import argparse
import shutil
import sys
import tempfile
import polars as pl
from pathlib import Path

import httpx

from pipeline.utils import download, extract_zip

# Ofcom Connected Nations 2025 - Fixed broadband performance (output area & local authority level)
# Source: https://www.ofcom.org.uk/phones-and-broadband/coverage-and-speeds/connected-nations-20252/data-downloads-2025
PERFORMANCE_URL = "https://www.ofcom.org.uk/siteassets/resources/documents/research-and-data/multi-sector/infrastructure-research/connected-nations-2025/202507_fixed_broadband_coverage_r01.zip?v=407830"

# Pre-staged file path. Ofcom put the entire ofcom.org.uk domain behind
# Cloudflare's Managed Challenge in 2026, which requires a JS-executing
# browser to pass — no amount of User-Agent / TLS-impersonation spoofing
# (curl_cffi chrome120..131, safari17, firefox133, chrome_android) gets
# past it. When the automated download fails, the user must download the
# zip manually from the Source URL above and place it at this path.
MANUAL_ZIP_PATH = Path("manual-data/fixed_broadband_coverage.zip")


def _manual_download_instructions() -> str:
    return (
        f"\nOfcom has blocked automated downloads via Cloudflare's Managed\n"
        f"Challenge. Download the zip manually and re-run:\n\n"
        f"  1. Open in a browser:\n"
        f"     {PERFORMANCE_URL}\n"
        f"  2. Save the downloaded zip to:\n"
        f"     {MANUAL_ZIP_PATH.resolve()}\n"
        f"  3. Re-run `make -f Makefile.data property-data/broadband.parquet`\n"
    )


def _obtain_zip(dest: Path) -> None:
    """Copy the pre-staged manual zip if present; otherwise attempt download."""
    if MANUAL_ZIP_PATH.exists():
        print(f"Using pre-staged zip: {MANUAL_ZIP_PATH}")
        shutil.copyfile(MANUAL_ZIP_PATH, dest)
        return

    try:
        download(PERFORMANCE_URL, dest)
    except httpx.HTTPStatusError as e:
        if e.response.status_code == 403:
            print(_manual_download_instructions(), file=sys.stderr)
        raise


def convert_to_parquet(extract_dir: Path, parquet_path: Path) -> None:
    # Find CSV files in the extracted directory
    csv_files = list(extract_dir.rglob("*.csv"))
    if not csv_files:
        raise FileNotFoundError(f"No CSV files found in {extract_dir}")

    print(f"Found {len(csv_files)} CSV files: {[f.name for f in csv_files]}")

    frames = []
    for csv_file in sorted(csv_files):
        print(f"Reading {csv_file.name}...")
        df = pl.read_csv(csv_file, infer_schema_length=10000, encoding="utf8-lossy")
        print(f"  Shape: {df.shape}")
        frames.append(df)

    combined = pl.concat(frames, how="diagonal_relaxed")
    print(f"Combined shape: {combined.shape}")

    parquet_path.parent.mkdir(parents=True, exist_ok=True)
    combined.write_parquet(parquet_path, compression="zstd")
    print(f"Saved {parquet_path} ({combined.shape[0]} rows)")


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

    with tempfile.TemporaryDirectory() as cache_dir:
        cache = Path(cache_dir)
        zip_path = cache / "broadband_performance.zip"
        extract_dir = cache / "extracted"
        extracted_again_dir = cache / "extracted-again"

        _obtain_zip(zip_path)
        extract_zip(zip_path, extract_dir)
        extract_zip(
            extract_dir
            / "202507_fixed_coverage_r01"
            / "202507_fixed_pc_coverage_r01.zip",
            extracted_again_dir,
        )

        convert_to_parquet(extracted_again_dir, args.output)


if __name__ == "__main__":
    main()