#!/bin/bash

[ ! -z "${DEBUG}" ] && set -x

USER=${1:-$( id -un )}
HOME="$( getent passwd $USER | cut -d ':' -f 6 )"
BASE="${HOME}"/Maildir
INOTIFY='/usr/bin/inotifywait'
INOTIFY_EVENTS='moved_to,moved_from'
INOTIFY_OPTIONS='--monitor --recursive --event'" ${INOTIFY_EVENTS}"
SPAMC='/usr/bin/spamc'

JUNK="${BASE}/Junk"
NONJUNK="${BASE}/Junk"
TRASH="${BASE}/Trash"
SENT="${BASE}/Sent"
DRAFTS="${BASE}/Drafts"

if [[ -f "${HOME}/.junkerrc" && -r "${HOME}/.junkerrc" ]]
then
    . "${HOME}/.junkerrc"
fi

function Log {
    echo -e "$( date +'%Y%m%d %H:%M:%S' )\t$@"
}

function Cleanup {
    Log "Exiting"
    exit 0
}

function Learn {
    [[ "$1" != "ham" && "$1" != "spam" ]] && return 3
    [[ ! -f "$2" || ! -r "$2" ]] && return 4
    Log "Learning $2 as $1"
    exec 9<"$2"
    ${SPAMC} --learntype $1 <&9
    ret=$?
    case $ret in
        0) Log "Done"
            ;;
        5) Log "Learned"
            ;;
        6) Log "Already known"
            ;;
        *) Log "Error occured, code $ret"
            ;;
    esac
    exec 9<&-
}

if [ ! -d "${BASE}" ]
then
    echo "Error: Mail directory not found at ${BASE}, exiting" >&2
    exit 1
fi
if [ ! -x ${INOTIFY} ]
then
    echo "Error: inotifywait not found, check path" >&2
    exit 1
fi
if [ ! -x ${SPAMC} ]
then
    echo "Error: spamc not found, check path" >&2
    exit 1
fi
checkfile=$( mktemp )
echo ${RANDOM} >${checkfile}
${SPAMC} --learntype forget <${checkfile} >/dev/null 2>&1
if [ $? -eq 74 ]
then
    echo "Error: spamd doesn't allow connections, needs --allow-tell" >&2
    rm -f ${checkfile}
    exit 1
fi
rm -f ${checkfile}

trap "Cleanup" EXIT SIGINT SIGTERM
trap "Reload" SIGHUP

while IFS='	' read -r dir event file
do
    if [[ "${dir}" != */cur/ && "${dir}" != */new/ ]]
    then
        continue
    fi
    case "${dir}" in
        ${TRASH}/*)
            ;&
        ${SENT}/*)
            ;&
        ${DRAFTS}/*)
            continue
    esac
    if [[ "${event}" == *MOVED_TO* && "${dir}" == "${JUNK}"/cur/ ]]
    then
        Learn "spam" "${dir}/${file}"
    elif [[ "${event}" == *MOVED_TO* && "${dir}" == "${JUNK}"/new/ ]]
    then
        Learn "spam" "${dir}/${file}"
    elif [[ "${event}" == *MOVED_TO* && "${dir}" == "${NONJUNK}"/cur/ ]]
    then
        Learn "ham" "${dir}/${file}"
    elif [[ "${event}" == *MOVED_FROM* && "${dir}" == "${JUNK}"/cur/ ]]
    then
        Learn "ham" "${dir}/${file}"
    elif [[ "${event}" == *MOVED_TO* && "${dir}" == ${BASE}/*/new/ ]]
    then
        Learn "ham" "${dir}/${file}"
    fi
done < <( ${INOTIFY} ${INOTIFY_OPTIONS} --format '%w	%e	%f' ${BASE} )