#!/bin/bash

################################################################################
#                                                                              #
# Author: Patrick Ditzel (patrick@central-computer.de)                         #
# Lizenz:  GNU GENERAL PUBLIC LICENSE v3                                       #
#                                                                              #
################################################################################

################################################################################
# Set up the backupenvironment and "global" functions
################################################################################

INSTALLATION_PATH_PREFIX=/usr/local

function set_config {
	if [ -r /etc/dbb.cfg ]; then
		# Check if configuration is found in /etc. If yes set configvar
		BACKUPCFG=/etc/dbb.cfg
	elif [ -r ~/.dbb.cfg ]; then
		# If config is found in the backupuser home directory set it into the configvar
		BACKUPCFG=~/.dbb.cfg
	else
		echo "No configuration file is found, please create one" | /usr/bin/logger -s -i -t databasebackup
	fi
}

function load_dbmodul_dfg {
	if [ -d $BACKUPCFG.d ]; then
		if [ ! "$(ls -A $BACKUPCFG.d)" ]; then
			echo "Configurationdirectory for modules exist but it is empty" | /usr/bin/logger -s -i -t databasebackup
		else
			for MODULCFG in $(ls $BACKUPCFG.d); do . $BACKUPCFG.d/MODULCFG; done
		fi
	else
		echo "Configurationdirectory does nort exists, can't load any configurationfile" | /usr/bin/logger -s -i -t databasebackup
	fi
}

function check_backup_env {
	# Check if the configuration exists and is not empty
	if [ -r $BACKUPCFG ] && [ -s $BACKUPCFG ]; then
		# If true then read it
		. $BACKUPCFG
		load_dbmodul_dfg
	else
		# If not throw an errormessage
		echo "The configfile does not exists or is empty" | /usr/bin/logger -s -i -t databasebackup
		echo "Please create the $BACKUPCFG or write your settings into" | /usr/bin/logger -s -i -t databasebackup
		exit 1
	fi
	if [ "$ENABLE_DEBUG" = "TRUE" ]; then
		# If debugoutput is enabled show the configurationfile without comments
		echo "################################################################################" | /usr/bin/logger -s -i -t databasebackup
		while read -r configline; do
			echo "$configline" | grep -v '^$' | grep -v '^#' | /usr/bin/logger -s -i -t databasebackup
		done <<< "$(cat $BACKUPCFG)"
		echo "################################################################################" | /usr/bin/logger -s -i -t databasebackup
	fi
	# Check if the target directory for the backupfiles exists
	if [ ! -d "$BACKUP_DIR" ]; then
		# If not create it
		mkdir -p "$BACKUP_DIR"
	fi
	# Check if the directory for tempfiles exists
	if [ ! -d "$TMP_DIR" ]; then
		# If not create it
		mkdir -p "$TMP_DIR"
	fi
	
}

function set_logger {
	# Check if log to syslog is enabled
	if [ "$ENABLE_SYSLOG" = "TRUE" ]; then
		# If true then define the logger
		LOGGER="/usr/bin/logger -s -i -t databasebackup"
	else
		# If not cat it out on stdout
		LOGGER="/bin/cat"
	fi
}

function debug {
        DEBUGMSG=$1
        if [ "$ENABLE_DEBUG" = "TRUE" ]; then
                echo "$DEBUGMSG" | $LOGGER
        fi
}

function load_dbmodules {
	if [ -d $BACKUPCFG.d ] && [ -d $INSTALLATION_PATH_PREFIX/lib/dbb-modules ]; then
		if [ ! "$(ls -A $BACKUPCFG.d)" ] && [ ! "$(ls -A $INSTALLATION_PATH_PREFIX/lib/dbb-modules)" ]; then
			debug "Configurationdirectory or directory for modules exist but it is empty"
		else
			for MODUL in $(ls $BACKUPCFG.d | cut -d "." -f1); do 
				. $INSTALLATION_PATH_PREFIX/lib/dbb-modules/$MODUL
				debug "Load module: $INSTALLATION_PATH_PREFIX/lib/dbb-modules/$MODUL"
				check_$MODUL_deps
			done
		fi
	else
		debug "Configurationdirectory does nort exists, can't load any configurationfile"
	fi
}

function is_interactive {
	SCRPT=$(basename "$0")
	debug "$SCRPT"

	if [ "$SCRPT" = "dbbi" ]; then
		# If the script is called for interactive use we have to chenge the calls of the functions
		# Setting the $LOGGER für interactive use to /bin/cat
		LOGGER="/bin/cat"
		# Here we set teh environment variable for interactive use
		debug "dbbi (DataBase Interactive Backup) is called"
		RADIOACTIVE=TRUE
	elif [ "$SCRPT" = "dbb" ]; then
		# Set the $LOGGER
		LOGGER="/usr/bin/logger -s -i -t databasebackup"
		# If the script is used noninteractive we have also to set the environmet variable with this information
		debug "dbb (DataBase Backup) is called"
		RADIOACTIVE=FALSE
		# unset the $LOGGER because this will be set later within the informatione in the configfile
		unset LOGGER
	else
		# If the switch between interactive and noninteractive does not work: tell it but before set the $LOGGER
		LOGGER="/usr/bin/logger -s -i -t databasebackup"
		debug "An error occured - don't know if to use interactive or noninteractive"
		exit 1
	fi
}

