#!/bin/bash

# ----- ----- ----- ----- ----- ----- ----- ----- ----- ----- ----- ----- #
# Script to create incremental snapshot backups of a passed directory.
# Backs up using rsync to a remote machine.
# 
# Copyright (C) 2008 Andrew "Weibullguy" Rowland 
# [darowland <AT> ieee <DOT> com]
#
# By using this script, you agree that all damage to your system, loss of
# data, and other undesired effects are your problem.  I make no warranty, 
# explicit or otherwise.  I make no guarantees, explicit or otherwise. I
# recommend you study the script, understand it, and independently validate
# it is the solution you desire and executing it on your machine will not
# result in the aforementioned bad juju.
#
# Since, there is no warranty, guarantee, promise, oath, contract, covenant,
# pledge, compact, treaty, pact, assurance, etc., I ask only that you keep
# the copyright statement above in the header.  However, you may add, delete,
# or edit anything in the script itself to make it safer, more useful, more 
# efficient, etc.  You are under no obligation, obviously, to provide your
# changes.  But you can, if you want, send your changes to me at the email
# address above.
# 
# Enjoy....
#
# Change the values in the User-Defined Defaults section below for your
# particular setup.
# ----- ----- ----- ----- ----- ----- ----- ----- ----- ----- ----- ----- #

# ----- ----- ----- ----- - User-Defined Defaults ----- ----- ----- ----- #
CALEN=${CALEN:-"monthly"}                       # Snapshot periodicity.
EXCLUDES=${EXCLUDES:-"$HOME/.file.list"}        # List of files to include/exclude from the transfer.
SOURCE=${SOURCE:-"$HOME/"}                      # Source directory.
HOST=${HOST:-""}                                # Host to backup to.
SNAPDIR=${SNAPDIR:-"/srv/samba/backups"}        # Destination directory.
MODULE=${MODULE:-`hostname | tr '[a-z]' '[A-Z]'`}
PWDFILE=${PWDFILE:-"$HOME/.secret"}
RSYNCOPTS="--delete --delete-before --delete-excluded --delay-updates"
# ----- ----- ----- ----- ----- ----- ----- ----- ----- ----- ----- ---- #

# ----- ----- ----- ----- -- System Commands --- ----- ----- ----- ----- #
DATE=`which date`
ECHO=`which echo`
ID=`which id`
NOTIFY=`which notify-send`
PING=`which ping`
RSYNC=`which rsync`
SSH=`which ssh`
# ----- ----- ----- ----- ----- ----- ----- ----- ----- ----- ----- ---- #

rotate() {

	# Function used to rotate old backups on the remote server.
	if [ "x$DRYRUN" == "x1" ]; then
		$ECHO -e "Execution would:"
		$ECHO -e "\t1. Delete directory $SNAPDIR/$MODULE/$CALEN.3 on $HOST."
		$ECHO -e "\t2. Move directory $SNAPDIR/$MODULE/$CALEN.2 to $SNAPDIR/$MODULE/$CALEN.3 on $HOST"
		$ECHO -e "\t3. Move directory $SNAPDIR/$MODULE/$CALEN.1 to $SNAPDIR/$MODULE/$CALEN.2 on $HOST"
		$ECHO -e "\t4. Copy directory $SNAPDIR/$MODULE/$CALEN.0 to $SNAPDIR/$MODULE/$CALEN.1 on $HOST"
	else
		# Step 1: delete the oldest snapshot, if it exists.
		$SSH -t -t $RUSER@$HOST rm -fr $SNAPDIR/$MODULE/$CALEN.3

		# Step 2: shift the middle snapshots(s) back by one, if they exist.
		$SSH -t -t $RUSER@$HOST mv $SNAPDIR/$MODULE/$CALEN.2 $SNAPDIR/$MODULE/$CALEN.3
		$SSH -t -t $RUSER@$HOST mv $SNAPDIR/$MODULE/$CALEN.1 $SNAPDIR/$MODULE/$CALEN.2

		# Step 3: make a hard-link-only (except for dirs) copy of the latest snapshot, if that exists.
		$SSH -t -t $RUSER@$HOST cp -al $SNAPDIR/$MODULE/$CALEN.0 $SNAPDIR/$MODULE/$CALEN.1
	fi

