#!/usr/bin/env python3

import os.path
import qrcode
import qrcode.image.svg
from svgutils import transform as st
from ch_kreuz import swisscross as get_swisscross

class qr_rechnung():
    data = ''
    error_correction = None

    def __init__(self, data=None, textfile=None):
        if textfile is not None:
            self.set_data_from_textfile(textfile)

    def set_data(self, data):
        self.data = data

    def set_data_from_textfile(self, textfile):
        with open(textfile, 'r') as f:
            self.data = f.read()

    def write_file(self, filepath, force=False):
        global qrcode
        mode = 'w' if force else 'x'
        try:
            assert force or not os.path.isfile(filepath)
            factory = qrcode.image.svg.SvgPathImage
            img = qrcode.make(
                self.data,
                error_correction=qrcode.constants.ERROR_CORRECT_M,
                image_factory=qrcode.image.svg.SvgPathImage
            )
            img.save(filepath)
        except AssertionError:
            print(f"ERROR: Datei {filepath} existiert bereits.")
            return 1

        qrcode = st.fromfile(filepath)
        offset = self.calc_move_offset(qrcode.get_size()[0])
        swisscross = get_swisscross()
        swisscross.moveto(
            x=offset['offset'],
            y=offset['offset'],
            scale_x=offset['scale'],
            scale_y=offset['scale']
        )
        qrcode.append(swisscross)
        qrcode.save(filepath)

    def calc_move_offset(self, size):
        org = float(size[:-2])
        return {
            'offset': org*0.427935156,
            'scale': org/137.364857143
        }


def help(args):
    return '{0}: Ungültige Eingabe\nAufruf: \
    {0} TEXTDATEI [SVG-ZIELDATEI]'.format(args[0])


def main(args):
    try:
        textfile = args[1]
    except IndexError:
        print(help(args))
        return 1
    try:
        svgfile = args[2]
    except IndexError:
        try:
            assert textfile[-4:] == '.txt'
            svgfile = textfile[:-4]+'.svg'
        except AssertionError:
            print(help(args))
            return 1
    try:
        x = qr_rechnung(textfile=textfile)
        x.write_file(svgfile, force=False)
    except (PermissionError, FileNotFoundError) as e:
        print(e)
        return 1
    return 0


if __name__ == '__main__':
    import sys
    sys.exit(main(sys.argv))