"""Download UK PMTiles extract from the latest Protomaps daily build."""

import argparse
import platform
import stat
import subprocess
import sys
import tarfile
import urllib.request
from datetime import datetime, timedelta
from io import BytesIO
from pathlib import Path

PROTOMAPS_BASE = "https://build.protomaps.com"
UK_BBOX = "-10.5,49.5,2.5,61"
MAX_AGE_DAYS = 14


def find_latest_build() -> str:
    """Find the most recent available Protomaps daily build."""
    today = datetime.utcnow().date()
    for i in range(MAX_AGE_DAYS):
        d = today - timedelta(days=i)
        url = f"{PROTOMAPS_BASE}/{d:%Y%m%d}.pmtiles"
        req = urllib.request.Request(url, method="HEAD")
        try:
            urllib.request.urlopen(req)
            print(f"Found build: {d:%Y%m%d}")
            return url
        except urllib.error.HTTPError:
            continue
    print(
        f"ERROR: No Protomaps build found in the last {MAX_AGE_DAYS} days",
        file=sys.stderr,
    )
    sys.exit(1)


def ensure_pmtiles_cli(bin_path: Path, version: str) -> None:
    """Download the pmtiles CLI if not already present."""
    if bin_path.exists():
        return
    machine = platform.machine()
    if machine == "x86_64":
        arch = "x86_64"
    elif machine == "aarch64":
        arch = "arm64"
    else:
        arch = machine
    url = (
        f"https://github.com/protomaps/go-pmtiles/releases/download/"
        f"v{version}/go-pmtiles_{version}_Linux_{arch}.tar.gz"
    )
    print(f"Downloading pmtiles CLI v{version}...")
    data = urllib.request.urlopen(url).read()
    with tarfile.open(fileobj=BytesIO(data), mode="r:gz") as tar:
        member = tar.getmember("pmtiles")
        f = tar.extractfile(member)
        assert f is not None
        bin_path.parent.mkdir(parents=True, exist_ok=True)
        bin_path.write_bytes(f.read())
    bin_path.chmod(bin_path.stat().st_mode | stat.S_IEXEC)


def main():
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument("--output", type=Path, required=True, help="Output .pmtiles path")
    parser.add_argument(
        "--pmtiles-version", default="1.22.3", help="go-pmtiles release version"
    )
    args = parser.parse_args()

    bin_path = args.output.parent / "pmtiles"
    ensure_pmtiles_cli(bin_path, args.pmtiles_version)

    source_url = find_latest_build()
    print(f"Extracting UK tiles from {source_url}...")

    subprocess.run(
        [str(bin_path), "extract", source_url, str(args.output), f"--bbox={UK_BBOX}"],
        check=True,
    )

    size_mb = args.output.stat().st_size / (1024 * 1024)
    print(f"Wrote {args.output} ({size_mb:.1f} MB)")


if __name__ == "__main__":
    main()