#!/bin/sh

# paperconfig: configuration of system paper name
#
# Copyright (C) 1996, Yves Arrouye <arrouye@debian.org>
#               2001, Adrian Bunk  <bunk@fs.tum.de>
#               2021-2022, Reuben Thomas <rrt@sc3d.org>
#
# This file is part of the libpaper Debian package.
#
# This program is free software: you can redistribute it and/or modify it
# under the terms of the GNU General Public License version 2 as published
# by the Free Software Foundation.
#
# 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
# <https://www.gnu.org/licenses/gpl-2.0.html>.

sysconfdir="/etc"
PAPERSIZE="$sysconfdir/papersize"
PAPERRUNPARTSDIR="$sysconfdir/paper.d"
PAPER_PROGRAM="/usr/bin/paper"

usage() {
    echo "Usage: `basename $0` [--version|--help|--paper NAME|--choose]"

    cat <<EOF

Options: -V, --version          print version information and exit
         -h, --help             print this help and exit
         -p, --paper NAME       specify the paper to use
         -c, --choose           choose paper interactively
EOF
    exit $1
}

choose=0

if [ "$#" -eq 0 ]; then
    exec "$PAPER_PROGRAM" --no-size
fi

while [ $# -ne 0 ]; do
    case "$1" in
	-V|--version)
	    echo "`basename $0` version 2" \
		"by Yves Arrouye <arrouye@debian.org>"
	    exit 0
	    ;;
	-h|--help)
	    usage 0
	    ;;
	-p|--paper)
	    test $# -gt 1 || usage
	    paper="$2"
	    shift
	    ;;
	-c|--choose)
	    choose=1
	    ;;
	*)
	    usage 1
	    ;;
    esac
    shift
done

invalidpaper() {
    ! "$PAPER_PROGRAM" --no-size "$1" 2>/dev/null 1>&2
}

setpaper() {
    paperright=`"$PAPER_PROGRAM" --no-size "$1" 2>/dev/null`

    ok=0

    if 2>/dev/null echo "$paperright" >${PAPERSIZE}.new; then
	if 2>/dev/null mv -f ${PAPERSIZE}.new $PAPERSIZE; then
	    if 2>/dev/null chmod 644 $PAPERSIZE; then
		ok=1
	    fi
	fi
    fi

    if [ $ok -eq 0 ]; then
	echo `basename $0`: cannot create $PAPERSIZE
	exit 2
    else
	if [ -d $PAPERRUNPARTSDIR ]; then
	    run-parts $PAPERRUNPARTSDIR
	fi
    fi
}

if [ ! -z "$paper" ]; then
    if invalidpaper $paper; then
	>&2 echo `basename $0`: \"$paper\" is not a known paper name
	exit 3
    fi
    setpaper "$paper"
    exit 0
fi

knownpapers="`"$PAPER_PROGRAM" --all --no-size`"

prompt=
width=72

paper=`"$PAPER_PROGRAM" --no-size 2>/dev/null || true`
dftpaper=`"$PAPER_PROGRAM" --no-size`

if [ $choose -eq 1 ]; then
    echo

    LESS="-X -E $LESS"
    export LESS

    (
	cat <<EOF
The system paper can be chosen from many known papers that are
currently recognized:

EOF
	echo "$knownpapers" | sed 's/^/    /'
	echo
    ) | /usr/bin/sensible-pager

    : ${paper:=$dftpaper}

    echo -n "Default paper name? [$paper] "
    read ans
    : ${ans:=$paper}
    paper=$ans

    while invalidpaper "$paper"; do
        if [ -z "$paper" ]; then
	    echo "Please choose a paper from the available papers list."
        else
	    echo "Unknown paper \"$paper\"," \
	        "please choose one from the available papers list."
        fi

        paper=$dftpaper

        echo -n "Default paper name? [$paper] "
        read ans
        paper=$ans
    done
fi

if invalidpaper "$paper"; then
    echo "Invalid paper \"$paper\": not setting the system default."
    exit 4
elif [ "`"$PAPER_PROGRAM" --no-size 2>/dev/null`" != "$paper" ] || grep -q "[#	]" $PAPERSIZE; then
    setpaper "$paper"
fi