#! /usr/bin/python3

import sys
import os.path
import re

line = ""

# Maps from user-friendly version number to its protocol encoding.
VERSION = {"1.0": 0x01,
           "1.1": 0x02,
           "1.2": 0x03,
           "1.3": 0x04,
           "1.4": 0x05,
           "1.5": 0x06}

NX_VENDOR_ID = 0x00002320
ONF_VENDOR_ID = 0x4f4e4600

OFPT_VENDOR = 4
OFPT10_STATS_REQUEST = 16
OFPT10_STATS_REPLY = 17
OFPT11_STATS_REQUEST = 18
OFPT11_STATS_REPLY = 19
OFPST_VENDOR = 0xffff

n_errors = 0


def decode_version_range(range):
    if range in VERSION:
        return (VERSION[range], VERSION[range])
    elif range.endswith('+'):
        return (VERSION[range[:-1]], max(VERSION.values()))
    elif range == '<all>':
        return (0x01, 0xff)
    else:
        a, b = re.match(r'^([^-]+)-([^-]+)$', range).groups()
        return (VERSION[a], VERSION[b])


def get_line():
    global line
    global line_number
    line = input_file.readline()
    line_number += 1
    if line == "":
        fatal("unexpected end of input")


def error(msg):
    global n_errors
    sys.stderr.write("%s:%d: %s\n" % (file_name, line_number, msg))
    n_errors += 1


def fatal(msg):
    error(msg)
    sys.exit(1)


def usage():
    argv0 = os.path.basename(sys.argv[0])
    print('''\
%(argv0)s, for extracting OpenFlow message types from header files
usage: %(argv0)s INPUT OUTPUT
  where INPUT is the name of the input header file
    and OUTPUT is the output file name.
Despite OUTPUT, the output is written to stdout, and the OUTPUT argument
only controls #line directives in the output.\
''' % {"argv0": argv0})
    sys.exit(0)


def make_sizeof(s):
    m = re.match(r'(.*) up to (.*)', s)
    if m:
        struct, member = m.groups()
        return "offsetof(%s, %s)" % (struct, member)
    else:
        return "sizeof(%s)" % s


def extract_ofp_msgs(output_file_name):
    all_hdrs = {}
    all_raws = {}
    all_raws_order = []

    while True:
        get_line()
        if re.match('enum ofpraw', line):
            break

    while True:
        get_line()
        first_line_number = line_number
        here = '%s:%d' % (file_name, line_number)
        if (line.startswith('/*')
            or line.startswith(' *')
            or not line
            or line.isspace()):
            continue
        elif re.match('}', line):
            break

        if not line.lstrip().startswith('/*'):
            fatal("unexpected syntax between ofpraw types")

        comment = line.lstrip()[2:].strip()
        while not comment.endswith('*/'):
            get_line()
            if line.startswith('/*') or not line or line.isspace():
                fatal("unexpected syntax within message")
            comment += ' %s' % line.lstrip('* \t').rstrip(' \t\r\n')
        comment = comment[:-2].rstrip()

        m = re.match(
            r'([A-Z]+) ([-.+\d]+|<all>) \((\d+)\): ([^.]+)\.$', comment
        )
        if not m:
            fatal("unexpected syntax between messages")
        type_, versions, number, contents = m.groups()
        number = int(number)

        get_line()
        m = re.match(r'\s+(?:OFPRAW_%s)(\d*)_([A-Z0-9_]+),?$' % type_, line)
        if not m:
            fatal("syntax error expecting OFPRAW_ enum")
        vinfix, name = m.groups()
        rawname = 'OFPRAW_%s%s_%s' % (type_, vinfix, name)

        min_version, max_version = decode_version_range(versions)

        human_name = '%s_%s' % (type_, name)
        if type_.endswith('ST'):
            if rawname.endswith('_REQUEST'):
                human_name = human_name[:-8] + " request"
            elif rawname.endswith('_REPLY'):
                human_name = human_name[:-6] + " reply"
            else:
                fatal("%s messages are statistics but %s doesn't end "
                      "in _REQUEST or _REPLY" % (type_, rawname))

