import qrcode, os, sys
from PIL import Image, ImageDraw, ImageFont, ImagePalette, ImageColor

def main(id):
    fontHeightMax = 40
    fontsize = 1
    qr = qrcode.QRCode()
    qr.border = 2
    qr.add_data(id)
    qr.make(fit=True)
    img = qr.make_image()
    img = img.transform((250, 294), Image.Transform.EXTENT, (0, 0, 250, 294), fillcolor='white')
    cwd = os.path.dirname(os.path.abspath(__file__))
    fontfile = os.path.join(cwd, 'fonts', 'Helvetica.ttf')
    font = ImageFont.truetype(fontfile, fontsize)
    while font.getsize(id)[1] <= fontHeightMax and font.getsize(id)[0] <= 240:
        fontsize += 1
        font = ImageFont.truetype(fontfile, fontsize)
    fontsize -= 1

    captionx = (250 - font.getsize(id)[0]) / 2
    draw = ImageDraw.Draw(img)
    draw.text((captionx, 242), id, font=font)

    img.convert('RGB').save(f'{id}.png')

if __name__ == '__main__':
    if len(sys.argv) != 2:
        print('Usage: python gen_qrcode.py <id>')
        sys.exit(1)
    else:
        id = sys.argv[1]
        main(id)