#!/bin/sh

set -eu
umask 022

LOCKFILE="/var/run/sync-mirrors/lockfile"
LOGFILE="/var/log/sync-mirrors/sync-mirrors-$(date +%Y%m%d%H%M%S).log"
CONFDIR="/etc/sync-mirrors"

usage() {
    echo "Usage: $(basename "$0") [-v] [mirror]" 1>&2
    echo "       $(basename "$0") -l" 1>&2
}

list_mirrors() {
    for f in "$CONFDIR"/*.conf ; do
        basename "$f" ".conf"
    done
}

logmsg() {
    "$VERBOSE" && echo "$1"
    echo "$(date '+%Y/%m/%d %H:%M:%S') [$$] $1" >> "$LOGFILE"
}

logstream() {
    while read -r line; do
        logmsg "$line"
    done
}

if [ ! -d "$CONFDIR" ]; then
    echo "ERR: Config directory [${CONFDIR}] missing" 1>&2
    exit 1
fi

VERBOSE=false
NOOP=""
EXTRA_OPTS=""
while getopts "vhln" c ; do
    case $c in
        v)
            VERBOSE=true
            EXTRA_OPTS="${EXTRA_OPTS} -v --progress"
            ;;
        h)
            usage
            exit 0
            ;;
        l)
            echo "Available mirrors:"
            list_mirrors | sed -e 's/^/  /'
            exit 0
            ;;
        n)
            NOOP=" (DRY RUN)"
            EXTRA_OPTS="${EXTRA_OPTS} -n"
            ;;
        *)
            usage
            exit 1
            ;;
    esac
done

shift "$((OPTIND - 1))"

if [ $# -eq 0 ]; then
    set -- $(list_mirrors)
    if [ $# -eq 0 ]; then
        echo "ERR: No configured mirrors found" 1>&2
        exit 1
    fi
else
    for mirror in "$@" ; do
        if [ ! -f "${CONFDIR}/$1.conf" ]; then
            echo "ERR: No mirror named [$1]" 1>&2
            exit 1
        fi
    done
fi

if [ "$(whoami)" != "mirror" ]; then
    echo "ERR: Script needs to be run as mirror user" 1>&2
    exit 1
fi

if [ -f "$LOCKFILE" ]; then
    if kill -0 "$(cat $LOCKFILE)" ; then
        STARTED=" ($(stat --format='%y' $LOCKFILE))"
        echo "ERR: Lockfile exists${STARTED}, exiting" 1>&2
        exit 1
    else
        echo "WARN: Removing stale lock file..." 1>&2
        rm -f "$LOCKFILE"
    fi
fi
trap 'rm -f $LOCKFILE' INT TERM EXIT
echo "$$" > "$LOCKFILE"

for mirror in "$@" ; do
    POSTCMD=""
    SRC=""
    RSYNCOPTS=""
    # shellcheck source=/dev/null
    . "${CONFDIR}/${mirror}.conf"
    if [ "$SRC" = "" ]; then
        echo "ERR: No SRC set for mirror ${mirror} ..." 1>&2
        exit 1
    fi
    logmsg "Starting ${mirror} sync${NOOP}..."
    rsync -aH -4 $EXTRA_OPTS --numeric-ids --delete --delete-delay \
        --delay-updates --no-motd $RSYNCOPTS --log-file="$LOGFILE" \
        --exclude=.~tmp~/ "$SRC" "/srv/mirrors/${mirror}/"
    STATUS=$?
    if [ $STATUS -ne 0 ]; then
        echo "WARN: Encountered errors on ${mirror} sync, see ${LOGFILE} for details" 1>&2
    fi
    logmsg "Finished ${mirror} sync with exit status ${STATUS}${NOOP} ..."
    if [ "$POSTCMD" != "" ]; then
        logmsg "Running post for ${mirror} ..."
        $POSTCMD 2>&1 | logstream
        logmsg "Finished post for ${mirror} ..."
    fi
done