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"""
Convert --help output of a program into asciidoc text format.
"""
from __future__ import print_function
from __future__ import unicode_literals
from __future__ import division
from __future__ import absolute_import


import re, sys
from qpid_dispatch_internal.compat import PY_STRING_TYPE
from qpid_dispatch_internal.compat.subproc import check_output


def help2txt(help_out):
    VALUE = r"(?:[\w-]+|<[^>]+>)"
    DEFAULT = r"(?: +\([^)]+\))?"
    OPTION = r"-[\w-]+(?:[ =]%s)?%s" % (VALUE, DEFAULT) # -opt[(=| )value][(default)]
    OPTIONS = r"%s(?:, *%s)*" % (OPTION, OPTION)        # opt[,opt...]
    HELP = r"(?:[ \t]+\w.*$)|(?:(?:\n[ \t]+[^-\s].*$)+)" # same line or following lines indented.
    OPT_HELP = r"^\s+(%s)(%s)" % (OPTIONS, HELP)
    SUBHEAD = r"^((?: +\w+)*):$"

    # check_output returns binary in py3
    if not isinstance(help_out, PY_STRING_TYPE):
        help_out = help_out.decode()

    options = re.search("^Options:$", help_out, re.IGNORECASE | re.MULTILINE)
    if (options): help_out = help_out[options.end():]
    result = ""

    def heading(text, depth):
        return "%s %s\n\n" % ("="*depth, text)

    for item in re.finditer(r"%s|%s" % (OPT_HELP, SUBHEAD), help_out, re.IGNORECASE | re.MULTILINE):
        if item.group(3):
            result += heading(item.group(3).strip(), 3)
        else:
            result += "%s\n:   %s\n\n" % (item.group(1), re.sub(r"\s+", " ", item.group(2)).strip())
    return result

def main(argv):
    if len(argv) < 2: raise ValueError("Wrong number of arguments\nUsage %s"
                                       " <program> [args,...]" % argv[0])
    program = argv[1:]
    print(help2txt(check_output(program)))

if __name__ == "__main__":
    main(sys.argv)