#!/usr/bin/env bash
set -o pipefail

echo "*** START $0 ${*}"

# ------- Settings
MAX_AGE_DAYS=1

SourceHost=office-oleg-02.cvtt.vpn
SourceDir=/localdisk/backup/qcow2

DownloadTgtDir=/mnt/host_usb3/qcow2

ShrunkDir=/mnt/host_usb3/qcow2/shrunk
TmpDir=/mnt/host_usb3/tmp
# ------- Settings

download_latest() {
    local ssh_opts=(
        -o StrictHostKeyChecking=accept-new
    )

    local rsync_rsh="ssh -o StrictHostKeyChecking=accept-new"

    local FindCmd=(
        ssh
        "${ssh_opts[@]}"
        "$SourceHost"
        find "$SourceDir"
        -type f
        "-mtime -${MAX_AGE_DAYS}"
        "-printf '%P\0'"
    )

    local RsyncCmd=(
        rsync 
        # -n
        -avh 
        --progress 
        --partial 
        --append-verify 
        --from0
        --files-from=-
        "-e $rsync_rsh"
        "${SourceHost}:${SourceDir}/"
        "${DownloadTgtDir}/"
    )

    echo "-------------------"
    echo "Running:"
    set -x
    "${FindCmd[@]}" | "${RsyncCmd[@]}"
    { set +x; } 2>/dev/null
}

compress_qcow2_file() {
    local file=${1}
    local out_file=${2}

    mkdir -p "${ShrunkDir}"
    mkdir -p "${TmpDir}"

    local ShrunkFile="${out_file}.shrunk"

    echo "Sparsifying file ${file}..."
    local Cmd="/usr/bin/virt-sparsify"
    Cmd+=" --check-tmpdir=fail"
    Cmd+=" --tmp=${TmpDir}"
    Cmd+=" --compress"
    if [[ ! -t 1 ]]; then
        Cmd+=" -q"
    fi
    Cmd+=" ${file} ${ShrunkFile}"
    echo "${Cmd}"
    ${Cmd}
    
    if [ ${?} -ne 0 ] ; then
        echo "Compression failed. Removing ${ShrunkFile}"
        rm "${ShrunkFile}"
        return 255
    else
        filesz=$(stat -c %s "${file}")
        if [ "${filesz}" == "0" ]; then
            return 254
        fi
        cfilesz=$(stat -c %s "${ShrunkFile}")

        ratio=$((cfilesz * 100 / filesz))
        echo "Compression is successful. Compression ratio is ${ratio}%"
    fi
    echo "*** DONE: $file -> $ShrunkFile"
    return 0
}


echo "-------------------"
echo "Downloading files from ${SourceHost}:${SourceDir}"
download_latest 
# exit
echo "-------------------"
echo "Download completed"

for qcow2_file in "${DownloadTgtDir}"/*.qcow2; do
    shrunk_file="${ShrunkDir}/$(basename "${qcow2_file}")"
    compress_qcow2_file "${qcow2_file}" "${shrunk_file}"
    if [ ${?} -ne 0 ] ; then
        echo "ERROR: File ${qcow2_file} compression FAILED"
    else
        echo "SUCCESS: File ${qcow2_file} is compressed to ${shrunk_file}"
        echo "Removing file ${qcow2_file} ..."
        rm  "${qcow2_file}"
    fi    
done

echo "*** DONE $0 ${*}"