# SPDX-License-Identifier: GPL-2.0-only
########################################################################
#
# (C) Copyright 2020-2022, Alejandro Colomar
# These functions are free software; you can redistribute them and/or
# modify them under the terms of the GNU General Public License
# as published by the Free Software Foundation; version 2.
#
# These functions are distributed in the hope that they 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
# (http://www.gnu.org/licenses/gpl-2.0.html).
#
########################################################################

########################################################################
#	Exit status

EX_USAGE=64;

########################################################################
#	C

#  sed_rm_ccomments()  removes C comments.
# It can't handle mixed //... and /*...*/ comments.
# Use as a filter (see man_lsfunc() in this file).

sed_rm_ccomments()
{
	perl -p -e 's%/\*.*?\*/%%g' \
	|sed -E '\%/\*%, \%\*/% {\%(\*/|/\*)%!d}' \
	|sed -E '\%/\*% {s%/\*.*%%; n; s%.*\*/%%;}' \
	|sed -E '\%/\*% {s%/\*.*%%; n; s%.*\*/%%;}' \
	|sed 's%//.*%%';
}

########################################################################
#	Linux man-pages

#  man_section()  prints specific manual page sections (DESCRIPTION, SYNOPSIS,
# ...) of all manual pages in a directory (or in a single manual page file).
# Usage example:  .../man-pages$ man_section man2 SYNOPSIS 'SEE ALSO';

man_section()
{
	if [ $# -lt 2 ]; then
		>&2 echo "Usage: ${FUNCNAME[0]} <dir> <section>...";
		return $EX_USAGE;
	fi

	local page="$1";
	shift;
	local sect="$*";

	find "$page" -type f \
	|xargs wc -l \
	|grep -v -e '\b1 ' -e '\btotal\b' \
	|awk '{ print $2 }' \
	|sort \
	|while read -r manpage; do
		(sed -n '/^\.TH/,/^\.SH/{/^\.SH/!p}' <"$manpage";
		 for s in $sect; do
			<"$manpage" \
			sed -n \
				-e "/^\.SH $s/p" \
				-e "/^\.SH $s/,/^\.SH/{/^\.SH/!p}";
		 done;) \
		|mandoc -Tutf8 2>/dev/null \
		|col -pbx;
	done;
}

#  man_lsfunc()  prints the name of all C functions declared in the SYNOPSIS
# of all manual pages in a directory (or in a single manual page file).
# Each name is printed in a separate line
# Usage example:  .../man-pages$ man_lsfunc man2;

man_lsfunc()
{
	if [ $# -lt 1 ]; then
		>&2 echo "Usage: ${FUNCNAME[0]} <manpage|manNdir>...";
		return $EX_USAGE;
	fi

	for arg in "$@"; do
		man_section "$arg" 'SYNOPSIS';
	done \
	|sed_rm_ccomments \
	|pcregrep -Mn '(?s)^ [\w ]+ \**\w+\([\w\s(,)[\]*]*?(...)?\s*\); *$' \
	|grep '^[0-9]' \
	|sed -E 's/syscall\(SYS_(\w*),?/\1(/' \
	|sed -E 's/^[^(]+ \**(\w+)\(.*/\1/' \
	|uniq;
}

#  man_lsvar()  prints the name of all C variables declared in the SYNOPSIS
# of all manual pages in a directory (or in a single manual page file).
# Each name is printed in a separate line
# Usage example:  .../man-pages$ man_lsvar man3;

man_lsvar()
{
	if [ $# -lt 1 ]; then
		>&2 echo "Usage: ${FUNCNAME[0]} <manpage|manNdir>...";
		return $EX_USAGE;
	fi

	for arg in "$@"; do
		man_section "$arg" 'SYNOPSIS';
	done \
	|sed_rm_ccomments \
	|pcregrep -Mv '(?s)^ [\w ]+ \**\w+\([\w\s(,)[\]*]+?(...)?\s*\); *$' \
	|pcregrep -Mn \
	  -e '(?s)^ +extern [\w ]+ \**\(\*+[\w ]+\)\([\w\s(,)[\]*]+?\s*\); *$' \
	  -e '^ +extern [\w ]+ \**[\w ]+; *$' \
	|grep '^[0-9]' \
	|grep -v 'typedef' \
	|sed -E 's/^[0-9]+: +extern [^(]+ \**\(\*+(\w* )?(\w+)\)\(.*/\2/' \
	|sed    's/^[0-9]\+: \+extern .* \**\(\w\+\); */\1/' \
	|uniq;
}

#  pdfman()  renders a manual page in PDF
# Usage example:  .../man-pages$ pdfman man2/membarrier.2;

pdfman()
{
	if [ $# -eq 0 ]; then
		>&2 echo "Usage: ${FUNCNAME[0]} [man(1) options] [section] page";
		return $EX_USAGE;
	fi;

	local tmp="$(mktemp -t "${!###*/}.XXXXXX")";

	man -Tps "$@" \
	|ps2pdf - - \
	>"$tmp";
	xdg-open "$tmp";
}

#  man_gitstaged  prints a list of all files with changes staged for commit
# (basename only if the files are within <man?/>), separated by ", ".
# Usage example:  .../man-pages$ git commit -m "$(man_gitstaged): msg";

man_gitstaged()
{
	git diff --staged --name-only					\
	|sed 's/$/, /'							\
	|sed 's%.*/%%'							\
	|tr -d '\n'							\
	|sed 's/, $//'
}