}

backup() {

	# Function to backup the local directory to the remote server.
	if [ "x$DRYRUN" == "x1" ]; then
		$ECHO -e "\t5. rsync the latest $DIRECTORY from $SOURCE to $HOST.  The following will occur:"
	fi

	# Step 4: rsync from the system into the latest snapshot.
	if [ "x$PROTO" == "x1" ];		# Use with servers running a rsync daemon.
	then
		/usr/bin/rsync $RSYNCOPTS $SOURCE rsync://$RUSER@$HOST/$MODULE/$DIRECTORY/
	elif [ "x$PROTO" == "x2" ];		# Use with servers needing to SSH with rsync.
	then
		/usr/bin/rsync $RSYNCOPTS $SOURCE/ $RUSER@$HOST:$SNAPDIR/$MODULE/$DIRECTORY/

	fi

	if [ "x$CALEN" != 'x' ];
	then
		# Step 5: update the mtime of $CALEN.0 to reflect the snapshot time.
		$SSH -t -t $RUSER@$HOST touch $SNAPDIR/$MODULE/$DIRECTORY

		# Step 6: update the file with the backup date and time.
		NOWD=`$DATE +%m-%d-%Y`
		NOWT=`$DATE +%H%M`
		if [ ! -f $TIMEFILE ];
		then
			echo "hourly.0 $NOWD $NOWT" > $TIMEFILE
			echo "daily.0 $NOWD $NOWT" >> $TIMEFILE
			echo "weekly.0 $NOWD $NOWT" >> $TIMEFILE
			echo "monthly.0 $NOWD $NOWT" >> $TIMEFILE
			# Step 7: copy the snapshot time file to the remote server.
			scp $TIMEFILE $RUSER@$HOST:$SNAPDIR/$MODULE/
		#else
		#	OLDD=`grep $CALEN.$SNAP $TIMEFILE | awk '{print $2}'`
		#	OLDT=`grep $CALEN.$SNAP $TIMEFILE | awk '{print $3}'`
		#	sed -i "/${CALEN}.$SNAP/ s/${OLDD}/${NOWD}/" ${TIMEFILE}
		#	sed -i "/${CALEN}.$SNAP/ s/${OLDT}/${NOWT}/" ${TIMEFILE}
		fi
	fi

}

restore() {

	# Function to update the local directory from the remote server.
	if [ "x$DRYRUN" == "x1" ]; then
		$ECHO -e "\trsync the latest $CALEN.$SNAP from $HOST to $SOURCE.  The following will occur:"
	fi

	# Step 1: rsync from the latest snapshot to the system.
	if [ "x$PROTO" == "x1" ];		# Use with servers running a rsync daemon.
	then
		/usr/bin/rsync $RSYNCOPTS rsync://$RUSER@$HOST/$MODULE/$DIRECTORY $SOURCE
	elif [ "x$PROTO" == "x2" ];		# Use with servers needing to SSH with rsync.
	then
		/usr/bin/rsync $RSYNCOPTS $RUSER@$HOST:$SNAPDIR/$MODULE/$DIRECTORY/ $SOURCE/
	fi

