#!/bin/bash

function cryptsetup_open {
    for DEVICE in /dev/disk/by-partlabel/ext*backup*; do
        if ! [ -L "$DEVICE" ]; then
            continue
        fi
        DISKNAME="$(basename "$DEVICE")"
        CRYPTNAME="crypt-$DISKNAME"
        echo "> cryptsetup luksOpen $DEVICE $CRYPTNAME"
        cryptsetup luksOpen "$DEVICE" "$CRYPTNAME" --key-file "/etc/lukskeys/${DISKNAME}"
        mkdir -p /run/ext-backup-crypt/
        ln -s "/dev/mapper/$CRYPTNAME" /run/ext-backup-crypt/
    done
}

function cryptsetup_close {
    for CRYPTDEVICE in /dev/mapper/crypt-ext*backup*; do
        if ! [ -L "$CRYPTDEVICE" ]; then
            continue
        fi
        CRYPTNAME="$(basename "$CRYPTDEVICE")"
        echo "> cryptsetup luksClose $CRYPTNAME"
        cryptsetup luksClose "$CRYPTNAME"
        rm -f "/run/ext-backup-crypt/$CRYPTNAME"
    done
}

function pool_import {
    echo "> zpool import -d /run/ext-backup-crypt -a"
    zpool import -d /run/ext-backup-crypt -a

    ZPOOLNAME="$(zpool list -H -o name|grep 'ext.*backup'|head -n1)"
    if [ -z "$ZPOOLNAME" ]; then
        echo "Error! Could not find pool!"
        return 1
    fi

    echo "> Found: $ZPOOLNAME"
}

function pool_export {
    echo "> zpool export $ZPOOLNAME"
    for _ in $(seq 60); do
        zpool export "$ZPOOLNAME" && break
        sleep 1
    done
}

function pool_setup {
    zfs set mountpoint="/mnt/$ZPOOLNAME" "$ZPOOLNAME"
    chmod 0700 "/mnt/$ZPOOLNAME"
    zfs set compression=lz4 "$ZPOOLNAME"
    zfs set devices=off "$ZPOOLNAME"
    zfs set exec=off "$ZPOOLNAME"
    zfs set setuid=off "$ZPOOLNAME"
    zfs set xattr=sa "$ZPOOLNAME"
    zfs set acltype=posixacl "$ZPOOLNAME"
}

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 {
    zfs get all -s local -H > /root/zfs-props.txt
    cryptsetup_open
    pool_import
    pool_setup
    sync_snapshots
    cleanup_snapshots
    pool_export
    cryptsetup_close
}