"""#118: una quota non misurata dalla visione e' una misura con value NULL (NaN), sempre fail.

Il valore NULL non deve far cadere statistiche, report, CSV e liste, e non entra
nei calcoli numerici (medie, indici, istogramma); conta solo nell'esito.
"""
import csv

from httpx import AsyncClient
from sqlalchemy.ext.asyncio import AsyncSession

from src.backend.models.orm.measurement import Measurement
from src.backend.models.orm.user import User
from src.backend.services import measurement_service
from src.backend.tests.conftest import auth_headers, create_test_recipe
from src.backend.tests.test_statistics import _seed_measurements


async def _recipe_with_nan(client, db_session, tec_user):
    """Una ricetta con tre misure numeriche e una NaN (value NULL, fail)."""
    recipe = await create_test_recipe(db_session, tec_user.id)
    subtask_id, version_id = await _seed_measurements(
        client, tec_user, recipe.id, [10.0, 10.1, 9.9],
    )
    nan = await measurement_service.save_measurement(
        db_session, subtask_id=subtask_id, version_id=version_id,
        measured_by=tec_user.id, value=None, input_method="camera",
        enforce_tolerance_gate=False,
    )
    await db_session.commit()
    return recipe, subtask_id, version_id, nan


async def test_save_measurement_none_is_fail_without_deviation(
    client: AsyncClient, db_session: AsyncSession, measurement_tec_user: User,
):
    _, _, _, nan = await _recipe_with_nan(client, db_session, measurement_tec_user)
    assert nan.value is None
    assert nan.pass_fail == "fail"
    assert nan.deviation is None


async def test_manual_create_still_requires_a_value(
    client: AsyncClient, db_session: AsyncSession, measurement_tec_user: User,
):
    """Solo il percorso visione puo' produrre NaN: la creazione manuale resta float."""
    recipe = await create_test_recipe(db_session, measurement_tec_user.id)
    subtask_id, version_id = await _seed_measurements(
        client, measurement_tec_user, recipe.id, [],
    )
    resp = await client.post(
        "/api/measurements/", headers=auth_headers(measurement_tec_user),
        json={"subtask_id": subtask_id, "version_id": version_id, "value": None},
    )
    assert resp.status_code == 422


async def test_statistics_skip_the_nan_measurement(
    client: AsyncClient, db_session: AsyncSession,
    measurement_tec_user: User, metrologist_user: User,
):
    recipe, subtask_id, _, _ = await _recipe_with_nan(
        client, db_session, measurement_tec_user,
    )
    params = {"recipe_id": recipe.id, "subtask_id": subtask_id}
    headers = auth_headers(metrologist_user)

    cap = await client.get("/api/statistics/capability", headers=headers, params=params)
    assert cap.status_code == 200
    assert cap.json()["n"] == 3
    assert abs(cap.json()["mean"] - 10.0) < 1e-9

    chart = await client.get("/api/statistics/control-chart", headers=headers, params=params)
    assert chart.status_code == 200
    assert len(chart.json()["values"]) == 3

    hist = await client.get("/api/statistics/histogram", headers=headers, params=params)
    assert hist.status_code == 200

    summary = await client.get(
        "/api/statistics/summary", headers=headers, params={"recipe_id": recipe.id},
    )
    assert summary.status_code == 200


async def test_measurement_list_returns_null_value(
    client: AsyncClient, db_session: AsyncSession, measurement_tec_user: User,
):
    _, _, version_id, nan = await _recipe_with_nan(client, db_session, measurement_tec_user)
    resp = await client.get(
        "/api/measurements/", headers=auth_headers(measurement_tec_user),
        params={"version_id": version_id, "per_page": 50},
    )
    assert resp.status_code == 200
    rows = {m["id"]: m for m in resp.json()["items"]}
    assert rows[nan.id]["value"] is None
    assert rows[nan.id]["pass_fail"] == "fail"
    assert rows[nan.id]["deviation"] is None


async def test_csv_export_writes_nan(
    client: AsyncClient, db_session: AsyncSession, measurement_tec_user: User,
):
    _, _, _, nan = await _recipe_with_nan(client, db_session, measurement_tec_user)
    resp = await client.get(
        "/api/measurements/export/csv", headers=auth_headers(measurement_tec_user),
    )
    assert resp.status_code == 200
    rows = list(csv.reader(resp.text.splitlines()))
    header = rows[0]
    by_id = {r[header.index("id")]: r for r in rows[1:]}
    row = by_id[str(nan.id)]
    assert row[header.index("value")] == "NaN"
    assert row[header.index("pass_fail")] == "fail"
    assert row[header.index("deviation")] == "NaN"  # #124