from __future__ import annotations

import json
import re
import uuid
from collections.abc import Callable, Collection, Sequence
from dataclasses import dataclass
from pathlib import Path
from typing import Literal, NoReturn, TypedDict

import pytest
import requests
from _pytest.mark.structures import ParameterSet


RouteKind = Literal[
    "head_asset_hash",
    "list_assets",
    "get_asset",
    "get_asset_content",
    "create_from_hash",
    "upload_asset",
    "update_asset",
    "delete_asset",
    "get_tags",
    "add_asset_tags",
    "delete_asset_tags",
    "get_tags_refine",
    "seed_assets",
    "get_seed_status",
    "cancel_seed",
    "prune_missing_assets",
]


@dataclass(frozen=True, slots=True)
class RouteSpec:
    method: str
    path: str
    kind: RouteKind
    xfail_reason: str | None = None


@dataclass(frozen=True, slots=True)
class SmokeContext:
    http: requests.Session
    api_base: str
    seeded_asset: SmokeAsset
    make_asset_bytes: Callable[[str, int], bytes]


class SmokeAsset(TypedDict):
    id: str
    hash: str


ROUTES_PY = Path(__file__).resolve().parents[2] / "app/assets/api/routes.py"

ROUTE_DECORATOR_RE = re.compile(
    r"@ROUTES\.(?P<method>get|post|put|delete|head)\((?:f)?[\"'](?P<path>.*?)[\"']\)",
    re.DOTALL,
)
NESTED_PARAM_RE = re.compile(r"\{(?P<name>[A-Za-z_][A-Za-z0-9_]*)\:\{[^{}]+\}\}")
PATH_PARAM_RE = re.compile(r"\{(?P<name>[A-Za-z_][A-Za-z0-9_]*)\:[^{}]+\}")


ROUTE_SPECS: tuple[RouteSpec, ...] = (
    RouteSpec("HEAD", "/api/assets/hash/{hash}", "head_asset_hash"),
    RouteSpec("GET", "/api/assets", "list_assets"),
    RouteSpec("GET", "/api/assets/{id}", "get_asset"),
    RouteSpec("GET", "/api/assets/{id}/content", "get_asset_content"),
    RouteSpec("POST", "/api/assets/from-hash", "create_from_hash"),
    RouteSpec("POST", "/api/assets", "upload_asset"),
    RouteSpec("PUT", "/api/assets/{id}", "update_asset"),
    RouteSpec("DELETE", "/api/assets/{id}", "delete_asset"),
    RouteSpec("GET", "/api/tags", "get_tags"),
    RouteSpec("POST", "/api/assets/{id}/tags", "add_asset_tags"),
    RouteSpec("DELETE", "/api/assets/{id}/tags", "delete_asset_tags"),
    RouteSpec("GET", "/api/assets/tags/refine", "get_tags_refine"),
    RouteSpec("POST", "/api/assets/seed", "seed_assets"),
    RouteSpec("GET", "/api/assets/seed/status", "get_seed_status"),
    RouteSpec("POST", "/api/assets/seed/cancel", "cancel_seed"),
    RouteSpec("POST", "/api/assets/prune", "prune_missing_assets"),
)

EXPECTED_ROUTE_KEYS = {f"{spec.method} {spec.path}" for spec in ROUTE_SPECS}


def _assert_never(value: NoReturn) -> NoReturn:
    raise AssertionError(f"unhandled route kind: {value!r}")


def _normalize_route_path(raw_path: str) -> str:
    path = raw_path.replace("{{", "{").replace("}}", "}")
    path = NESTED_PARAM_RE.sub(r"{\g<name>}", path)
    return PATH_PARAM_RE.sub(r"{\g<name>}", path)


def parse_route_keys(source: str) -> set[str]:
    return {
        f"{match.group('method').upper()} {_normalize_route_path(match.group('path'))}"
        for match in ROUTE_DECORATOR_RE.finditer(source)
    }


def assert_routes_covered(route_keys: Collection[str], covered_keys: Collection[str]) -> None:
    route_set = set(route_keys)
    covered_set = set(covered_keys)
    missing = sorted(route_set - covered_set)
    extra = sorted(covered_set - route_set)
    if missing or extra:
        raise AssertionError(f"route coverage mismatch: missing={missing}, extra={extra}")


def _route_key(spec: RouteSpec) -> str:
    return f"{spec.method} {spec.path}"


def _make_route_param(spec: RouteSpec) -> ParameterSet:
    marks = ()
    if spec.xfail_reason is not None:
        marks = (pytest.mark.xfail(strict=True, reason=spec.xfail_reason),)
    return pytest.param(spec, marks=marks, id=_route_key(spec))


ROUTE_PARAMS: tuple[ParameterSet, ...] = tuple(_make_route_param(spec) for spec in ROUTE_SPECS)


