import argparse
import httpx
import polars as pl
from pathlib import Path
import tempfile

# Management information - state-funded schools - latest inspections (as at 30 Apr 2025)
# Source: https://www.gov.uk/government/statistical-data-sets/monthly-management-information-ofsteds-school-inspections-outcomes
URL = "https://assets.publishing.service.gov.uk/media/681cd390275cb67b18d870fc/Management_information_-_state-funded_schools_-_latest_inspections_as_at_30_Apr_2025.csv"


def download_file(url: str, output_path: Path) -> None:
    with httpx.stream("GET", url, follow_redirects=True, timeout=60) as response:
        response.raise_for_status()  # pyright: ignore[reportUnusedCallResult]
        total = int(response.headers.get("content-length", 0))
        downloaded = 0
        with open(output_path, "wb") as f:
            for chunk in response.iter_bytes(chunk_size=8192):
                f.write(chunk)
                downloaded += len(chunk)
                if total:
                    print(
                        f"\rDownloaded {downloaded / 1024 / 1024:.1f} MB / {total / 1024 / 1024:.1f} MB",
                        end="",
                    )
    print(f"\nSaved to {output_path}")


def convert_to_parquet(csv_path: Path, parquet_path: Path) -> None:
    print("Reading CSV...")

    df = pl.read_csv(
        csv_path,
        infer_schema_length=10000,
        encoding="utf8-lossy",
        null_values=["NULL", "Not applicable"],
    )

    print(f"Shape: {df.shape}")
    print(f"Columns: {df.columns}")

    df.write_parquet(parquet_path, compression="zstd")
    print(f"Saved to {parquet_path}")


def main() -> None:
    parser = argparse.ArgumentParser(
        description="Download Ofsted school inspection outcomes data"
    )
    parser.add_argument(
        "--output", type=Path, required=True, help="Output parquet file path"
    )
    args = parser.parse_args()

    with tempfile.TemporaryDirectory() as cache_dir:
        csv_path = Path(cache_dir) / "ofsted_latest_inspections.csv"
        download_file(URL, csv_path)
        convert_to_parquet(csv_path, args.output)


if __name__ == "__main__":
    main()