#!/bin/bash

backup_dir="/var/dobackup-pool"
command="dobackup"

function showHelp {
        echo "usage: $command filepath_relative_or_absolute [comment]"
	echo "The backup file will be stored in the directory $backup_dir."
	echo "Its filename (once stored) will the the absolute path (in which the character / is replaced by two dashes) + the actual filename + a timestamp"
	echo "The comment will be stored in the same directory; the filename will be the one of the backuped file plus the postfix 'comment'."
        echo ""
        exit
}

function getAbsolutePath {
    input_path=$(readlink -f $1)
}

# input arguments
input_filename=$1
comment=$2


############################################
## BEGIN - SHOW HELP
############################################
show_help=0
if [ "$input_filename" = "-h" ]
    then
        showHelp
fi

if [ "$input_filename" = "--help" ]
    then
        showHelp
fi

if [ "$input_filename" = "" ]
    then
        showHelp
fi
############################################
## END - SHOW HELP
############################################

# Does the backup directory already exist?
if [ ! -d $backup_dir ]
    then
        mkdir -p $backup_dir
fi

# Does the input filename exist?
if [ ! -e $input_filename ]
    then
        echo "ERROR: Input file doesn't exist."
        exit
fi

# We are ready to do the actual backup
getAbsolutePath $input_filename;
#echo $input_path;

# Replacing '/' with '--'; this lets the input filename be an absolute path 
input_path_replacement=$(echo $input_path | sed 's/\//--/g')
#echo $input_path_replacement;

backup_filename=$backup_dir/$input_path_replacement-$(date +%Y%m%d)-$(date +%H%M%S)
#echo $backup_filename;

cp $input_path $backup_filename
#echo ""

# checking the existance of the output file
file_created=0
if [ -e $backup_filename ]
    then
        file_created=1
	echo "Backup file created - $backup_filename"	
    else
	echo "Backup file NOT created - Some problems occurred." 
fi

if [ "$comment" != "" ]
    then
        backup_comment_filename=$backup_dir/$input_path_replacement-$(date +%Y%m%d)-$(date +%H%M%S)-comment
        touch $backup_comment_filename
        echo $comment > $backup_comment_filename
        echo "Backup file comment created - $backup_comment_filename"
fi

if [ $file_created == 1 ]
    then
#        echo ""
        echo "Rollback:"
        echo "mv $backup_filename $input_path"
        echo ""
fi