#! /bin/sh
dbhost=`grep db_host ../config.xml | tr '[\<\>]' '[  ]' | head -1 | awk '{print $2}'`
dbuser=`grep db_user ../config.xml | tr '[\<\>]' '[  ]' | head -1 | awk '{print $2}'`
dbname=`grep db_name ../config.xml | tr '[\<\>]' '[  ]' | head -1 | awk '{print $2}'`
MYSQL="mysql -D $dbname -h $dbhost -u $dbuser -N -B"

DECAY_TIME=30*86400

function median_query() {
  $MYSQL --execute="
     create temporary table medians (id int auto_increment primary key)
       select $1 from host 
       where rpc_time>unix_timestamp(now())-($DECAY_TIME)
             and credit_per_cpu_sec>0
       order by $1; 
     create temporary table ids
       select round(avg(id)-0.5) as id from medians;
     insert into ids select round(avg(id)+0.5) from medians;
     select avg($1) from medians where id in (
       select id from ids
     );
     drop table medians;
     drop table ids;"
}

median_credit_per_cpu_sec=`median_query credit_per_cpu_sec`
median_p_fpops=`median_query p_fpops`
median_p_iops=`median_query p_iops`
ratio=`$MYSQL --execute="select ($median_p_fpops+$median_p_iops)/($median_credit_per_cpu_sec)*5.787037037037e-13"`

nrows=`$MYSQL --execute="select count(id) from credit_multiplier"`
if [ $nrows = 0 ] ; then
  $MYSQL --execute="insert into credit_multiplier values (0,unix_timestamp(now())-86400,1.0)"
fi

last_value=`$MYSQL --execute="select multiplier from credit_multiplier where (unix_timestamp(now())-time)=(select min(unix_timestamp(now())-time) from credit_multiplier)"`
last_time=`$MYSQL --execute="select unix_timestamp(now())-time from credit_multiplier where (unix_timestamp(now())-time)=(select min(unix_timestamp(now())-time) from credit_multiplier)"`

value=`$MYSQL --execute="select ($last_value*(($DECAY_TIME)-$last_time)+$ratio*$last_time)/($DECAY_TIME)"`

$MYSQL --execute="insert into credit_multiplier values (0,unix_timestamp(now()),$value);"

exit 0