#! /usr/bin/sh

WATCHLIST="$(systemd-path user-shared)"/package-alert/watchlist

agg_results=""

if [ -f "${WATCHLIST}" ]; then
    while read -r pattern; do
        pat_results=$(apt-cache search --names-only "${pattern}")
        if [ -n "${pat_results}" ]; then
            agg_results="${agg_results:+${agg_results}
}Packages matching \"${pattern}\":
${pat_results}
"
        fi
    done < "${WATCHLIST}"
fi

if [ -n "${agg_results}" ]; then
    printf '%s' "${agg_results}" | /usr/sbin/sendmail "${USER}"
fi