"""Tests that need neither a dataflow nor a display."""

import io

import cv2
import numpy as np
import pyarrow as pa
import pytest
from PIL import Image

from dora_image_view import bbox, decode, depth, intrinsics
from dora_image_view.view import Bboxes, View

WIDTH, HEIGHT = 12, 8


def _meta(encoding: str, width: int | None = None, height: int | None = None) -> dict:
    """Build message metadata as a node sending a flat buffer attaches it."""
    return {"encoding": encoding, "width": width, "height": height}


class FakeStorage:
    """Stands in for the Arrow array dora hands to the node."""

    def __init__(self, data: np.ndarray) -> None:
        self._data = data

    def to_numpy(self) -> np.ndarray:
        return self._data


@pytest.fixture
def frame() -> np.ndarray:
    rng = np.random.default_rng(seed=0)
    return rng.integers(0, 255, (HEIGHT, WIDTH, 3), dtype=np.uint8)


def test_bgr8_round_trips_unchanged(frame):
    decoded = decode.to_bgr(FakeStorage(frame.ravel()), _meta("bgr8", WIDTH, HEIGHT))

    np.testing.assert_array_equal(decoded, frame)


def test_rgb8_round_trips_unchanged(frame):
    rgb = cv2.cvtColor(frame, cv2.COLOR_BGR2RGB)

    decoded = decode.to_bgr(FakeStorage(rgb.ravel()), _meta("rgb8", WIDTH, HEIGHT))

    np.testing.assert_array_equal(decoded, frame)


@pytest.mark.parametrize(("suffix", "encoding"), [
    (".png", "png"),
    (".jpg", "jpeg"),
    (".bmp", "bmp"),
    (".webp", "webp"),
])
def test_self_describing_encodings_need_no_dimensions(frame, suffix, encoding):
    ok, buffer = cv2.imencode(suffix, frame)
    assert ok

    decoded = decode.to_bgr(FakeStorage(buffer.ravel()), _meta(encoding))

    assert decoded.shape == (HEIGHT, WIDTH, 3)


def test_yuv420_is_decoded(frame):
    planes = cv2.cvtColor(frame, cv2.COLOR_BGR2YUV_I420)

    decoded = decode.to_bgr(FakeStorage(planes.ravel()), _meta("yuv420", WIDTH, HEIGHT))

    assert decoded.shape == (HEIGHT, WIDTH, 3)


def test_avif_is_decoded(frame):
    buffer = io.BytesIO()
    Image.fromarray(cv2.cvtColor(frame, cv2.COLOR_BGR2RGB)).save(buffer, format="AVIF")
    payload = np.frombuffer(buffer.getvalue(), dtype=np.uint8)

    decoded = decode.to_bgr(FakeStorage(payload), _meta("avif"))

    assert decoded.shape == (HEIGHT, WIDTH, 3)


def test_decoded_frame_is_writable():
    storage = FakeStorage(np.arange(2 * 3 * 3, dtype=np.uint8))

    decoded = decode.to_bgr(storage, _meta("bgr8", 3, 2))

    # The frame is annotated in place, so it must not be a read-only view.
    decoded[0, 0] = 0


def test_raw_encodings_need_dimensions():
    storage = FakeStorage(np.zeros(18, dtype=np.uint8))
    with pytest.raises(RuntimeError, match="width"):
        decode.to_bgr(storage, _meta("bgr8"))


def test_short_payload_is_rejected():
    storage = FakeStorage(np.zeros(4, dtype=np.uint8))
    with pytest.raises(RuntimeError, match="expected at least"):
        decode.to_bgr(storage, _meta("bgr8", 3, 2))


def test_unsupported_encoding_is_rejected():
    storage = FakeStorage(np.zeros(4, dtype=np.uint8))
    with pytest.raises(RuntimeError, match="unsupported image encoding"):
        decode.to_bgr(storage, _meta("tiff"))


def test_xywh_is_converted_to_corners():
    value = pa.array(
        [
            {
                "bbox": np.array([10.0, 20.0, 4.0, 6.0]),
                "conf": np.array([0.5]),
                "labels": np.array(["cat"]),
            },
        ],
    )

    boxes = bbox.parse(value, "xywh")

    np.testing.assert_allclose(boxes.corners, [[8.0, 17.0, 12.0, 23.0]])
    assert list(boxes.labels) == ["cat"]


