"""AZ-270 — Composition Root AC tests.

Verifies the contract at ``_docs/02_document/contracts/shared_config/composition_root_protocol.md`` v1.0.0.
"""

from __future__ import annotations

import ast
from collections.abc import Iterator
from dataclasses import dataclass
from pathlib import Path

import pytest

from gps_denied_onboard.config import Config
from gps_denied_onboard.runtime_root import (
    RuntimeRoot,
    StrategyNotLinkedError,
    clear_strategy_registry,
    compose_operator,
    compose_root,
    list_registered_strategies,
    register_strategy,
)

_REPO_ROOT = Path(__file__).resolve().parents[2]


@dataclass(frozen=True)
class _C1Block:
    strategy: str = "okvis2"


@dataclass(frozen=True)
class _C4Block:
    strategy: str = "opencv_gtsam"


@dataclass(frozen=True)
class _C5Block:
    strategy: str = "gtsam_isam2"


@dataclass(frozen=True)
class _C11Block:
    strategy: str = "ardupilot_tile_manager"


@dataclass
class _OrderRecorder:
    constructed: list[str]


@pytest.fixture(autouse=True)
def _isolated_registry() -> Iterator[None]:
    """Reset the strategy registry around every test."""
    clear_strategy_registry()
    yield
    clear_strategy_registry()


@pytest.fixture
def _airborne_env(monkeypatch: pytest.MonkeyPatch) -> None:
    for name, value in (
        ("GPS_DENIED_FC_PROFILE", "ardupilot_plane"),
        ("GPS_DENIED_TIER", "1"),
        ("DB_URL", "postgresql+psycopg://gps_denied:dev@db:5432/gps_denied"),
        ("CAMERA_CALIBRATION_PATH", "/etc/gps-denied/calib.yml"),
        ("LOG_LEVEL", "INFO"),
        ("LOG_SINK", "console"),
        ("INFERENCE_BACKEND", "pytorch_fp16"),
        ("FDR_PATH", "/var/lib/gps-denied/fdr"),
        ("TILE_CACHE_PATH", "/var/lib/gps-denied/tiles"),
        ("MAVLINK_SIGNING_KEY", "ZZZZZZZZ"),
    ):
        monkeypatch.setenv(name, value)


@pytest.fixture
def _operator_env(monkeypatch: pytest.MonkeyPatch) -> None:
    for name, value in (
        ("GPS_DENIED_FC_PROFILE", "ardupilot_plane"),
        ("GPS_DENIED_TIER", "1"),
        ("DB_URL", "postgresql+psycopg://gps_denied:dev@db:5432/gps_denied"),
        ("CAMERA_CALIBRATION_PATH", "/etc/gps-denied/calib.yml"),
        ("LOG_LEVEL", "INFO"),
        ("LOG_SINK", "console"),
        ("INFERENCE_BACKEND", "pytorch_fp16"),
        ("FDR_PATH", "/var/lib/gps-denied/fdr"),
        ("TILE_CACHE_PATH", "/var/lib/gps-denied/tiles"),
        ("SATELLITE_PROVIDER_URL", "http://localhost:8080"),
    ):
        monkeypatch.setenv(name, value)


def _register_okvis2(recorder: _OrderRecorder) -> None:
    def factory(config: Config, components: dict[str, object]) -> object:
        recorder.constructed.append("c1_vio")
        return ("c1_vio", "okvis2")

    register_strategy("c1_vio", "okvis2", factory, tier="airborne")


def _register_c4(recorder: _OrderRecorder) -> None:
    def factory(config: Config, components: dict[str, object]) -> object:
        recorder.constructed.append("c4_pose")
        return ("c4_pose", "opencv_gtsam")

    register_strategy("c4_pose", "opencv_gtsam", factory, tier="airborne")


def _register_c5(recorder: _OrderRecorder) -> None:
    def factory(config: Config, components: dict[str, object]) -> object:
        assert "c1_vio" in components, "c5_state factory ran before c1_vio existed"
        assert "c4_pose" in components, "c5_state factory ran before c4_pose existed"
        recorder.constructed.append("c5_state")
        return ("c5_state", "gtsam_isam2")

    register_strategy(
        "c5_state",
        "gtsam_isam2",
        factory,
        tier="airborne",
        depends_on=("c1_vio", "c4_pose"),
    )


def test_ac1_default_deployment_composes(_airborne_env: None) -> None:
    recorder = _OrderRecorder(constructed=[])
    _register_okvis2(recorder)
    _register_c4(recorder)
    _register_c5(recorder)
    config = Config.with_blocks(
        c1_vio=_C1Block(),
        c4_pose=_C4Block(),
        c5_state=_C5Block(),
    )
    root = compose_root(config)
    assert isinstance(root, RuntimeRoot)
    assert root.binary == "airborne"
    assert set(root.components.keys()) == {"c1_vio", "c4_pose", "c5_state"}


