#!/bin/bash
########################################################
# autoBackupToUSB.sh  - Version 1.5 (2019-01-19)
# by Axel Werner [axel.werner.1973@gmail.com]
# free to use for personal use. NO COMMERCIAL USE ALLOWED!
# Patches and Improvements are welcome.
# 
# this is a cronjob script for install at /etc/crontab 
# and to be run as root. Its intension is to autodetect
# one or more hot plugable backup hard-disks (e.g. USB block devices)
# with a specific given Filesystem Label. e.g. BACKUP1 or
# BACKUP2. If a backup drive has been detected the drive
# will be automatically mounted under /mnt with the
# name of the Label and a rsync will be started to backup 
# all Data from $sourceDir to the given backup drive.
# 
# WARNING:
# It is asumed that the backup drives are used as
# whole and do not contain any other data than just the 
# data to be backed up. the backup drives are supposed to 
# act like a 1:1 mirror of the sourceDir. Any additional
# files on the backup drives WILL BE DELETED when this 
# script is started. 
# 
# Use at your own risk.
#
########################################################
set -e 

#debugEnabled=true
maxNoBackupDrives=12
validBackupDrives=$( eval echo /dev/disk/by-label/BACKUP{$(seq -s ',' 1 ${maxNoBackupDrives})})
scriptName=$(basename $0)
lockFile="/var/run/${scriptName}.lock"
sourceDir="/mnt/yourValuableDataHere/"
logFile="/var/log/${scriptName}.log"



# define some colors for console output
 
RED='\033[91m'
YELLOW='\033[93m'
GREEN='\033[92m'
BLUE='\033[96m'
NOCOLOR='\033[0m'
NC=$NOCOLOR

 
 
function getTime {
    echo $(date +%F-%H%M%S)
}

function print {
	echo -e "$@" | tee -a "${logFile}"
}
 
function printInfo {
	echo -e "$NC""$@""$NC" | tee -a "${logFile}"
}
 
function printWarning {
	echo -e "$YELLOW""$@""$NC" | tee -a "${logFile}"
}
 
function printError {
	echo -e "$RED""$@""$NC" | tee -a "${logFile}" >&2 
}
 
function printDebug {
    if test -v debugEnabled ; then
        echo -e "$BLUE""DEBUG: $(getTime) $@""$NC" | tee -a "${logFile}"
    fi
}

function unmount {
    if umount -l "$mountPoint" ; then
        printDebug "unmounting successfull."
        printDebug "removing mountpoint $mountPoint ..."
        rmdir "$mountPoint"
        printDebug "removing lock file $lockFile ..."
        rm "$lockFile"   
    else
        printError "ERROR: Failed to unmount '$mountPoint'. Aborting."
        printError $(mount | grep /mnt)
	printError $(lsof)
        printError "ERROR: Leaving lock file behind to prevent another rerun."
        exit -1
    fi
}


printDebug "Checking if $scriptName is already running..."
if test -f "$lockFile" ; then 
    printDebug "$scriptName seems already running. Exiting."
    printDebug $(ls -la "$lockFile")
    exit -1
else
    printDebug "creating lockFile '$lockFile' ..."
    echo $$ > "$lockFile"
fi

if ! test -x /usr/bin/pv ; then
	printError "ERROR: /usr/bin/pv not found. make sure you have 'pipe view' installed."
	exit -1
fi

printDebug "Checking if a valid backup drive is connected ..."
printDebug "\$validBackupDrives = $validBackupDrives"

for drive in $validBackupDrives ; do
    printDebug "Drive to test next = $drive"
    if test -b "$drive" ; then
        printDebug "Valid Backup Drive \"$(basename $drive)\"found."
        backupDrive="$drive"
	break
    fi
done

if test -z "$backupDrive" ; then
    printDebug "NO Backup Drive found. Aborting."
    printDebug "removing lock file $lockFile ..."
    rm "$lockFile"   
    exit 0
fi

mountPoint=/mnt/"$(basename $backupDrive)"
mkdir -p "$mountPoint"

if ! mount "$backupDrive" "$mountPoint" ; then
    printError "ERROR: mounting the backup drive '$backupDrive' on mountpoint '$mountPoint' failed."
    exit -1
fi

 
printDebug "DEBUG: recent mount table:"
printDebug $( mount | grep /mnt )

todaysDate=$(date +%F)
printDebug "Checking for min. age of backup ..."
if test -e "$mountPoint/$scriptName-dateOfBackup-$todaysDate" ; then
    printDebug "Seems the Backup already had run today. Skipping until tomorrow."
    printDebug "DEBUG: ls -la $mountPoint"
    printDebug $( ls -la "$mountPoint" )
    unmount
    exit   
fi

if test -f "$mountPoint/$scriptName-dateOfBackup-*" ; then
    rm "$mountPoint/$scriptName-dateOfBackup-*"
fi

printDebug "rsyncing source to destination..."

rsync_param="-av --delete-before --delete-excluded --exclude='.Trash-1000/'"
rsync $rsync_param "$sourceDir" "$mountPoint" | \
    pv -lep -s $(rsync $rsync_param -n  \
    "$sourceDir" "$mountPoint" | awk 'NF' | wc -l)

touch "$mountPoint/$scriptName-dateOfBackup-$todaysDate"
printDebug "DEBUG: ls -la $mountPoint"
printDebug $( ls -la "$mountPoint" )

unmount