#!/bin/sh -pe
#
# update-langlist maintains the LANGUAGE priority list. It does so in
# a simplified manner, unlike the UI in language-selector-gnome for
# setting the user language which provides full control.

first_language=$1
homedir=$2
renewed_langlist=

[ -n "$first_language" -a -n "$homedir" ] || exit 1

get_old_langlist() {
    if [ -r "$homedir/.pam_environment" ]; then
        while read line; do
            if [ "$( echo "${line%=*}" | sed -r 's/\s+DEFAULT$//' )" = 'LANGUAGE' ]; then
                old_langlist=${line#*=}
                break
            fi
        done < $homedir/.pam_environment
    fi
}

old_langlist=
english=true
if [ ${first_language%%[_@]*} != 'en' ]; then
    get_old_langlist
    english=false
fi

if [ -n "$old_langlist" ] && ! $english; then
    if expr $old_langlist : ".*:$first_language:" > /dev/null ; then
        renewed_langlist=$( echo $old_langlist | sed -r "s/(.+:)($first_language:)/\2\1/" )
    elif [ ${old_langlist%%:*} = $first_language ]; then
        # no change
        renewed_langlist=$old_langlist
    else
        renewed_langlist=$first_language:$old_langlist
    fi
else
    # build fresh list with 'en' as the last element
    # no other languages needed if English was selected
    renewed_langlist=$first_language
    [ $first_language != 'en' ] && renewed_langlist=$renewed_langlist:en
fi

echo $renewed_langlist