#!/bin/sh

# Copyright (C) 2001, 2002, 2003 Marc Vertes

# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2, or (at your option)
# any later version.

# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.

# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
# 02111-1307, USA.

# release 1.7.1

usage()
{
cat << EOT
NAME
  txt2man - convert flat ASCII text to man page format
SYNOPSIS
  txt2man [-hpTX] [-t mytitle] [-P pname] [-r rel] [-s sect]
          [-v vol] [-I txt] [-B txt] [-d date] [ifile]
DESCRIPTION
  txt2man converts the input text into nroff/troff standard man(7)
  macros used to format Unix manual pages. Nice pages can be generated
  specially for commands (section 1 or 8) or for C functions reference
  (sections 2, 3), with the ability to recognize and format command and
  function names, flags, types and arguments.

  txt2man is also able to recognize and format sections, paragraphs,
  lists (standard, numbered, description, nested), cross references and
  literal display blocks.

  If input file ifile is omitted, standard input is used. Result is
  displayed on standard output.

  Here is how text patterns are recognized and processed:
  Sections    These headers are defined by a line in upper case, starting
              column 1. If there is one or more leading spaces, a
              sub-section will be generated instead. Optionally, the
              Section name can be preceded by a blank line. This is useful
              for a better visualization of the source text to be used to
              generate the manpage.
  Paragraphs  They must be separated by a blank line, and left aligned.
              Alternatively two blank spaces can be used to produce the
              same result. This option will provide a better visualization
              of the source text to be used to generate the manpage.
  Tag list    The item definition is separated from the item description
              by at least 2 blank spaces, even before a new line, if
              definition is too long. Definition will be emphasized
              by default.
  Bullet list  
              Bullet list items are defined by the first word being "-"
              or "*" or "o".
  Enumerated list  
              The first word must be a number followed by a dot.
  Literal display blocks  
              This paragraph type is used to display unmodified text,
              for example source code. It must be separated by a blank
              line and be indented by a TAB. It is primarily used to format
              unmodified source code. It will be printed using fixed font
              whenever possible (troff).
  Cross references  
              A cross reference (another man page) is defined by a word
              followed by a number in parenthesis.

  Special sections:
  NAME      The function or command name and short description are set in
            this section.
  SYNOPSIS  This section receives a special treatment to identify command
            name, flags and arguments, and propagate corresponding
            attributes later in the text. If a C like function is recognized
            (word immediately followed by an open parenthesis), txt2man will
            print function name in bold font, types in normal font, and
            variables in italic font. The whole section will be printed using
            a fixed font family (courier) whenever possible (troff).

  It is a good practice to embed documentation into source code, by using
  comments or constant text variables. txt2man allows one to do that, keeping
  the document source readable, usable even without further formatting
  (i.e. for online help) and easy to write. The result is high quality
  and standard complying document.
OPTIONS
  -h          The option -h displays help.
  -d date     Set date in header. Defaults to current date.
  -P pname    Set pname as project name in header. Default to uname -s.
  -p          Probe title, section name and volume.
  -t mytitle  Set mytitle as title of generated man page.
  -r rel      Set rel as project name and release.
  -s sect     Set sect as section in heading, usually a value from 1 to 8.
  -v vol      Set vol as volume name, i.e. "Unix user 's manual".
  -I txt      Italicize txt in output. Can be specified more than once.
  -B txt      Emphasize (bold) txt in output. Can be specified more than once.
  -T          Text result previewing using PAGER, usually more(1).
  -X          X11 result previewing using gxditview(1).
ENVIRONMENT
  PAGER              name of paging command, usually more(1), or less(1). If not set
                     falls back to more(1).
  SOURCE_DATE_EPOCH  Unix timestamp that is used for date in header instead
                     of current date.
EXAMPLES
  Try this command to format this text itself:

    $ txt2man -h 2>&1 | txt2man -T

  The following command will generate a manpage level 1 to foo-1.1.0 program,
  from foo.txt file, used as source code to previously mentioned manpage:

