"""``AlikedLightGlueMatcher`` — C3 secondary CrossDomainMatcher (AZ-346).

Mirrors :mod:`gps_denied_onboard.components.c3_matcher.disk_lightglue`
modulo backbone choice: ALIKED replaces DISK for the per-frame
keypoint+descriptor extraction step; LightGlue + RANSAC stages are
unchanged.

ALIKED is the documented fallback if a future D-C3-1 IT-12 verdict
shifts away from DISK, or if DISK's licensing / upstream maintenance
changes mid-cycle. Both backbones ship in airborne / research
binaries (ADR-002 allows multiple matchers at link time; only one is
selected at runtime by ``config.matcher.strategy``).

Preprocessor parameters (input size, normalisation) are hard-coded
per AZ-346 Constraint — weights-coupled, same rule as DISK.

See ``disk_lightglue.py`` for the layering + composition rationale;
this module follows the same pattern.
"""

from __future__ import annotations

import logging
from typing import TYPE_CHECKING, Final, Literal

import cv2
import numpy as np

from gps_denied_onboard._types.inference import (
    BuildConfig,
    PrecisionMode,
)
from gps_denied_onboard._types.matching import KeypointSet
from gps_denied_onboard.components.c3_matcher._engine_output_assertion import (
    assert_keypoint_engine_output_schema,
)
from gps_denied_onboard.components.c3_matcher._pipeline import (
    TileExtractError,
    run_lightglue_pipeline,
)
from gps_denied_onboard.components.c3_matcher.inference_runtime_cut import (
    InferenceRuntimeCut,
)

if TYPE_CHECKING:
    from gps_denied_onboard._types.calibration import CameraCalibration
    from gps_denied_onboard._types.matcher import MatchResult, MatcherHealth
    from gps_denied_onboard._types.nav import NavCameraFrame
    from gps_denied_onboard._types.rerank import RerankResult
    from gps_denied_onboard.clock import Clock
    from gps_denied_onboard.components.c3_matcher._health_window import (
        RollingHealthWindow,
    )
    from gps_denied_onboard.config.schema import Config
    from gps_denied_onboard.fdr_client import FdrClient
    from gps_denied_onboard.helpers.lightglue_runtime import LightGlueRuntime
    from gps_denied_onboard.helpers.ransac_filter import RansacFilter

__all__ = ["MODEL_NAME", "AlikedLightGlueMatcher", "create"]


MODEL_NAME: Final[str] = "aliked"
_MATCHER_LABEL: Final[Literal["aliked_lightglue"]] = "aliked_lightglue"
_FDR_PRODUCER_ID: Final[str] = "c3_matcher.aliked_lightglue"
_LOG_KIND_READY: Final[str] = "c3.matcher.ready"

# ALIKED input contract: NCHW float32 RGB at 480x480, ImageNet-style
# normalisation. Hard-coded per Constraint — weights-coupled.
_INPUT_SIZE: Final[int] = 480
_INPUT_KEY: Final[str] = "image"
_OUTPUT_KEYPOINTS: Final[str] = "keypoints"
_OUTPUT_DESCRIPTORS: Final[str] = "descriptors"

# ImageNet mean/std for ALIKED. Same convention as UltraVPR's preprocessor.
_IMAGENET_MEAN: Final[tuple[float, float, float]] = (0.485, 0.456, 0.406)
_IMAGENET_STD: Final[tuple[float, float, float]] = (0.229, 0.224, 0.225)


class AlikedLightGlueMatcher:
    """ALIKED + LightGlue cross-domain matcher.

