#!/bin/bash

: <<=cut
=pod

=head1 NAME

pdfman - View man page as PDF


=head1 SYNOPSIS

B<pdfman> I<manentry>


=head1 DESCRIPTION

B<pdfman> uses B<man -t> to generate a PDF-version of the man page. It
is then displayed using $PDFVIEWER.

If $PDFVIEWER is unset, it tries B<okular>, B<evince>, and B<gv>.

If a viewer of the page is already running, a new viewer will not be
started.

=head1 EXAMPLE

Show man page for pdfman:

  pdfman pdfman

=head1 AUTHOR

Copyright (C) 2017 Ole Tange,
http://ole.tange.dk and Free Software Foundation, Inc.


=head1 LICENSE

Copyright (C) 2012 Free Software Foundation, Inc.

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 3 of the License, 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, see <http://www.gnu.org/licenses/>.


=head1 DEPENDENCIES

B<pdfman> uses B<man> and B<ps2pdf>.


=head1 SEE ALSO

B<man>


=cut


dir=/tmp/pdfman-`echo $USER "$@" | md5sum|cut -d ' ' -f 1`
pdf="$dir/$@"
viewer=$PDFVIEWER

if which okular >/dev/null; then
    viewer=${viewer:-okular}
fi
if which evince >/dev/null; then
    viewer=${viewer:-evince}
fi
if which gv >/dev/null; then
    viewer=${viewer:-gv}
fi

cleanup() {
    if [ "$noclean" == 1 ] ; then
	true
    else
	rm $pdf
	rmdir $dir
    fi
}

control_c() {
    echo -en "\n$0: CTRL-C hit: Exiting.\n" >&2
    cleanup 2>/dev/null
}

pdfviewer() {
    if [ "$noview" == 1 ] ; then
	true
    else
	$viewer "$1"
    fi
}


trap control_c SIGINT

if [ -d "$dir" ] ; then
    # PDF-viewer already running for this $pdf
    # Assume it will re-read new file and do the cleanup
    noclean=1
    noview=1
else
    mkdir "$dir"
fi


man -w "$@" |
    parallel 'zcat {} || cat {}' 2>/dev/null |
    # Convert ˆ to ^
    #   remove lines like: .    ds ^ \&
    perl -ne '/^\s*\.\s*ds\s+\S*\^/ or print' |
    perl -pe '
      # replace ^ with \(ha
      s/\^/\\(ha/g;
      # replace \*(-- with \-\-
      s/\\\*\(--/\-\-/g;
      # replace \*(L" or \*(R" with "
      s/\\\*\([LR]"/"/g;
    ' |
    # Todo ~
    # Convert -- to -
    (
	echo '.tr \--';
	cat -
    ) |
    man -tl - |
    perl -pe "s/'/\\\\010/g" |
    ps2pdf - >$pdf && pdfviewer $pdf
cleanup 2>/dev/null