from __future__ import annotations

from pathlib import Path

import pytest

from yovision_brain.config import parse_input_config
from yovision_brain.decode import DecoderError, DecoderPipeline, decode_packets
from yovision_brain.input import CancellationToken, InputPacket, LocalFileInput, SyntheticInput


def synthetic_packets():
    config = parse_input_config(
        {
            "schema": "brain.internal.input/v1",
            "logical_device_id": "synthetic-01",
            "profile": {"id": "main", "width": 2, "height": 1, "fps": 5},
            "source": {"kind": "synthetic", "seed": 3, "frame_count": 2},
        }
    )
    return SyntheticInput(config).packets()


def local_packets(path: Path, *, width: int = 2, height: int = 1, chunk_size: int = 5):
    config = parse_input_config(
        {
            "schema": "brain.internal.input/v1",
            "logical_device_id": "local-01",
            "profile": {"id": "archive", "width": width, "height": height, "fps": 25},
            "source": {"kind": "local_file", "path": str(path), "chunk_size": chunk_size},
        }
    )
    return LocalFileInput(config).packets()


def test_rgb24_pipeline_preserves_order_timestamps_and_metadata() -> None:
    frames = list(decode_packets(synthetic_packets()))
    assert [frame.sequence for frame in frames] == [0, 1]
    assert [frame.timestamp_ns for frame in frames] == [0, 200_000_000]
    assert all(frame.logical_device_id == "synthetic-01" for frame in frames)
    assert all(frame.profile_id == "main" for frame in frames)
    assert all((frame.width, frame.height, frame.pixel_format) == (2, 1, "rgb24") for frame in frames)


def test_rgb24_dimension_change_is_explicit() -> None:
    packets = [
        InputPacket(0, 0, "camera", "main", 1, 1, "rgb24", b"abc"),
        InputPacket(1, 1, "camera", "main", 2, 1, "rgb24", b"abcdef"),
    ]
    frames = list(decode_packets(packets))
    assert [frame.dimensions_changed for frame in frames] == [False, True]


def test_invalid_rgb_payload_and_unsupported_format_are_clear() -> None:
    bad = [InputPacket(0, 0, "camera", "main", 2, 2, "rgb24", b"short")]
    with pytest.raises(DecoderError, match="expected 12"):
        list(decode_packets(bad))
    unknown = [InputPacket(0, 0, "camera", "main", 1, 1, "opaque", b"data")]
    with pytest.raises(DecoderError, match="no decoder registered"):
        list(DecoderPipeline().decode(unknown))


def test_y4m_local_video_decodes_across_input_chunks(tmp_path: Path) -> None:
    video = tmp_path / "anonymous.y4m"
    first, second = b"abcdef", b"ghijkl"
    video.write_bytes(b"YUV4MPEG2 W2 H1 F25:1 C444\nFRAME\n" + first + b"FRAME\n" + second)
    frames = list(decode_packets(local_packets(video)))
    assert [frame.payload for frame in frames] == [first, second]
    assert [frame.timestamp_ns for frame in frames] == [0, 40_000_000]
    assert all(frame.pixel_format == "yuv444p" for frame in frames)
    assert all((frame.width, frame.height) == (2, 1) for frame in frames)
    assert all(frame.profile_id == "archive" for frame in frames)


def test_y4m_clean_eof_and_cancellation_are_normal(tmp_path: Path) -> None:
    video = tmp_path / "empty.y4m"
    video.write_bytes(b"YUV4MPEG2 W2 H1 F25:1 C444\n")
    assert list(decode_packets(local_packets(video))) == []

    token = CancellationToken()
    token.cancel()
    assert list(decode_packets(local_packets(video), token)) == []


@pytest.mark.parametrize(
    ("payload", "message"),
    [
        (b"not-video\n", "expected YUV4MPEG2"),
        (b"YUV4MPEG2 W2 H1 F25:1 C420\n", "only C444"),
        (b"YUV4MPEG2 W2 H1 F25:1 C444\nFRAME\nabc", "truncated Y4M frame"),
    ],
)
def test_y4m_damage_and_unsupported_content_are_clear(tmp_path: Path, payload: bytes, message: str) -> None:
    video = tmp_path / "broken.y4m"
    video.write_bytes(payload)
    with pytest.raises(DecoderError, match=message):
        list(decode_packets(local_packets(video)))


def test_y4m_profile_dimension_mismatch_is_rejected(tmp_path: Path) -> None:
    video = tmp_path / "mismatch.y4m"
    video.write_bytes(b"YUV4MPEG2 W2 H1 F25:1 C444\n")
    with pytest.raises(DecoderError, match="do not match"):
        list(decode_packets(local_packets(video, width=3)))