"""FT-P-02 — Cumulative drift between satellite anchors on Derkachi (AC-1.3).

The full scenario:

1. Replay the Derkachi MP4 at 30 fps through the SUT's file-frame source.
2. Replay ``data_imu.csv`` at 10 Hz through the FC inbound (1 IMU per 3
   video frames).
3. Observe the SUT's outbound estimate stream + the FDR archive.
4. Detect every (visual_propagated|dead_reckoned) → satellite_anchored
   transition; compute drift = ||propagated_centre − new_anchor||.
5. Bin drifts by ``last_satellite_anchor_age_ms``; assert AC-2/AC-3/AC-4.
6. Emit ``e2e-results/run-${RUN_ID}/ft-p-02.csv`` with one row per pair.

What this file owns:

* The AC-1.3 logic above, wired through the harness's ``fc_adapter`` /
  ``vio_strategy`` parametrize matrix (AC-5).
* CSV evidence emission via the AZ-410-owned ``anchor_pair_detector``.

What this file does NOT own:

* The MP4 video-replay path → ``runner.helpers.frame_source_replay``
  (still a stub; AZ-408 was about the synthetic-injection injectors,
  not the video replayer); the scenario is marked
  ``@pytest.mark.deferred_ac(reason=...)`` until that helper lands.
* The FDR-archive iteration → ``runner.helpers.fdr_reader`` (owned by
  AZ-441); same skip gate.
* The MAVLink ``GLOBAL_POSITION_INT`` GT replay → handled by the
  ``imu_replay`` helper which currently raises NotImplementedError
  (owned by AZ-407 in spec, but the helper file was not touched by
  the AZ-407 batch).

When all three upstream helpers land, this file's runtime path activates
automatically — the skip is keyed off the ``NotImplementedError`` from
the helper imports, not off a hard-coded marker.
"""

from __future__ import annotations

from pathlib import Path

import pytest

from runner.helpers import anchor_pair_detector as apd


@pytest.fixture(scope="module")
def _harness_helpers_implemented() -> bool:
    """True iff every upstream helper FT-P-02 needs has a real impl.

    Used to gate the full-replay scenarios. Helper-level NotImplementedError
    is the signal — we don't hard-code a "deferred until task X" marker
    because then a developer who lands the helper would have to also
    remember to flip the marker. The auto-detect pattern is also what
    other downstream scenarios will reuse.
    """
    from runner.helpers import fdr_reader, frame_source_replay, imu_replay
    from runner.helpers.frame_source_replay import FrameSourceReplayer
    try:
        # The cheapest sentinel for each helper:
        # - FrameSourceReplayer.replay_video raises NotImplementedError
        # - fdr_reader.iter_records raises NotImplementedError
        # - ImuReplayer.replay raises NotImplementedError
        # We check by inspecting __doc__ / source rather than calling, so
        # the gate stays cheap.
        replayer = FrameSourceReplayer(sink=_NullSink())  # type: ignore[arg-type]
        try:
            replayer.replay_video(Path("/tmp/non-existent.mp4"))
        except NotImplementedError:
            return False
        try:
            list(fdr_reader.iter_records(Path("/tmp/non-existent")))
        except NotImplementedError:
            return False
        try:
            imu_replay.ImuReplayer(emitter=_NullImuEmitter()).replay(Path("/tmp/non-existent.csv"))  # type: ignore[arg-type]
        except NotImplementedError:
            return False
        return True
    except Exception:
        return False


class _NullSink:
    def write_frame(self, jpeg_bytes: bytes, timestamp_ms: int) -> None:
        return None


class _NullImuEmitter:
    def emit(self, sample: object) -> None:
        return None


@pytest.mark.traces_to("AC-1.3,AC-1,AC-2,AC-3,AC-4,AC-5")
def test_ft_p_02_derkachi_drift(
    fc_adapter: str,
    vio_strategy: str,
    evidence_dir,  # type: ignore[no-untyped-def]
    run_id: str,
    nfr_recorder,  # type: ignore[no-untyped-def]
    _harness_helpers_implemented: bool,
) -> None:
    """Full FT-P-02 scenario (AC-1.3). See module docstring.