def test_ac2_strategy_not_linked_raises_with_payload(_airborne_env: None) -> None:
    # Only okvis2 is registered; config asks for vins_mono.
    recorder = _OrderRecorder(constructed=[])
    _register_okvis2(recorder)
    config = Config.with_blocks(c1_vio=_C1Block(strategy="vins_mono"))
    with pytest.raises(StrategyNotLinkedError) as info:
        compose_root(config)
    assert info.value.strategy_name == "vins_mono"
    assert info.value.component_slug == "c1_vio"
    assert info.value.available_strategies == ["okvis2"]


def test_ac3_operator_excludes_airborne_only(_operator_env: None) -> None:
    # c1_vio is registered as airborne; an operator config that references it must fail.
    recorder = _OrderRecorder(constructed=[])
    _register_okvis2(recorder)
    config = Config.with_blocks(c1_vio=_C1Block())
    with pytest.raises(StrategyNotLinkedError) as info:
        compose_operator(config)
    assert info.value.component_slug == "c1_vio"
    assert "airborne" in info.value.reason or "tier" in info.value.reason


def test_ac4_runtime_root_smoke_exit_zero(_airborne_env: None) -> None:
    # A Config with no component blocks must compose cleanly (every required
    # component is hard-wired by its bootstrap; no strategy to resolve).
    config = Config()
    root = compose_root(config)
    assert isinstance(root, RuntimeRoot)
    assert root.components == {}


def test_ac5_construction_order_respects_dependencies(_airborne_env: None) -> None:
    recorder = _OrderRecorder(constructed=[])
    # Register in reverse order to make the topological pass non-trivial.
    _register_c5(recorder)
    _register_c4(recorder)
    _register_okvis2(recorder)
    config = Config.with_blocks(
        c1_vio=_C1Block(),
        c4_pose=_C4Block(),
        c5_state=_C5Block(),
    )
    root = compose_root(config)
    # Dependencies must construct strictly before dependents.
    assert recorder.constructed.index("c1_vio") < recorder.constructed.index("c5_state")
    assert recorder.constructed.index("c4_pose") < recorder.constructed.index("c5_state")
    assert root.construction_order[-1] == "c5_state"


def test_ac6_only_compose_root_imports_concrete_strategies() -> None:
    """Architecture lint: no module under ``components.*`` imports another component's concrete strategy.

    We accept only:
    * the composition root (``runtime_root.py``);
    * per-component public re-exports inside the component's own subpackage
      (e.g. ``components.c5_state`` importing ``components.c5_state.interface``).
    Imports across components (e.g. ``components.c5_state`` importing
    ``components.c1_vio.okvis2``) are violations.
    """
    components_root = _REPO_ROOT / "src" / "gps_denied_onboard" / "components"
    violations: list[str] = []
    for module_path in components_root.rglob("*.py"):
        own_component = module_path.relative_to(components_root).parts[0]
        try:
            tree = ast.parse(module_path.read_text(encoding="utf-8"))
        except SyntaxError:
            continue
        for node in ast.walk(tree):
            if isinstance(node, ast.ImportFrom) and node.module:
                if node.module.startswith("gps_denied_onboard.components."):
                    referenced = node.module.split(".")[2]
                    if referenced != own_component:
                        violations.append(
                            f"{module_path.relative_to(_REPO_ROOT)} imports {node.module}"
                        )
            elif isinstance(node, ast.Import):
                for alias in node.names:
                    if alias.name.startswith("gps_denied_onboard.components."):
                        referenced = alias.name.split(".")[2]
                        if referenced != own_component:
                            violations.append(
                                f"{module_path.relative_to(_REPO_ROOT)} imports {alias.name}"
                            )
    assert not violations, (
        "components.* may not import other components — only the composition root may; "
        f"violations: {violations}"
    )


def test_nfr_reliability_partial_construction_closed_on_failure(_airborne_env: None) -> None:
    closed: list[str] = []

    class _Closable:
        def __init__(self, slug: str) -> None:
            self.slug = slug

        def close(self) -> None:
            closed.append(self.slug)

    def good_factory(config: Config, components: dict[str, object]) -> _Closable:
        return _Closable("c1_vio")

    def failing_factory(config: Config, components: dict[str, object]) -> object:
        raise RuntimeError("boom from c5_state factory")

    register_strategy("c1_vio", "okvis2", good_factory, tier="airborne")
    register_strategy(
        "c5_state",
        "gtsam_isam2",
        failing_factory,
        tier="airborne",
        depends_on=("c1_vio",),
    )
    config = Config.with_blocks(c1_vio=_C1Block(), c5_state=_C5Block())
    with pytest.raises(RuntimeError, match=r"boom"):
        compose_root(config)
    assert closed == ["c1_vio"], "prior instances must be .close()d on mid-composition failure"


def test_list_registered_strategies_returns_sorted_names() -> None:
    register_strategy("c1_vio", "okvis2", lambda c, m: None, tier="airborne")
    register_strategy("c1_vio", "vins_mono", lambda c, m: None, tier="airborne")
    register_strategy("c2_vpr", "netvlad", lambda c, m: None, tier="airborne")
    assert list_registered_strategies("c1_vio") == ["okvis2", "vins_mono"]
    assert list_registered_strategies("c2_vpr") == ["netvlad"]
    assert list_registered_strategies("c99_unknown") == []