from __future__ import annotations

import importlib.util
from pathlib import Path
import sys

import pytest


ROOT = Path(__file__).resolve().parents[2]


def load_sample_preparer():
    script_path = ROOT / "scripts" / "prepare_operator_real_data_samples.py"
    spec = importlib.util.spec_from_file_location("operator_sample_preparer", script_path)
    assert spec is not None
    assert spec.loader is not None
    module = importlib.util.module_from_spec(spec)
    sys.modules[spec.name] = module
    spec.loader.exec_module(module)
    return module


def test_operator_sample_registry_includes_kempen_reference_and_background_candidates() -> None:
    module = load_sample_preparer()

    expected_reference_slugs = {"geel", "mol", "turnhout", "herentals", "balen", "retie", "westerlo"}
    expected_background_slugs = {"postel_bos", "lommel_heide", "kasterlee_bos"}

    assert expected_reference_slugs.issubset(module.SAMPLES)
    assert expected_background_slugs.issubset(module.SAMPLES)
    assert all(not module.SAMPLES[slug].allow_empty_reference for slug in expected_reference_slugs)
    assert all(module.SAMPLES[slug].allow_empty_reference for slug in expected_background_slugs)
    assert all(module.SAMPLES[slug].sample_role == "background_candidate" for slug in expected_background_slugs)


def test_background_candidate_can_write_empty_reference_geojson(tmp_path: Path, monkeypatch) -> None:
    module = load_sample_preparer()

    class EmptyFeatureResponse:
        headers = {"content-type": "application/geo+json"}

        def raise_for_status(self) -> None:
            return None

        def json(self) -> dict:
            return {"type": "FeatureCollection", "features": []}

    class FakeRequests:
        @staticmethod
        def get(*args, **kwargs):
            return EmptyFeatureResponse()

    monkeypatch.setattr(module, "requests", FakeRequests)
    monkeypatch.setattr(module, "prepared_url", lambda url, params: f"{url}?prepared=true")

    sample = module.OperatorSample(
        slug="background",
        display_name="Background",
        center_lon=5.0,
        center_lat=51.0,
        allow_empty_reference=True,
        sample_role="background_candidate",
    )
    reference_path = tmp_path / "background.geojson"

    source_url, feature_count = module.fetch_reference(sample, reference_path, [4.9, 50.9, 5.1, 51.1])

    assert source_url.endswith("?prepared=true")
    assert feature_count == 0
    payload = reference_path.read_text(encoding="utf-8")
    assert '"features": []' in payload
    assert '"sample_role": "background_candidate"' in payload


def test_reference_sample_still_rejects_empty_grb_response(tmp_path: Path, monkeypatch) -> None:
    module = load_sample_preparer()

    class EmptyFeatureResponse:
        def raise_for_status(self) -> None:
            return None

        def json(self) -> dict:
            return {"type": "FeatureCollection", "features": []}

    class FakeRequests:
        @staticmethod
        def get(*args, **kwargs):
            return EmptyFeatureResponse()

    monkeypatch.setattr(module, "requests", FakeRequests)
    monkeypatch.setattr(module, "prepared_url", lambda url, params: f"{url}?prepared=true")

    sample = module.OperatorSample(
        slug="urban",
        display_name="Urban",
        center_lon=5.0,
        center_lat=51.0,
    )

    with pytest.raises(SystemExit, match="returned no building features"):
        module.fetch_reference(sample, tmp_path / "urban.geojson", [4.9, 50.9, 5.1, 51.1])