#!/usr/bin/env sh

if [ $# != 3 ]; then
    echo "usage: $0 <cache-fs> <base-pool> <percentage>"
    exit 1
fi

CACHEFS="${1}"
BASEPOOL="${2}"
PERCENTAGE=${3}

set -o errexit
while [ $(df "${CACHE}" | tail -n1 | awk '{print $5}' | cut -d'%' -f1) -gt ${PERCENTAGE} ]
do
    # Find the file with the oldest access time
    FILE=$(find "${CACHE}" -type f -printf '%A@ %P\n' | \
               sort | \
               head -n 1 | \
               cut -d' ' -f2-)
    # If no file found, exit
    test -n "${FILE}" || exit 0
    # Move file
    rsync \
        --archive \
        --acls \
        --xattrs \
        --atimes \
        --hard-links \
        --one-file-system \
        --quiet \
        --preallocate \
        --remove-source-files \
        --relative \
        --log-file=/tmp/mergerfs-cache-rsync.log \
        "${CACHE}/./${FILE}" \
        "${BACKING}/"
done