#!/bin/bash

# Run cputhrottle for a list of applications in order to limit their CPU usage.
# This script needs `pidof` and `cputhrottle` installed, which can be installed from homebrew.
# NOTE: This script was tested on MacOS only.

if [[ $EUID > 0 ]]; then
  echo "Please run this script as root/sudo"
  exit 1
fi

# Pass --kill as argument to kill all running cputhrottles
if [ $1 = "--kill" ]; then
  echo "Looking for running cputhrottles..."
  pids=`pidof cputhrottle`
  for pid in ${pids}; do
    echo "> Killing PID ${pid}"
    sudo kill ${pid}
  done
  printf "Done!\n\n"
  exit 0
fi

# Start cputhrottle if it's not running yet for the given PID
set_cpu_limit() {
  pid=$1
  cpu_limit=$2
  if [[ "$pid" == "" || "$cpu_limit" == "" || $cpu_limit -lt 1 || $cpu_limit -gt 100 ]]; then
    echo "! Invalid arguments: pid=$pid, cpu_limit=$cpu_limit"
    return
  fi

  printf "> PID=${pid}, CPU=${cpu_limit}"

  service_cpu=$(ps aux | grep "sudo cputhrottle $pid $cpu_limit" | grep -v grep | wc -l)
  if [[ ! $service_cpu -gt 0 ]]; then
    sudo cputhrottle $pid $cpu_limit &
    printf "\n"
  else
    printf " [already running]\n"
  fi
}

declare -a applications

# Syntax='application-name;max-cpu%(1-100)'
applications[0]='Chrome;50'
applications[1]='idea;65'
applications[2]='pycharm;40'
applications[3]='webstorm;40'
applications[4]='datagrip;40'

for i in "${applications[@]}"; do
  app=(${i//;/ })
  app_name=${app[0]}
  cpu_limit=${app[1]}
  printf "\nLooking for ${app_name}...\n"
  pids=`pidof ${app}`
  for pid in ${pids}; do
    set_cpu_limit ${pid} ${cpu_limit}
  done
done

printf "\nDone!\n"
printf "Run this script passing '--kill' as argument to remove all cputhrottles.\n\n"