import asyncio
from decimal import Decimal
from typing import Any

import httpx
from opentelemetry.sdk.metrics import MeterProvider
from opentelemetry.sdk.metrics.export import InMemoryMetricReader

from app.config import Settings
from app.controllers.v1.delivery import get_aggregator_service
from app.observability.metrics import reset_metrics_for_tests, setup_metrics
from app.schemas.request import DeliveryEntity, DeliveryRequest
from app.schemas.response import DeliveryPrice
from app.services.aggregator import AggregatorService, AggregatorServiceError


class ToggleAggregatorService:
    def __init__(self) -> None:
        self.should_fail = False

    async def get_all_prices(self, request: DeliveryRequest) -> list[DeliveryPrice]:
        _ = request
        if self.should_fail:
            raise AggregatorServiceError("failed")
        return []


class StubProvider:
    def __init__(self, name: str, *, fail: bool) -> None:
        self.name = name
        self.fail = fail
        self.cache_ttl_seconds = 120

    async def get_price(self, request: DeliveryRequest) -> DeliveryPrice:
        _ = request
        if self.fail:
            raise RuntimeError("provider unavailable")
        return DeliveryPrice(
            provider=self.name,
            service_name="economy",
            price=Decimal("99.90"),
            currency="RUB",
            delivery_days_min=2,
            delivery_days_max=3,
        )


class StubCache:
    async def get(self, key: str) -> object | None:
        _ = key
        return None

    async def set(self, key: str, value: object, ttl: int | None = None) -> None:
        _ = key, value, ttl


class StubCacheHit:
    def __init__(self, payload: object) -> None:
        self.payload = payload

    async def get(self, key: str) -> object | None:
        _ = key
        return self.payload

    async def set(self, key: str, value: object, ttl: int | None = None) -> None:
        _ = key, value, ttl


def _build_payload() -> dict[str, object]:
    return {
        "entity": "individual",
        "from_city": "Moscow",
        "to_city": "Kazan",
        "weight_kg": 2.5,
        "length_cm": 30.0,
        "width_cm": 20.0,
        "height_cm": 10.0,
    }


def _build_request() -> DeliveryRequest:
    return DeliveryRequest(
        entity=DeliveryEntity.INDIVIDUAL,
        from_city="Moscow",
        to_city="Kazan",
        weight_kg=2.5,
        length_cm=30.0,
        width_cm=20.0,
        height_cm=10.0,
    )


def _iter_data_points(metrics_data: Any, metric_name: str) -> list[Any]:
    points: list[Any] = []
    if metrics_data is None:
        return points
    for resource_metric in metrics_data.resource_metrics:
        for scope_metric in resource_metric.scope_metrics:
            for metric in scope_metric.metrics:
                if metric.name == metric_name:
                    points.extend(metric.data.data_points)
    return points


def test_metrics_export_requests_errors_latency_and_provider_availability() -> None:
    reset_metrics_for_tests()
    metric_reader = InMemoryMetricReader()
    meter_provider = MeterProvider(metric_readers=[metric_reader])
    setup_metrics(
        service_name="g2s-tests",
        otlp_endpoint="",
        meter_provider=meter_provider,
    )

    from app.main import create_app

    toggle_service = ToggleAggregatorService()
    app = create_app(
        settings=Settings(
            observability={
                "service_name": "g2s-tests",
                "otlp_endpoint": "",
                "log_level": "INFO",
            }
        )
    )

    async def override_service() -> ToggleAggregatorService:
        return toggle_service

    app.dependency_overrides[get_aggregator_service] = override_service

    async def run_requests() -> tuple[httpx.Response, httpx.Response]:
        transport = httpx.ASGITransport(app=app, raise_app_exceptions=False)
        async with httpx.AsyncClient(
            transport=transport,
            base_url="http://testserver",
        ) as client:
            success = await client.post("/api/v1/delivery/price", json=_build_payload())
            toggle_service.should_fail = True
            failure = await client.post("/api/v1/delivery/price", json=_build_payload())
            return success, failure

    success_response, failure_response = asyncio.run(run_requests())
    assert success_response.status_code == 200
    assert failure_response.status_code == 503

    availability_service = AggregatorService(
        providers=[
            StubProvider("available-provider", fail=False),
            StubProvider("unavailable-provider", fail=True),
        ],
        cache=StubCache(),
    )
    asyncio.run(availability_service.get_all_prices(_build_request()))

    metrics_data = metric_reader.get_metrics_data()
    request_points = _iter_data_points(metrics_data, "http.server.request.count")
    error_points = _iter_data_points(metrics_data, "http.server.error.count")
    latency_points = _iter_data_points(metrics_data, "http.server.request.latency")
    availability_points = _iter_data_points(metrics_data, "delivery.provider.availability")

    assert sum(point.value for point in request_points) == 2
    assert sum(point.value for point in error_points) == 1
    assert sum(point.count for point in latency_points) == 2
    assert sum(point.count for point in availability_points) == 2
    assert sorted(point.sum for point in availability_points) == [0.0, 1.0]

    reset_metrics_for_tests()


def test_provider_availability_not_recorded_on_cache_hit() -> None:
    reset_metrics_for_tests()
    metric_reader = InMemoryMetricReader()
    meter_provider = MeterProvider(metric_readers=[metric_reader])
    setup_metrics(
        service_name="g2s-tests",
        otlp_endpoint="",
        meter_provider=meter_provider,
    )

    cached_price = DeliveryPrice(
        provider="cached-provider",
        service_name="economy",
        price=Decimal("95.50"),
        currency="RUB",
        delivery_days_min=2,
        delivery_days_max=3,
    ).model_dump(mode="json")
    provider = StubProvider("cached-provider", fail=True)
    service = AggregatorService(
        providers=[provider],
        cache=StubCacheHit(cached_price),
    )

    result = asyncio.run(service.get_all_prices(_build_request()))
    assert len(result) == 1
    assert result[0].provider == "cached-provider"

    metrics_data = metric_reader.get_metrics_data()
    availability_points = _iter_data_points(metrics_data, "delivery.provider.availability")
    assert availability_points == []

    reset_metrics_for_tests()