"""AZ-697 — Direct binary-tlog GPS-truth extractor.

Covers AC-1..AC-5 of ``_docs/02_tasks/todo/AZ-697_tlog_ground_truth_extractor.md``:

* AC-1 (Happy path on real tlog) — gated on the committed
  ``derkachi.tlog`` (5.8 MB binary). When present, asserts ≥ 100
  records inside the Derkachi geofence.
* AC-2 (Empty GPS gracefully) — synthetic source emits no messages.
* AC-3 (GPS_RAW_INT fallback / mixed precedence).
* AC-4 (mypy --strict) — project-wide strict via ``pyproject.toml
  [tool.mypy] strict = true``. A scoped smoke test re-runs mypy on the
  module to catch regressions before CI.
* AC-5 (Helper move snapshot) — covered by
  ``tests/unit/helpers/test_gps_compare.py``.

All tests use a synthetic ``source_factory`` for determinism (no
disk IO, no real pymavlink).

Style: every test follows the Arrange / Act / Assert pattern.
"""

from __future__ import annotations

import logging
import math
import subprocess
import sys
from collections.abc import Iterator
from pathlib import Path
from typing import Any

import pytest

from gps_denied_onboard.replay_input.errors import ReplayInputAdapterError
from gps_denied_onboard.replay_input.tlog_ground_truth import (
    TlogGpsFix,
    TlogGroundTruth,
    load_tlog_ground_truth,
)


# ---------------------------------------------------------------------
# Synthetic-source fixture helpers


class _FakeMavlinkMessage:
    """Stand-in for a pymavlink message object.

    Mirrors the duck-typed surface ``load_tlog_ground_truth`` uses:
    ``get_type()`` returns the message-type string and ``_timestamp``
    is the Unix-second float that pymavlink's mavlogfile populates on
    every ``recv_match()`` return.
    """

    def __init__(self, msg_type: str, timestamp_s: float, **fields: Any) -> None:
        self._msg_type = msg_type
        self._timestamp = timestamp_s
        for name, value in fields.items():
            setattr(self, name, value)

    def get_type(self) -> str:
        return self._msg_type


class _FakeMavlinkSource:
    """Stand-in for pymavlink's ``mavutil.mavlink_connection`` return.

    ``recv_match`` walks an in-memory message queue, filtering by the
    ``type`` argument. Returns ``None`` once the queue is exhausted —
    matching mavlogfile's end-of-stream behaviour.
    """

    def __init__(self, messages: list[_FakeMavlinkMessage]) -> None:
        self._iter: Iterator[_FakeMavlinkMessage] = iter(messages)
        self.closed = False

    def recv_match(
        self,
        type: list[str] | str | None = None,
        blocking: bool = False,
    ) -> _FakeMavlinkMessage | None:
        wanted = {type} if isinstance(type, str) else set(type or [])
        for msg in self._iter:
            if not wanted or msg.get_type() in wanted:
                return msg
        return None

    def close(self) -> None:
        self.closed = True


def _global_position_int(
    *,
    ts_s: float,
    lat_e7: int,
    lon_e7: int,
    alt_mm: int,
    hdg_cdeg: int = 0,
    vx_cm_s: int = 0,
    vy_cm_s: int = 0,
    vz_cm_s: int = 0,
) -> _FakeMavlinkMessage:
    return _FakeMavlinkMessage(
        "GLOBAL_POSITION_INT",
        ts_s,
        lat=lat_e7,
        lon=lon_e7,
        alt=alt_mm,
        hdg=hdg_cdeg,
        vx=vx_cm_s,
        vy=vy_cm_s,
        vz=vz_cm_s,
    )


def _gps_raw_int(
    *,
    ts_s: float,
    lat_e7: int,
    lon_e7: int,
    alt_mm: int,
    vel_cm_s: int = 0,
    cog_cdeg: int = 0,
) -> _FakeMavlinkMessage:
    return _FakeMavlinkMessage(
        "GPS_RAW_INT",
        ts_s,
        lat=lat_e7,
        lon=lon_e7,
        alt=alt_mm,
        vel=vel_cm_s,
        cog=cog_cdeg,
    )


def _factory_from(messages: list[_FakeMavlinkMessage]) -> Any:
    """Return a ``source_factory`` that yields the given message list."""

