"""AZ-297 — C7 inference runtime Protocol + DTO + error + factory conformance.

Covers all 8 ACs of AZ-297 plus NFR-perf-factory and
NFR-reliability-error-family. The factory ACs (AC-4 / AC-5) substitute
fake strategy modules at ``sys.modules`` boundaries so the test never
touches TensorRT, ONNX Runtime, or PyTorch.
"""

from __future__ import annotations

import dataclasses
import re
import sys
import time
import types
from pathlib import Path

import pytest

from gps_denied_onboard.components.c7_inference import (
    BuildConfig,
    C7InferenceConfig,
    CalibrationCacheError,
    EngineBuildError,
    EngineCacheEntry,
    EngineDeserializeError,
    EngineHandle,
    EngineHashMismatchError,
    EngineSchemaMismatchError,
    EngineSidecarMissingError,
    InferenceError,
    InferenceRuntime,
    OptimizationProfile,
    OutOfMemoryError,
    PrecisionMode,
    TelemetryUnavailableError,
    ThermalState,
)
from gps_denied_onboard.components.c7_inference import (
    RuntimeError as C7RuntimeError,
)
from gps_denied_onboard.components.c7_inference.config import KNOWN_RUNTIMES
from gps_denied_onboard.config.schema import Config, ConfigError
from gps_denied_onboard.runtime_root.errors import RuntimeNotAvailableError
from gps_denied_onboard.runtime_root.inference_factory import (
    build_inference_runtime,
)

_CONTRACT_PATH = (
    Path(__file__).resolve().parents[3]
    / "_docs/02_document/contracts/c7_inference/inference_runtime_protocol.md"
)
_STRATEGY_MODULES: dict[str, tuple[str, str, str]] = {
    "tensorrt": (
        "gps_denied_onboard.components.c7_inference.tensorrt_runtime",
        "TensorrtRuntime",
        "BUILD_TENSORRT_RUNTIME",
    ),
    "onnx_trt_ep": (
        "gps_denied_onboard.components.c7_inference.onnx_trt_ep_runtime",
        "OnnxTrtEpRuntime",
        "BUILD_ONNX_TRT_EP_RUNTIME",
    ),
    "pytorch_fp16": (
        "gps_denied_onboard.components.c7_inference.pytorch_fp16_runtime",
        "PytorchFp16Runtime",
        "BUILD_PYTORCH_FP16_RUNTIME",
    ),
}


# ----------------------------------------------------------------------
# Fakes that structurally satisfy the InferenceRuntime Protocol.


class _FullInferenceRuntime:
    def __init__(self, config: Config) -> None:
        self.config = config
        self._label = config.components["c7_inference"].runtime

    def compile_engine(self, model_path, build_config):
        raise NotImplementedError

    def deserialize_engine(self, entry):
        raise NotImplementedError

    def infer(self, handle, inputs):
        raise NotImplementedError

    def release_engine(self, handle):
        return None

    def thermal_state(self):
        return ThermalState(
            cpu_temp_c=None,
            gpu_temp_c=None,
            thermal_throttle_active=False,
            measured_clock_mhz=None,
            measured_at_ns=0,
            is_telemetry_available=False,
        )

    def current_runtime_label(self):
        return self._label


class _PartialInferenceRuntime:
    def compile_engine(self, model_path, build_config):
        raise NotImplementedError

    def deserialize_engine(self, entry):
        raise NotImplementedError

    def infer(self, handle, inputs):
        raise NotImplementedError

    def release_engine(self, handle):
        return None

    def thermal_state(self):
        raise NotImplementedError


def _config_with_runtime(runtime: str) -> Config:
    return Config.with_blocks(
        c7_inference=C7InferenceConfig(runtime=runtime)
    )


def _install_fake_strategy(runtime_label: str) -> type:
    module_name, class_name, _flag = _STRATEGY_MODULES[runtime_label]

    class _FakeStrategy(_FullInferenceRuntime):
        pass

    _FakeStrategy.__name__ = class_name
    module = types.ModuleType(module_name)
    setattr(module, class_name, _FakeStrategy)
    sys.modules[module_name] = module
    return _FakeStrategy


