#!/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,struct,zlib,os
from optparse import OptionParser
from intelhex import IntelHex

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)r 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'] = b''
    print('%(signature)r %(num)d, alt setting: %(altsetting)r, name: %(name)r, 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)r, %(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']

    trgt = b'Target'
    st = b'ST...'
    tdata = struct.pack('<6sBI255s2I',trgt,0,1,st,len(tdata),len(target)) + tdata
    data += tdata

  dfu_se = b'DfuSe'
  ufd = b'UFD'
  data = struct.pack('<5sBIB',dfu_se,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,ufd,16)
  crc   = compute_crc(data)
  data += struct.pack('<I',crc)
  open(file,'wb').write(data)

if __name__=="__main__":
  usage = """
%prog [-d|--dump] infile.dfu
%prog {-b|--build} address:file.bin [-b address:file.bin ...] [{-D|--device}=vendor:device] outfile.dfu
%prog {-i|--ihex} file.hex [-i file.hex ...] [{-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("-i", "--ihex", action="append", dest="hexfiles",
    help="build a DFU file from given HEXFILES", metavar="HEXFILES")
  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 or options.hexfiles) and len(args)==1:
    target = []
    
    if options.binfiles:
      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() })
    
    if options.hexfiles:
      for hex in options.hexfiles:
        ih = IntelHex(hex)
        address = ih.minaddr()
        data = ih.tobinstr()
        try:
          address = address & 0xFFFFFFFF
        except ValueError:
          print("Address %s invalid." % address)
          sys.exit(1)
        target.append({ 'address': address, 'data': data })
    
    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)