#!/usr/bin/env sh

## Data Format

### user.txt
# <username>

### hosts.txt
# <host 1 address> <host 1 port> <host 1 root zfs>
# <host 2 address> <host 2 port> <host 2 root zfs>
# ...

### rootzfs.txt
# <root zfs>

### datasets.txt (Only required for aggregator setup.)
# <dataset 1>
# <dataset 1>/<dataset 1a>
# <dataset 1>/<dataset 1b>
# <dataset 2>
# <dataset 2>/<dataset 2a>
# <dataset 3>
# ...

if [ ! -f user.txt ]; then echo "No user specified."; exit 2; fi
if [ ! -f hosts.txt ]; then echo "No hosts specified."; exit 2; fi
if [ ! -f rootzfs.txt ]; then echo "No rootzfs specified."; exit 2; fi

BAKRNG_ROOT=`cat rootzfs.txt`

list_filesets()
{
    zfs list | tail -n +2 | cut -d' ' -f1|grep ${BAKRNG_ROOT}
}

get_latest_snapshot()
{
    zfs list -t snapshot |
        grep ${BAKRNG_ROOT} |
        tail -n1 |
        cut -d'@' -f2 |
        cut -d' ' -f 1
}

setup_aggregator()
{
    zfs allow -u `cat user.txt` send,snapshot,hold ${BAKRNG_ROOT}
    for dataset in `cat datasets.txt`; do
	    zfs create $dataset
    done
}

setup_mirror()
{
    zfs allow -u `cat user.txt` send,snapshot,hold ${BAKRNG_ROOT}
    zfs allow -du `cat user.txt` \
        compression,mountpoint,receive,create,mount ${BAKRNG_ROOT}
}

create_snapshot()
{
    id="`date -I`-`date +%s`"
    echo zfs snapshot -r ${BAKRNG_ROOT}@${id}
}

send_single_snapshot()
{
    BAKRNG_SEND_SNAPSHOT=`get_latest_snapshot`
    while read BAKRNG_REMOTE_ADDR BAKRNG_REMOTE_PORT BAKRNG_REMOTE_ROOT; do
        echo "zfs send -R ${BAKRNG_ROOT}@${BAKRNG_SEND_SNAPSHOT} |
            ssh -i ~/.ssh/id_rsa \
            -o port=${BAKRNG_REMOTE_PORT} ${BAKRNG_REMOTE_ADDR} \
            zfs receive -dvu ${BAKRNG_REMOTE_ROOT}@${BAKRNG_SEND_SNAPSHOT}"
    done
    # echo $BAKRNG_SEND_SNAPSHOT > "last-snapshot.txt"
}

send_incremental_snapshop()
{
    BAKRNG_SEND_SNAPSHOT=`get_latest_snapshot`
    while read BAKRNG_REMOTE_ADDR BAKRNG_REMOTE_PORT BAKRNG_REMOTE_ROOT; do
        echo "zfs send -R -i `cat last-snapshot.txt` \
            ${BAKRNG_ROOT}@${BAKRNG_SEND_SNAPSHOT} | ssh -i ~/.ssh/id_rsa \
            -o port=${BAKRNG_REMOTE_PORT} ${BAKRNG_REMOTE_ADDR} \
            zfs receive -dvu ${BAKRNG_REMOTE_ROOT}@${BAKRNG_SEND_SNAPSHOT}"
    done
    # echo $BAKRNG_SEND_SNAPSHOT > "last-snapshot.txt"
}


if [ -f "last-snapshot.txt" ]; then
    send_incremental_snapshop
else
    send_single_snapshot
fi