#!/usr/bin/env python3

import sys, os, unicodedata, argparse
import chardet                     # install with `pip3 install chardet`
from fontTools.ttLib import TTFont # install with `pip3 install fonttools`

FONTS_PATHS = [
   "/usr/share/fonts",
   "/usr/local/share/fonts",
   "~/.fonts",
   "~/.local/share/fonts",
]

def is_font_file(file):
   return os.path.splitext(file)[1] in (".otf", ".ttf", ".ttc")

def font_files(path):
   path = os.path.expanduser(path)
   path = os.path.expandvars(path)
   if not os.path.exists(path):
      return
   if os.path.isfile(path):
      if is_font_file(path):
         yield path
   else:
      for root, dirs, files in os.walk(path):
         for file in files:
            if is_font_file(file):
               yield os.path.join(root, file)

def all_font_files(paths):
   return (file for path in paths for file in font_files(path))

def get_font_name(font):
   FONT_SPECIFIER_NAME_ID = 4
   for record in font["name"].names:
      if record.nameID != FONT_SPECIFIER_NAME_ID:
         continue
      enc = chardet.detect(record.string)
      name = record.string.decode(enc["encoding"])
      if '\0' in name:
         name = record.string.decode("UTF-16 BE")
      return name
   raise Exception("cannot find font name")

def get_font_chars(font):
   cs = set()
   for table in font["cmap"].tables:
      cs.update(table.cmap.keys())
   return cs

def get_matching_fonts(paths, chars):
   fonts = {}
   for font_path in all_font_files(paths):
      font = TTFont(font_path, fontNumber=0)
      font_name, font_chars = get_font_name(font), get_font_chars(font)
      font.close()
      if font_chars.issuperset(chars):
         fonts.setdefault(font_name, set()).add(font_path)
   return fonts

if __name__ == "__main__":
   parser = argparse.ArgumentParser(description="Locate fonts that can display a set of characters")
   parser.add_argument("char", nargs="*", help="a character to look for")
   args = parser.parse_args()
   chars = set()
   for char in args.char:
      if len(char) > 1:
         char = int(char, 16)
      else:
         char = ord(char)
      chars.add(char)
   font_names = get_matching_fonts(FONTS_PATHS, chars)
   for name in sorted(font_names):
      print(name)