        these_hdrs = []
        for version in range(min_version, max_version + 1):
            if type_ == 'OFPT':
                if number == OFPT_VENDOR:
                    fatal("OFPT (%d) is used for vendor extensions"
                          % number)
                elif (version == VERSION["1.0"]
                      and (number == OFPT10_STATS_REQUEST
                           or number == OFPT10_STATS_REPLY)):
                    fatal("OFPT 1.0 (%d) is used for stats messages"
                          % number)
                elif (version != VERSION["1.0"]
                      and (number == OFPT11_STATS_REQUEST
                           or number == OFPT11_STATS_REPLY)):
                    fatal("OFPT 1.1+ (%d) is used for stats messages"
                          % number)
                hdrs = (version, number, 0, 0, 0)
            elif type_ == 'OFPST' and name.endswith('_REQUEST'):
                if version == VERSION["1.0"]:
                    hdrs = (version, OFPT10_STATS_REQUEST, number, 0, 0)
                else:
                    hdrs = (version, OFPT11_STATS_REQUEST, number, 0, 0)
            elif type_ == 'OFPST' and name.endswith('_REPLY'):
                if version == VERSION["1.0"]:
                    hdrs = (version, OFPT10_STATS_REPLY, number, 0, 0)
                else:
                    hdrs = (version, OFPT11_STATS_REPLY, number, 0, 0)
            elif type_ == 'ONFT':
                hdrs = (version, OFPT_VENDOR, 0, ONF_VENDOR_ID, number)
            elif type_ == 'ONFST' and name.endswith('_REQUEST'):
                if version == VERSION["1.0"]:
                    hdrs = (version, OFPT10_STATS_REQUEST, OFPST_VENDOR,
                            ONF_VENDOR_ID, number)
                else:
                    hdrs = (version, OFPT11_STATS_REQUEST, OFPST_VENDOR,
                            ONF_VENDOR_ID, number)
            elif type_ == 'ONFST' and name.endswith('_REPLY'):
                if version == VERSION["1.0"]:
                    hdrs = (version, OFPT10_STATS_REPLY, OFPST_VENDOR,
                            ONF_VENDOR_ID, number)
                else:
                    hdrs = (version, OFPT11_STATS_REPLY, OFPST_VENDOR,
                            ONF_VENDOR_ID, number)
            elif type_ == 'NXT':
                hdrs = (version, OFPT_VENDOR, 0, NX_VENDOR_ID, number)
            elif type_ == 'NXST' and name.endswith('_REQUEST'):
                if version == VERSION["1.0"]:
                    hdrs = (version, OFPT10_STATS_REQUEST, OFPST_VENDOR,
                            NX_VENDOR_ID, number)
                else:
                    hdrs = (version, OFPT11_STATS_REQUEST, OFPST_VENDOR,
                            NX_VENDOR_ID, number)
            elif type_ == 'NXST' and name.endswith('_REPLY'):
                if version == VERSION["1.0"]:
                    hdrs = (version, OFPT10_STATS_REPLY, OFPST_VENDOR,
                            NX_VENDOR_ID, number)
                else:
                    hdrs = (version, OFPT11_STATS_REPLY, OFPST_VENDOR,
                            NX_VENDOR_ID, number)
            else:
                fatal("type '%s' unknown" % type_)

            if hdrs in all_hdrs:
                error("Duplicate message definition for %s." % str(hdrs))
                sys.stderr.write("%s: Here is the location "
                                 "of the previous definition.\n"
                                 % (all_hdrs[hdrs]))
            all_hdrs[hdrs] = here
            these_hdrs.append(hdrs)

        extra_multiple = '0'
        if contents == 'void':
            min_body = '0'
        else:
            min_body_elem = []
            for c in [s.strip() for s in contents.split(",")]:
                if c.endswith('[]'):
                    if extra_multiple == '0':
                        extra_multiple = make_sizeof(c[:-2])
                    else:
                        error("Cannot have multiple [] elements")
                else:
                    min_body_elem.append(c)

            if min_body_elem:
                min_body = " + ".join([make_sizeof(s)
                                       for s in min_body_elem])
            else:
                if extra_multiple == '0':
                    error("Must specify contents (use 'void' if empty)")
                min_body = 0

        if rawname in all_raws:
            fatal("%s: Duplicate name" % rawname)

        all_raws[rawname] = {"hdrs": these_hdrs,
                             "min_version": min_version,
                             "max_version": max_version,
                             "min_body": min_body,
                             "extra_multiple": extra_multiple,
                             "type": type_,
                             "human_name": human_name,
                             "line": first_line_number}
        all_raws_order.append(rawname)

        continue

    while True:
        get_line()
        if re.match('enum ofptype', line):
            break

    all_types = []
    while True:
        get_line()
        if re.match(r'\s*/?\*', line) or line.isspace():
            continue
        elif re.match('}', line):
            break

