"""Тесты для GET /{cad_num}/connection-capacity (Forgejo #2119 Phase A).

FastAPI TestClient + mock сервиса get_connection_capacity — без Postgres.
"""

from __future__ import annotations

from typing import Any
from unittest.mock import patch

import pytest
from fastapi.testclient import TestClient

from app.main import app

_VALID_CAD = "66:41:0204016:10"


def _power_point(
    name: str = "ПС 110/10 Уктус",
    reserve: float | None = 15.0,
    load_index: str | None = "open",
    distance_m: float = 850.0,
) -> dict[str, Any]:
    return {
        "name": name,
        "dzo_name": "Россети Урал",
        "voltage_class": "110/10",
        "load_index": load_index,
        "installed_capacity_mva": 40.0,
        "current_load_mva": 25.0,
        "reserve_mva": reserve,
        "reserve_asof": "2026-06-30",
        "distance_m": distance_m,
        "lat": 56.78,
        "lon": 60.61,
    }


def _make_response(
    power_points: list[dict[str, Any]] | None = None,
    water: list[dict[str, Any]] | None = None,
) -> dict[str, Any]:
    if power_points is None:
        power_points = [_power_point()]
    if water is None:
        water = [
            {
                "system_kind": "water",
                "system_name": "ЗФС, ГСВ",
                "reserve_thousand_m3_day": -168.5,
                "note": "дефицит",
                "period": "2026-Q1",
            }
        ]
    by_load_index: dict[str, int] = {}
    for p in power_points:
        li = p["load_index"] or "unknown"
        by_load_index[li] = by_load_index.get(li, 0) + 1
    nearest = next((p for p in power_points if p["reserve_mva"] and p["reserve_mva"] > 0), None)
    return {
        "power_points": power_points,
        "power_summary": {
            "total_power_points": len(power_points),
            "by_load_index": by_load_index,
            "nearest_with_reserve": nearest,
        },
        "water": water,
    }


def test_connection_capacity_returns_power_and_water() -> None:
    full = _make_response()
    with patch(
        "app.api.v1.parcels.get_connection_capacity",
        return_value=full,
    ):
        client = TestClient(app)
        r = client.get(f"/api/v1/parcels/{_VALID_CAD}/connection-capacity")

    assert r.status_code == 200, r.text
    body = r.json()
    assert len(body["power_points"]) == 1
    assert body["power_points"][0]["voltage_class"] == "110/10"
    assert body["power_summary"]["total_power_points"] == 1
    assert body["power_summary"]["by_load_index"]["open"] == 1
    assert body["power_summary"]["nearest_with_reserve"]["reserve_mva"] == pytest.approx(15.0)
    # water: отрицательный резерв (дефицит) сохраняет знак.
    assert body["water"][0]["reserve_thousand_m3_day"] == pytest.approx(-168.5)
    assert body["water"][0]["system_name"] == "ЗФС, ГСВ"


def test_connection_capacity_empty() -> None:
    empty = _make_response(power_points=[], water=[])
    with patch(
        "app.api.v1.parcels.get_connection_capacity",
        return_value=empty,
    ):
        client = TestClient(app)
        r = client.get(f"/api/v1/parcels/{_VALID_CAD}/connection-capacity")

    assert r.status_code == 200, r.text
    body = r.json()
    assert body["power_points"] == []
    assert body["power_summary"]["total_power_points"] == 0
    assert body["power_summary"]["nearest_with_reserve"] is None
    assert body["water"] == []


def test_connection_capacity_no_reserve_nearest_null() -> None:
    """Все ЦП без положительного резерва → nearest_with_reserve=null."""
    pts = [_power_point(reserve=None, load_index="closed")]
    with patch(
        "app.api.v1.parcels.get_connection_capacity",
        return_value=_make_response(power_points=pts),
    ):
        client = TestClient(app)
        r = client.get(f"/api/v1/parcels/{_VALID_CAD}/connection-capacity")

    assert r.status_code == 200, r.text
    body = r.json()
    assert body["power_summary"]["nearest_with_reserve"] is None
    assert body["power_summary"]["by_load_index"]["closed"] == 1


def test_connection_capacity_parcel_not_found_404() -> None:
    with patch(
        "app.api.v1.parcels.get_connection_capacity",
        side_effect=ValueError("Участок '66:41:9999999:1' не найден в БД"),
    ):
        client = TestClient(app)
        r = client.get("/api/v1/parcels/66:41:9999999:1/connection-capacity")

    assert r.status_code == 404
    assert "не найден" in r.json()["detail"]


def test_connection_capacity_passes_radius() -> None:
    with patch("app.api.v1.parcels.get_connection_capacity") as mock_svc:
        mock_svc.return_value = _make_response()
        client = TestClient(app)
        r = client.get(f"/api/v1/parcels/{_VALID_CAD}/connection-capacity?radius_m=5000")
        assert r.status_code == 200
        call = mock_svc.call_args
        assert call[0][2] == 5000 or call[1].get("radius_m") == 5000


def test_connection_capacity_radius_too_small_422() -> None:
    client = TestClient(app)
    r = client.get(f"/api/v1/parcels/{_VALID_CAD}/connection-capacity?radius_m=50")
    assert r.status_code == 422


def test_connection_capacity_radius_too_large_422() -> None:
    client = TestClient(app)
    r = client.get(f"/api/v1/parcels/{_VALID_CAD}/connection-capacity?radius_m=20000")
    assert r.status_code == 422