#!/bin/bash

set -e

if [[ "$UID" != 0 ]]; then
    sudo $0 $@
    exit
fi

SNAPSHOT_TIME="00:00"
SNAPSHOT_SRC="PATH/TO/.liked"
SNAPSHOT_DST_PREFIX="PATH/TO/BTRFS/SNAPSHOT/DIR"
ARCHIVE_DST="PATH/TO/ARCHIVE/DIR"
ARCHIVE_DST_PENDING="${ARCHIVE_DST}/pending"

PRUNING_BINARY="PRUNING/EXECUTABLE"
KEEP_BLOCKS="1000"

MAIN_ARCHIVE_LIST=(
    "data/application.db"
    "data/blockstore.db"
    "data/cs.wal"
    "data/evidence.db"
    "data/state.db"
    "data/priv_validator_state.json"
)

SEPARATED_ARCHIVE_LIST=(
    "data/tx_index.db"
)

echo "$(date -Iseconds) - Starting liked service"
systemctl start liked

while true; do
    # `expr` will return non-zero code if the result is `0`, so wrapping using `echo`
    TO_SLEEP=$(echo $(expr $(date -d "${SNAPSHOT_TIME}" +%s) - $(date -d "now" +%s)))
    if [ ${TO_SLEEP} -lt 0 ]; then
        TO_SLEEP=$(echo $(expr ${TO_SLEEP} "+" 86400))
    fi
    echo "$(date -Iseconds) - Wait until ${SNAPSHOT_TIME}, sleeping for ${TO_SLEEP} seconds"
    sleep ${TO_SLEEP}
    echo "$(date -Iseconds) - Stopping service"
    systemctl stop liked
    echo "$(date -Iseconds) - Service stopped, creating snapshot"
    SNAPSHOT_DST="${SNAPSHOT_DST_PREFIX}/$(date -Isecond)"
    btrfs subvolume snapshot "${SNAPSHOT_SRC}" "${SNAPSHOT_DST}"
    echo "$(date -Iseconds) - Snapshot created, Starting service"
    systemctl start liked
    echo "$(date -Iseconds) - Service started, prunning snapshot"
    "${PRUNING_BINARY}" prune-and-compact "${SNAPSHOT_DST} ${KEEP_BLOCKS}"
    echo "$(date -Iseconds) - Prunned snapshot, archiving snapshot"
    TIMESTAMP=$(date +%F)
    pushd "${SNAPSHOT_DST}"
        mkdir -p ${ARCHIVE_DST_PENDING}

        TARGET="${ARCHIVE_DST_PENDING}/liked-data-${TIMESTAMP}.tar.zst"
        tar -c ${MAIN_ARCHIVE_LIST[@]} \
        | pv -s $(du -sb ${MAIN_ARCHIVE_LIST[@]} | awk '{sum+=$1;} END {print sum;}') \
        | zstd -T0 \
        > "${TARGET}"
        LATEST_TARGET="${ARCHIVE_DST_PENDING}/liked-data-latest.tar.zst"
        rm -f "${LATEST_TARGET}"
        ln -s "${TARGET}" "${LATEST_TARGET}"

        for ARCHIVE in ${SEPARATED_ARCHIVE_LIST[@]}; do
            NAME=$(basename $ARCHIVE)
            TARGET="${ARCHIVE_DST_PENDING}/liked-data-${TIMESTAMP}-${NAME}.tar.zst"
            tar -c $ARCHIVE \
            | pv -s $(du -sb $ARCHIVE | awk '{sum+=$1;} END {print sum;}') \
            | zstd -T0 \
            > ${TARGET}
        done

        mv "${ARCHIVE_DST_PENDING}/*" "${ARCHIVE_DST}"
    popd > /dev/null
    echo "$(date -Iseconds) - Archived snapshot"
    # btrfs subvolume delete "${SNAPSHOT_DST}"
done