function backup_file_handler {
	# translate the vars to make it more readable
	BFH_TMP_DIR=$1
	BFH_BACKUPDIR_DIR=$2
	BFH_FILE=$3
	# If enabled put out some debug infos
	debug "BFH_TMP_DIR: $BFH_TMP_DIR"
	debug "BFH_BACKUPDIR_DIR: $BFH_BACKUPDIR_DIR"
	debug "FILE: $BFH_FILE"
	# Check if the script should keep a filehistorie
	if [ "$KEEP_BACKUP_FILES" = "TRUE" ]; then
		debug "Keep history"
		# Set some vars to manage the files
		BACKUP_DAY=$(date +%x)
		REMOVE_NUMBER=$(( $BACKUP_FILES_DAYS + 1 ))
		BFH_FILE_PREFIX_NAME_TO_REMOVE=$(date -d "$REMOVE_NUMBER days ago" "+%x")
		# ... and if it is turned on give some debig info
		debug "BACKUP_DAY: $BACKUP_DAY"
		debug "REMOVE_NUMBER: $REMOVE_NUMBER"
		debug "FILE_PREFIX_NAME_TO_REMOVE: $BFH_FILE_PREFIX_NAME_TO_REMOVE-$BFH_FILE"
		# Check if there is an backupfile from the current day
		if [ -f "$BFH_BACKUPDIR_DIR"/"$BACKUP_DAY"-"$BFH_FILE" ]; then
			# If yes append miniutes and seconds to the date-profix of the filename
			debug "File $BFH_BACKUPDIR_DIR/$BACKUP_DAY-$BFH_FILE already exists. Rename the new one."
			DATE_TIME_SUFFIX=$(date +%H%M%S)
			# ... and move it into the targetdir
			mv "$BFH_TMP_DIR"/"$BFH_FILE" "$BFH_BACKUPDIR_DIR"/"$BACKUP_DAY"-"$DATE_TIME_SUFFIX"-"$BFH_FILE"
		else
			# If there is no backupfile of the current day move it to the backupfolder
			mv "$BFH_TMP_DIR"/"$BFH_FILE" "$BFH_BACKUPDIR_DIR"/"$BACKUP_DAY"-"$BFH_FILE"
		fi
		# Check if there are files older then the days to keep set in the config
		if [ -f "$BFH_BACKUPDIR_DIR"/"$BFH_FILE_PREFIX_NAME_TO_REMOVE"-"$BFH_FILE" ]; then
			# if yes remove it
			rm "$BFH_BACKUPDIR_DIR"/"$BFH_FILE_PREFIX_NAME_TO_REMOVE"-"$BFH_FILE"
			# Also remove the files with the extended prefix in the name
			# If there is ab file with the extende prefix then there has to be a file with tne normal prefix
			rm "$BFH_BACKUPDIR_DIR"/"$BFH_FILE_PREFIX_NAME_TO_REMOVE"?????-"$BFH_FILE"
		else
			# If no file exists do nothing but some debuginfo
			debug "File $BFH_BACKUPDIR_DIR/$BFH_FILE_PREFIX_NAME_TO_REMOVE-$BFH_FILE does not exists, so can not remove it."
		fi
	else
		# If we do not keep a filehistory do the following
		# Check if the targefile exists
		if [ -f "$BFH_BACKUPDIR_DIR"/"$BFH_FILE" ]; then
			debug "$BFH_FILE exists ... make a diff"
			# Check if there are differences betwenn last backup and the actual one
			diff "$BFH_TMP_DIR"/"$BFH_FILE" "$BFH_BACKUPDIR_DIR"/"$BFH_FILE" > /dev/null 2>&1
			if [ $? -ne 0 ]; then
				# If yes then move it to the backupfolder
				debug "Differences found between old and new $BFH_FILE -> moving to BACKUP_DIR"
				mv "$BFH_TMP_DIR"/"$BFH_FILE" "$BFH_BACKUPDIR_DIR"/"$BFH_FILE"
			else
				# If not do nothing
				debug "No differences found between old an new $BFH_FILE"
			fi
		else
			# If there is a new databasedumpfile move it to the backupfolder
			debug "New Backupfile $BFH_FILE -> moving to $BFH_BACKUPDIR_DIR"
			mv "$BFH_TMP_DIR"/"$BFH_FILE" "$BFH_BACKUPDIR_DIR"/"$BFH_FILE"
		fi
	fi
}

function check_global_deps {
	# Check the dependencys
	if [ ! -e /usr/bin/sudo ]; then
		echo "It seems that you dont have sudo installed. Please install sudo and restart" | /usr/bin/logger -s -i -t databasebackup
		exit 1
	fi
}

################################################################################

# The mainfunktion
function main {
	check_global_deps
	is_interactive
	if [ "$RADIOACTIVE" = "TRUE" ]; then
		debug "Unsing dbbi (dbb interactive = dbbi) is for future use"
	fi
	if [ "$RADIOACTIVE" = "FALSE" ]; then
		debug "running noninteractive"
		# Set up the configuration for the noninteractive mode
		set_config
		# Configure logging (from configurationfil)e
		set_logger
		# Check if the backupenvironment is setup properly
		check_backup_env
		# Run modul-main-functions
		for MODULMAIN in $(ls $BACKUPCFG.d | cut -d "." -f1); do 
			$MODULMAIN_main
		done
			# The final action: remove the dumps
		rm -rf "$TMP_DIR"
	fi

}

main