}

CRON=0
DRYRUN=0
PROTO=1
RESTORE=0
SNAP=0

# Get command line arguments.
while [ $# -gt 0 ]; 
do
	case "$1" in

		-c|--calendar)
			CALEN=$2
			;;
		-d|--cron)
			CRON=1
			;;
		-e|--exclude)
			EXCLUDES=$2
			if [ ! -f $EXCLUDES ];
			then
				$ECHO "Error: No such file or directory $EXCLUDES."
				exit 1
			fi
			;;
		-h|--host)
			HOST=$2
			$PING -c 3 $HOST >/dev/null 2>&1
			ROUT=$?
			if [ $ROUT != 0 ];
			then
				$ECHO "Error: No route to $HOST."
				exit 1
			fi
			;;
		-l|--logfile)
			LOGFILE=$2
			;;
		-m|--module)
			MODULE=$2
			;;
		-n|--dry-run)
			DRYRUN=1
			;;
		-p|--protocol)
			PROTO=$2
			;;
		-r|--restore)
			RESTORE=1
			;;
		-s|--source)
			SOURCE=$2
			if [ ! -d $SOURCE ];
			then
				$ECHO "Error: No such directory $SOURCE."
				exit 1
			fi
			;;
		-t|--target)
			SNAPDIR=$2
			;;
		-u|--user)
			RUSER=$2
			;;
		-z|--snapshot)
			SNAP=$2
			;;
		--help)
			$ECHO -e "-c, --calendar INT\t\twhether this is hourly, daily, weekly, or monthly snapshot.  Leave blank for non-snapshot backup."
			$ECHO -e "-d, --cron \t\t\texecute script using cron."
			$ECHO -e "-e, --exclude FILE\t\tfile containing exclude patterns."
			$ECHO -e "-h, --host HOST\t\t\thost name of rsync server."
			$ECHO -e "-l, --logfile LOGFILE\t\tname and path of the file used to log ouput."
			$ECHO -e "-m, --module MODULE\t\trsync module on rsync server."
			$ECHO -e "-n, --dry-run\t\t\tperform a dry run of the snapshot."
			$ECHO -e "-p, --protocol\t\t\tspecify the rsync protocol to use."
			$ECHO -e "\t\t\t\t\t1 = rsync daemon on remote server (default)"
			$ECHO -e "\t\t\t\t\t2 = rsync+ssh"
			$ECHO -e "\t\t\t\t\t3 = http(s)"
			$ECHO -e "-r, --restore\t\t\trestore from snapshot on remote host."
			$ECHO -e "-s, --source SOURCE\t\tbase directory on local machine."
			$ECHO -e "-t, --target TARGET\t\ttarget directory on remote server."
			$ECHO -e "-u, --user USER\t\t\tuser on remote rsync server."
			$ECHO -e "-z, --snapshot VERSION\t\twhich snapshot to restore from.  Options are 0, 1, 2, or 3.  Defaults to 0."
			$ECHO -e "--help\t\t\t\tthis help."

			exit 0
			;;
	esac
	shift
done

TIMEFILE="$HOME/.local/var/log/$MODULE.time"

# If running as a cron job, then get the SSH password from the keychain.
LOCALHOST=`hostname -f`
if [ "x$CRON" == "x1" ]; 
then
	source $HOME/.keychain/$LOCALHOST-sh
	source $HOME/.keychain/$LOCALHOST-sh-gpg
else
	RSYNCOPTS="${RSYNCOPTS} --progress"
fi

# Set rsync options depending on the connection protocol to use.
if [ "x$PROTO" == "x1" ];		# Use with servers running a rsync daemon.
then
	RSYNCOPTS="-var ${RSYNCOPTS} --password-file=$HOME/.secret --exclude-from=$EXCLUDES"
elif [ "x$PROTO" == "x2" ];		# Use with servers needing to SSH with rsync.
then
	RSYNCOPTS="-iramlHP ${RSYNCOPTS} -e $SSH --exclude-from=$EXCLUDES"
fi

# Log file stuff.
if [ "x$LOGFILE" == "x" ];
then
	LOGFILE="$HOME/.local/var/log/$MODULE_$CALEN.log"
fi

if [ "x$LOGFILE" != "x" ];
then

	if [ -f $LOGFILE ];
	then
		rm $LOGFILE
	fi

	RSYNCOPTS="${RSYNCOPTS} --log-file=$LOGFILE"

fi

if [ "x$DRYRUN" == "x1" ];
then
	RSYNCOPTS="--dry-run ${RSYNCOPTS}"
fi

if [ "x$RESTORE" == "x1" ];
then

	if [ "x$CALEN" == "x" ];
	then
		SNAP=""
		DIRECTORY=""
	else
		DIRECTORY="$CALEN.$SNAP"
	fi

	restore

	if [ "x$NOTIFY" != "x" ]; then
		$NOTIFY 'SnapShot' "Update of $MODULE from $CALEN.$SNAP on $HOST is complete." -i dialog-information
	fi

else

	if [ "x$CALEN" == "x" ];
	then
		SNAP=""
		DIRECTORY=""
	else
		DIRECTORY="$CALEN.$SNAP"
		rotate
	fi
	
	backup

	if [ "x$NOTIFY" != "x" ]; then
		$NOTIFY 'SnapShot' "Snapshot $CALEN.$SNAP for $MODULE to $HOST is complete." -i dialog-information
	fi

fi

exit 0