#!/bin/bash
# These are the formats I prefer seeing dates and times
# -- altblue
proper_date_format='%Y-%m-%d'
proper_time_format='%H:%M:%S'

ref_date='1970-04-01 20:09:08'
epoch=$(date --date="$ref_date" +%s)
dcmd="date --date=@$epoch"
proper_date=$($dcmd "+$proper_date_format")
proper_time=$($dcmd "+$proper_time_format")

cat <<EOT
Reference:
   date: $ref_date
  epoch: $epoch

Expected format:
   date: $proper_date_format – $proper_date
   time: $proper_time_format – $proper_time

Which English locales yield the expected date & time formatting?
EOT

date_fail=0
time_fail=0
date_ok=0
time_ok=0
ok_locales=0

while read locale ; do
    date=$(LC_TIME=$locale $dcmd +%x)
    time=$(LC_TIME=$locale $dcmd +%X)
    ok=0
    if [[ $date = $proper_date ]] ; then
        date_ok=$((date_ok + 1))
        ok=$((ok + 1))
    else
        date_fail=$((date_fail + 1))
    fi
    if [[ $time = $proper_time ]] ; then
        time_ok=$((time_ok + 1))
        ok=$((ok + 1))
    else
        time_fail=$((time_fail + 1))
    fi
    result=' '
    if [[ $ok = 2 ]] ; then
        ok_locales=$((ok_locales + 1))
        result='✔'
    fi
    name=${locale%.*}
    name=${name#en_}
    printf '%s  %s:  %-10s  %s\n' "$result" "$name" "$date" "$time"
done < <(locale -a |grep ^en_ |grep utf8)

cat <<EOT

$date_fail date failures, $time_fail time failures, $date_ok date successes, $time_ok time successes.

$ok_locales English locales format dates as $proper_date_format and time as $proper_time_format.

EOT