def test_headless_show_draws_without_a_window():
    view = View(headless=True, text="hello")
    view.bboxes = Bboxes(
        corners=np.array([[1.0, 1.0, 5.0, 5.0]]),
        conf=np.array([0.9]),
        labels=np.array(["cat"]),
    )
    frame = np.zeros((32, 32, 3), dtype=np.uint8)
    view.panels["image"] = frame

    assert view.show() is False
    assert frame.any(), "the overlays should have marked the frame"


def test_show_with_no_panels_is_a_no_op():
    assert View(headless=True).show() is False


def test_panels_are_tiled_left_to_right_at_a_common_height():
    view = View(headless=True)
    view.panels["image"] = np.zeros((20, 10, 3), dtype=np.uint8)
    # Half the height and half the width: scaling to the common height should
    # double both, so it contributes 20 columns, not 10.
    view.panels["depth"] = np.zeros((10, 10, 3), dtype=np.uint8)

    composite = view.compose()

    assert composite.shape[0] == 20
    assert composite.shape[1] == 10 + 20


def test_depth_decodes_millimetres_and_reshapes():
    values = np.array([100.0, 200.0, 300.0, 400.0], dtype=np.float32)

    decoded = depth.to_millimetres(FakeStorage(values), {"shape": [2, 2]})

    np.testing.assert_allclose(decoded, [[100.0, 200.0], [300.0, 400.0]])


def test_depth_reinterprets_a_float32_payload_sent_as_bytes():
    values = np.array([1500.0, 2500.0], dtype=np.float32)

    decoded = depth.to_millimetres(
        FakeStorage(values.view(np.uint8)),
        {"shape": [1, 2], "dtype": "float32"},
    )

    np.testing.assert_allclose(decoded, [[1500.0, 2500.0]])


def test_depth_converts_metres_to_millimetres():
    decoded = depth.to_millimetres(
        FakeStorage(np.array([1.5, 2.0], dtype=np.float32)),
        {"shape": [1, 2], "units": "m"},
    )

    np.testing.assert_allclose(decoded, [[1500.0, 2000.0]])


def test_depth_normalises_non_finite_values_to_missing():
    values = np.array([np.inf, np.nan, 500.0, 0.0], dtype=np.float32)

    decoded = depth.to_millimetres(FakeStorage(values), {"shape": [2, 2]})

    np.testing.assert_allclose(decoded, [[0.0, 0.0], [500.0, 0.0]])


def test_depth_without_a_shape_is_an_error():
    with pytest.raises(RuntimeError, match="shape"):
        depth.to_millimetres(FakeStorage(np.zeros(4, dtype=np.float32)), {})


def test_colorize_leaves_missing_depth_black_and_colours_the_rest():
    depth_mm = np.array([[0.0, 500.0], [1000.0, 1500.0]], dtype=np.float32)

    frame = depth.colorize(depth_mm)

    assert frame.shape == (2, 2, 3)
    np.testing.assert_array_equal(frame[0, 0], [0, 0, 0])
    assert frame[1, 1].any(), "valid depth should be coloured"


def test_depth_range_is_pinned_by_the_environment(monkeypatch):
    monkeypatch.setenv("VIEW_DEPTH_MIN_MM", "200")
    monkeypatch.setenv("VIEW_DEPTH_MAX_MM", "600")

    assert depth.resolve_range(np.array([[1000.0]], dtype=np.float32)) == (200.0, 600.0)


def test_one_pinned_end_leaves_the_other_auto_ranged(monkeypatch):
    monkeypatch.setenv("VIEW_DEPTH_MIN_MM", "0")

    low, high = depth.resolve_range(np.array([[100.0, 900.0]], dtype=np.float32))

    assert low == 0.0
    assert high > 0.0


def test_depth_range_of_an_empty_frame_does_not_divide_by_zero():
    low, high = depth.resolve_range(np.zeros((2, 2), dtype=np.float32))

    assert high > low


def test_camera_info_reads_the_compact_four_value_form():
    values = np.array([600.0, 601.0, 320.0, 240.0], dtype=np.float32)

    model = intrinsics.parse(FakeStorage(values), {"distortion": [0.1, 0.2]})

    assert (model.fx, model.fy, model.cx, model.cy) == (600.0, 601.0, 320.0, 240.0)
    assert model.distortion == (0.1, 0.2)


def test_camera_info_reads_a_ros_k_matrix():
    # Row-major K: [fx, 0, cx, 0, fy, cy, 0, 0, 1].
    k = np.array(
        [600.0, 0.0, 320.0, 0.0, 601.0, 240.0, 0.0, 0.0, 1.0],
        dtype=np.float32,
    )

