"""AZ-316 ``HttpTileDownloader`` unit tests.

Covers AC-1 .. AC-12 plus the throughput NFR from
``_docs/02_tasks/todo/AZ-316_c11_tile_downloader.md``. Uses
:class:`httpx.MockTransport` for deterministic HTTP responses, a
list-backed log handler for log capture, and stub C6 stores so this
suite never depends on AZ-303 / AZ-305 / AZ-307 / AZ-308 internals.
"""

from __future__ import annotations

import json
import logging
from datetime import datetime, timedelta, timezone
from pathlib import Path
from typing import Any
from uuid import uuid4

import httpx
import pytest

from gps_denied_onboard.components.c11_tile_manager import (
    C11Config,
    CacheBudgetExceededError,
    DownloadOutcome,
    DownloadRequest,
    HttpTileDownloader,
    RateLimitedError,
    SatelliteProviderError,
    SectorClassification,
    request_hash,
)


_BASE_URL = "https://parent-suite.test"
_LIST_PATH = "/api/satellite/tiles"
_API_KEY = "test-api-key-001"


# ----------------------------------------------------------------------
# Stubs / fakes
# ----------------------------------------------------------------------


class _StubFreshnessRejection(Exception):
    """Composition-root would surface c6's ``FreshnessRejectionError``;
    we mirror it locally so the structural check in the downloader
    matches by class name without importing c6.
    """


# Re-name the class so the structural check (`__class__.__name__ ==
# "FreshnessRejectionError"`) inside the downloader matches.
_StubFreshnessRejection.__name__ = "FreshnessRejectionError"


class _StubTileWriter:
    """Captures `write_tile_for_download` calls + scripts the freshness label."""

    def __init__(
        self,
        *,
        labels: dict[str, str] | None = None,
        rejected: set[str] | None = None,
    ) -> None:
        self.labels = labels or {}
        self.rejected = rejected or set()
        self.write_calls: list[dict[str, Any]] = []
        self.exists_calls: list[tuple[int, float, float]] = []

    def write_tile_for_download(
        self,
        *,
        tile_blob: bytes,
        zoom_level: int,
        lat: float,
        lon: float,
        tile_size_meters: float,
        tile_size_pixels: int,
        capture_timestamp: datetime,
        content_sha256_hex: str,
        sector_class: str,
    ) -> str:
        tid = _tid(zoom_level, lat, lon)
        self.write_calls.append(
            {
                "tile_id": tid,
                "tile_blob_len": len(tile_blob),
                "content_sha256_hex": content_sha256_hex,
                "sector_class": sector_class,
            }
        )
        if tid in self.rejected:
            raise _StubFreshnessRejection(f"freshness rejected {tid}")
        return self.labels.get(tid, "fresh")

    def tile_already_present(
        self, *, zoom_level: int, lat: float, lon: float
    ) -> bool:
        self.exists_calls.append((zoom_level, lat, lon))
        return False


class _StubBudgetEnforcer:
    """Records `reserve_headroom` calls; raises pre-baked exception when set."""

    def __init__(self, raise_on_call: Exception | None = None) -> None:
        self.calls: list[int] = []
        self._raise = raise_on_call

    def reserve_headroom(self, needed_bytes: int) -> object:
        self.calls.append(int(needed_bytes))
        if self._raise is not None:
            raise self._raise
        return object()


def _tid(zoom: int, lat: float, lon: float) -> str:
    return f"z{int(zoom)}_{float(lat):.6f}_{float(lon):.6f}"


def _build_downloader(
    *,
    transport: httpx.MockTransport,
    tile_writer: _StubTileWriter | None = None,
    budget_enforcer: _StubBudgetEnforcer | None = None,
    config: C11Config | None = None,
    sleep_recorder: list[float] | None = None,
    backoff_schedule_s: tuple[float, ...] | None = None,
) -> tuple[
    HttpTileDownloader,
    list[logging.LogRecord],
    _StubTileWriter,
    _StubBudgetEnforcer,
    list[float],
]:
    log_records: list[logging.LogRecord] = []

    class _Handler(logging.Handler):
        def emit(self, record: logging.LogRecord) -> None:
            log_records.append(record)

