#!/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
import binascii
from optparse import OptionParser

try:
    from intelhex import IntelHex
except ImportError:
    IntelHex = None

DEFAULT_DEVICE = "0x0483:0xdf11"
DEFAULT_NAME = b"ST..."

# Prefix and Suffix sizes are derived from ST's DfuSe File Format Specification (UM0391), DFU revision 1.1a
PREFIX_SIZE = 11
SUFFIX_SIZE = 16


def named(tuple, names):
    return dict(list(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(bytestring):
    return bytestring.partition(b"\0")[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[:SUFFIX_SIZE]),
        "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[SUFFIX_SIZE:]
    if data:
        print("PARSE ERROR")


def checkbin(binfile):
    data = open(binfile, "rb").read()
    if len(data) < SUFFIX_SIZE:
        return
    crc = compute_crc(data[:-4])
    suffix = named(
        struct.unpack("<4H3sBI", data[-SUFFIX_SIZE:]),
        "device product vendor dfu ufd len crc",
    )
    if crc == suffix["crc"] and suffix["ufd"] == b"UFD":
        print(
            "usb: %(vendor)04x:%(product)04x, device: 0x%(device)04x, dfu: 0x%(dfu)04x, %(ufd)s, %(len)d, 0x%(crc)08x"
            % suffix
        )
        print("It looks like the file %s has a DFU suffix!" % binfile)
        print("Please remove any DFU suffix and retry.")
        sys.exit(1)


def build(file, targets, name=DEFAULT_NAME, 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"]
            )
            ealt = image["alt"]
        tdata = (
            struct.pack(
                "<6sBI255s2I", b"Target", ealt, 1, name, len(tdata), len(target)
            )
            + tdata
        )
        data += tdata
    data = (
        struct.pack(
            "<5sBIB", b"DfuSe", 1, PREFIX_SIZE + len(data) + SUFFIX_SIZE, len(targets)
        )
        + data
    )
    v, d = [int(x, 0) & 0xFFFF for x in device.split(":", 1)]
    data += struct.pack("<4H3sB", 0, d, v, 0x011A, b"UFD", SUFFIX_SIZE)
    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 {-s|--build-s19} file.s19 [{-D|--device}=vendor:device] outfile.dfu
%prog {-i|--build-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="Include a raw binary file, to be loaded at the specified address. The BINFILES argument is of the form address:path-to-file. The address can have @X appended where X is the alternate interface number for this binary file. Note that the binary files must not have any DFU suffix!",
        metavar="BINFILES",
    )
    parser.add_option(
        "-i",
        "--build-ihex",
        action="append",
        dest="hexfiles",
        help="build a DFU file from given Intel HEX HEXFILES",
        metavar="HEXFILES",
    )
    parser.add_option(
        "-s",
        "--build-s19",
        type="string",
        dest="s19files",
        help="build a DFU file from given S19 S-record S19FILE",
        metavar="S19FILE",
    )
    parser.add_option(
        "-D",
        "--device",
        action="store",
        dest="device",
        help="build for DEVICE, defaults to %s" % DEFAULT_DEVICE,
        metavar="DEVICE",
    )
    parser.add_option(
        "-a",
        "--alt-intf",
        action="store",
        dest="alt",
        help="build for alternate interface number ALTINTF, defaults to 0",
        metavar="ALTINTF",
    )
    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()

    targets = []

    if options.alt:
        try:
            default_alt = int(options.alt)
        except ValueError:
            print("Alternate interface option argument %s invalid." % options.alt)
            sys.exit(1)
    else:
        default_alt = 0

    if (options.binfiles or options.hexfiles) and len(args) == 1:
        target = []
        old_ealt = None

        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, alts = address.split("@", 1)
                    if alts:
                        try:
                            ealt = int(alts)
                        except ValueError:
                            print("Alternate interface number %s invalid." % alts)
                            sys.exit(1)
                    else:
                        ealt = default_alt
                except ValueError:
                    ealt = default_alt
                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)
                checkbin(binfile)
                if old_ealt is not None and ealt != old_ealt:
                    targets.append(target)
                    target = []
                target.append(
                    {
                        "address": address,
                        "alt": ealt,
                        "data": open(binfile, "rb").read(),
                    }
                )
                old_ealt = ealt
            targets.append(target)

        if options.hexfiles:
            if not IntelHex:
                print("Error: IntelHex python module could not be found")
                sys.exit(1)
            for hexf in options.hexfiles:
                ih = IntelHex(hexf)
                for address, end in ih.segments():
                    try:
                        address = address & 0xFFFFFFFF
                    except ValueError:
                        print("Address %s invalid." % address)
                        sys.exit(1)
                    target.append(
                        {
                            "address": address,
                            "alt": default_alt,
                            "data": ih.tobinstr(start=address, end=end - 1),
                        }
                    )
            targets.append(target)

        outfile = args[0]
        device = DEFAULT_DEVICE
        if options.device:
            device = options.device
        try:
            v, d = [int(x, 0) & 0xFFFF for x in device.split(":", 1)]
        except:
            print("Invalid device '%s'." % device)
            sys.exit(1)
        build(outfile, targets, DEFAULT_NAME, device)
    elif options.s19files and len(args) == 1:
        address = 0
        data = ""
        target = []
        name = DEFAULT_NAME
        with open(options.s19files) as f:
            lines = f.readlines()
            for line in lines:
                curaddress = 0
                curdata = ""
                line = line.rstrip()
                if line.startswith("S0"):
                    name = binascii.a2b_hex(line[8 : len(line) - 2])
                elif line.startswith("S3"):
                    try:
                        curaddress = int(line[4:12], 16) & 0xFFFFFFFF
                    except ValueError:
                        print("Address %s invalid." % address)
                        sys.exit(1)
                    curdata = binascii.unhexlify(line[12:-2])
                elif line.startswith("S2"):
                    try:
                        curaddress = int(line[4:10], 16) & 0xFFFFFFFF
                    except ValueError:
                        print("Address %s invalid." % address)
                        sys.exit(1)
                    curdata = binascii.unhexlify(line[10:-2])
                elif line.startswith("S1"):
                    try:
                        curaddress = int(line[4:8], 16) & 0xFFFFFFFF
                    except ValueError:
                        print("Address %s invalid." % address)
                        sys.exit(1)
                    curdata = binascii.unhexlify(line[8:-2])
                if address == 0:
                    address = curaddress
                    data = curdata
                elif address + len(data) != curaddress:
                    target.append(
                        {"address": address, "alt": default_alt, "data": data}
                    )
                    address = curaddress
                    data = curdata
                else:
                    data += curdata
        outfile = args[0]
        device = DEFAULT_DEVICE
        if options.device:
            device = options.device
        try:
            v, d = [int(x, 0) & 0xFFFF for x in device.split(":", 1)]
        except:
            print("Invalid device '%s'." % device)
            sys.exit(1)
        build(outfile, [target], name, 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()
        if not IntelHex:
            print("Note: Intel hex files support requires the IntelHex python module")
        sys.exit(1)