"""Download Historic England conservation area polygons.

Source: Historic England Conservation Areas
License: Open Government Licence v3.0
"""

import argparse
from pathlib import Path

import httpx
import pyogrio

URL = (
    "https://opendata-historicengland.hub.arcgis.com/api/download/v1/items/"
    "446bc9bf8b5b440386d0c504caa3dac5/geoPackage?layers=0"
)


def main() -> None:
    parser = argparse.ArgumentParser(
        description="Download Historic England conservation area polygons"
    )
    parser.add_argument(
        "--output", type=Path, required=True, help="Output GeoPackage file path"
    )
    args = parser.parse_args()
    args.output.parent.mkdir(parents=True, exist_ok=True)
    tmp_path = args.output.with_name(f"{args.output.stem}.tmp{args.output.suffix}")

    print("Downloading Historic England conservation areas...")
    with httpx.stream("GET", URL, follow_redirects=True, timeout=300) as response:
        response.raise_for_status()
        with tmp_path.open("wb") as fh:
            for chunk in response.iter_bytes():
                fh.write(chunk)

    info = pyogrio.read_info(tmp_path)
    features = info.get("features", 0)
    geometry_type = info.get("geometry_type")
    if features <= 0:
        raise ValueError("Downloaded conservation areas file contains no features")
    if "Polygon" not in str(geometry_type):
        raise ValueError(f"Expected polygon geometry, got {geometry_type!r}")

    tmp_path.replace(args.output)
    size_mb = args.output.stat().st_size / (1024 * 1024)
    print(f"Saved {features} conservation areas to {args.output} ({size_mb:.1f} MB)")


if __name__ == "__main__":
    main()