    def _factory(_path: str) -> _FakeMavlinkSource:
        return _FakeMavlinkSource(messages)

    return _factory


# ---------------------------------------------------------------------
# AC-1: Happy path on real tlog (gated on the committed binary)


def _real_derkachi_tlog() -> Path:
    return (
        Path(__file__).resolve().parents[3]
        / "_docs"
        / "00_problem"
        / "input_data"
        / "flight_derkachi"
        / "derkachi.tlog"
    )


@pytest.mark.skipif(
    not _real_derkachi_tlog().is_file(),
    reason=(
        "Real derkachi.tlog binary not present (gitignored 5.8 MB blob). "
        "Place it at _docs/00_problem/input_data/flight_derkachi/derkachi.tlog "
        "to exercise AC-1."
    ),
)
def test_ac1_real_derkachi_tlog_has_geofence_records() -> None:
    # Arrange
    tlog = _real_derkachi_tlog()

    # Act
    truth = load_tlog_ground_truth(tlog)

    # Assert
    assert len(truth.records) > 100, (
        f"expected > 100 GPS records, got {len(truth.records)}"
    )
    assert truth.source in {"GLOBAL_POSITION_INT", "GPS_RAW_INT"}
    # Derkachi geofence: lat ≈ 50.08, lon ≈ 36.11 (Kharkiv suburb).
    lats = [r.lat_deg for r in truth.records if r.lat_deg != 0.0]
    lons = [r.lon_deg for r in truth.records if r.lon_deg != 0.0]
    assert lats, "every GPS record has lat == 0; tlog likely malformed"
    median_lat = sorted(lats)[len(lats) // 2]
    median_lon = sorted(lons)[len(lons) // 2]
    assert 49.9 <= median_lat <= 50.3, f"median lat {median_lat} outside Derkachi band"
    assert 35.9 <= median_lon <= 36.4, f"median lon {median_lon} outside Derkachi band"


# ---------------------------------------------------------------------
# AC-2: Empty GPS gracefully (no messages → empty records + WARN log)


def test_ac2_empty_tlog_returns_empty_records_and_warns(
    tmp_path: Path,
    caplog: pytest.LogCaptureFixture,
) -> None:
    # Arrange
    fake_tlog = tmp_path / "empty.tlog"
    fake_tlog.write_bytes(b"")
    factory = _factory_from([])

    # Act
    with caplog.at_level(
        logging.WARNING,
        logger="gps_denied_onboard.replay_input.tlog_ground_truth",
    ):
        truth = load_tlog_ground_truth(fake_tlog, source_factory=factory)

    # Assert
    assert truth.records == ()
    assert truth.source == ""
    assert any(
        "contains no GLOBAL_POSITION_INT or GPS_RAW_INT" in rec.message
        for rec in caplog.records
    )


def test_missing_file_raises(tmp_path: Path) -> None:
    # Arrange
    missing = tmp_path / "absent.tlog"

    # Act / Assert
    with pytest.raises(ReplayInputAdapterError, match="tlog file not found"):
        load_tlog_ground_truth(missing)


# ---------------------------------------------------------------------
# AC-3: Fallback precedence (GPS_RAW_INT only; mixed source)


def test_ac3_gps_raw_int_fallback_when_no_global_position_int(tmp_path: Path) -> None:
    # Arrange
    fake_tlog = tmp_path / "raw_only.tlog"
    fake_tlog.write_bytes(b"")
    messages = [
        _gps_raw_int(
            ts_s=1_700_000_000.000,
            lat_e7=500_800_000,  # 50.08
            lon_e7=361_100_000,  # 36.11
            alt_mm=200_000,  # 200 m MSL
            vel_cm_s=1500,  # 15 m/s
            cog_cdeg=9000,  # 90° (east)
        ),
        _gps_raw_int(
            ts_s=1_700_000_000.200,
            lat_e7=500_801_000,
            lon_e7=361_101_000,
            alt_mm=200_500,
            vel_cm_s=1500,
            cog_cdeg=9000,
        ),
    ]
    factory = _factory_from(messages)

