"""Tests for the GIAS-driven has_sixth_form flag (spec 2026-07-07 §3).

The filter and payloads must use dim_school.has_sixth_form, not the old
age_range-contains-"18" substring heuristic. The key regression case is a
16-19 sixth-form college: flag true, but "16-19" contains no "18".
"""

import numpy as np
import pandas as pd
import pytest
from fastapi.testclient import TestClient


def _schools_df() -> pd.DataFrame:
    """Latest-year snapshot rows as produced by load_latest_school_data."""
    base = {
        "local_authority": "Testshire",
        "school_type": "Academy",
        "phase": "Secondary",
        "address": "1 Test Street",
        "town": "Testtown",
        "postcode": "TS1 1AA",
        "religious_denomination": None,
        "gender": "Mixed",
        "admissions_policy": None,
        "ofsted_grade": np.nan,
        "ofsted_date": None,
        "ofsted_framework": None,
        "latitude": 51.5,
        "longitude": -0.1,
        "year": 202425,
        "total_pupils": 1000,
        "rwm_expected_pct": np.nan,
        "attainment_8_score": 50.0,
    }
    return pd.DataFrame(
        [
            # 11-18 school WITH a registered sixth form
            {**base, "urn": 100001, "school_name": "Alpha High",
             "age_range": "11-18", "has_sixth_form": True},
            # 16-19 college: old heuristic said NO ("16-19" has no "18"),
            # GIAS flag says YES — must appear in the yes-filter results
            {**base, "urn": 100002, "school_name": "Beta Sixth Form College",
             "age_range": "16-19", "has_sixth_form": True},
            # 11-18 age range on paper but NO registered sixth form:
            # old heuristic said YES, GIAS flag says NO
            {**base, "urn": 100003, "school_name": "Gamma Academy",
             "age_range": "11-18", "has_sixth_form": False},
            # Missing flag (pipeline not yet re-run) — must not crash,
            # must not match the yes-filter
            {**base, "urn": 100004, "school_name": "Delta School",
             "age_range": "11-16", "has_sixth_form": None},
        ]
    )


@pytest.fixture()
def client(monkeypatch):
    from backend import app as app_module

    monkeypatch.setattr(app_module, "load_latest_school_data", _schools_df)
    monkeypatch.setattr(app_module, "load_school_data", _schools_df)
    monkeypatch.setattr(app_module, "get_supplementary_data", lambda db, urn: {})
    return TestClient(app_module.app, raise_server_exceptions=False)


def _urns(resp):
    return sorted(s["urn"] for s in resp.json()["schools"])


def test_filter_yes_uses_flag_not_age_range(client):
    resp = client.get("/api/schools?has_sixth_form=yes")
    assert resp.status_code == 200, resp.text
    # 16-19 college included; 11-18-without-sixth-form excluded
    assert _urns(resp) == [100001, 100002]


def test_filter_no_uses_flag_not_age_range(client):
    resp = client.get("/api/schools?has_sixth_form=no")
    assert resp.status_code == 200, resp.text
    # Gamma (flag false) and Delta (flag missing => not true)
    assert _urns(resp) == [100003, 100004]


def test_list_payload_includes_flag(client):
    resp = client.get("/api/schools")
    assert resp.status_code == 200, resp.text
    by_urn = {s["urn"]: s for s in resp.json()["schools"]}
    assert by_urn[100002]["has_sixth_form"] is True
    assert by_urn[100003]["has_sixth_form"] is False
    assert by_urn[100004]["has_sixth_form"] is None


def test_detail_payload_includes_flag(client):
    resp = client.get("/api/schools/100002")
    assert resp.status_code == 200, resp.text
    assert resp.json()["school_info"]["has_sixth_form"] is True