#!/bin/sh -e
#
# - 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

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