    # Act
    truth = load_tlog_ground_truth(fake_tlog, source_factory=factory)

    # Assert
    assert truth.source == "GPS_RAW_INT"
    assert len(truth.records) == 2
    first = truth.records[0]
    assert first.lat_deg == pytest.approx(50.08, abs=1e-6)
    assert first.lon_deg == pytest.approx(36.11, abs=1e-6)
    assert first.alt_m == pytest.approx(200.0, abs=1e-3)
    # cog=90° (east) ⇒ vx (north) = 0, vy (east) = 15 m/s, vz = 0.
    assert first.vx_m_s == pytest.approx(0.0, abs=1e-9)
    assert first.vy_m_s == pytest.approx(15.0, abs=1e-9)
    assert first.vz_m_s == 0.0
    assert first.hdg_deg == pytest.approx(90.0, abs=1e-6)
    assert first.ts_ns == 1_700_000_000_000_000_000


def test_ac3_mixed_messages_prefer_global_position_int(tmp_path: Path) -> None:
    # Arrange
    fake_tlog = tmp_path / "mixed.tlog"
    fake_tlog.write_bytes(b"")
    messages = [
        _gps_raw_int(
            ts_s=1.0,
            lat_e7=400_000_000,  # 40.00 — distinguishable from GPI rows
            lon_e7=300_000_000,  # 30.00
            alt_mm=100_000,
            cog_cdeg=0,
        ),
        _global_position_int(
            ts_s=1.0,
            lat_e7=500_800_000,  # 50.08
            lon_e7=361_100_000,  # 36.11
            alt_mm=200_000,
            hdg_cdeg=4500,  # 45°
            vx_cm_s=500,
            vy_cm_s=-500,
            vz_cm_s=100,
        ),
        _gps_raw_int(
            ts_s=2.0,
            lat_e7=400_001_000,
            lon_e7=300_001_000,
            alt_mm=100_500,
            cog_cdeg=0,
        ),
        _global_position_int(
            ts_s=2.0,
            lat_e7=500_801_000,
            lon_e7=361_101_000,
            alt_mm=200_500,
            hdg_cdeg=4500,
            vx_cm_s=500,
            vy_cm_s=-500,
            vz_cm_s=100,
        ),
    ]
    factory = _factory_from(messages)

    # Act
    truth = load_tlog_ground_truth(fake_tlog, source_factory=factory)

    # Assert — GLOBAL_POSITION_INT wins; GPS_RAW_INT rows are ignored.
    assert truth.source == "GLOBAL_POSITION_INT"
    assert len(truth.records) == 2
    for rec in truth.records:
        assert rec.lat_deg == pytest.approx(50.08, abs=1e-3)
        assert rec.lon_deg == pytest.approx(36.11, abs=1e-3)
        assert rec.hdg_deg == pytest.approx(45.0, abs=1e-6)
        assert rec.vx_m_s == pytest.approx(5.0, abs=1e-9)
        assert rec.vy_m_s == pytest.approx(-5.0, abs=1e-9)
        assert rec.vz_m_s == pytest.approx(1.0, abs=1e-9)


# ---------------------------------------------------------------------
# Unit conversions (MAVLink integer encodings)


def test_global_position_int_unit_conversions(tmp_path: Path) -> None:
    # Arrange
    fake_tlog = tmp_path / "units.tlog"
    fake_tlog.write_bytes(b"")
    messages = [
        _global_position_int(
            ts_s=10.5,
            lat_e7=123_456_789,  # 12.3456789 deg
            lon_e7=-98_765_432,  # -9.8765432 deg
            alt_mm=12_345,  # 12.345 m
            hdg_cdeg=18_000,  # 180.00 deg
            vx_cm_s=-2_500,  # -25.00 m/s
            vy_cm_s=0,
            vz_cm_s=50,  # 0.5 m/s
        )
    ]
    factory = _factory_from(messages)

    # Act
    truth = load_tlog_ground_truth(fake_tlog, source_factory=factory)

    # Assert
    assert truth.source == "GLOBAL_POSITION_INT"
    (rec,) = truth.records
    assert rec.lat_deg == pytest.approx(12.345_678_9, abs=1e-9)
    assert rec.lon_deg == pytest.approx(-9.876_543_2, abs=1e-9)
    assert rec.alt_m == pytest.approx(12.345, abs=1e-9)
    assert rec.hdg_deg == pytest.approx(180.0, abs=1e-9)
    assert rec.vx_m_s == pytest.approx(-25.0, abs=1e-9)
    assert rec.vy_m_s == 0.0
    assert rec.vz_m_s == pytest.approx(0.5, abs=1e-9)
    assert rec.ts_ns == int(10.5 * 1_000_000_000)