    AC-1: anchor-pair detection from FDR stream — covered by
          ``anchor_pair_detector.detect_anchor_pairs``; unit-tested in
          ``test_anchor_pair_detector.py``.
    AC-2: visual-only drift bound (≥95 % < 100 m) — covered by aggregate().
    AC-3: IMU-fused drift bound (≥95 % < 50 m) — covered by aggregate().
    AC-4: bin medians monotonic with age — covered by check_monotonic().
    AC-5: parametrized across (fc_adapter, vio_strategy).
    """
    if not _harness_helpers_implemented:
        pytest.skip(
            "FT-P-02 full replay requires runner.helpers.{frame_source_replay,"
            "fdr_reader,imu_replay} — currently AZ-441 / AZ-407 leftovers. "
            "Pure-logic ACs covered by e2e/_unit_tests/helpers/test_anchor_pair_detector.py."
        )

    # Once the helpers land, the body below activates. We keep it
    # under the gate rather than commenting it out so the wiring stays
    # under code review.
    from runner.helpers import fdr_reader, frame_source_replay, imu_replay
    from runner.helpers.frame_source_replay import FrameSourceReplayer

    # 1. Spin up the SUT through the boundary-driving fixtures
    #    (mock_suite_sat URL + sitl_observer for the requested fc_adapter +
    #     a frame-sink + a MAVLink emitter for the requested vio_strategy).
    #    The actual wiring lives in helpers; the scenario only orchestrates.
    sitl_host = "sitl-ardupilot" if fc_adapter == "ardupilot" else "sitl-inav"

    # 2. Replay video + IMU.
    sink = _resolve_frame_sink()
    emitter = _resolve_fc_inbound_emitter(fc_adapter, sitl_host)
    video_path = Path("/test-data/flight_derkachi/flight_derkachi.mp4")
    imu_csv = Path("/test-data/flight_derkachi/data_imu.csv")
    FrameSourceReplayer(sink).replay_video(video_path)
    imu_replay.ImuReplayer(emitter).replay(imu_csv)

    # 3. Crawl the FDR archive for the outbound estimate stream.
    fdr_root = Path(evidence_dir).parent / f"run-{run_id}" / "fdr"
    estimates: list[apd.FdrEstimate] = []
    for rec in fdr_reader.iter_records(fdr_root):
        if rec.record_type == "estimate":
            payload = rec.payload
            estimates.append(
                apd.FdrEstimate(
                    monotonic_ms=int(rec.monotonic_ms),
                    lat_deg=float(payload["lat_deg"]),  # type: ignore[arg-type]
                    lon_deg=float(payload["lon_deg"]),  # type: ignore[arg-type]
                    source_label=str(payload["source_label"]),  # type: ignore[arg-type]
                    imu_fused=bool(payload.get("imu_fused", False)),
                    cov_semi_major_m=float(payload.get("cov_semi_major_m", 0.0)),  # type: ignore[arg-type]
                    last_satellite_anchor_age_ms=int(
                        payload.get("last_satellite_anchor_age_ms", 0)  # type: ignore[arg-type]
                    ),
                )
            )

    # 4. Aggregate + AC checks.
    report = apd.aggregate(estimates)
    apd.write_csv_evidence(report, evidence_dir / f"ft-p-02-{fc_adapter}-{vio_strategy}.csv")

    # 5. Record metrics for the NFR/csv reporter.
    nfr_recorder.record_metric(
        "ft_p_02.visual_only_pass_fraction", report.visual_only_pass_fraction, ac_id="AC-2"
    )
    nfr_recorder.record_metric(
        "ft_p_02.imu_fused_pass_fraction", report.imu_fused_pass_fraction, ac_id="AC-3"
    )
    nfr_recorder.record_metric("ft_p_02.total_pairs", float(len(report.pairs)), ac_id="AC-1")

    # 6. AC assertions.
    if len(report.visual_only_pairs) > 0:
        assert report.visual_only_pass_fraction >= 0.95, (
            f"AC-2 (visual-only drift <100 m) failed at "
            f"{report.visual_only_pass_fraction:.2%} over {len(report.visual_only_pairs)} pairs"
        )
    if len(report.imu_fused_pairs) > 0:
        assert report.imu_fused_pass_fraction >= 0.95, (
            f"AC-3 (IMU-fused drift <50 m) failed at "
            f"{report.imu_fused_pass_fraction:.2%} over {len(report.imu_fused_pairs)} pairs"
        )
    if len(report.pairs) >= 20:
        # AC-4 requires statistical power; small-N flights skip the
        # monotonicity check per the spec's "N<20 flagged" note.
        assert not report.monotonic_violations, (
            "AC-4 (monotonic drift vs anchor age) failed: "
            + "; ".join(report.monotonic_violations)
        )
    else:
        nfr_recorder.partial("AC-4", reason=f"N={len(report.pairs)} < 20 — statistical power flagged")


def _resolve_frame_sink():  # type: ignore[no-untyped-def]
    """Stub helper resolved when the underlying replayer lands."""
    raise NotImplementedError(
        "frame sink resolution is owned by AZ-441 / runner.helpers.frame_source_replay"
    )


def _resolve_fc_inbound_emitter(fc_adapter: str, host: str):  # type: ignore[no-untyped-def]
    """Stub helper resolved when the FC inbound emitter lands."""
    raise NotImplementedError(
        "FC inbound emitter resolution is owned by AZ-416/AZ-417 / runner.helpers.imu_replay"
    )