#!/bin/sh

# The database name is had from the filename, so ensure the file is named
# backup_DATABASENAME.sh or this will crash. Set the other relevant vars here.

# Definitely need to change these:
USER='USER_NAME'
PASSWORD='PASSWORD'

# Might need to change these:
HOST=localhost
FOLDER='backups/'
#!/bin/sh

########################### Do not edit below this line #######################

TARGET=`expr match "$0" '\(.*\)bash/backup_.*'`
TARGET=$TARGET$FOLDER
DB=`expr match "$0" '.*backup_\(.*\).sh'`
# Simpler to just use seconds everywhere
NOW=`date +"%s"`

mysqldump -h $HOST -u $USER -p$PASSWORD $DB > $TARGET$DB'_'$NOW.sql

bzip2 -f $TARGET$DB'_'$NOW.sql

echo Backed up database $DB on $HOST to $TARGET$DB'_'$NOW.sql.bz2



days_diff()
# Echos difference in days between exisiting files and arg1 an epoch timestamp.
{
    ref_time=$1
    FILE_2=`expr match "$2" '.*_\(.*\)\.sql.*'`
    INTER=$(($ref_time-$FILE_2))
    echo $(($INTER/86400))
}

divisible_by_six() # The frequency with which we'll delete files.
{
    REMAINDER=$(( $1 % 6 ))
    if [ $REMAINDER -eq 0 ]
    then
        echo "1"
    else
        echo "0"
    fi
}

process_files() # Removes every sixth file that's more than a week old.
{
    COUNTER=0
    find $1 -maxdepth 1 -type f | while read -r dir
    do
        VAL=$(basename ${dir})
        DIFF=`days_diff $2 $VAL`
        if [ "$DIFF" -gt 6 ]
        then
            let COUNTER=$COUNTER+1 # Only care about older files
            DIV=`divisible_by_six "$COUNTER"`
            if [ $DIV -eq 1 ]
                then
                echo "Deleting $1$VAL"
                rm "$1$VAL"
            fi
        fi
    done
}

echo `process_files $TARGET $NOW`

exit 0