"""Download England country boundary GeoJSON from ONS Open Geography Portal.

Source: ONS Countries (December 2024) Boundaries UK BGC (Generalised Clipped)
Licence: OGL v3
"""

import argparse
from pathlib import Path

import httpx

# ArcGIS REST API — query for England only, generalised (BGC) resolution
URL = (
    "https://services1.arcgis.com/ESMARspQHYMw9BZ9/arcgis/rest/services/"
    "Countries_December_2024_Boundaries_UK_BGC/FeatureServer/0/query"
    "?where=CTRY24NM%3D%27England%27&outFields=CTRY24NM&f=geojson"
)


def main() -> None:
    parser = argparse.ArgumentParser(
        description="Download England country boundary GeoJSON"
    )
    parser.add_argument(
        "--output", type=Path, required=True, help="Output GeoJSON file path"
    )
    args = parser.parse_args()
    args.output.parent.mkdir(parents=True, exist_ok=True)

    print("Downloading England boundary from ONS...")
    response = httpx.get(URL, follow_redirects=True, timeout=60)
    response.raise_for_status()

    data = response.json()
    features = data.get("features", [])
    if len(features) != 1:
        raise ValueError(f"Expected 1 feature for England, got {len(features)}")

    args.output.write_text(response.text)
    size_kb = args.output.stat().st_size / 1024
    print(f"Saved to {args.output} ({size_kb:.0f} KB)")


if __name__ == "__main__":
    main()