"""Tests for sitemap generation (spec 2026-08-20, workstream W1).

The sitemap is built from the in-memory school DataFrame, so these inject a
small frame via monkeypatch rather than touching a database.
"""

import numpy as np
import pandas as pd
import pytest


def _schools_df() -> pd.DataFrame:
    """Two schools: one with results, one with neither results nor Ofsted."""
    base = {
        "local_authority": "Testshire",
        "school_type": "Academy",
        "phase": "Primary",
        "year": 202425,
        "ofsted_date": None,
    }
    return pd.DataFrame(
        [
            {**base, "urn": 100001, "school_name": "Alpha Primary",
             "rwm_expected_pct": 62.0, "attainment_8_score": np.nan,
             "ofsted_grade": 2.0},
            {**base, "urn": 100002, "school_name": "Ghost Primary",
             "rwm_expected_pct": np.nan, "attainment_8_score": np.nan,
             "ofsted_grade": np.nan},
        ]
    )


@pytest.fixture()
def sitemap(monkeypatch) -> str:
    """The sitemap index."""
    from backend import app as app_module

    monkeypatch.setattr(app_module, "load_school_data", _schools_df)
    return app_module.build_sitemap()


@pytest.fixture()
def schools_child(monkeypatch) -> str:
    """The first school child sitemap, where school URLs actually live."""
    from backend import app as app_module

    monkeypatch.setattr(app_module, "load_school_data", _schools_df)
    return app_module.build_sitemaps()["schools-1.xml"]


@pytest.fixture()
def static_child(monkeypatch) -> str:
    from backend import app as app_module

    monkeypatch.setattr(app_module, "load_school_data", _schools_df)
    return app_module.build_sitemaps()["static.xml"]


def test_every_loc_uses_the_www_host(sitemaps):
    # The apex 301s to www. A <loc> that redirects burns a crawl per URL.
    # Checked across every file, index included, not just one.
    #
    # A child can legitimately be empty — this fixture holds two schools and no
    # town clearing the threshold — so the presence check applies only to files
    # that carry URLs. The absence check applies to all of them.
    for name, xml in sitemaps.items():
        assert "https://schoolcompare.co.uk" not in xml, name
        if "<loc>" in xml:
            assert "https://www.schoolcompare.co.uk" in xml, name


def test_school_with_results_is_listed(schools_child):
    assert "/school/100001-alpha-primary" in schools_child


def test_school_with_no_results_and_no_ofsted_is_omitted(schools_child):
    # Nothing for a search result to say about it. Submitting it spends crawl
    # budget and drags the corpus-wide quality signal down.
    #
    # Asserted against the child, not the index: the index carries no school
    # URLs at all, so it would pass this trivially and prove nothing.
    assert "/school/100002" not in schools_child


def test_no_invented_priority_or_changefreq(sitemaps):
    # Google ignores both. They were noise dressed as signal.
    for name, xml in sitemaps.items():
        assert "<priority>" not in xml, name
        assert "<changefreq>" not in xml, name


def test_ofsted_date_becomes_lastmod(monkeypatch):
    from backend import app as app_module
    import datetime

    def _df():
        base = _schools_df()
        base.loc[base["urn"] == 100001, "ofsted_date"] = datetime.date(2024, 3, 14)
        return base

    monkeypatch.setattr(app_module, "load_school_data", _df)
    xml = app_module.build_sitemaps()["schools-1.xml"]
    assert "<lastmod>2024-03-14</lastmod>" in xml


def test_no_lastmod_invented_when_date_unknown(monkeypatch):
    # An always-now lastmod is a claim Google learns to distrust. Absent
    # honestly means unknown.
    from backend import app as app_module

    def _df():
        df = _schools_df()
        df["ofsted_date"] = None
        return df

    monkeypatch.setattr(app_module, "load_school_data", _df)
    # The child only. The index legitimately carries a lastmod, because there
    # it means "when this sitemap file changed", which we do know.
    xml = app_module.build_sitemaps()["schools-1.xml"]
    assert "<lastmod>" not in xml


def test_static_routes_are_listed(static_child):
    for path in ("/", "/rankings", "/compare", "/admissions"):
        assert f"<loc>https://www.schoolcompare.co.uk{path}</loc>" in static_child