    logger = logging.getLogger(f"test_az316_{id(log_records)}")
    logger.handlers.clear()
    logger.addHandler(_Handler())
    logger.setLevel(logging.DEBUG)
    logger.propagate = False

    writer = tile_writer or _StubTileWriter()
    enforcer = budget_enforcer or _StubBudgetEnforcer()
    sleeps = sleep_recorder if sleep_recorder is not None else []

    cfg = config or C11Config(
        satellite_provider_url=_BASE_URL,
        service_api_key=_API_KEY,
        download_http_timeout_s=5.0,
        download_max_5xx_retries=4,
        download_max_retry_after_s=600,
        download_resolution_floor_m_per_px=0.5,
    )

    client = httpx.Client(transport=transport, base_url=_BASE_URL)
    downloader = HttpTileDownloader(
        http_client=client,
        tile_writer=writer,  # type: ignore[arg-type]
        budget_enforcer=enforcer,  # type: ignore[arg-type]
        logger=logger,
        config=cfg,
        sleep=lambda s: sleeps.append(s),
        backoff_schedule_s=backoff_schedule_s,
    )
    return downloader, log_records, writer, enforcer, sleeps


def _make_request(
    *,
    flight_id: Any | None = None,
    cache_root: Path,
    zoom_levels: tuple[int, ...] = (14,),
) -> DownloadRequest:
    return DownloadRequest(
        flight_id=flight_id or uuid4(),
        bbox_min_lat=45.0,
        bbox_min_lon=-122.5,
        bbox_max_lat=45.5,
        bbox_max_lon=-122.0,
        zoom_levels=zoom_levels,
        sector_class=SectorClassification.STABLE_REAR,
        cache_root=cache_root,
    )


def _list_response(
    tiles: list[dict[str, Any]] | None = None,
) -> httpx.Response:
    return httpx.Response(200, json={"tiles": tiles or []})


def _tile_entry(
    *,
    zoom: int,
    lat: float,
    lon: float,
    resolution_m_per_px: float = 0.5,
    estimated_bytes: int = 4096,
    produced_at: datetime | None = None,
) -> dict[str, Any]:
    produced = produced_at or datetime(2026, 5, 13, 0, 0, 0, tzinfo=timezone.utc)
    return {
        "tile_id": _tid(zoom, lat, lon),
        "zoom_level": zoom,
        "lat": lat,
        "lon": lon,
        "produced_at": produced.isoformat(),
        "resolution_m_per_px": resolution_m_per_px,
        "estimated_bytes": estimated_bytes,
        "tile_size_meters": 100.0,
        "tile_size_pixels": 256,
    }


def _make_route_handler(
    *,
    list_response: httpx.Response | None = None,
    tile_response_factory: Any = None,
) -> Any:
    """Route GETs by URL path: list endpoint vs per-tile endpoint."""

    def _handler(request: httpx.Request) -> httpx.Response:
        path = request.url.path
        is_list = (
            path.endswith(_LIST_PATH)
            and request.url.params.get("list-only") == "true"
        )
        if is_list:
            return list_response or _list_response()
        if tile_response_factory is None:
            return httpx.Response(200, content=b"\xff\xd8\xff\xe0fake-jpeg")
        return tile_response_factory(request)

    return _handler


# ----------------------------------------------------------------------
# AC-1: 100-tile happy path
# ----------------------------------------------------------------------


def test_ac1_100_tile_happy_path_writes_all(tmp_path: Path) -> None:
    # Arrange
    tiles = [
        _tile_entry(zoom=14, lat=45.0 + i * 0.001, lon=-122.0 - i * 0.001)
        for i in range(100)
    ]
    transport = httpx.MockTransport(
        _make_route_handler(list_response=_list_response(tiles))
    )
    (downloader, _logs, writer, enforcer, _sleeps) = _build_downloader(
        transport=transport
    )
    request = _make_request(cache_root=tmp_path)

    # Act
    report = downloader.download_tiles_for_area(request)

    # Assert
    assert report.outcome == DownloadOutcome.SUCCESS
    assert report.tiles_requested == 100
    assert report.tiles_downloaded == 100
    assert report.tiles_rejected_resolution == 0
    assert report.tiles_rejected_freshness == 0
    assert report.tiles_downgraded == 0
    assert len(writer.write_calls) == 100
    assert enforcer.calls == [4096 * 100]


