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

URL = "https://assets.publishing.service.gov.uk/media/691ded34513046b952c500bd/File_5_IoD2025_Scores_for_the_Indices_of_Deprivation.xlsx"


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()
        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(xlsx_path: Path, parquet_path: Path) -> None:
    print("Reading Excel file (sheet 2)...")

    # Read the 2nd sheet (index 1) - IoD2025 Scores
    df = pl.read_excel(
        xlsx_path,
        sheet_id=2,  # 1-indexed, so 2 = second sheet
    )

    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 and convert Index of Deprivation data"
    )
    parser.add_argument(
        "--output", type=Path, required=True, help="Output parquet file path"
    )
    args = parser.parse_args()

    with tempfile.TemporaryDirectory() as cache_dir:
        xlsx_path = Path(cache_dir) / "IoD2025_Scores.xlsx"
        download_file(URL, xlsx_path)
        convert_to_parquet(xlsx_path, args.output)


if __name__ == "__main__":
    main()