#!/usr/bin/env python3

# Written by Antonio Galea - 2010/11/18
# Distributed under Gnu LGPL 3.0
# see http://www.gnu.org/licenses/lgpl-3.0.txt

import sys
import struct
import zlib
import os
from optparse import OptionParser

DEFAULT_DEVICE = "0x0483:0xdf11"


def named(tuple, names):
    return dict(zip(names.split(), tuple))


def consume(fmt, data, names):
    n = struct.calcsize(fmt)
    return named(struct.unpack(fmt, data[:n]), names), data[n:]


def cstring(string):
    return string.split(b'\0', 1)[0]


def compute_crc(data):
    return 0xFFFFFFFF & -zlib.crc32(data) - 1


def parse(file, dump_images=False):
    print('File: "%s"' % file)
    data = open(file, 'rb').read()
    crc = compute_crc(data[:-4])
    prefix, data = consume('<5sBIB', data, 'signature version size targets')
    print('%(signature)s v%(version)d, image size: %(size)d, targets: %(targets)d' % prefix)
    for t in range(prefix['targets']):
        tprefix, data = consume('<6sBI255s2I', data, 'signature altsetting named name size elements')
        tprefix['num'] = t
        if tprefix['named']:
            tprefix['name'] = cstring(tprefix['name'])
        else:
            tprefix['name'] = ''
        print('%(signature)s %(num)d, alt setting: %(altsetting)s, name: "%(name)s", size: %(size)d, elements: %(elements)d' % tprefix)
        tsize = tprefix['size']
        target, data = data[:tsize], data[tsize:]
        for e in range(tprefix['elements']):
            eprefix, target = consume('<2I', target, 'address size')
            eprefix['num'] = e
            print('  %(num)d, address: 0x%(address)08x, size: %(size)d' % eprefix)
            esize = eprefix['size']
            image, target = target[:esize], target[esize:]
            if dump_images:
                out = '%s.target%d.image%d.bin' % (file, t, e)
                open(out, 'wb').write(image)
                print('    DUMPED IMAGE TO "%s"' % out)
        if len(target):
            print("target %d: PARSE ERROR" % t)
    suffix = named(struct.unpack('<4H3sBI', data[:16]), 'device product vendor dfu ufd len crc')
    print('usb: %(vendor)04x:%(product)04x, device: 0x%(device)04x, dfu: 0x%(dfu)04x, %(ufd)s, %(len)d, 0x%(crc)08x' % suffix)
    if crc != suffix['crc']:
        print("CRC ERROR: computed crc32 is 0x%08x" % crc)
    data = data[16:]
    if data:
        print("PARSE ERROR")


def build(file, targets, device=DEFAULT_DEVICE):
    data = b''
    for t, target in enumerate(targets):
        tdata = b''
        for image in target:
            tdata += struct.pack('<2I', image['address'], len(image['data']))+image['data']
        tdata = struct.pack('<6sBI255s2I', b'Target', 0, 1, b'ST...', len(tdata), len(target)) + tdata
        data += tdata
    data = struct.pack('<5sBIB', b'DfuSe', 1, len(data)+11, len(targets)) + data
    v, d = map(lambda x: int(x, 0) & 0xFFFF, device.split(':', 1))
    data += struct.pack('<4H3sB', 0, d, v, 0x011a, b'UFD', 16)
    crc = compute_crc(data)
    data += struct.pack('<I', crc)
    open(file, 'wb').write(data)


def main():
    usage = """
%prog [-d|--dump] infile.dfu
%prog {-b|--build} address:file.bin [-b address:file.bin ...] [{-D|--device}=vendor:device] outfile.dfu"""
    parser = OptionParser(usage=usage)
    parser.add_option("-b", "--build", action="append", dest="binfiles",
                      help="build a DFU file from given BINFILES", metavar="BINFILES")
    parser.add_option("-D", "--device", action="store", dest="device",
                      help="build for DEVICE, defaults to %s" % DEFAULT_DEVICE, metavar="DEVICE")
    parser.add_option("-d", "--dump", action="store_true", dest="dump_images",
                      default=False, help="dump contained images to current directory")
    (options, args) = parser.parse_args()

    if options.binfiles and len(args) == 1:
        target = []
        for arg in options.binfiles:
            try:
                address, binfile = arg.split(':', 1)
            except ValueError:
                print("Address:file couple '%s' invalid." % arg)
                sys.exit(1)
            try:
                address = int(address, 0) & 0xFFFFFFFF
            except ValueError:
                print("Address %s invalid." % address)
                sys.exit(1)
            if not os.path.isfile(binfile):
                print("Unreadable file '%s'." % binfile)
                sys.exit(1)
            target.append(
                {'address': address, 'data': open(binfile, 'rb').read()})
        outfile = args[0]
        device = DEFAULT_DEVICE
        if options.device:
            device = options.device
        try:
            v, d = map(lambda x: int(x, 0) & 0xFFFF, device.split(':', 1))
        except:
            print("Invalid device '%s'." % device)
            sys.exit(1)
        build(outfile, [target], device)
    elif len(args) == 1:
        infile = args[0]
        if not os.path.isfile(infile):
            print("Unreadable file '%s'." % infile)
            sys.exit(1)
        parse(infile, dump_images=options.dump_images)
    else:
        parser.print_help()
        sys.exit(1)

if __name__ == '__main__':
    main()
