_util = sa.orisys.util
    sa.orisys.util = types.SimpleNamespace(
        draw_arrows=lambda *args, **kwargs: np.zeros((32, 32, 3), dtype=np.uint8)
    )
    try:
        snap = _snapshot_from_sensor(sensor, raw_image=sensor.frame, processed_image=sensor.img)
    finally:
        sa.orisys.util = original_util

    sensor.compute_deformation.assert_called_once_with(decompose=True, check_motion=False)
    assert snap is not None
    assert snap.normal_force == pytest.approx(12345.0)
    assert snap.shear_x == pytest.approx(-100.0)
    assert snap.shear_y == pytest.approx(50.0)
    assert snap.normal_force_calibrated == pytest.approx(calibrate_normal_force(12345.0))