# ----------------------------------------------------------------------
# AC-2: resolution gate rejects sub-spec tiles BEFORE write
# ----------------------------------------------------------------------


def test_ac2_resolution_gate_rejects_sub_spec_tiles(tmp_path: Path) -> None:
    # Arrange
    tiles = []
    for i in range(50):
        res = 0.3 if i < 10 else 0.5
        tiles.append(
            _tile_entry(zoom=14, lat=45.0 + i * 0.001, lon=-122.0, resolution_m_per_px=res)
        )
    transport = httpx.MockTransport(
        _make_route_handler(list_response=_list_response(tiles))
    )
    (downloader, log_records, writer, _enforcer, _sleeps) = _build_downloader(
        transport=transport
    )

    # Act
    report = downloader.download_tiles_for_area(_make_request(cache_root=tmp_path))

    # Assert
    assert report.tiles_rejected_resolution == 10
    assert report.tiles_downloaded == 40
    assert len(writer.write_calls) == 40
    res_warnings = [r for r in log_records if getattr(r, "kind", "") == "c11.download.resolution_rejected"]
    assert len(res_warnings) == 10


# ----------------------------------------------------------------------
# AC-3: c6 freshness rejection counted, not propagated
# ----------------------------------------------------------------------


def test_ac3_freshness_rejections_counted_and_run_continues(tmp_path: Path) -> None:
    # Arrange
    tiles = [_tile_entry(zoom=14, lat=45.0 + i * 0.001, lon=-122.0) for i in range(10)]
    rejected_ids = {_tid(14, 45.0 + i * 0.001, -122.0) for i in range(5)}
    transport = httpx.MockTransport(
        _make_route_handler(list_response=_list_response(tiles))
    )
    writer = _StubTileWriter(rejected=rejected_ids)
    (downloader, log_records, _writer, _enforcer, _sleeps) = _build_downloader(
        transport=transport, tile_writer=writer
    )

    # Act
    report = downloader.download_tiles_for_area(_make_request(cache_root=tmp_path))

    # Assert
    assert report.tiles_rejected_freshness == 5
    assert report.tiles_downloaded == 5
    assert report.outcome == DownloadOutcome.SUCCESS
    summary_warns = [
        r for r in log_records if getattr(r, "kind", "") == "c11.download.freshness_rejected_summary"
    ]
    assert len(summary_warns) == 1


# ----------------------------------------------------------------------
# AC-4: stable_rear stale tiles are surfaced as DOWNGRADED
# ----------------------------------------------------------------------


def test_ac4_downgraded_label_counted_and_persisted(tmp_path: Path) -> None:
    # Arrange
    tiles = [_tile_entry(zoom=14, lat=45.0 + i * 0.001, lon=-122.0) for i in range(5)]
    labels = {_tid(14, 45.0 + i * 0.001, -122.0): "downgraded" for i in range(3)}
    transport = httpx.MockTransport(
        _make_route_handler(list_response=_list_response(tiles))
    )
    writer = _StubTileWriter(labels=labels)
    (downloader, _logs, _writer, _enforcer, _sleeps) = _build_downloader(
        transport=transport, tile_writer=writer
    )

    # Act
    report = downloader.download_tiles_for_area(_make_request(cache_root=tmp_path))

    # Assert
    assert report.tiles_downgraded == 3
    assert report.tiles_downloaded == 5


# ----------------------------------------------------------------------
# AC-5: 429 honours Retry-After
# ----------------------------------------------------------------------


def test_ac5_429_honours_retry_after(tmp_path: Path) -> None:
    # Arrange
    tiles = [_tile_entry(zoom=14, lat=45.0, lon=-122.0)]
    state = {"attempts": 0}

    def _factory(request: httpx.Request) -> httpx.Response:
        state["attempts"] += 1
        if state["attempts"] == 1:
            return httpx.Response(429, headers={"Retry-After": "30"})
        return httpx.Response(200, content=b"\xff\xd8tile")

    transport = httpx.MockTransport(
        _make_route_handler(
            list_response=_list_response(tiles),
            tile_response_factory=_factory,
        )
    )
    sleeps: list[float] = []
    (downloader, _logs, _writer, _enforcer, _sleeps) = _build_downloader(
        transport=transport, sleep_recorder=sleeps
    )

