#!/usr/bin/env bash
# Usage: {script} RULE_FILENAME
# Update list of language codes (ISO-639-2)

set -euo pipefail

declare -r IFS=$'\n'
declare -r URL="http://www.loc.gov/standards/iso639-2/ISO-639-2_utf-8.txt"
declare -r RULE_FILENAME="${1}"
declare -r TEMPORARY_LIST=$(mktemp)

download_list()
{
  echo "Downloading list from '${URL}'"
  curl --silent --location "${1}" --output "${2}"
}

update_currency_codes()
{
  local -r filename_rule="${1}"
  local -r filename_list="${2}"
  local -r temporary_rule=$(mktemp)

  echo "Updating list in '${filename_rule}'"
  {
    sed -n '/^</,/    protected/p' "${filename_rule}"
    while read line; do
      local alpha_3=$(cut --delimiter '|' --fields 1 <<< "${line}" | tr -cd '[a-z]' | tr '[a-z]' '[A-Z]')
      local alpha_2=$(cut --delimiter '|' --fields 3 <<< "${line}" | tr '[a-z]' '[A-Z]')
      local name=$(cut --delimiter '|' --fields 4 <<< "${line}")
      echo "        ['${alpha_2}', '${alpha_3}'], // ${name}"
    done < "${filename_list}"
    sed -n '/^    ]/,/^}/p' "${filename_rule}"
  } > "${temporary_rule}"

  mv "${temporary_rule}" "${filename_rule}"
}

download_list "${URL}" "${TEMPORARY_LIST}"
update_currency_codes "${RULE_FILENAME}" "${TEMPORARY_LIST}"