@pytest.fixture
def strategy_module_cleanup():
    """Pop every fake strategy module before/after each factory test."""
    for module_name, _, _ in _STRATEGY_MODULES.values():
        sys.modules.pop(module_name, None)
    yield
    for module_name, _, _ in _STRATEGY_MODULES.values():
        sys.modules.pop(module_name, None)


# ----------------------------------------------------------------------
# AC-1: Protocol is conformance-checkable.


def test_ac1_inference_runtime_conformance_full() -> None:
    instance = _FullInferenceRuntime(_config_with_runtime("pytorch_fp16"))
    assert isinstance(instance, InferenceRuntime)


def test_ac1_inference_runtime_conformance_partial_missing_label() -> None:
    assert not isinstance(_PartialInferenceRuntime(), InferenceRuntime)


# ----------------------------------------------------------------------
# AC-2: frozen DTOs reject mutation.


@pytest.mark.parametrize(
    "dto, field_name, new_value",
    [
        (
            BuildConfig(
                precision=PrecisionMode.FP16,
                workspace_mb=512,
                calibration_dataset=None,
                optimization_profiles=(),
            ),
            "precision",
            PrecisionMode.INT8,
        ),
        (
            EngineCacheEntry(
                engine_path=Path("/var/lib/x.engine"),
                sha256_hex="a" * 64,
                sm=87,
                jp="6.2",
                trt="10.3",
                precision=PrecisionMode.FP16,
                extras={},
            ),
            "sha256_hex",
            "b" * 64,
        ),
        (
            ThermalState(
                cpu_temp_c=40.0,
                gpu_temp_c=45.0,
                thermal_throttle_active=False,
                measured_clock_mhz=918,
                measured_at_ns=1_000_000,
                is_telemetry_available=True,
            ),
            "thermal_throttle_active",
            True,
        ),
        (
            OptimizationProfile(
                input_name="input",
                min_shape=(1, 3, 224, 224),
                opt_shape=(1, 3, 384, 384),
                max_shape=(1, 3, 512, 512),
            ),
            "input_name",
            "renamed",
        ),
    ],
)
def test_ac2_frozen_dtos_reject_mutation(dto, field_name: str, new_value) -> None:
    original_value = getattr(dto, field_name)
    with pytest.raises(dataclasses.FrozenInstanceError):
        setattr(dto, field_name, new_value)
    assert getattr(dto, field_name) == original_value


# ----------------------------------------------------------------------
# AC-3: error hierarchy catchable as a single family.


@pytest.mark.parametrize(
    "exc_factory",
    [
        EngineBuildError,
        EngineDeserializeError,
        EngineHashMismatchError,
        EngineSchemaMismatchError,
        EngineSidecarMissingError,
        CalibrationCacheError,
        InferenceError,
        OutOfMemoryError,
        TelemetryUnavailableError,
    ],
)
def test_ac3_all_runtime_errors_caught_as_family(exc_factory) -> None:
    with pytest.raises(C7RuntimeError):
        raise exc_factory("boom")


def test_ac3_unrelated_exception_not_caught_as_family() -> None:
    with pytest.raises(ValueError):
        try:
            raise ValueError("not us")
        except C7RuntimeError:
            pytest.fail("ValueError must not be caught as c7 RuntimeError")


def test_ac3_runtime_not_available_outside_family() -> None:
    with pytest.raises(RuntimeNotAvailableError):
        try:
            raise RuntimeNotAvailableError("composition-time")
        except C7RuntimeError:
            pytest.fail(
                "RuntimeNotAvailableError is a composition-root error and "
                "MUST NOT be in the c7 runtime family"
            )


# ----------------------------------------------------------------------
# AC-4 + AC-5: factory honours config + BUILD flag gate.