    $ txt2man -d "15 May 2016" -t foo -r foo-1.1.0 -s 1 -v "show stars on screen" foo.txt > foo.1
HINTS
  To obtain an overall good formatting of output document, keep paragraphs
  indented correctly. If you have unwanted bold sections, search for
  multiple spaces between words, which are used to identify a tag list
  (term followed by a description). Choose also carefully the name of
  command line or function parameters, as they will be emphasized each
  time they are encountered in the document.
SEE ALSO
  man(1), mandoc(7), rman(1), groff(1), more(1), gxditview(1), troff(1).
BUGS
  - Automatic probe (-p option) works only if input is a regular file (i.e.
  not stdin).
AUTHOR
  Marc Vertes <mvertes@free.fr>
EOT
}

sys=$(uname -s)
rel=
volume=
section=
title=untitled
doprobe=
itxt=
btxt=
post=cat
while getopts :d:hpTXr:s:t:v:P:I:B: opt
do
	case $opt in
	(d) date=$OPTARG;;
	(r) rel=$OPTARG;;
	(t) title=$OPTARG;;
	(s) section=$OPTARG;;
	(v) volume=$OPTARG;;
	(P) sys=$OPTARG;;
	(p) doprobe=1;;
	(I) itxt="$OPTARG§$itxt";;
	(B) btxt="$OPTARG§$btxt";;
	(T) post="groff -mandoc -Tlatin1 | ${PAGER:-more}";;
	(X) post="groff -mandoc -TX100-12 -rS12";;
	(*) usage; exit;;
	esac
done
shift $(($OPTIND - 1))

# Compatibility wrapper for BSD/GNU date, for parsing dates
if date -j >/dev/null 2>&1; then
  pdate() { date -u -j -f '@%s' "$@"; }
else
  pdate() { date -u -d "$@"; }
fi

if [ -n "$SOURCE_DATE_EPOCH" ]; then
  date=$(LC_ALL=C pdate "@$SOURCE_DATE_EPOCH" +'%d %B %Y')
fi
date=${date:-$(LC_ALL=C date -u +'%d %B %Y')}

if test "$doprobe"
then
	title=${1##*/}; title=${title%.txt}
	if grep -q '#include ' $1
	then
		section=${section:-3}
		volume=${volume:-"$sys Programmer's Manual"}
	else
		section=${section:-1}
		volume=${volume:-"$sys Reference Manual"}
	fi
	# get release from path
	rel=${rel:-"$(pwd | sed 's:/.*[^0-9]/::g; s:/.*::g')"}
fi

head="\" Text automatically generated by txt2man
.TH $title $section \"$rel\" \"$volume\""

