#!/usr/bin/env python
# posix.py - Convert The Open Group troff sources to posix man pages
#
# Copyright (C) 2013 Felix Janda
#
# Permission is hereby granted, free of charge, to any person
# obtaining a copy of this software and associated documentation files
# (the "Software"), to deal in the Software without restriction,
# including without limitation the rights to use, copy, modify, merge,
# publish, distribute, sublicense, and/or sell copies of the Software,
# and to permit persons to whom the Software is furnished to do so,
# subject to the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
# BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
# ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.

import sys
import os.path
import re

# Helper for troff()
def quote(arg):
    if " " in arg or "\\" in arg: return '"{}"'.format(arg)
    else: return arg

# troff(".BL", "some text", ",") --> '.B "some text" ,\n'
def troff(macro, *args):
    if len(args) == 1 and type(args[0]) is list:
        args = args[0]
    args = [quote(arg) for arg in args]
    s = ".{} {}".format(macro, " ".join(args))
    return s.strip(" ") + "\n"

# For first processing
# Replace a macro by a string
brepl = {"mH":".SH",
         "Cm":".I",
         "Ev":".I",
         "Ar":".I",
         "yS":".LP\n.nf",
         "yE":".fi",
         "Cs":".sp\n.RS 4\n.nf\n",
         "Ce":".fi\n.P\n.RE",
         "HU":".SS",
         "cV":".B",
         "Fi":".B",
         "rS":'.LP\n.I "The following sections are informative."',
         "Cd":".I"}
# Surround the argument of a macro by two strings.
sur = {"LM":["{", "}"],
       "Hd":[".I <", "> "],
       "tK":["<", ">"],
       "cH":[".B '", "' "],
       "sG":[".B \\(dq", "\\(dq "],
       "Fn":["\\fI","\\fR()"],
       "Er":[".B [", "] "]}
# Delete a macro
delete = {"xR",
          "iX",
          "sS",
          "sE",
          "sP",
          "TH",
          "SK",
          "sT",
          "mS",
          "mE",
          "rE",
          "po",
          "if",
          "ne",
          "nr",
          "tr",
          "in"}
# Places where we might need to insert .RS to get indentation right
indentpoint = {"P", "BL", "DL", "VL", "AL", "Cs", "Ns"}
# Places where we might need to insert .RE to get indentation right
indentend = {"LE", "LI", "Ne"}
# Generic replacements in the seconds processing
repl = {"\\f1":"\\fR",
        "\\f2":"\\fI",
        "\\f3":"\\fB",
        "\\f5":"\\fR",
        "\\f6":"\\fI",
        "\\f7":"\\fB",
        "XBD\n":"the \\*(Zz,\n",
        "XSH\n":"the \\*(Zy,\n",
        "XCU\n":"the \\*(Zx,\n",
        "XRAT\n":"the \\*(zj,\n",
        "\\*(x":"",
        "\\*(z!":"",
        "\\*(z?":"",
        ".TS H":".TS",
        "\\(*D":" ",
        "\\(mi":"\-",
        ".B ":".BR ",
        ".I ":".IR ",
        '" "$':"$"}

# Here it starts

if len(sys.argv) == 1:
    progname = os.path.basename(sys.argv[0])
    sys.stderr.write("Usage: {} SECTION [FILE...]\n".format(progname))
    exit(2)
section = sys.argv[1]

# Add the escape sequences from _strings to the repl dictionary
lines=open("_strings").readlines()
for l in lines:
    p = l.partition("\t")
    repl[p[0]] = p[2].strip("\n")

# Generate refdictorig from the ,xref file. It will be later extended to
# the refdict dictionary with table and figure names from the current man
# page
refdictregs = [[r'\\fB<([a-zA-Z0-9\._/]*)>\\fP$', r'.BR \1 ({}p)'],
               [r'\\fI([a-zA-Z0-9_]*)\\fR\\\^\(\\\|\)$', r'.BR \1 ({}p)'],
               [r'\\fI([a-zA-Z0-9]*)\\fR\\\^$', r'.BR \1 ({}p)']]
refdictorig = dict()
lines = open(",xref").readlines()
nsec = -1 # current section
for l in lines:
    if l.startswith("intro_"): nsec += 1
    p = l.partition(" ")
    s = p[2].strip("\n").replace(', ', '" ", " "')
    for reg in refdictregs: # Format references to other man pages
        s = re.sub(reg[0], reg[1].format([0, 3, 1][nsec]), s)
    if s[0] != ".": # Otherwise make it italic
        s = '.I "{}"'.format(s)
    if ".h" in s: s = s.replace("/", "_") # for <sys/types.h>
    refdictorig[p[0]] = s

for file in sys.argv[2:]:
    input = open(file)
    lines = input.readlines()
    input.close()

