/usr/bin/slim-theme

#!/bin/sh
# slim-theme: manage SLiM themes
# Aleksej Bobylev <al.bobylev@gmail.com>, 2013-2014

ME=$(basename $0)
VERSION=20130525
CONF=/etc/slim.conf

help()
{
    cat >&2 << EOT
$ME: Manage SLiM themes

Usage: $ME OPTION [NAME]

Options:
  -h       Display this short help and exit
  -l       List available themes (comma separated)
  -g       Get the name of current theme (note, it can be comma separated list)
  -s NAME  Set NAME theme as current; name of previous theme will be stored
           (note, you can set comma separated list for random theme behavior)
  -f NAME  Forget about NAME theme and return to previous used theme
  -V       Display information about $ME version
  -t       Translate current theme\'s strings according to global LANG value
           (note, its done auto when -s processed)
  -T LANG  Same as above, but use specified language

Set option works like stack: you can "set" theme several times (every time you
install new SLiM theme). Use "forget" option at every theme uninstall to revert
to previous theme, if it was current.
EOT
    exit 0
}

get_current() { awk '/current_theme/ { print $2 }' $CONF ; } #Braces and trailing ";" added by s243a
get_prev()    { awk '/previous_theme/ { print $2 }' $CONF ; } #Braces and trailing ";" added by s243a
set_current() { sed -i 's|^current_theme .*$|current_theme '$1'|' $CONF ; } #Braces and trailing ";" added by s243a
set_prev()
{
    sed -i '/^previous_theme/d' $CONF
    [ x$1 != x ] && echo "previous_theme      $1" >> $CONF
}
find_theme()
{
    cd /usr/share/slim/themes
    theme=$(ls -Ad $1 2>/dev/null | head -n1)
    [ x$theme == x ] && echo "Theme \"$1\" not exist!" >&2 && exit 1
    echo $theme
}
i18n()
{
    lang=$1
    curr=$(get_current)
    strings=/usr/share/slim/themes/$curr/strings
    [ ! -e $strings ] && strings=/usr/share/slim/strings
    conf=/usr/share/slim/themes/$curr/slim.theme
    for str in welcome_msg username_msg password_msg; do
        # ll_CC.UTF-8@euro ; ll_CC.UTF-8 ; ll_CC ; ll ; en
        for langtry in $lang ${lang%@*} ${lang%\.*} ${lang%_*} en; do
            try="$(grep '^'${str:0:1}':'$langtry'   ' $strings | cut -d'    ' -f2)"
            [ x"$try" != x ] && break
        done
        sed -i 's|^\('$str'\).*$|\1             '"$try"'|' $conf
        echo "$str[$langtry]=$try" >&2
    done
}

set_theme()
{
    theme=$(find_theme "$1")
    curr=$(get_current)
    prev=$(get_prev)
    if [ x$theme != x$curr ]; then
        echo "Set theme $theme" >&2
        [ x$prev != x ] && curr=$curr:$prev
        set_prev $curr
        set_current $theme
    else
        echo "Already set" >&2
    fi

    i18n $LANG
    exit 0
}

forget_theme()
{
    theme=$(find_theme "$1")
    curr=$(get_current)
    prev=$(get_prev)
    echo "Forget theme \"$theme\"" >&2
    if [ x$theme == x$curr ]; then
        last=$(echo $prev | cut -d: -f1); [ x$last == x ] && last=base
        rest=${prev#*:}; [ x$rest == x$prev ] && rest=
        prev=$rest; set_prev $prev
        echo "Back to \"$last\" theme" >&2
        set_current $last
    fi
    prev=$(echo $(echo $prev | tr ':' '\n' | sed "/$theme/d") | tr ' ' ':')
    set_prev $prev

    exit 0
}


# parse only first option
getopts ":lgs:f:VhtT:" opt
case $opt in
    l)
        list=$(find /usr/share/slim/themes/*/slim.theme | sort | awk -F/ '{ print $6 }')
        echo $list | tr ' ' ','; exit 0 ;;
    g)
        get_current; exit 0 ;;
    s)
        set_theme "$OPTARG" ;;
    f)
        forget_theme "$OPTARG" ;;
    V)
        echo $VERSION; exit 0 ;;
    h)
        help; exit 0 ;;
    t)
        i18n $LANG; exit 0 ;;
    T)
        i18n $OPTARG; exit 0 ;;
    *)
        if [ x$OPTARG == xs -o x$OPTARG == xf -o x$OPTARG == xT ]; then
            echo "Option \"$OPTARG\" requires an argument."
        else
            [ x$OPTARG != x ] && echo "Illegal option \"$OPTARG\"."
        fi
        echo "$ME -h for help."; exit 1 ;;
esac

help