@pytest.fixture()
def sitemaps(monkeypatch) -> dict:
    from backend import app as app_module

    monkeypatch.setattr(app_module, "load_school_data", _schools_df)
    return app_module.build_sitemaps()


def test_index_lists_each_child(sitemaps):
    index = sitemaps["sitemap.xml"]
    assert "<sitemapindex" in index
    assert "https://www.schoolcompare.co.uk/sitemaps/static.xml" in index
    assert "https://www.schoolcompare.co.uk/sitemaps/schools-1.xml" in index


def test_index_carries_no_url_elements(sitemaps):
    # A sitemap index holds <sitemap> entries only; mixing in <url> is invalid.
    assert "<url>" not in sitemaps["sitemap.xml"]


def test_index_does_not_list_itself(sitemaps):
    assert "<loc>https://www.schoolcompare.co.uk/sitemap.xml</loc>" not in sitemaps["sitemap.xml"]


def test_static_child_holds_the_static_routes(sitemaps):
    static = sitemaps["static.xml"]
    for path in ("/", "/rankings", "/compare", "/admissions"):
        assert f"<loc>https://www.schoolcompare.co.uk{path}</loc>" in static


def test_school_child_holds_the_schools(sitemaps):
    assert "/school/100001-alpha-primary" in sitemaps["schools-1.xml"]


def test_children_are_chunked_under_the_limit(monkeypatch):
    # Sitemaps cap at 50,000 URLs per file. Chunk at 10,000 so a child stays
    # small enough to eyeball in Search Console.
    from backend import app as app_module
    import pandas as _pd

    rows = [
        {"urn": 200000 + i, "school_name": f"School {i}", "year": 202425,
         "rwm_expected_pct": 60.0, "attainment_8_score": None,
         "ofsted_grade": 2.0, "ofsted_date": None}
        for i in range(10_001)
    ]
    monkeypatch.setattr(app_module, "load_school_data", lambda: _pd.DataFrame(rows))

    maps = app_module.build_sitemaps()
    assert maps["schools-1.xml"].count("<url>") == 10_000
    assert maps["schools-2.xml"].count("<url>") == 1


def test_build_sitemap_still_returns_the_index(sitemap):
    # lifespan and the admin endpoint call build_sitemap(); keep it working.
    assert "<sitemapindex" in sitemap


def test_school_with_results_in_an_earlier_year_is_still_listed(monkeypatch):
    """Regression: The Mallard Academy (150367).

    Real KS2 results 2015-16 to 2018-19, then null rows from 2022-23 onward
    because the school stopped reporting. The first cut tested the latest
    year's row alone and dropped it, along with ~220 others, even though its
    detail page shows all four years of results.
    """
    from backend import app as app_module
    import pandas as _pd

    base = {"local_authority": "Testshire", "school_type": "Academy",
            "phase": "Primary", "ofsted_date": None, "ofsted_grade": np.nan,
            "attainment_8_score": np.nan, "urn": 150367,
            "school_name": "Mallard Academy"}
    df = _pd.DataFrame([
        {**base, "year": 201819, "rwm_expected_pct": 67.0},
        {**base, "year": 202324, "rwm_expected_pct": np.nan},
        {**base, "year": 202425, "rwm_expected_pct": np.nan},
    ])
    monkeypatch.setattr(app_module, "load_school_data", lambda: df)

    xml = app_module.build_sitemaps()["schools-1.xml"]
    assert "/school/150367-mallard-academy" in xml


def test_school_with_no_results_in_any_year_is_still_omitted(monkeypatch):
    """The fix must not turn into "list everything"."""
    from backend import app as app_module
    import pandas as _pd