    model = intrinsics.parse(FakeStorage(k), {})

    assert (model.fx, model.fy, model.cx, model.cy) == (600.0, 601.0, 320.0, 240.0)


def test_camera_info_reinterprets_a_payload_sent_as_bytes():
    values = np.array([600.0, 601.0, 320.0, 240.0], dtype=np.float32)

    model = intrinsics.parse(FakeStorage(values.view(np.uint8)), {})

    assert model.fx == 600.0
    assert model.cy == 240.0


def test_camera_info_that_is_too_short_is_an_error():
    with pytest.raises(RuntimeError, match="camera_info"):
        intrinsics.parse(FakeStorage(np.zeros(3, dtype=np.float32)), {})


def test_intrinsics_are_read_from_frame_metadata():
    model = intrinsics.from_metadata(
        {"fx": 600.0, "fy": 601.0, "cx": 320.0, "cy": 240.0},
    )

    assert model is not None
    assert (model.fx, model.cy) == (600.0, 240.0)


def test_frame_metadata_without_intrinsics_yields_none():
    assert intrinsics.from_metadata({"width": 640, "height": 480}) is None


def test_the_camera_model_is_drawn_on_the_composite():
    view = View(headless=True)
    view.panels["image"] = np.zeros((40, 80, 3), dtype=np.uint8)

    without = view.compose().copy()
    view.intrinsics = intrinsics.Intrinsics(600.0, 601.0, 320.0, 240.0)
    with_model = view.compose()

    assert not np.array_equal(without, with_model), "the model should be drawn"


def _image_struct(frame: np.ndarray, encoding: str = "bgr8"):
    """Build a payload shaped like std/media/v1/Image."""
    return pa.array(
        [{
            "width": frame.shape[1],
            "height": frame.shape[0],
            "encoding": encoding,
            "data": frame.tobytes(),
        }],
        type=decode.IMAGE_TYPE,
    )


def test_image_struct_is_decoded(frame):
    # No metadata at all: the struct describes itself.
    decoded = decode.to_bgr(_image_struct(frame), {})

    np.testing.assert_array_equal(decoded, frame)


def test_image_struct_wins_over_message_metadata(frame):
    # Metadata disagreeing with the struct must not be consulted.
    decoded = decode.to_bgr(_image_struct(frame), _meta("rgb8", 1, 1))

    np.testing.assert_array_equal(decoded, frame)


def test_image_struct_carrying_an_encoded_frame_is_decoded(frame):
    ok, encoded = cv2.imencode(".png", frame)
    assert ok
    payload = np.frombuffer(encoded.tobytes(), dtype=np.uint8).reshape(1, -1)

    decoded = decode.to_bgr(_image_struct(payload, "png"), {})

    np.testing.assert_array_equal(decoded, frame)


def test_a_decoded_image_struct_frame_is_writable(frame):
    decoded = decode.to_bgr(_image_struct(frame), {})
    decoded[0, 0] = (1, 2, 3)

    assert tuple(decoded[0, 0]) == (1, 2, 3)


def test_depth_is_decoded_from_an_image_struct():
    values = np.array([[100.0, 200.0], [300.0, 400.0]], dtype=np.float32)

    # No shape metadata: the struct carries its own dimensions.
    decoded = depth.to_millimetres(_image_struct(values, "32FC1"), {})

    np.testing.assert_allclose(decoded, values)


def test_depth_image_struct_reads_a_uint16_encoding():
    values = np.array([[1500, 2500]], dtype=np.uint16)

    decoded = depth.to_millimetres(_image_struct(values, "16UC1"), {})

    np.testing.assert_allclose(decoded, [[1500.0, 2500.0]])


def test_depth_image_struct_still_honours_the_units_metadata():
    values = np.array([[1.5, 2.0]], dtype=np.float32)

    decoded = depth.to_millimetres(_image_struct(values, "32FC1"), {"units": "m"})

    np.testing.assert_allclose(decoded, [[1500.0, 2000.0]])


def test_depth_image_struct_with_an_unsupported_encoding_is_rejected():
    values = np.zeros((1, 2), dtype=np.float32)

    with pytest.raises(RuntimeError, match="unsupported depth encoding"):
        depth.to_millimetres(_image_struct(values, "rgb8"), {})


def test_a_decoded_depth_struct_is_writable():
    values = np.array([[100.0, 0.0]], dtype=np.float32)

    decoded = depth.to_millimetres(_image_struct(values, "32FC1"), {})
    decoded[0, 0] = 42.0

    assert decoded[0, 0] == 42.0