#!/bin/bash

# Full path of configuration file
CONF_FILE="/etc/incremental_backup/incremental_backup.conf"

echo "----------------- RIBS ----------------"
echo "--- Rod's Incremental Backup System ---"
echo ""

# Read the configuration file
echo -n "Reading configuration file... "
source $CONF_FILE
if [ $? -ne 0 ]; then
        echo -e "\e[31mFAILED\e[0m"
        echo "Aborting."
        exit 1
else
        echo -e "\e[32mOK\e[0m"
fi

# Today's date
DAY0=`date -I`
echo "Today's date: $DAY0"

# Previous backup's date
DAY1=`ls $BACKUP_ROOT | grep -v lost+found | tail -n1`
if [ "$DAY1" == "" ]; then
	DAY1=`date -I -d "yesterday"`
	echo "No previous backup date. Using yesterday's date."
elif [ "$DAY1" == "$DAY0" ]; then
	DAY1=`ls $BACKUP_ROOT | grep -v lost+found | tail -n1 | head -n1`
	echo "Previous backup date: $DAY1"
else
	echo "Previous backup date: $DAY1"
fi

# target directory
TRG="$BACKUP_ROOT/$DAY0"

# link destination directory:
LNK="$BACKUP_ROOT/$DAY1"

# rsync options
OPT="-ah --delete --link-dest=$LNK --exclude-from=$EXC_FILE"
if [ "$DRY_RUN" -eq 1 ]; then
        OPT="$OPT -n"
fi


echo -n "Run started "
date
echo ""
# -------- Start backup -------
echo "Starting incremental backup."
if [ "$DRY_RUN" -eq 1 ]; then
	echo "This will be a dry run. Nothing will actually be backed up."
	sleep 10
fi
# Check to see if the backup drive is connected
echo -n "Checking if device connected... "
if [ ! -b "$BACKUP_DEV" ]; then
	echo -e "\e[31mFAILED\e[0m"
	echo "The backup device is not present."
	echo "Check to make sure it's connected and powered on and that the"
	echo "device name in $CONF_FILE is correct."
	echo "Aborting."
	exit 1
else
	echo -e "\e[32mOK\e[0m"
fi
# Check that the backup drive serial number is correct
echo -n "Checking device serial number... "
dev_sn=`smartctl -a $BACKUP_DEV|grep "Serial Number:"|cut -d: -f2| sed 's/[[:space:]]//g'`
if [ "$dev_sn" != "$BACKUP_DEV_SN" ]; then
	echo -e "\e[31mFAILED\e[0m"
	echo "The backup device that is attached does not have the correct"
	echo "serial number. Make sure the correct device is connected and"
	echo "check that the serial number in $CONF_FILE"
	echo "matches the serial number of the device as reported by"
	echo "smartctl -a $BACKUP_DEV"
	echo "Aborting."
	exit 1
else
        echo -e "\e[32mOK\e[0m"
fi
# Mount the backup drive
# First, check to see that drive is mounted 
mount|grep -q $BACKUP_PART
if [ $? -ne 0 ]; then
	echo -n "Backup device partition not mounted. Mounting read-only... "
	mount $BACKUP_PART $BACKUP_ROOT -o ro
	if [ $? -ne 0 ]; then
		echo -e "\e[31mFAILED\e[0m"
		echo "An error was encountered while attempting to mount"
		echo "$BACKUP_PART on $BACKUP_ROOT"
		echo "Aborting."
		exit 1
	else
		echo -e "\e[32mOK\e[0m"
	fi
fi
# Next, if it's mounted ro, remount it rw
mount|grep $BACKUP_PART |grep -q "(rw)"
if [ $? -ne 0 ]; then
	echo "Backup device partition mounted read-only."
	echo -n " Remounting read-write... "
	mount $BACKUP_PART $BACKUP_ROOT -o remount,rw
	if [ $? -ne 0 ]; then
		echo -e "\e[31mFAILED\e[0m"
		echo "An error was encountered while attempting to mount"
		echo "$BACKUP_PART on $BACKUP_ROOT in read-write mode."
		echo "Aborting."
		exit 1
	else
		echo -e "\e[32mOK\e[0m"
	fi
else
	echo "Backup device partition already mounted read-write. Continuing"
fi

# Execute the backup
echo -n "running rsync backup... "
rsync $OPT $SRC $TRG
if [ $? -ne 0 ]; then
	echo -e "\e[31mFAILED\e[0m"
	echo "An error was encountered while attempting to backup. No old"
	echo "backups will be removed."
	if [ "$REMOUNT" -eq 1 ]; then
		mount $BACKUP_PART $BACKUP_ROOT -o remount,ro
	else
		umount $BACKUP_ROOT
	fi
	exit 1
else
        echo -e "\e[32mOK\e[0m"
fi


# Date of $DAY_LMT
DAY_TO_REMOVE=`date -I -d "$DAY_LMT days ago"`

# Delete the specified backup, if it exists
if [ "$DRY_RUN" -eq 1 ]; then
	echo "This is a dry run, so no old backups will be removed."
else
	if [ -d $BACKUP_ROOT/$DAY_TO_REMOVE ]; then
		echo -n "Removing oldest backup... "
		rm -r $BACKUP_ROOT/$DAY_TO_REMOVE
		if [ $? -ne 0 ];then
			echo -e "\e[31mFAILED\e[0m"
		else
			echo -e "\e[32mOK\e[0m"
		fi
	fi
fi

# Unmount the backup drive and exit
echo -n "Syncing disks... "
sync
if [ $? -ne 0 ];then
	echo -e "\e[31mFAILED\e[0m"
else
	echo -e "\e[32mOK\e[0m"
fi
if [ "$REMOUNT" -eq 1 ]; then
	echo -n "Remounting backup device read-only... "
	mount $BACKUP_PART $BACKUP_ROOT -o remount,ro
	if [ $? -ne 0 ]; then
        	echo -e "\e[31mFAILED\e[0m"
	else
        	echo -e "\e[32mOK\e[0m"
	fi
else
	echo -n "Unmounting backup device... "
	umount $BACKUP_PART
	if [ $? -ne 0 ]; then
        	echo -e "\e[31mFAILED\e[0m"
	else
        	echo -e "\e[32mOK\e[0m"
	fi
fi
echo "Backup complete."
echo ""
echo -n "Run ended "
date
echo ""

exit 0