    Stateless per-frame except for the rolling health window. See
    module docstring for the architectural picture and the
    ``cross_domain_matcher_protocol.md`` v1.0.0 contract for the
    public invariants this class satisfies.
    """

    def __init__(
        self,
        config: "Config",
        *,
        lightglue_runtime: "LightGlueRuntime",
        ransac_filter: type["RansacFilter"],
        inference_runtime: InferenceRuntimeCut,
        health_window: "RollingHealthWindow",
        engine_handle: object,
        clock: "Clock",
        fdr_client: "FdrClient | None",
        logger: logging.Logger,
    ) -> None:
        block = config.components["c3_matcher"]
        self._config = config
        self._lightglue_runtime = lightglue_runtime
        self._ransac_filter = ransac_filter
        self._inference_runtime = inference_runtime
        self._engine_handle = engine_handle
        self._health_window = health_window
        self._clock = clock
        self._fdr_client = fdr_client
        self._logger = logger
        self._min_inliers_threshold: int = int(block.min_inliers_threshold)
        self._residual_warn_threshold_px: float = float(
            block.residual_warn_threshold_px
        )
        self._ransac_threshold_px: float = float(block.ransac_threshold_px)

    def match(
        self,
        frame: "NavCameraFrame",
        rerank_result: "RerankResult",
        calibration: "CameraCalibration",
    ) -> "MatchResult":
        del calibration
        return run_lightglue_pipeline(
            frame=frame,
            rerank_result=rerank_result,
            matcher_label=_MATCHER_LABEL,
            extract_features=self._extract_features,
            lightglue_runtime=self._lightglue_runtime,
            ransac_filter=self._ransac_filter,
            health_window=self._health_window,
            clock=self._clock,
            fdr_client=self._fdr_client,
            fdr_producer_id=_FDR_PRODUCER_ID,
            min_inliers_threshold=self._min_inliers_threshold,
            ransac_threshold_px=self._ransac_threshold_px,
            residual_warn_threshold_px=self._residual_warn_threshold_px,
            logger=self._logger,
        )

    def health_snapshot(self) -> "MatcherHealth":
        return self._health_window.snapshot()

    def _extract_features(self, image_bgr: np.ndarray) -> KeypointSet:
        tensor = _preprocess_aliked(image_bgr)
        outputs = self._inference_runtime.infer(
            self._engine_handle, {_INPUT_KEY: tensor}
        )
        return _outputs_to_keypoint_set(outputs)


def _preprocess_aliked(image_bgr: np.ndarray) -> np.ndarray:
    """BGR → RGB 480×480 ImageNet-normalised float32 NCHW.

    Hard-coded weights-coupled preprocessing. Accepts (H, W, 3) BGR
    or (H, W) grayscale (broadcast to 3 channels).
    """
    if image_bgr.ndim == 3:
        rgb = cv2.cvtColor(image_bgr, cv2.COLOR_BGR2RGB)
    elif image_bgr.ndim == 2:
        rgb = cv2.cvtColor(image_bgr, cv2.COLOR_GRAY2RGB)
    else:
        raise TileExtractError(
            f"ALIKED preprocessor: image must be 2-D (gray) or 3-D (BGR); "
            f"got ndim={image_bgr.ndim} shape={image_bgr.shape}"
        )
    if rgb.shape[0] != _INPUT_SIZE or rgb.shape[1] != _INPUT_SIZE:
        rgb = cv2.resize(
            rgb, (_INPUT_SIZE, _INPUT_SIZE), interpolation=cv2.INTER_AREA
        )
    rgb_f = rgb.astype(np.float32) / 255.0
    mean = np.asarray(_IMAGENET_MEAN, dtype=np.float32)
    std = np.asarray(_IMAGENET_STD, dtype=np.float32)
    normalised = (rgb_f - mean) / std
    tensor = np.transpose(normalised, (2, 0, 1))[None, :, :, :]
    return np.ascontiguousarray(tensor, dtype=np.float32)


