#!/usr/bin/env python3
"""Download IoD2025 Deprivation Scores and convert to Parquet."""

import httpx
import polars as pl
from pathlib import Path

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

BASE_DATA_PATH = Path("./data_sources")
BASE_DATA_PATH.mkdir(exist_ok=True)
XLSX_PATH = BASE_DATA_PATH / "IoD2025_Scores.xlsx"
PARQUET_PATH = BASE_DATA_PATH / "IoD2025_Scores.parquet"


def download_file(url: str, output_path: Path) -> None:
    """Download file from URL."""
    print(f"Downloading from {url}...")
    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:
    """Convert Excel sheet 2 to Parquet."""
    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}")
    print(f"Excel size: {xlsx_path.stat().st_size / 1024 / 1024:.1f} MB")
    print(f"Parquet size: {parquet_path.stat().st_size / 1024 / 1024:.1f} MB")


def main() -> None:
    if not XLSX_PATH.exists():
        download_file(URL, XLSX_PATH)
    else:
        print(f"Excel file already exists at {XLSX_PATH}, skipping download")

    convert_to_parquet(XLSX_PATH, PARQUET_PATH)


if __name__ == "__main__":
    main()