    # Complete the ref descriptions
    refdict = refdictorig
    for i, l in enumerate(lines):
        l = l.strip("\n")
        if l.startswith(".xR ") and l[4] in ["6", "7"]:
            key = l.split(" ")[2]
            # Add numbers to tables and figures in current page
            lines[i - 1] += ' " ' + refdict[key].split(" ")[2]
            refdict[key] = '{}, {}"'.format(refdict[key].strip('"'),
                                            prev.split(' "')[1].strip('"'))
        prev = l

    in_DSI = 0 # Are we in a display?
    list_stack = [["BL"]] # stack of groff_mm lists we are in
    list_num_stack = [] # stack of current list item numbers
    needindent = 0 # do we need to insert .RS before the next paragraph?

    # First processing
    for i, l in enumerate(lines):
        # only consider lines with macros
        if not l or l[0] != ".": continue

        # read out macro name with its arguments
        macro = l.strip("\n").partition(" ")[0][1:]
        args = ["".join(t) for t in re.findall(r'([^\s"][^\s]*"*)|"([^"]*)"',
                                                             l.strip("\n"))][1:]

        # strip comments
        if macro.startswith('\\"'): lines[i] = ""

        insert = "" # string to be inserted in front of current line
        if needindent > 0:
            if macro in indentpoint:
                insert = ".RS {} \n".format(needindent)
                needindent = -1
        if needindent == -1 and macro in indentend:
            insert = ".RE\n"

        # "Note:" macros
        if macro == "Ns":
            lines[i] = ".TP 10\n.B Note"
            if args: lines[i] += "s"
            lines[i] += ":\n"
            needindent = 10
        if macro == "Ne":
            lines[i] = troff("P")
            needindent = -1

        # Read the name of the current man page from the mS macro
        if macro == "mS": name = args[0]

        # mm display macros
        if macro == "DS":
            if "I" in args:
                lines[i] = ".sp\n.RS\n"
                in_DSI = 1
            else: lines[i] = ""
        elif macro == "DE":
            if in_DSI: lines[i] = troff("RE")
            else: lines[i] = ""
            in_DSI = 0

        # Fix table and figure captions
        if macro == "TB":
            if len(args) == 1: args.append("")
            lines[i] = ".sp\n.ce 1\n\\fBTable{}: {}\\fR\n".format(args[1], args[0])
        elif macro == "FG":
            if len(args) == 1: args.append("")
            lines[i] = ".sp\n.ce 1\n\\fBFigure{}: {}\\fR\n".format(args[1], args[0])
        # strip unecessary macros around figures
        elif macro == "F+":
            lines[i] = lines[i + 1] = lines[i + 2] = ""

        # mm list macro processing
        elif macro in {"BL", "DL", "VL", "AL"}: # start of a list
            needindent = 0
            list_stack.insert(0, [macro, args])
            if list_stack[0][0] == "AL":
                list_num_stack.insert(0, 1)
            lines[i] = ""
        elif macro == "LI": # list item
            # Strip some unecessary escape sequences to make the regexes for
            # formatting the ERRORS section happy
            if args: args[0] = args[0].replace("\\*!", "")

            needindent = 4
            if list_stack[0][0] == "BL": # bullet list
                li_args = [" *", "4"]
            elif list_stack[0][0] == "DL": # dashed list
                li_args = ["--", "4"]
            elif list_stack[0][0] == "VL": # variable item list
                needindent = (int(list_stack[0][1][0]) - 8) // 2 + 8
                li_args = [args[0], str(needindent)]
            elif list_stack[0][0] == "AL": # advanced list
                num = list_num_stack[0]
                s = ""
                if not list_stack[0][1]: # 1. 2. 3.
                     s = str(num)
                elif list_stack[0][1][0] == "a": # a. b. c.
                     s = chr(num + 96)
                elif list_stack[0][1][0] == "i": # i. ii. iii.
                     needindent += 1
                     s = "".join(["i" for j in range(num)])
                li_args = ["{:>2s}.".format(s), str(needindent)]
                list_num_stack[0] += 1
            lines[i] = troff("IP", li_args)
        elif macro == "LE": # list end
            if list_stack[0][0] == "AL":
                del list_num_stack[0]
            del list_stack[0]
            lines[i] = ""
            needindent = -1
            if len(list_stack) >= 2:
                 lines[i] = troff("LE") + troff("RE")

