#!/bin/bash

# ============ R e q u i r e s  package guestfs-tools

if [ "$(id -u)" -ne 0 ]; then
  echo "This script must be run as root." >&2
  exit 1
fi

# ------ Settings
TmpDir=/localdisk/tmp

# ------ Settings

mkdir -p ${TmpDir}
file=${1}
out_file=${2}

SparseFile="${out_file}.sparse"
ShrunkFile="${out_file}.shrunk"

echo "Compressing file ${file}..."
Cmd="/usr/bin/virt-sparsify"
Cmd="${Cmd} --check-tmpdir=continue"
Cmd="${Cmd} --tmp=${TmpDir}"
Cmd="${Cmd} -q"
Cmd="${Cmd} ${file} ${SparseFile}"
Cmd="${Cmd} && /usr/bin/qemu-img convert"
Cmd="${Cmd} -c"
Cmd="${Cmd} -O qcow2"
Cmd="${Cmd} ${SparseFile} ${ShrunkFile}"
echo ${Cmd}
eval ${Cmd}

if [ ${?} -ne 0 ]
then
    echo "Compression failed. Removing ${ShrunkFile}"
    rm ${ShrunkFile}
else
    filesz=$(stat -c %s ${file})
    cfilesz=$(stat -c %s ${ShrunkFile})

    ratio=$((cfilesz * 100 / filesz))
    echo "Compression is successful. Compression ratio is ${ratio}%"
    rm ${SparseFile}
fi
    
echo "Done $0 $*"