@pytest.mark.parametrize("runtime", sorted(_STRATEGY_MODULES))
def test_ac4_build_inference_runtime_returns_protocol_impl(
    monkeypatch, strategy_module_cleanup, runtime
) -> None:
    _, _, flag = _STRATEGY_MODULES[runtime]
    monkeypatch.setenv(flag, "ON")
    fake_cls = _install_fake_strategy(runtime)
    config = _config_with_runtime(runtime)
    instance = build_inference_runtime(config)
    assert isinstance(instance, fake_cls)
    assert isinstance(instance, InferenceRuntime)


@pytest.mark.parametrize("runtime", sorted(_STRATEGY_MODULES))
def test_ac5_build_inference_runtime_flag_off_no_import(
    monkeypatch, strategy_module_cleanup, runtime
) -> None:
    module_name, _, flag = _STRATEGY_MODULES[runtime]
    monkeypatch.delenv(flag, raising=False)
    config = _config_with_runtime(runtime)
    with pytest.raises(RuntimeNotAvailableError) as exc_info:
        build_inference_runtime(config)
    assert runtime in str(exc_info.value)
    assert flag in str(exc_info.value)
    assert module_name not in sys.modules


@pytest.mark.parametrize(
    "runtime",
    sorted(rt for rt in _STRATEGY_MODULES if rt != "pytorch_fp16"),
)
def test_ac5_build_inference_runtime_flag_on_but_module_missing(
    monkeypatch, strategy_module_cleanup, runtime
) -> None:
    """``BUILD_*=ON`` but the strategy module hasn't been written yet.

    ``pytorch_fp16`` is excluded because AZ-300 shipped its concrete
    module — the corresponding case is covered by
    ``test_pytorch_fp16_runtime.test_ac1_protocol_conformance`` which
    constructs the real strategy. The TRT / ORT runtimes (AZ-298 /
    AZ-299) remain pending; this test still guards their factory path.
    """
    _, _, flag = _STRATEGY_MODULES[runtime]
    monkeypatch.setenv(flag, "ON")
    config = _config_with_runtime(runtime)
    with pytest.raises(RuntimeNotAvailableError) as exc_info:
        build_inference_runtime(config)
    assert runtime in str(exc_info.value)


# ----------------------------------------------------------------------
# AC-6: unknown runtime label rejected at config load.


@pytest.mark.parametrize(
    "bad_label",
    ["tensorflow_lite", "onnx", "trt", "TENSORRT", ""],
)
def test_ac6_unknown_runtime_rejected_at_config_load(bad_label: str) -> None:
    with pytest.raises(ConfigError) as exc_info:
        C7InferenceConfig(runtime=bad_label)
    msg = str(exc_info.value)
    assert bad_label in msg or "runtime" in msg
    for valid in KNOWN_RUNTIMES:
        assert valid in msg


# ----------------------------------------------------------------------
# AC-7: current_runtime_label() matches config exactly.


@pytest.mark.parametrize("runtime", sorted(_STRATEGY_MODULES))
def test_ac7_current_runtime_label_matches_config(
    monkeypatch, strategy_module_cleanup, runtime
) -> None:
    _, _, flag = _STRATEGY_MODULES[runtime]
    monkeypatch.setenv(flag, "ON")
    _install_fake_strategy(runtime)
    config = _config_with_runtime(runtime)
    instance = build_inference_runtime(config)
    assert instance.current_runtime_label() == runtime
    assert instance.current_runtime_label() == config.components["c7_inference"].runtime


# ----------------------------------------------------------------------
# AC-8: contract file matches Protocol shape.


_METHOD_TABLE_RE = re.compile(r"^\|\s*`(?P<name>[a-z_][a-z0-9_]*)`\s*\|", re.MULTILINE)


def _methods_from_contract() -> set[str]:
    text = _CONTRACT_PATH.read_text(encoding="utf-8")
    surface_start = text.index("### Protocol surface")
    next_section = text.find("\n### ", surface_start + len("### Protocol surface"))
    section = text[surface_start:next_section] if next_section != -1 else text[surface_start:]
    return {m.group("name") for m in _METHOD_TABLE_RE.finditer(section)}


def _protocol_methods(proto: type) -> set[str]:
    return {
        name
        for name in dir(proto)
        if not name.startswith("_") and callable(getattr(proto, name))
    }


