#!/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 -sf "/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 pool_maybe_scrub {
    local now
    local last_scrub
    local last_scrub_days_ago
    now="$(date +%s)"
    last_scrub="$(zpool status "$ZPOOLNAME"|sed -nE 's/scan: scrub repaired.* on (.*)/\1/p')"
    last_scrub_days_ago=$(((now - $(date --date="${last_scrub:-1970-01-01}" +%s)) / 86400))

    if [ $last_scrub_days_ago -lt 7 ]; then
        return
    fi

    echo "> zpool scrub $ZPOOLNAME"
    zpool scrub "$ZPOOLNAME"

    while zpool status "$ZPOOLNAME" | grep -q "scrub in progress"; do
        echo -n .
        sleep 60
    done
    echo " done"
}

function syncoidw {
    echo "> syncoid $1"
    syncoid "$@" --identifier "$ZPOOLNAME"
}

function snapshot_cleanup {
    echo "> Cleaning snapshots"
    sanoid --configdir=/etc/sanoid/ext-backup --verbose --prune-snapshots

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

function main {
    zfs get all -s local -H > /root/zfs-props.txt
    cryptsetup_open
    pool_import
    pool_setup
    snapshot_sync
    snapshot_cleanup
    pool_maybe_scrub
    pool_export
    cryptsetup_close
}