"""Generate local first-frame PNG previews for the Telegram emoji catalog."""

from __future__ import annotations

import argparse
import re
import sys
from concurrent.futures import ThreadPoolExecutor, as_completed
from io import BytesIO
from pathlib import Path
from urllib.parse import quote
from urllib.request import Request, urlopen

from PIL import Image


ROOT = Path(__file__).resolve().parent
CATALOG_DIR = ROOT / "js" / "components"
OUTPUT_DIR = ROOT / "assets" / "emoji" / "telegram-previews"
ASSET_BASE_URL = "https://raw.githubusercontent.com/Tarikul-Islam-Anik/Telegram-Animated-Emojis/main/"
FILE_PATTERN = re.compile(r'"file"\s*:\s*"([^"]+\.webp)"', re.IGNORECASE)


def catalog_files() -> list[str]:
    files: set[str] = set()
    for path in sorted(CATALOG_DIR.glob("telegram-emoji-*.js")):
        files.update(FILE_PATTERN.findall(path.read_text(encoding="utf-8")))
    return sorted(files)


def preview_path(source_file: str) -> Path:
    return OUTPUT_DIR / Path(source_file).with_suffix(".png")


def generate_one(source_file: str, force: bool) -> tuple[str, str]:
    output = preview_path(source_file)
    if output.exists() and not force:
        return source_file, "cached"

    url = ASSET_BASE_URL + quote(source_file, safe="/")
    request = Request(url, headers={"User-Agent": "SHiNE emoji preview generator"})
    with urlopen(request, timeout=30) as response:
        payload = response.read()

    with Image.open(BytesIO(payload)) as source:
        source.seek(0)
        frame = source.convert("RGBA")
        frame.thumbnail((96, 96), Image.Resampling.LANCZOS)
        canvas = Image.new("RGBA", (96, 96), (0, 0, 0, 0))
        offset = ((96 - frame.width) // 2, (96 - frame.height) // 2)
        canvas.alpha_composite(frame, offset)
        output.parent.mkdir(parents=True, exist_ok=True)
        canvas.save(output, format="PNG", optimize=True)
    return source_file, "generated"


def main() -> int:
    parser = argparse.ArgumentParser()
    parser.add_argument("--force", action="store_true", help="Regenerate existing previews")
    parser.add_argument("--workers", type=int, default=8)
    args = parser.parse_args()

    files = catalog_files()
    if not files:
        print("No catalog files found", file=sys.stderr)
        return 1

    print(f"Generating {len(files)} previews into {OUTPUT_DIR}")
    failures: list[tuple[str, str]] = []
    generated = cached = 0
    with ThreadPoolExecutor(max_workers=max(1, args.workers)) as executor:
        futures = {executor.submit(generate_one, source_file, args.force): source_file for source_file in files}
        for future in as_completed(futures):
            source_file = futures[future]
            try:
                _, status = future.result()
            except Exception as error:  # noqa: BLE001 - report all asset failures together
                failures.append((source_file, str(error)))
                continue
            generated += status == "generated"
            cached += status == "cached"

    print(f"Generated: {generated}; cached: {cached}; failed: {len(failures)}")
    for source_file, error in failures:
        print(f"FAILED {source_file}: {error}", file=sys.stderr)
    return 1 if failures else 0


if __name__ == "__main__":
    raise SystemExit(main())