import argparse
import sys
import urllib.request
from concurrent.futures import ThreadPoolExecutor, as_completed
from pathlib import Path

from pipeline.transform.transform_poi import NAPTAN_EMOJIS, _CATEGORIES

GLYPHS_BASE = "https://protomaps.github.io/basemaps-assets/fonts"
TWEMOJI_BASE = "https://cdn.jsdelivr.net/gh/twitter/twemoji@14.0.2/assets/72x72"

# Font stacks used by @protomaps/basemaps with lang='en'
FONT_STACKS = ["Noto Sans Regular", "Noto Sans Italic", "Noto Sans Medium"]

# Fallback emoji not in any category
_FALLBACK_EMOJIS = ["📍"]


def collect_twemoji_codes() -> list[str]:
    """Derive twemoji hex codes from transform_poi categories.

    Matches the frontend's emojiToTwemojiUrl() which does
    emoji.codePointAt(0).toString(16).
    """
    emojis: set[str] = set()

    for _group, _name, emoji, _osm_keys in _CATEGORIES:
        emojis.add(emoji)

    for emoji in NAPTAN_EMOJIS.values():
        emojis.add(emoji)

    for emoji in _FALLBACK_EMOJIS:
        emojis.add(emoji)

    # First codepoint hex, matching frontend logic
    return sorted({f"{ord(e[0]):x}" for e in emojis})


def download_file(url: str, dest: Path) -> tuple[bool, str]:
    """Download a single file. Returns (success, url)."""
    dest.parent.mkdir(parents=True, exist_ok=True)
    try:
        urllib.request.urlretrieve(url, dest)
        return True, url
    except urllib.error.HTTPError as e:
        print(f"  {e.code} {url}", file=sys.stderr)
        return False, url
    except Exception as e:
        print(f"  ERROR {url}: {e}", file=sys.stderr)
        return False, url


def main():
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument(
        "--output",
        type=Path,
        required=True,
        help="Output directory",
    )
    args = parser.parse_args()
    out: Path = args.output

    twemoji_codes = collect_twemoji_codes()

    # Build download list
    tasks: list[tuple[str, Path]] = []

    # Font glyphs: 256 range files per font stack
    for font in FONT_STACKS:
        font_encoded = font.replace(" ", "%20")
        font_dir = out / "fonts" / font
        for start in range(0, 65536, 256):
            end = start + 255
            name = f"{start}-{end}.pbf"
            url = f"{GLYPHS_BASE}/{font_encoded}/{name}"
            tasks.append((url, font_dir / name))

    # Twemoji PNGs
    twemoji_dir = out / "twemoji"
    for code in twemoji_codes:
        url = f"{TWEMOJI_BASE}/{code}.png"
        tasks.append((url, twemoji_dir / f"{code}.png"))

    # Skip already-downloaded files
    remaining = [(url, dest) for url, dest in tasks]

    print(f"Downloading {len(remaining)} assets")

    ok = 0
    fail = 0
    with ThreadPoolExecutor(max_workers=20) as pool:
        futures = {
            pool.submit(download_file, url, dest): url for url, dest in remaining
        }
        for future in as_completed(futures):
            success, url = future.result()
            if success:
                ok += 1
            else:
                fail += 1

    print(f"Done: {ok} downloaded, {fail} failed")


if __name__ == "__main__":
    main()