@pytest.fixture
def smoke_context(
    http: requests.Session,
    api_base: str,
    seeded_asset: SmokeAsset,
    make_asset_bytes: Callable[[str, int], bytes],
) -> SmokeContext:
    return SmokeContext(
        http=http,
        api_base=api_base,
        seeded_asset=seeded_asset,
        make_asset_bytes=make_asset_bytes,
    )


@pytest.fixture
def seeded_asset(
    asset_factory: Callable[[str, Sequence[str], dict[str, object], bytes], dict[str, object]],
    make_asset_bytes: Callable[[str, int], bytes],
) -> SmokeAsset:
    name = f"surface-smoke-{uuid.uuid4().hex}.safetensors"
    body = asset_factory(
        name,
        ["models", "model_type:checkpoints", "unit-tests", "smoke"],
        {"purpose": "smoke"},
        make_asset_bytes(name, 512),
    )
    return {
        "id": str(body["id"]),
        "hash": str(body["hash"]),
    }


def _request_for_spec(spec: RouteSpec, ctx: SmokeContext) -> requests.Response:
    seeded = ctx.seeded_asset
    asset_id = str(seeded["id"])
    asset_hash = str(seeded["hash"])

    match spec.kind:
        case "head_asset_hash":
            return ctx.http.head(f"{ctx.api_base}/api/assets/hash/{asset_hash}", timeout=120)
        case "list_assets":
            return ctx.http.get(f"{ctx.api_base}/api/assets", params={"limit": "1"}, timeout=120)
        case "get_asset":
            return ctx.http.get(f"{ctx.api_base}/api/assets/{asset_id}", timeout=120)
        case "get_asset_content":
            return ctx.http.get(f"{ctx.api_base}/api/assets/{asset_id}/content", timeout=120)
        case "create_from_hash":
            return ctx.http.post(
                f"{ctx.api_base}/api/assets/from-hash",
                json={
                    "hash": asset_hash,
                    "name": f"smoke-copy-{uuid.uuid4().hex}.safetensors",
                    "tags": ["models", "unit-tests", "smoke"],
                    "user_metadata": {"purpose": "smoke"},
                },
                timeout=120,
            )
        case "upload_asset":
            name = f"smoke-upload-{uuid.uuid4().hex}.bin"
            return ctx.http.post(
                f"{ctx.api_base}/api/assets",
                files={"file": (name, ctx.make_asset_bytes(name, 512), "application/octet-stream")},
                data={
                    "tags": json.dumps(["input", "unit-tests", "smoke"]),
                    "name": name,
                    "user_metadata": json.dumps({"purpose": "smoke"}),
                },
                timeout=120,
            )
        case "update_asset":
            return ctx.http.put(
                f"{ctx.api_base}/api/assets/{asset_id}",
                json={"name": f"smoke-renamed-{uuid.uuid4().hex}.safetensors"},
                timeout=120,
            )
        case "delete_asset":
            return ctx.http.delete(f"{ctx.api_base}/api/assets/{asset_id}", timeout=120)
        case "get_tags":
            return ctx.http.get(f"{ctx.api_base}/api/tags", params={"limit": "1"}, timeout=120)
        case "add_asset_tags":
            return ctx.http.post(
                f"{ctx.api_base}/api/assets/{asset_id}/tags",
                json={"tags": ["smoke-tag"]},
                timeout=120,
            )
        case "delete_asset_tags":
            return ctx.http.delete(
                f"{ctx.api_base}/api/assets/{asset_id}/tags",
                json={"tags": ["unit-tests"]},
                timeout=120,
            )
        case "get_tags_refine":
            return ctx.http.get(
                f"{ctx.api_base}/api/assets/tags/refine",
                params={"limit": "1"},
                timeout=120,
            )
        case "seed_assets":
            return ctx.http.post(
                f"{ctx.api_base}/api/assets/seed?wait=true",
                json={"roots": ["models"]},
                timeout=120,
            )
        case "get_seed_status":
            return ctx.http.get(f"{ctx.api_base}/api/assets/seed/status", timeout=120)
        case "cancel_seed":
            return ctx.http.post(f"{ctx.api_base}/api/assets/seed/cancel", timeout=120)
        case "prune_missing_assets":
            return ctx.http.post(f"{ctx.api_base}/api/assets/prune", timeout=120)
        case _:
            _assert_never(spec.kind)


def test_route_coverage_guard_rejects_extra_route() -> None:
    with pytest.raises(AssertionError, match=r"GET /api/extra"):
        assert_routes_covered(
            ["GET /api/assets", "POST /api/assets", "GET /api/extra"],
            ["GET /api/assets", "POST /api/assets"],
        )


def test_route_coverage_matches_routes_py() -> None:
    assert_routes_covered(
        parse_route_keys(ROUTES_PY.read_text(encoding="utf-8")),
        sorted(EXPECTED_ROUTE_KEYS),
    )


@pytest.mark.parametrize("spec", ROUTE_PARAMS)
def test_api_surface(spec: RouteSpec, smoke_context: SmokeContext) -> None:
    response = _request_for_spec(spec, smoke_context)
    assert response.status_code < 500, f"{_route_key(spec)} returned {response.status_code}"