#!/bin/sh

set -eu
shopt -s failglob

usage="Usage:
    $0 list
    $0 show-rand
    $0 email lockers...
    $0 purge lockers..."

clean_locker() {
    echo "${1%%@scripts.mit.edu}"
}

list() {
    echo "Top twenty users by number of queued messages:"
    mailq | tail -n +2 | grep -v '^ *(' | awk 'BEGIN { RS = "" } { print $8 }' | sort | uniq -c | sort -n | tail -n 20
}

show_rand() {
    files=$(ls /var/spool/postfix/deferred/?/* | shuf | head -n 3)
    for file in $files; do
        echo ">>>> $file";
        strings "$file"
        echo;
    done
}

tmpl_email() {
    sender=${SSH_GSSAPI_NAME%%/*}
    if [[ $# -eq 0 ]]; then
        echo "Please specific a locker to generate template for." >&2
        exit 1
    fi
    for locker in "$@"; do
        locker=$(clean_locker "$locker")
        echo "fs la /mit/$locker/"
        fs la "/mit/$locker"
        echo
        cat <<-EOF
The scripts.mit.edu servers currently have a large number of email
messages destined for the *$locker* account that are not being handled by
your account and are being queued. Sufficiently large numbers of queued
messages can cause stability issues for the servers, so we would like
you to ensure that your account can handle all messages it receives by
two weeks from now.

You will be able to process the incoming messages if you sign up for the
mail scripts service (http://scripts.mit.edu/mail/). You're welcome to
simply forward all incoming mail to another address (the default is to
forward it to the mit.edu address of the user who signs up); otherwise,
you can configure mail scripts to process the incoming messages in some
suitable fashion.

Frequently, large numbers of queued messages are a sign that some wiki,
blog, forum, or other site has been spammed. If this is the case, you
should apply some appropriate spam-blocking mechanism.

If you have any questions, feel free to contact us.

Thanks,
scripts.mit.edu team
scripts@mit.edu --- semi-private
scripts-root@mit.edu --- service maintainers only
EOF
        echo;echo
    done
}

purge() {
    if [[ $# -eq 0 ]]; then
        echo "Please specific a locker to purge emails for." >&2
        exit 1
    fi
    for locker in "$@"; do
        locker=$(clean_locker "$locker")
        echo "$locker..."
        mailq | tail -n +2 | grep -v '^ *(' | awk "BEGIN { RS = \"\" } (\$8 == \"$locker@scripts.mit.edu\" && \$9 == \"\") { print \$1 }" | tr -d '*!' | postsuper -d -
        echo
    done
}

op=${1:-}
shift
case $op in
    list) list;;
    show-rand) show_rand;;
    email) tmpl_email "$@";;
    purge) purge "$@";;
    *)
        echo "$usage" >&2;
        exit 1
        ;;
esac

# vim: set sts=4 sw=4 et:
