"""
MX-Font
Copyright (c) 2021-present NAVER Corp.
MIT license
"""

from fontTools.ttLib import TTFont
from PIL import Image, ImageFont, ImageDraw
import numpy as np


def get_defined_chars(fontfile):
    ttf = TTFont(fontfile)
    chars = [chr(y) for y in ttf["cmap"].tables[0].cmap.keys()]
    return chars


def get_filtered_chars(fontpath):
    ttf = read_font(fontpath)
    defined_chars = get_defined_chars(fontpath)
    avail_chars = []

    for char in defined_chars:
        img = np.array(render(ttf, char))
        if img.mean() == 255.:
            pass
        else:
            avail_chars.append(char.encode('utf-16', 'surrogatepass').decode('utf-16'))

    return avail_chars


def read_font(fontfile, size=150):
    font = ImageFont.truetype(str(fontfile), size=size)
    return font


def render(font, char, size=(128, 128), pad=20):
    width, height = font.getsize(char)
    max_size = max(width, height)

    if width < height:
        start_w = (height - width) // 2 + pad
        start_h = pad
    else:
        start_w = pad
        start_h = (width - height) // 2 + pad

    img = Image.new("L", (max_size+(pad*2), max_size+(pad*2)), 255)
    draw = ImageDraw.Draw(img)
    draw.text((start_w, start_h), char, font=font)
    img = img.resize(size, 2)
    return img