import polars as pl
from pyproj import Transformer

from pipeline.download.places import (
    _assign_london_display_city,
    _display_city_from_tags,
    _is_dlr_station,
    _is_tram_station,
    _naptan_dlr_stations,
    _ofs_universities,
    _select_university_name,
    _station_display_name,
)

WGS84_TO_BNG = Transformer.from_crs("EPSG:4326", "EPSG:27700", always_xy=True)


def _postcode_row(postcode: str, lat: float, lon: float, *, london: bool) -> dict:
    easting, northing = WGS84_TO_BNG.transform(lon, lat)
    return {
        "pcds": postcode,
        "doterm": None,
        "ctry25cd": "E92000001",
        "east1m": int(round(easting)),
        "north1m": int(round(northing)),
        "rgn25cd": "E12000007" if london else "E12000008",
        "lad25cd": "E09000008" if london else "E07000208",
        "cty25cd": "E13000002" if london else "E10000030",
    }


def test_dlr_light_rail_is_not_treated_as_tram():
    dlr_tags = {
        "name": "Lewisham DLR",
        "railway": "station",
        "station": "light_rail",
        "network": "Docklands Light Railway",
    }

    assert _is_dlr_station(dlr_tags)
    assert not _is_tram_station(dlr_tags)
    assert _station_display_name("Lewisham DLR", dlr_tags) == "Lewisham DLR station"
    assert (
        _station_display_name("Tower Gateway Station DLR", dlr_tags)
        == "Tower Gateway DLR station"
    )


def test_tram_light_rail_is_still_excluded():
    tram_tags = {
        "name": "East Croydon",
        "railway": "station",
        "station": "light_rail",
        "network": "London Trams",
    }

    assert not _is_dlr_station(tram_tags)
    assert _is_tram_station(tram_tags)


def test_naptan_dlr_stations_are_deduplicated_by_atco_code(tmp_path):
    naptan = tmp_path / "naptan.parquet"
    pl.DataFrame(
        {
            "id": [
                "4900ZZDLSHA3",
                "9400ZZDLSHA",
                "4900ZZDLGRE1",
                "490002076RV",
                "4900ZZLUBNK",
            ],
            "name": [
                "Shadwell DLR",
                "Shadwell DLR Station",
                "Greenwich Station",
                "Tower Gateway Station DLR",
                "Bank",
            ],
            "category": [
                "Tube station",
                "Tube station",
                "Rail station",
                "Bus stop",
                "Tube station",
            ],
            "lat": [51.51156, 51.511693, 51.47794, 51.510575, 51.5131],
            "lng": [-0.055595, -0.056643, -0.01442, -0.07514, -0.0894],
        }
    ).write_parquet(naptan)

    stations = _naptan_dlr_stations(naptan)

    assert [station["name"] for station in stations] == [
        "Greenwich DLR station",
        "Shadwell DLR station",
    ]
    shadwell = next(
        station for station in stations if station["name"].startswith("Shadwell")
    )
    assert shadwell["lat"] == (51.51156 + 51.511693) / 2
    assert shadwell["place_type"] == "station"
    assert shadwell["travel_destination"] is True


def test_select_university_name_prefers_public_trading_name_for_noisy_legal_name():
    assert (
        _select_university_name(
            "The Chancellor, Masters and Scholars of the University of Oxford",
            "Oxford University\nThe University of Oxford",
        )
        == "Oxford University"
    )
    assert (
        _select_university_name(
            "Bournemouth University Higher Education Corporation",
            "Bournemouth University",
        )
        == "Bournemouth University"
    )
    assert (
        _select_university_name("The University of Surrey", "Not applicable")
        == "University of Surrey"
    )


def test_ofs_universities_extracts_university_title_rows_with_postcode_coords():
    raw_register = pl.DataFrame(
        [
            ["OfS Register", None, None, None],
            ["Note row", None, None, None],
            [
                "Provider's legal name",
                "Provider's trading name(s)",
                "Provider's contact address",
                "Does the provider have the right to use university in its title?",
            ],
            [
                "The Chancellor, Masters and Scholars of the University of Oxford",
                "Oxford University\nThe University of Oxford",
                "University Offices\nWellington Square\nOxford\nOX1 2JD\nUnited Kingdom",
                "Yes",
            ],
            [
                "Example College",
                "Not applicable",
                "Example Street\nLondon\nSW1A 1AA\nUnited Kingdom",
                "No",
            ],
        ],
        orient="row",
    )

    universities, skipped = _ofs_universities(
        raw_register, {"OX12JD": (51.7585, -1.2643)}
    )

    assert skipped == 0
    assert universities == [
        {
            "name": "Oxford University",
            "place_type": "university",
            "lat": 51.7585,
            "lon": -1.2643,
            "population": 0,
            "travel_destination": True,
            "display_city": None,
        }
    ]


def test_display_city_from_tags_uses_explicit_london_context():
    assert _display_city_from_tags({"is_in": "Croydon, London, UK"}) == "London"
    assert _display_city_from_tags({"is_in": "Croydon, Cambridgeshire, UK"}) is None


def test_assign_london_display_city_uses_nearest_active_postcode_admin(tmp_path):
    postcodes = tmp_path / "postcodes.parquet"
    pl.DataFrame(
        [
            _postcode_row("CR0 1SZ", 51.371273, -0.101793, london=True),
            _postcode_row("KT19 8AG", 51.3326, -0.2678, london=False),
        ]
    ).write_parquet(postcodes)

    places = [
        {
            "name": "Croydon",
            "place_type": "town",
            "lat": 51.3713049,
            "lon": -0.101957,
            "population": 173314,
            "travel_destination": False,
            "display_city": None,
        },
        {
            "name": "East Croydon railway station",
            "place_type": "station",
            "lat": 51.375845,
            "lon": -0.092732,
            "population": 0,
            "travel_destination": True,
            "display_city": None,
        },
        {
            "name": "Epsom",
            "place_type": "town",
            "lat": 51.3326,
            "lon": -0.2678,
            "population": 31489,
            "travel_destination": False,
            "display_city": None,
        },
    ]

    assigned = _assign_london_display_city(places, postcodes)

    assert assigned == 2
    assert [place["display_city"] for place in places] == ["London", "London", None]