#!/bin/bash

SRCDIR=$1
DSTDIR=$2
CURRENTDATE=$(date +%s)

#CHECK FOR THE LAST UPDATE LOG
if [[ -s lastupdate.log ]]; then
	LASTUPDATE=$(<lastupdate.log)
else
	>lastupdate.log
	LASTUPDATE=${CURRENTDATE}
fi

echo "Creating a backup of ${SRCDIR} in ${DSTDIR}"

if [[ -z "${SRCDIR}" ]]; then
	echo "You must specify a source directory"
	exit 1
fi

if [[ -z "${DSTDIR}" ]]; then
	echo "You must specify a destination directory"
	exit 1
fi

DSTDIR="${DSTDIR}/${CURRENTDATE}"
mkdir -p "${DSTDIR}"

find "${SRCDIR}" -maxdepth 1 -type f -newer lastupdate.log -exec cp {} "${DSTDIR}/ \; -exec echo {} was updated, creating a copy \;
find "${SRCDIR}" -maxdepth 1 \( -newer lastupdate.log \) -prune -o -type f -exec ln {} "${DSTDIR}/ \; -exec echo {} was not updated, creating a hard link \;

#Store the new date in the log
echo "${CURRENTDATE}" > lastupdate.log