    # Act
    report = downloader.download_tiles_for_area(_make_request(cache_root=tmp_path))

    # Assert
    assert state["attempts"] == 2
    assert sleeps and sleeps[0] >= 30
    assert report.retry_count >= 1
    assert report.outcome == DownloadOutcome.SUCCESS


# ----------------------------------------------------------------------
# AC-6: persistent 5xx aborts with structured error
# ----------------------------------------------------------------------


def test_ac6_persistent_5xx_raises_satellite_provider_error(tmp_path: Path) -> None:
    # Arrange
    tiles = [_tile_entry(zoom=14, lat=45.0, lon=-122.0)]
    state = {"attempts": 0}

    def _factory(request: httpx.Request) -> httpx.Response:
        state["attempts"] += 1
        return httpx.Response(503)

    transport = httpx.MockTransport(
        _make_route_handler(
            list_response=_list_response(tiles),
            tile_response_factory=_factory,
        )
    )
    (downloader, _logs, _writer, _enforcer, _sleeps) = _build_downloader(
        transport=transport
    )

    # Act / Assert
    with pytest.raises(SatelliteProviderError):
        downloader.download_tiles_for_area(_make_request(cache_root=tmp_path))
    assert state["attempts"] >= 5


# ----------------------------------------------------------------------
# AC-7: 401 fails fast (no retry)
# ----------------------------------------------------------------------


def test_ac7_401_fails_fast_no_retry(tmp_path: Path) -> None:
    # Arrange
    tiles = [_tile_entry(zoom=14, lat=45.0, lon=-122.0)]
    state = {"attempts": 0}

    def _factory(request: httpx.Request) -> httpx.Response:
        state["attempts"] += 1
        return httpx.Response(401)

    transport = httpx.MockTransport(
        _make_route_handler(
            list_response=_list_response(tiles),
            tile_response_factory=_factory,
        )
    )
    (downloader, log_records, _writer, _enforcer, _sleeps) = _build_downloader(
        transport=transport
    )

    # Act / Assert
    with pytest.raises(SatelliteProviderError):
        downloader.download_tiles_for_area(_make_request(cache_root=tmp_path))
    assert state["attempts"] == 1


# ----------------------------------------------------------------------
# AC-8: idempotent re-run after success
# ----------------------------------------------------------------------


def test_ac8_idempotent_rerun_yields_no_op(tmp_path: Path) -> None:
    # Arrange
    tiles = [_tile_entry(zoom=14, lat=45.0 + i * 0.001, lon=-122.0) for i in range(5)]
    state = {"tile_gets": 0}

    def _factory(request: httpx.Request) -> httpx.Response:
        state["tile_gets"] += 1
        return httpx.Response(200, content=b"\xff\xd8tile")

    transport = httpx.MockTransport(
        _make_route_handler(
            list_response=_list_response(tiles),
            tile_response_factory=_factory,
        )
    )
    (downloader, _logs, _writer, _enforcer, _sleeps) = _build_downloader(
        transport=transport
    )
    request = _make_request(cache_root=tmp_path)

    # Act — first run
    first = downloader.download_tiles_for_area(request)
    first_get_count = state["tile_gets"]
    # Act — second run (same request, same cache_root → idempotent)
    second = downloader.download_tiles_for_area(request)

    # Assert
    assert first.outcome == DownloadOutcome.SUCCESS
    assert second.outcome == DownloadOutcome.IDEMPOTENT_NO_OP
    assert state["tile_gets"] == first_get_count, "second run must NOT fetch"
    assert second.tiles_downloaded == first.tiles_downloaded


