#!/usr/bin/env python3
"""Filter the bookshelf font pool (stdin: bookshelf-listallfonts output).

Drops fonts whose file is larger than MAX_MB or that are colour/emoji
fonts. luaotfload parses a font into Lua tables the first time it is used;
for the 20-190 MB CJK/emoji faces that takes minutes and gigabytes, and a
random draw of one of them for a spine (2026-09-24: the CJK title on the
shelf, tried against up to 100 random fonts) hung the spine build until the
process was killed. Small fonts load in milliseconds.
"""
import os, re, sys

MAX_MB = 12
out = kept = dropped = 0
for line in sys.stdin:
    m = re.search(r'\[([^\]]+)\]', line)
    path = m.group(1) if m else ''
    low = (line + path).lower()
    try:
        size = os.path.getsize(path) if path else 0
    except OSError:
        size = 0
    if 'emoji' in low or size > MAX_MB * 1024 * 1024:
        dropped += 1
        continue
    sys.stdout.write(line)
    kept += 1
print(f'bookshelf-filterfonts: kept {kept}, dropped {dropped} (> {MAX_MB} MB or emoji)', file=sys.stderr)