        if not re.match(r'\s*OFPTYPE_.*/\*', line):
            fatal("unexpected syntax between OFPTYPE_ definitions")

        syntax = line.strip()
        while not syntax.endswith('*/'):
            get_line()
            if not line.strip().startswith('*'):
                fatal("unexpected syntax within OFPTYPE_ definition")
            syntax += ' %s' % line.strip().lstrip('* \t')
            syntax = syntax.strip()

        m = re.match(r'(OFPTYPE_[A-Z0-9_]+),\s*/\* (.*) \*/', syntax)
        if not m:
            fatal("syntax error in OFPTYPE_ definition")

        ofptype, raws_ = m.groups()
        raws = [s.rstrip('.') for s in raws_.split()]
        for raw in raws:
            if not re.match('OFPRAW_[A-Z0-9_]+$', raw):
                fatal("%s: invalid OFPRAW_* name syntax" % raw)
            if raw not in all_raws:
                fatal("%s: not a declared OFPRAW_* name" % raw)
            if "ofptype" in all_raws[raw]:
                fatal("%s: already part of %s"
                      % (raw, all_raws[raw]["ofptype"]))
            all_raws[raw]["ofptype"] = ofptype

        all_types.append(all_raws[raws[0]]["human_name"])

    input_file.close()

    if n_errors:
        sys.exit(1)

    output = []
    output.append("/* Generated automatically; do not modify!     "
                  "-*- buffer-read-only: t -*- */")
    output.append("")

    for raw in all_raws_order:
        r = all_raws[raw]
        output.append("static struct raw_instance %s_instances[] = {"
                      % raw.lower())
        for hdrs in r['hdrs']:
            output.append("    { {0, NULL}, {%d, %d, %d, 0x%x, %d}, %s, 0 },"
                          % (hdrs + (raw,)))

        output.append("};")

    output.append("")

    output.append("static struct raw_info raw_infos[] = {")
    for raw in all_raws_order:
        r = all_raws[raw]
        if "ofptype" not in r:
            error("%s: no defined OFPTYPE_" % raw)
            continue
        output.append("    {")
        output.append("        %s_instances," % raw.lower())
        output.append("        %d, %d," % (r["min_version"], r["max_version"]))
        output.append("#line %s \"%s\"" % (r["line"], file_name))
        output.append("        %s," % r["min_body"])
        output.append("#line %s \"%s\"" % (r["line"], file_name))
        output.append("        %s," % r["extra_multiple"])
        output.append("#line %s \"%s\"" % (len(output) + 2, output_file_name))
        output.append("        %s," % r["ofptype"])
        output.append("        \"%s\"," % r["human_name"])
        output.append("    },")

        if r['type'].endswith("ST"):
            for hdrs in r['hdrs']:
                op_hdrs = list(hdrs)
                if hdrs[0] == VERSION["1.0"]:
                    if hdrs[1] == OFPT10_STATS_REQUEST:
                        op_hdrs[1] = OFPT10_STATS_REPLY
                    elif hdrs[1] == OFPT10_STATS_REPLY:
                        op_hdrs[1] = OFPT10_STATS_REQUEST
                    else:
                        assert False
                else:
                    if hdrs[1] == OFPT11_STATS_REQUEST:
                        op_hdrs[1] = OFPT11_STATS_REPLY
                    elif hdrs[1] == OFPT11_STATS_REPLY:
                        op_hdrs[1] = OFPT11_STATS_REQUEST
                    else:
                        assert False
                if tuple(op_hdrs) not in all_hdrs:
                    if r["human_name"].endswith("request"):
                        fatal("%s has no corresponding reply"
                              % r["human_name"])
                    else:
                        fatal("%s has no corresponding request"
                              % r["human_name"])
    output.append("};")

    output.append("")
    output.append("static const char *type_names[] = {")
    for t in all_types:
        output.append("    \"%s\"," % t)
    output.append("};")

    if n_errors:
        sys.exit(1)

    return output


if __name__ == '__main__':
    if '--help' in sys.argv:
        usage()
    elif len(sys.argv) != 3:
        sys.stderr.write("exactly two non-option arguments required; "
                         "use --help for help\n")
        sys.exit(1)
    else:
        global file_name
        global input_file
        global line_number
        file_name = sys.argv[1]
        input_file = open(file_name)
        line_number = 0

        for line in extract_ofp_msgs(sys.argv[2]):
            print(line)
