#!/usr/bin/env python

manufacturer = 'Mullvad'
product = 'MTA1-USB-V1'
serial = "68de5d27-e223-4874-bc76-a54d6e84068f"

def descriptor_to_string(descriptor):
    """ Convert a bytes object containing a USB string descriptor into a python string"""
    bLength = descriptor[0]
    if bLength != len(descriptor):
        raise Exception('Descriptor length mismatch, length_field:{} actual_length:{}'.format(
                bLength,
                len(descriptor)
                ))

    bDescriptorType = descriptor[1]
    if bDescriptorType != 0x03:
        raise Exception('Descriptor type mismatch, bDescriptorType:{02x} expected:0x03'.format(
            bDescriptorType
            ))

    return descriptor[2:].decode('utf-16', errors='strict')

def string_to_descriptor(string):
    """ Convert a python string into a bytes object containing a USB string descriptor"""
    descriptor = bytearray()
    descriptor.append(0x00) # placeholder for length
    descriptor.append(0x03)
    descriptor.extend(string.encode('utf-16')[2:]) # crop the BOM
    descriptor[0] = len(descriptor)

    return bytes(descriptor)


if __name__ == "__main__":
    #serial = bytes([
    #    0x14,0x03,
    #    0x32,0x00,0x30,0x00,0x31,0x00,0x37,0x00,0x2D,0x00,
    #    0x32,0x00,0x2D,0x00,
    #    0x32,0x00,0x35,0x00
    #    ])
    #print(descriptor_to_string(serial))
    
    #sample_product = bytes([
    #    0x14,0x03,
    #    0x43,0x00,0x48,0x00,0x35,0x00,0x35,0x00,0x34,0x00,0x5F,0x00,
    #    0x43,0x00,0x44,0x00,0x43,0x00
    #    ])
    #print(descriptor_to_string(sample_product))
    #rt = string_to_descriptor(descriptor_to_string(sample_product))
    #print(descriptor_to_string(rt))
    #
    #print(['{:02x} '.format(i) for i in sample_product])
    #print(['{:02x} '.format(i) for i in rt])
    
    
    #sample_mfr = bytes([
    #    0x0A,0x03,
    #    0x5F,0x6c,0xCF,0x82,0x81,0x6c,0x52,0x60,
    #    ])
    #print(descriptor_to_string(sample_mfr))
    #rt = string_to_descriptor(descriptor_to_string(sample_mfr))
    #print(descriptor_to_string(rt))
    #
    #print(['{:02x} '.format(i) for i in sample_mfr])
    #print(['{:02x} '.format(i) for i in rt])
    
    
    
    with open('usb_strings.h', 'w') as f:
        f.write('#ifndef USB_STRINGS\n')
        f.write('#define USB_STRINGS\n')
    
        f.write('unsigned char __code Prod_Des[]={{  // "{}"\n'.format(product))
        f.write('    ')
        f.write(', '.join(['0x{:02x}'.format(i) for i in string_to_descriptor(product)]))
        f.write('\n};\n')
        
        f.write('unsigned char __code Manuf_Des[]={{  // "{}"\n'.format(manufacturer))
        f.write('    ')
        f.write(', '.join(['0x{:02x}'.format(i) for i in string_to_descriptor(manufacturer)]))
        f.write('\n};\n')
    
        f.write('unsigned char __code SerDes[]={{  // "{}"\n'.format(serial))
        f.write('    ')
        f.write(', '.join(['0x{:02x}'.format(i) for i in string_to_descriptor(serial)]))
        f.write('\n};\n')
    
    
        f.write('#endif\n')