#!/bin/bash

function find_device {
    for DEVICE in /dev/disk/by-partlabel/ext*backup*; do
        if [ -L "$DEVICE" ]; then
            ZPOOLNAME="$(basename "$DEVICE")"
            CRYPTNAME="crypt-$(basename "$DEVICE")"
            echo "> Found: $ZPOOLNAME -> $(readlink -e "$DEVICE")"
            return
        fi
    done

    echo "ERROR! Couldn't find a backup device"
    exit 1
}

function pool_import {
    if ! zpool status "$ZPOOLNAME" &> /dev/null; then
        echo "> cryptsetup luksOpen $DEVICE $CRYPTNAME"
        cryptsetup luksOpen "$DEVICE" "$CRYPTNAME" --key-file "/etc/lukskeys/${ZPOOLNAME}"
        echo "> zpool import $ZPOOLNAME"
        zpool import "$ZPOOLNAME"
    fi
}

function pool_export {
    echo "> zpool export $ZPOOLNAME"
    for i in $(seq 10); do
        zpool export "$ZPOOLNAME" && break
    done
    echo "> cryptsetup luksClose $CRYPTNAME"
    cryptsetup luksClose "$CRYPTNAME"
}

function cleanup_snapshots {
    echo "> Cleaning snapshots"

    sanoid --configdir=/etc/sanoid/ext-backup --verbose --prune-snapshots

    zfs list -t snapshot -r "$ZPOOLNAME" -H -o name \
        | grep -F @syncoid_ \
        | grep -Fv "@syncoid_$ZPOOLNAME" \
        | xargs -rn1 zfs destroy -v
}

function syncoidw {
    syncoid --identifier "$ZPOOLNAME" "$@"
}

function main {
    find_device
    pool_import
    sync_snapshots
    cleanup_snapshots
    pool_export
}