def test_ac8_contract_methods_match_protocol() -> None:
    contract_methods = _methods_from_contract()
    protocol_methods = _protocol_methods(InferenceRuntime)
    missing_in_protocol = contract_methods - protocol_methods
    missing_in_contract = protocol_methods - contract_methods
    assert not missing_in_protocol, (
        "Methods declared in inference_runtime_protocol.md Shape section "
        f"but missing from the Protocol: {sorted(missing_in_protocol)}"
    )
    assert not missing_in_contract, (
        "Methods present on the Protocol but missing from the contract "
        f"Shape section: {sorted(missing_in_contract)}"
    )


def test_ac8_contract_lists_all_nine_error_subtypes() -> None:
    text = _CONTRACT_PATH.read_text(encoding="utf-8")
    expected = {
        "EngineBuildError",
        "EngineDeserializeError",
        "EngineHashMismatchError",
        "EngineSchemaMismatchError",
        "EngineSidecarMissingError",
        "CalibrationCacheError",
        "InferenceError",
        "OutOfMemoryError",
        "TelemetryUnavailableError",
    }
    for name in expected:
        assert name in text, (
            f"Contract file is missing the documented error subtype {name!r}"
        )


# ----------------------------------------------------------------------
# NFRs.


@pytest.mark.parametrize(
    "exc_type",
    [
        EngineBuildError,
        EngineDeserializeError,
        EngineHashMismatchError,
        EngineSchemaMismatchError,
        EngineSidecarMissingError,
        CalibrationCacheError,
        InferenceError,
        OutOfMemoryError,
        TelemetryUnavailableError,
    ],
)
def test_nfr_reliability_all_runtime_errors_subclass_family(exc_type) -> None:
    assert issubclass(exc_type, C7RuntimeError)


def test_nfr_reliability_runtime_not_available_not_in_family() -> None:
    assert not issubclass(RuntimeNotAvailableError, C7RuntimeError)


def test_nfr_perf_factory_under_200ms_p99(
    monkeypatch, strategy_module_cleanup
) -> None:
    """Factory p99 ≤ 200 ms across 1000 calls (NFR-perf-factory)."""
    runtime = "pytorch_fp16"
    _, _, flag = _STRATEGY_MODULES[runtime]
    monkeypatch.setenv(flag, "ON")
    _install_fake_strategy(runtime)
    config = _config_with_runtime(runtime)

    durations_ms: list[float] = []
    for _ in range(1000):
        t0 = time.perf_counter()
        build_inference_runtime(config)
        durations_ms.append((time.perf_counter() - t0) * 1000.0)

    durations_ms.sort()
    p99 = durations_ms[int(0.99 * len(durations_ms))]
    assert p99 <= 200.0, (
        f"build_inference_runtime() p99={p99:.3f} ms exceeds 200 ms NFR"
    )


# ----------------------------------------------------------------------
# Surface coverage.


def test_engine_handle_is_class_not_protocol() -> None:
    """C7 EngineHandle is an opaque class — not a runtime_checkable Protocol.

    Distinguishes it from the LightGlue ``_types.manifests.EngineHandle``
    Protocol (intentional dual-name design; see manifests.py docstring).
    """
    assert isinstance(EngineHandle, type)
    assert not hasattr(EngineHandle, "_is_runtime_protocol")


def test_c7_config_thermal_poll_hz_validation() -> None:
    with pytest.raises(ConfigError):
        C7InferenceConfig(thermal_poll_hz=0.0)
    with pytest.raises(ConfigError):
        C7InferenceConfig(thermal_poll_hz=-1.0)


def test_c7_config_engine_cache_dir_validation() -> None:
    with pytest.raises(ConfigError):
        C7InferenceConfig(engine_cache_dir="")


def test_precision_mode_enum_surface() -> None:
    assert {v.value for v in PrecisionMode} == {"fp16", "int8", "mixed"}


def test_thermal_state_invariant_i6_default_safe() -> None:
    """When telemetry is unavailable, throttle MUST be False (Invariant I-6)."""
    ts = ThermalState(
        cpu_temp_c=None,
        gpu_temp_c=None,
        thermal_throttle_active=False,
        measured_clock_mhz=None,
        measured_at_ns=0,
        is_telemetry_available=False,
    )
    assert ts.thermal_throttle_active is False
    assert ts.is_telemetry_available is False