def _outputs_to_keypoint_set(outputs: dict[str, np.ndarray]) -> KeypointSet:
    if _OUTPUT_KEYPOINTS not in outputs or _OUTPUT_DESCRIPTORS not in outputs:
        raise TileExtractError(
            f"ALIKED forward returned unexpected keys: "
            f"{sorted(outputs.keys())!r}; expected {_OUTPUT_KEYPOINTS!r} + "
            f"{_OUTPUT_DESCRIPTORS!r}"
        )
    keypoints = np.asarray(outputs[_OUTPUT_KEYPOINTS], dtype=np.float32)
    descriptors = np.asarray(outputs[_OUTPUT_DESCRIPTORS], dtype=np.float32)
    if keypoints.ndim != 2 or keypoints.shape[1] != 2:
        raise TileExtractError(
            f"ALIKED keypoints must have shape (N, 2); got {keypoints.shape}"
        )
    if descriptors.ndim != 2 or descriptors.shape[0] != keypoints.shape[0]:
        raise TileExtractError(
            f"ALIKED descriptors shape {descriptors.shape} inconsistent with "
            f"keypoints {keypoints.shape}"
        )
    return KeypointSet(keypoints=keypoints, descriptors=descriptors)


def _build_aliked_build_config() -> BuildConfig:
    return BuildConfig(
        precision=PrecisionMode.FP16,
        workspace_mb=512,
        calibration_dataset=None,
        optimization_profiles=(),
    )


def create(
    config: "Config",
    *,
    lightglue_runtime: "LightGlueRuntime",
    ransac_filter: type["RansacFilter"],
    inference_runtime: InferenceRuntimeCut,
    health_window: "RollingHealthWindow",
    clock: "Clock | None" = None,
    fdr_client: "FdrClient | None" = None,
    logger: logging.Logger | None = None,
) -> "AlikedLightGlueMatcher":
    """Module-level factory consumed by :func:`build_matcher_strategy`."""
    block = config.components["c3_matcher"]
    weights_path = block.aliked_weights_path
    if weights_path is None:
        raise ValueError(
            "AlikedLightGlueMatcher.create: config.components['c3_matcher']"
            ".aliked_weights_path is None; the runtime root MUST populate "
            "the ALIKED engine path before constructing this strategy."
        )

    if clock is None:
        from gps_denied_onboard.clock.wall_clock import WallClock

        clock = WallClock()
    if logger is None:
        logger = logging.getLogger("gps_denied_onboard.c3_matcher.aliked_lightglue")

    cache_entry = inference_runtime.compile_engine(
        weights_path, _build_aliked_build_config()
    )
    entry_for_deserialize = type(cache_entry)(
        engine_path=cache_entry.engine_path,
        sha256_hex=cache_entry.sha256_hex,
        sm=cache_entry.sm,
        jp=cache_entry.jp,
        trt=cache_entry.trt,
        precision=cache_entry.precision,
        extras={**cache_entry.extras, "model_name": MODEL_NAME},
    )
    engine_handle = inference_runtime.deserialize_engine(entry_for_deserialize)

    # AZ-346 AC-special-1: validate the engine's output schema once
    # at startup so a misconfigured ALIKED engine surfaces as a
    # composition-time ConfigError instead of a mid-flight
    # InsufficientInliersError cascade.
    assert_keypoint_engine_output_schema(
        inference_runtime,
        engine_handle,
        input_size=_INPUT_SIZE,
        input_key=_INPUT_KEY,
        keypoints_key=_OUTPUT_KEYPOINTS,
        descriptors_key=_OUTPUT_DESCRIPTORS,
    )

    logger.info(
        _LOG_KIND_READY,
        extra={
            "kind": _LOG_KIND_READY,
            "kv": {
                "strategy": _MATCHER_LABEL,
                "min_inliers_threshold": int(block.min_inliers_threshold),
                "residual_warn_threshold_px": float(
                    block.residual_warn_threshold_px
                ),
                "ransac_threshold_px": float(block.ransac_threshold_px),
            },
        },
    )

    return AlikedLightGlueMatcher(
        config,
        lightglue_runtime=lightglue_runtime,
        ransac_filter=ransac_filter,
        inference_runtime=inference_runtime,
        health_window=health_window,
        engine_handle=engine_handle,
        clock=clock,
        fdr_client=fdr_client,
        logger=logger,
    )