# All tabs converted to spaces
expand $* | 		
# gawk is needed because use of non standard regexp
gawk --re-interval -v head="$head" -v itxt="$itxt" -v btxt="$btxt" '
BEGIN {
	print ".\\" head
	avar[1] = btxt; avar[2] = itxt
	for (k in avar) {
		mark = (k == 1) ? "\\fB" : "\\fI"
		split(avar[k], tt, "§")
		for (i in tt)
			if (tt[i] != "")
				subwords["\\<" tt[i] "\\>"] = mark tt[i] "\\fP"
		for (i in tt)
			delete tt[i]
	}
	for (k in avar)
		delete avar[k]
}
{
	# to avoid some side effects in regexp
	gsub(/\.\.\./, "\\.\\.\\.")
	# remove spaces in empty lines
	sub(/^ +$/,"")
}
/^[:space:]*[[:upper:][:digit:]]+[[:upper:][:space:][:digit:][:punct:]]+$/ {
	# Section header
	if ((in_bd + 0) == 1) {
		in_bd = 0
		print ".fam T\n.fi"
	}
	if (section == "SYNOPSIS") {
		print ".fam T\n.fi"
		type["SYNOPSIS"] = ""
	}
	if ($0 ~/^[^[:space:]]/)
		print ".SH " $0
	else
		print ".SS" $0
	sub(/^ +/, "")
	section = $0
	if (section == "SYNOPSIS") {
		print ".nf\n.fam C"
		in_bd = 1
	}
	ls = 0		# line start index
	pls = 0		# previous line start index
	pnzls = 0	# previous non zero line start index
	ni = 0		# indent level
	ind[0] = 0	# indent offset table
	prevblankline = 0
	next
}
{
	# Compute line start index, handle start of example display block
	pls = ls
	if (ls != 0)
		pnzls = ls
	match($0, /[^ ]/)
	ls = RSTART
	if (in_bd == 0 && pls == 0 && pnzls > 0 && ls > pnzls && $1 !~ /^[\-\*o]$|^[0-9]+\.$/) {
		# example display block
		if (prevblankline == 1) {
			print ".PP"
			prevblankline = 0
		}
		print ".nf\n.fam C"
		in_bd = 1
		eoff = ls
	}
	if (ls > 0 && ind[0] == 0)
		ind[0] = ls
}
(in_bd + 0) == 1 {
	# In block display
	if (section == "SYNOPSIS")
		;
	else if (ls != 0 && ls < eoff) {
		# End of litteral display block
		in_bd = 0
		print ".fam T\n.fi"
	} else { print; next }
}
section == "NAME" {
	$1 = "\\fB" $1
	sub(/ \- /, " \\fP- ")
}
section == "SYNOPSIS" {
	# Identify arguments of fcts and cmds
	if (type["SYNOPSIS"] == "") {
		if ($0 ~ /\(/)
			type["SYNOPSIS"] = "fct"
		else if ($1 == "struct" || $2 == "struct")
			type["SYNOPSIS"] = "struct"
		else if ($1 && $1 !~ /^#|typedef|struct|union|enum/)
			type["SYNOPSIS"] = "cmd"
	}
	if (type["SYNOPSIS"] == "cmd") {
		# Line is a command line
		if ($1 !~ /^\[/) {
			b = $1
			sub(/^\*/, "", b)
			subwords["\\<" b "\\>"] = "\\fB" b "\\fP"
		}
		for (i = 2; i <= NF; i++) {
			a = $i
			gsub(/[\[\]\|]/, "", a)
			if (a ~ /^[^\-]/)
				subwords["\\<" a "\\>"] = "\\fI" a "\\fP"
		}
	} else if (type["SYNOPSIS"] == "fct") {
		# Line is a C function definition
		if ($1 == "typedef") {
			if ($0 !~ /\(\*/)
				subwords["\\<" $2 "\\>"] = "\\fI" $2 "\\fP"
		} else if ($1 == "#define")
			subwords["\\<" $2 "\\>"] = "\\fI" $2 "\\fP"
		for (i = 1; i <= NF; i++) {
			if ($i ~ /[,\)];*$/) {
				a = $i
				sub(/.*\(/, "", a)
				gsub(/\W/, "", a)
				subwords["\\<" a "\\>"] = "\\fI" a "\\fP"
			}
		}
	}
}
{
	# protect dots inside words
	while ($0  ~ /\w\.\w/)
		sub(/\./, "_dOt_")
	# identify func calls and cross refs
	for (i = 1; i <= NF; i++) {
		b = $i
		sub(/^\*/, "", b)
		if ((a = index(b, ")(")) > 3) {
			w = substr(b, 3, a - 3)
			subwords["\\<" w "\\>"] = "\\fI" w "\\fP"
		}
		if ((a = index(b, "(")) > 1) {
			w = substr(b, 1, a - 1)
			subwords["\\<" w "\\("] = "\\fB" w "\\fP("
		}
	}
	# word attributes
	n = asorti(subwords, indices)
	for (i = 1; i <= n; i++)
		gsub(indices[i], subwords[indices[i]])
	# shell options
	gsub(/\B\-+\w+(\-\w+)*/, "\\fB&\\fP")
	# unprotect dots inside words
	gsub(/_dOt_/, ".")

	if (section == "SYNOPSIS") {
		sub(/^  /, "")
		print
		next
	}
	if (match($0, /[^ ]  +/) > 0) {
		# tag list item
		adjust_indent()
		tag = substr($0, 1, RSTART)
		sub(/^ */, "", tag)
		if (RSTART+RLENGTH < length())
			$0 = substr($0, RSTART + RLENGTH)
		else
			$0 = ""
		print ".TP\n.B"
		print tag
		prevblankline = 0
		if (NF == 0)
			next
	} else if ($1 == "-"||$1 == "o"||$1 == "*") {
		# bullet list item
		adjust_indent()
		print ".IP \\(bu 3"
		prevblankline = 0
		$1 = ""
	} else if ($1 ~ /^[0-9]+[\).]$/) {
		# enum list item
		adjust_indent()
		print ".IP " $1 " 4"
		prevblankline = 0
		$1 = ""
	} else if (pls == 0) {
		# new paragraph
		adjust_indent()
	} else if (NF == 0) {
		# blank line
		prevblankline = 1
		next
	} else
		prevblankline = 0
	# flush vertical space
	if (prevblankline == 1) {
		print ".PP"
		prevblankline = 0
	}
	if (section != "SYNOPSIS" || $0 ~ /^ {1,4}/)
		sub(/ */,"")
	# Protect lines starting by simple quotes
	sub(/^'\''/, "\\(cq")
	print
}

function adjust_indent()
{
	if (ls > ind[ni]) {
		ind[++ni] = ls
		print ".RS"
	} else if (ls < ind[ni]) {
		while (ls < ind[ni]) {
			ni--
			print ".RE"
		}
	}
}
' | eval $post