    base = {"local_authority": "Testshire", "school_type": "Academy",
            "phase": "Primary", "ofsted_date": None, "ofsted_grade": np.nan,
            "attainment_8_score": np.nan, "rwm_expected_pct": np.nan,
            "urn": 100002, "school_name": "Ghost Primary"}
    df = _pd.DataFrame([{**base, "year": y} for y in (202324, 202425)])
    monkeypatch.setattr(app_module, "load_school_data", lambda: df)

    assert "/school/100002" not in app_module.build_sitemaps()["schools-1.xml"]


def _places_df() -> pd.DataFrame:
    base = {
        "local_authority": "Essex", "school_type": "Academy",
        "phase": "Primary", "year": 202425, "ofsted_grade": 2.0,
        "ofsted_date": None, "attainment_8_score": np.nan,
        "town": "Brentwood", "postcode": "CM13 1AA",
    }
    return pd.DataFrame([
        {**base, "urn": 100000 + i, "school_name": f"Brentwood School {i}",
         "rwm_expected_pct": 60.0}
        for i in range(6)
    ])


@pytest.fixture()
def place_sitemaps(monkeypatch) -> dict:
    from backend import app as app_module

    monkeypatch.setattr(app_module, "load_school_data", _places_df)
    monkeypatch.setattr(app_module, "_place_registry", None)
    return app_module.build_sitemaps()


def test_place_children_are_listed_in_the_index(place_sitemaps):
    index = place_sitemaps["sitemap.xml"]
    assert "/sitemaps/places-1.xml" in index
    assert "/sitemaps/outcodes-1.xml" in index


def test_town_and_authority_urls_use_their_own_namespaces(place_sitemaps):
    xml = place_sitemaps["places-1.xml"]
    assert "<loc>https://www.schoolcompare.co.uk/schools/brentwood</loc>" in xml
    assert "<loc>https://www.schoolcompare.co.uk/schools/authority/essex</loc>" in xml


def test_outcode_urls_live_in_their_own_child(place_sitemaps):
    assert "/schools/near/cm13" in place_sitemaps["outcodes-1.xml"]
    assert "/schools/near/cm13" not in place_sitemaps["places-1.xml"]


def test_place_urls_carry_no_priority_or_changefreq(place_sitemaps):
    for name in ("places-1.xml", "outcodes-1.xml"):
        assert "<priority>" not in place_sitemaps[name]
        assert "<changefreq>" not in place_sitemaps[name]


def test_phase_variants_are_submitted_where_the_phase_clears_the_threshold(place_sitemaps):
    # "primary schools in beccles" is the query shape the baseline showed, so
    # each variant is its own page and has to be submitted. Emitting only the
    # bare place URL left ~950 of them reachable by nothing.
    xml = place_sitemaps["places-1.xml"]
    assert "<loc>https://www.schoolcompare.co.uk/schools/brentwood/primary</loc>" in xml


def test_a_phase_below_its_own_threshold_is_not_submitted(place_sitemaps):
    # The fixture is six primaries and no secondaries.
    xml = place_sitemaps["places-1.xml"]
    assert "/schools/brentwood/secondary" not in xml


def test_outcodes_get_no_phase_variants(place_sitemaps):
    # Nobody searches "primary schools in CM13"; the routes do not exist.
    xml = place_sitemaps["outcodes-1.xml"]
    assert "/primary" not in xml and "/secondary" not in xml


def test_authority_phase_variants_are_submitted_in_their_own_namespace(place_sitemaps):
    """302 of these were already in the sitemap, and every one 404'd.

    The spec gives authorities a phase route; the plan built the bare
    authority route and dropped it. Nothing noticed because the sitemap was
    written from the registry, which was right, while the routes were written
    by hand. This test fails if the URL ever leaves the sitemap; the e2e
    journey fails if the route ever leaves the app.
    """
    xml = place_sitemaps["places-1.xml"]
    assert ("<loc>https://www.schoolcompare.co.uk"
            "/schools/authority/essex/primary</loc>") in xml
    # And never in the town namespace, which is a different set of schools.
    assert "/schools/essex/primary" not in xml