def all_ps
  # res = `ps -fxo pid,comm | awk '$2 ~ /_/ { print $1, $3 }'`
  res = `ps -xo pid,comm`.downcase
  res.lines.map { |line| line.split(/\s+/).last(2) }
end

def foreground_pid
  command = 'ps -o pid,comm $(xprop -id $(xprop -root -f _NET_ACTIVE_WINDOW 0x " \$0\\n" _NET_ACTIVE_WINDOW | awk "{ print \$2 }") -f _NET_WM_PID 0c " \$0\\n" _NET_WM_PID | awk "{print \$2}")'
  res = `#{ command }`
  res.lines.last.split(/\s+/).last(2)
end

def cpulimitted
  res = `pgrep cpulimit -a`
  res.lines.map { |line| [line.split(/\s+/)[0], line] }
end

def main
  fpid, fpname = foreground_pid
  cpulimitted = cpulimitted()

  puts "Foreground app: #{ fpname } #{ fpid }"

  ps_map = {
    'firefox' => true,
    'chrome' => :multi,
    'chromium-browse' => :multi,
  }

  all_ps.each do |pid, pname|
    catch :break do
      if config = ps_map[pname]
        puts "Analyzing #{ pid } #{ pname }"
        #ps_map[pname] = false if config == :multi

        if pid == fpid || config == :multi && fpname == pname
          # CPU no limit

          cpulimitted.each do |cpulimitpid, command|
            if command[pid]
              puts "Killing cpulimit for #{ pname }: #{ command }"
              `kill #{ cpulimitpid }`
            end
          end
        else
          # CPU limit

          cpulimitted.each do |cpulimitpid, command|
            throw :break if command[pid]
          end

          puts "cpulimit for #{ pname } (#{ pid })."

          Thread.new do
            `renice 7 #{ pid } && cpulimit -p #{ pid } -l 1 -z -b &`
          end
        end
      end
    end
  end
end

loop do
  main()
  sleep 1
end