        # References
        elif macro == "cX":
            key = args[0]
            if key in refdict: s = refdict[key]
            else: s = key
            if len(args) > 1: s += args[1]
            lines[i] = s + "\n"

        # Generic replacements
        if macro in delete:
            lines[i] = ""
        elif macro in brepl:
            lines[i] = l.replace("." + macro, brepl[macro], 1)
        elif macro in sur:
            lines[i] = sur[macro][0] + args[0] + sur[macro][1] + " ".join(args[1:]) + "\n"

        lines[i] = insert + lines[i]

    # Second processing
    in_SEE_ALSO = 0 # Are we in the SEE ALSO section?
    in_EQ = 0 # Are we in a displayed equation?
    for i, l in enumerate(lines):
        if l == ".SH \"SEE ALSO\"\n":
            in_SEE_ALSO = 1
        elif l == ".SH \"CHANGE HISTORY\"\n":
            lines = lines[:i] # We are not allowed to include the CHANGE HISTORY
            break
        elif l == ".EQ\n":
            in_EQ = 1
        elif l == ".EN\n":
            in_EQ = 0
        # hack the equations to be a bit better readable on terminals
        if in_EQ or '$' in l:
            l = re.sub(r' sup ([a-zA-Z0-9\\\(]*)', "\"^\" \\1\" \"", l)
            l = re.sub(r' sub ([a-zA-Z0-9\\\(]*)', "_ \\1\" \"", l)
            l = l.replace("left { ~\n", "")
            l = l.replace("~", ' " " ')
        # reformat the error codes in the ERRORS section
        l = re.sub(r'.IP \[(E[0-9A-Z]*)\] [0-9]*\n', ".TP\n.B \\1\n", l)
        l = re.sub(r'.IP "\[(E[0-9A-Z]*)\] or \[(E[0-9A-Z]*)\]" [0-9]*\n',
                                    ".TP\n.BR \\1 \" or \" \\2\n", l)
        # Strip some extra space in the beginning of lines
        l = re.sub(r'^\\ ', "", l)
        # Generic replacements
        for me in repl:
            l = l.replace(me, repl[me])
        for me in repl: # To be sure...
            l = l.replace(me, repl[me])
        if in_SEE_ALSO: l = re.sub(r'^the', "The", l)
        lines[i] = l

    name = re.sub(r'^<|>$', r'', name).replace("/", "_")
    # name printed on the top of the man page
    if section != "0p": NAME = name.upper()
    else: NAME = name
    lines.insert(0,
      "'\\\" et\n"
      ".TH {} \"{}\" 2017 \"IEEE/The Open Group\" \"POSIX Programmer's Manual\"\n"
      ".\\\"\n"
      ".SH PROLOG\n"
      "This manual page is part of the POSIX Programmer's Manual.\n"
      "The Linux implementation of this interface may differ (consult\n"
      "the corresponding Linux manual page for details of Linux behavior),\n"
      "or the interface may not be implemented on Linux.\n"
      ".\\\"\n"
      "".format(NAME, section.upper()))
    lines.append(
      ".\\\"\n"
      ".SH COPYRIGHT\n"
      "Portions of this text are reprinted and reproduced in electronic form\n"
      "from IEEE Std 1003.1-2017, Standard for Information Technology\n"
      "-- Portable Operating System Interface (POSIX), The Open Group Base\n"
      "Specifications Issue 7, 2018 Edition,\n"
      "Copyright (C) 2018 by the Institute of\n"
      "Electrical and Electronics Engineers, Inc and The Open Group.\n"
      "In the event of any discrepancy between this version and the original IEEE and\n"
      "The Open Group Standard, the original IEEE and The Open Group Standard\n"
      "is the referee document.  The original Standard can be obtained online at\n"
      ".UR http://www.opengroup.org/unix/online.html\n"
      ".UE .\n"
      ".PP\n"
      "Any typographical or formatting errors that appear\n"
      "in this page are most likely\n"
      "to have been introduced during the conversion of the source files to\n"
      "man page format.  To report such errors, see\n"
      ".UR https://www.kernel.org/doc/man-pages/reporting_bugs.html\n"
      ".UE .\n"
      )

    text = "".join(lines)
    # Final hacks for the indentation
    for i in [[".LE\n.RE\n.P", ".P"], [".LE\n.RE\n.RE", ".RE"],
              [".RE\n.LE\n.RE", ".RE"], ["\n.LE\n", "\n"]]:
        text = text.replace(i[0], i[1])
    output = open(name + "." + section, 'w')
    output.write(text)
    output.close()