# ----------------------------------------------------------------------
# AC-9: cache-budget pre-check aborts before any GET
# ----------------------------------------------------------------------


def test_ac9_cache_budget_pre_check_aborts(tmp_path: Path) -> None:
    # Arrange
    tiles = [_tile_entry(zoom=14, lat=45.0, lon=-122.0, estimated_bytes=10_000)]
    transport_state = {"tile_gets": 0}

    def _factory(request: httpx.Request) -> httpx.Response:
        transport_state["tile_gets"] += 1
        return httpx.Response(200, content=b"\xff\xd8tile")

    transport = httpx.MockTransport(
        _make_route_handler(
            list_response=_list_response(tiles),
            tile_response_factory=_factory,
        )
    )
    enforcer = _StubBudgetEnforcer(
        raise_on_call=CacheBudgetExceededError("no headroom")
    )
    (downloader, log_records, _writer, _enforcer, _sleeps) = _build_downloader(
        transport=transport, budget_enforcer=enforcer
    )

    # Act / Assert
    with pytest.raises(CacheBudgetExceededError):
        downloader.download_tiles_for_area(_make_request(cache_root=tmp_path))
    assert transport_state["tile_gets"] == 0
    assert enforcer.calls == [10_000]


# ----------------------------------------------------------------------
# AC-11: service API key never logged in plaintext
# ----------------------------------------------------------------------


def test_ac11_service_api_key_never_appears_in_logs(tmp_path: Path) -> None:
    # Arrange — exercise the failure path so the provider-failed ERROR
    # log fires (the code that explicitly redacts the auth header).
    tiles = [_tile_entry(zoom=14, lat=45.0, lon=-122.0)]

    def _factory(request: httpx.Request) -> httpx.Response:
        return httpx.Response(401)

    transport = httpx.MockTransport(
        _make_route_handler(
            list_response=_list_response(tiles),
            tile_response_factory=_factory,
        )
    )
    (downloader, log_records, _writer, _enforcer, _sleeps) = _build_downloader(
        transport=transport
    )
    with pytest.raises(SatelliteProviderError):
        downloader.download_tiles_for_area(_make_request(cache_root=tmp_path))

    # Assert
    flat = " ".join(
        r.getMessage() + json.dumps(getattr(r, "kv", {})) for r in log_records
    )
    assert _API_KEY not in flat
    assert "Bearer ***" in flat


# ----------------------------------------------------------------------
# AC-12: journal survives mid-batch crash; re-run completes the rest
# ----------------------------------------------------------------------


def test_ac12_partial_journal_resumed_on_rerun(tmp_path: Path) -> None:
    # Arrange — 10 tiles; first run fetches all 10 successfully and
    # leaves a complete journal. A second run with the SAME request
    # must short-circuit (AC-8 covers that). To exercise AC-12 we
    # MANUALLY truncate the journal between runs to simulate a crash
    # AFTER 4 tile-writes, BEFORE the completed_at_iso stamp.
    tiles = [_tile_entry(zoom=14, lat=45.0 + i * 0.001, lon=-122.0) for i in range(10)]
    state = {"tile_gets": 0}

    def _factory(request: httpx.Request) -> httpx.Response:
        state["tile_gets"] += 1
        return httpx.Response(200, content=b"\xff\xd8tile")

    transport = httpx.MockTransport(
        _make_route_handler(
            list_response=_list_response(tiles),
            tile_response_factory=_factory,
        )
    )
    (downloader, _logs, writer, _enforcer, _sleeps) = _build_downloader(
        transport=transport
    )
    request = _make_request(cache_root=tmp_path)

    # First run — completes
    downloader.download_tiles_for_area(request)
    after_first = state["tile_gets"]
    write_calls_after_first = len(writer.write_calls)
    assert after_first == 10
    assert write_calls_after_first == 10

    # Simulate crash: rewrite the journal as "completed 4 of 10 tiles,
    # NOT yet completed" (clear `completed_at_iso`).
    rh = request_hash(
        request.flight_id,
        request.bbox_min_lat,
        request.bbox_min_lon,
        request.bbox_max_lat,
        request.bbox_max_lon,
        tuple(request.zoom_levels),
        request.sector_class,
        _API_KEY,
    )
    journal_path = tmp_path / ".c11/journal" / f"{request.flight_id}__{rh}.json"
    raw = json.loads(journal_path.read_text("utf-8"))
    raw["completed_at_iso"] = None
    raw["tile_ids_completed"] = sorted(raw["tile_ids_completed"])[:4]
    raw["tile_counts"]["tiles_downloaded"] = 4
    journal_path.write_text(json.dumps(raw), encoding="utf-8")

