#!/usr/bin/env python2
# coding: utf

from Crypto.Hash import SHA256
from Crypto.PublicKey import RSA
from Crypto.Signature import PKCS1_v1_5

import qrcode

import base64
import json

PRIVATE_KEY_FILE = "domain.key"

BOX_SIZE = 5
BORDER = 2


def sign(message, private_key_str):
    priv_key = RSA.importKey(private_key_str)
    h = SHA256.new(message.encode("utf-8"))
    signature = PKCS1_v1_5.new(priv_key).sign(h)
    result = base64.b64encode(signature).decode()
    return result


def create_qr(orderId, skuList, output_filename):
    """
    Create a QR code for an order and write it as a PNG.
    Params:
        * orderId - order identifier.
        * skuList - list of SKUs of the order.
        * output_filename: the name of the output file.
    """
    with open(PRIVATE_KEY_FILE, "r") as file:
        key = file.read()


    # dump to str to avoid ordering issues when verifying signature
    order = json.dumps({"i": orderId, "sk": skuList})
    signed_order = sign(order, key)
    data = {"o": order, "s": signed_order}

    data_str = json.dumps(data)

    #data_str_compressed = zlib.compress(data_str)

    qr = qrcode.QRCode(version=1, error_correction=qrcode.constants.ERROR_CORRECT_L, box_size=BOX_SIZE, border=BORDER)
    qr.add_data(data_str)
    qr.make(fit=True)

    img = qr.make_image(fill_color="black", back_color="white")
    img.save(output_filename)


create_qr("1234-5678", ["001", "002", "003", "004", "005", "006", "007", "008", "009"], "output.png")