#!/bin/sh -pe
#
# - takes the first choice language in the LANGUAGE priority list as argument
# - outputs locale name corresponding to that language

lang=$1
locale_name=

test -n "$lang" || exit 1

# remove codeset if any
if [ "$lang" != "${lang%.*}" ]; then
    lang=$( echo $lang | sed -r 's/([^.]+)[^@]+(.*)/\1\2/' )
fi

langtoolsdir=/usr/share/language-tools

langcode=${lang%%[_@]*}
locales=
for loc in $( locale -a | grep -F .utf8 ); do
    # skip locales for other languages
    if [ $langcode = ${loc%%[._@]*} ]; then
        loc=${loc%.*}${loc#*.utf8}
        locales="$locales $loc"
    fi
done

# exact match
for loc in $locales; do
    if [ $lang = $loc ]; then
        locale_name=$( echo $loc | sed -r 's/([^@]+)/\1.UTF-8/' )
        break
    fi
done

if [ -z "$locale_name" -a $lang = ${lang%_[A-Z]*} ]; then

    # try the "main" country code if any
    main_country=
    while read line; do
        if [ "${line%%[[:space:]]*}" = $langcode ]; then
            main_country=${line##*[[:space:]]}
            if [ $lang != ${lang#*@} ]; then
                main_country=$main_country@${lang#*@}
            fi
            break
        fi
    done < $langtoolsdir/main-countries
    if [ -n "$main_country" ]; then
        for loc in $locales; do
            if [ $main_country = $loc ]; then
                locale_name=$( echo $loc | sed -r 's/([^@]+)/\1.UTF-8/' )
                break
            fi
        done
    fi

    # try out fitting locale with any country code
    if [ -z "$locale_name" -a $langcode != 'zh' ]; then
        for loc in $locales; do
            if [ "${loc%%[_@]*}" = $langcode ]; then
                locale_name=$( echo $loc | sed -r 's/([^@]+)/\1.UTF-8/' )
                break
            fi
        done
    fi
fi

echo $locale_name