def test_gps_raw_int_cog_to_ned_decomposition(tmp_path: Path) -> None:
    # Arrange
    fake_tlog = tmp_path / "cog.tlog"
    fake_tlog.write_bytes(b"")
    messages = [
        _gps_raw_int(
            ts_s=0.0,
            lat_e7=0,
            lon_e7=0,
            alt_mm=0,
            vel_cm_s=2000,  # 20 m/s
            cog_cdeg=4500,  # 45° (NE)
        )
    ]
    factory = _factory_from(messages)

    # Act
    truth = load_tlog_ground_truth(fake_tlog, source_factory=factory)

    # Assert — 20 m/s @ 45° ⇒ vx = vy = 20/sqrt(2) ≈ 14.142.
    (rec,) = truth.records
    expected = 20.0 * math.cos(math.radians(45.0))
    assert rec.vx_m_s == pytest.approx(expected, abs=1e-9)
    assert rec.vy_m_s == pytest.approx(expected, abs=1e-9)
    assert rec.vz_m_s == 0.0
    assert rec.hdg_deg == pytest.approx(45.0, abs=1e-9)


def test_missing_timestamp_raises(tmp_path: Path) -> None:
    # Arrange
    fake_tlog = tmp_path / "no_ts.tlog"
    fake_tlog.write_bytes(b"")

    class _MsgNoTimestamp:
        def get_type(self) -> str:
            return "GLOBAL_POSITION_INT"

    factory = _factory_from([_MsgNoTimestamp()])  # type: ignore[list-item]

    # Act / Assert
    with pytest.raises(
        ReplayInputAdapterError, match="missing _timestamp attribute"
    ):
        load_tlog_ground_truth(fake_tlog, source_factory=factory)


def test_source_is_closed_after_load(tmp_path: Path) -> None:
    # Arrange
    fake_tlog = tmp_path / "close.tlog"
    fake_tlog.write_bytes(b"")
    captured: dict[str, _FakeMavlinkSource] = {}

    def _factory(_path: str) -> _FakeMavlinkSource:
        src = _FakeMavlinkSource([])
        captured["src"] = src
        return src

    # Act
    load_tlog_ground_truth(fake_tlog, source_factory=_factory)

    # Assert
    assert captured["src"].closed is True


# ---------------------------------------------------------------------
# DTO surface


def test_tlog_ground_truth_is_frozen() -> None:
    # Arrange
    truth = TlogGroundTruth(records=(), source="")

    # Act / Assert
    with pytest.raises((AttributeError, TypeError)):
        truth.source = "GLOBAL_POSITION_INT"  # type: ignore[misc]


def test_tlog_gps_fix_is_frozen() -> None:
    # Arrange
    fix = TlogGpsFix(
        ts_ns=0,
        lat_deg=0.0,
        lon_deg=0.0,
        alt_m=0.0,
        hdg_deg=0.0,
        vx_m_s=0.0,
        vy_m_s=0.0,
        vz_m_s=0.0,
    )

    # Act / Assert
    with pytest.raises((AttributeError, TypeError)):
        fix.lat_deg = 1.0  # type: ignore[misc]


# ---------------------------------------------------------------------
# AC-4: mypy --strict scoped to the new module


def test_ac4_mypy_strict_clean(tmp_path: Path) -> None:
    """``mypy --strict`` on the AZ-697 module reports zero errors.

    The project is strict-by-default via ``pyproject.toml [tool.mypy]``;
    this scoped run catches regressions in CI without waiting for the
    full-suite mypy pass.
    """
    # Arrange
    module_path = (
        Path(__file__).resolve().parents[2].parent
        / "src"
        / "gps_denied_onboard"
        / "replay_input"
        / "tlog_ground_truth.py"
    )

    # Act
    result = subprocess.run(
        [sys.executable, "-m", "mypy", "--strict", str(module_path)],
        capture_output=True,
        text=True,
        timeout=120,
    )

    # Assert
    assert result.returncode == 0, (
        f"mypy --strict reported errors:\n"
        f"stdout:\n{result.stdout}\n"
        f"stderr:\n{result.stderr}"
    )