#!/usr/bin/env python3
#
# Copyright 2015-2022 The Mumble Developers. All rights reserved.
# Use of this source code is governed by a BSD-style license
# that can be found in the LICENSE file at the root of the
# Mumble source tree or at <https://www.mumble.info/LICENSE>.
#
#
# extract-emojione-flags.py
# Extract SVG flags from the Emoji One emoji collection.
#
# This script walks the Emoji One SVG collection and extracts
# flag emojis.
#
# Emoji One's emojis all use the Unicode code points (base 16) as
# their on-disk names. If a character consists of multiple code points,
# they are separated by a dash ('-').
#
# This script walks all the Emoji One SVGs, and finds the ones which
# only contain symbols in the Regional Indicator Symbol range.
# These are flag emojis.
#
# The flags are then copied to the destination directory, and named
# as the region's lower case ISO_3166-1_alpha-2 code with the ".svg"
# extension.

from __future__ import (unicode_literals, print_function, division)

import os
import shutil
import argparse

# Beginning and end of the Regional Indicator Symbol range,
# as defined by Unicode 6.0's emoji support.
#
# See https://en.wikipedia.org/wiki/Regional_Indicator_Symbol
# for more information.
REGIONAL_INDICATOR_SYMBOL_LETTER_A = 0x1F1E6
REGIONAL_INDICATOR_SYMBOL_LETTER_Z = 0x1F1FF

def is_region(points):
    for point in points:
        if point > REGIONAL_INDICATOR_SYMBOL_LETTER_Z \
                or point < REGIONAL_INDICATOR_SYMBOL_LETTER_A:
                    return False	
    return True


def region_name(points):
    name = ''
    for point in points:
        name += chr(point - REGIONAL_INDICATOR_SYMBOL_LETTER_A + ord('a'))
    return name


def main():
    parser = argparse.ArgumentParser(description="Extract SVG flags from the Emoji One (now joypixels) emoji collection.")
    parser.add_argument("emojione-svg-dir", help="Path to the directory containing Emoji One SVGs, such as $EMOJIONE_SRC_TREE/assets/svg")
    parser.add_argument("dst-dir", help="Path to which the resulting SVGs shall be written")

    args = parser.parse_args()


    files = os.listdir(args.emojione_svg_dir)
    for fn in files:
        base, ext = os.path.splitext(fn.lower())
        if not ext == '.svg':
            continue

        pointsStr = base.split('-')
        points = [int(p, 16) for p in pointsStr]

        if is_region(points):
            name = region_name(points)
            svgName = name + '.svg'
            shutil.copy(os.path.join(args.emojione_svg_dir, fn),
                    os.path.join(args.dst_dir, svgName))

if __name__ == '__main__':
    main()