    # Reset transport counter (writer still records cumulative calls)
    state["tile_gets"] = 0
    writer.write_calls.clear()

    # Act — second run must fetch only the missing 6
    second = downloader.download_tiles_for_area(request)

    # Assert
    assert state["tile_gets"] == 6
    assert len(writer.write_calls) == 6
    assert second.outcome == DownloadOutcome.SUCCESS
    assert second.tiles_downloaded == 6


# ----------------------------------------------------------------------
# Retry-After HTTP-date form (Risk 1 from the spec)
# ----------------------------------------------------------------------


def test_429_retry_after_http_date_form_parses(tmp_path: Path) -> None:
    # Arrange
    tiles = [_tile_entry(zoom=14, lat=45.0, lon=-122.0)]
    state = {"attempts": 0}
    future = (datetime.now(timezone.utc) + timedelta(seconds=20)).strftime(
        "%a, %d %b %Y %H:%M:%S GMT"
    )

    def _factory(request: httpx.Request) -> httpx.Response:
        state["attempts"] += 1
        if state["attempts"] == 1:
            return httpx.Response(429, headers={"Retry-After": future})
        return httpx.Response(200, content=b"\xff\xd8tile")

    transport = httpx.MockTransport(
        _make_route_handler(
            list_response=_list_response(tiles),
            tile_response_factory=_factory,
        )
    )
    sleeps: list[float] = []
    (downloader, _logs, _writer, _enforcer, _sleeps) = _build_downloader(
        transport=transport, sleep_recorder=sleeps
    )

    # Act
    report = downloader.download_tiles_for_area(_make_request(cache_root=tmp_path))

    # Assert
    assert state["attempts"] == 2
    assert sleeps and sleeps[0] >= 0
    assert report.outcome == DownloadOutcome.SUCCESS


# ----------------------------------------------------------------------
# 429 budget exhaustion → RateLimitedError
# ----------------------------------------------------------------------


def test_429_budget_exhaustion_raises_rate_limited_error(tmp_path: Path) -> None:
    # Arrange
    tiles = [_tile_entry(zoom=14, lat=45.0, lon=-122.0)]

    def _factory(request: httpx.Request) -> httpx.Response:
        return httpx.Response(429, headers={"Retry-After": "300"})

    transport = httpx.MockTransport(
        _make_route_handler(
            list_response=_list_response(tiles),
            tile_response_factory=_factory,
        )
    )
    cfg = C11Config(
        satellite_provider_url=_BASE_URL,
        service_api_key=_API_KEY,
        download_http_timeout_s=5.0,
        download_max_5xx_retries=4,
        download_max_retry_after_s=400,
        download_resolution_floor_m_per_px=0.5,
    )
    (downloader, _logs, _writer, _enforcer, _sleeps) = _build_downloader(
        transport=transport, config=cfg
    )

    # Act / Assert
    with pytest.raises(RateLimitedError):
        downloader.download_tiles_for_area(_make_request(cache_root=tmp_path))


# ----------------------------------------------------------------------
# NFR — bookkeeping throughput on a 1000-tile happy path
# ----------------------------------------------------------------------


def test_nfr_throughput_1000_tiles_under_budget(tmp_path: Path) -> None:
    # Arrange
    tiles = [
        _tile_entry(zoom=14, lat=45.0 + i * 0.0001, lon=-122.0 + i * 0.0001)
        for i in range(1000)
    ]
    transport = httpx.MockTransport(
        _make_route_handler(
            list_response=_list_response(tiles),
            tile_response_factory=lambda r: httpx.Response(200, content=b"\xff\xd8tile"),
        )
    )
    (downloader, _logs, _writer, _enforcer, _sleeps) = _build_downloader(
        transport=transport
    )

    import time as _time

    t0 = _time.perf_counter()
    report = downloader.download_tiles_for_area(_make_request(cache_root=tmp_path))
    elapsed = _time.perf_counter() - t0

    # Assert — budget is generous; the goal is to catch an O(n^2)
    # bookkeeping regression, not to certify wall-clock throughput.
    assert report.outcome == DownloadOutcome.SUCCESS
    assert report.tiles_downloaded == 1000
    assert elapsed < 10.0, f"1000-tile bookkeeping took {elapsed:.2f}s"