#!/bin/sh

BAK_ROOT="/backup"
BAK_TARGET="/home/tommy/backup"
DATE_STR=`date +%u`
WEEK=${DATE_STR}


function backup_full
{

	# Decide the backup folder
	# $BAK_ROOT
	# 	backup_old
	#	backup
	# if the backup floder existed

	if [ -d "$BAK_ROOT/backup_old" ]; then
		echo "Remove the oldest backup"
		rm -rf $BAK_ROOT/backup_old
	fi
	
	if [ -d "$BAK_ROOT/backup_week" ]; then
		mv $BAK_ROOT/backup_week $BAK_ROOT/backup_old
	fi
	BAK_DIR="$BAK_ROOT/backup_week"
	mkdir $BAK_DIR
	echo "Backup  $BAK_TARGET to $BAK_DIR/$BAK_NAME"
	tar czfv $BAK_DIR/backup_full.tgz $BAK_TARGET
}

function backup_change
{
	find $BAK_TARGET -mtime -1 \! -type d -print>/tmp/filelist.daily
	tar czfv $BAK_DIR/backup_$WEEK.tgz -T /tmp/filelist.daily 
}

if [ $WEEK = 7 ]; then
	backup_full
else
	if [ -e "$BAK_ROOT/backup_week/backup_full.tgz" ]; then
		n=1
		MODE="CHANGE"
		while [ $n -lt $WEEK ]; do
			if [ ! -f "$BAK_ROOT/backup_week/$backup_$n.tgz" ]; then
				MODE="FULL"
			fi
			n=`expr $n + 1`
		done
		if [ MODE = "FULL" ]; then
			backup_full
			n=1
			while [ $n -le $WEEK ]; do
				touch "$BAK_ROOT/backup_week/$backup_$n.tgz" 
				n=`expr $n + 1`
			done
		else
			backup_change
		fi
	else
		if [ ! -d "$BAK_ROOT/backup_week" ]; then
			mkdir $BAK_ROOT/backup_week
		fi
		tar czfv $BAK_ROOT/backup_week/backup_full.tgz $BAK_TARGET
		n=1
		while [ $n -le $WEEK ]; do
			touch "$BAK_ROOT/backup_week/$backup_$n.tgz" 
			n=`expr $n + 1`
		done
	fi
fi