require 'rubygems'
require 'windows/process'
require 'windows/handle'

module Process
  class << self
    include Windows::Process
    include Windows::Handle
    PRIO_SYM_MAP = {
      ABOVE_NORMAL_PRIORITY_CLASS => :above_normal,
      BELOW_NORMAL_PRIORITY_CLASS => :below_normal,
      HIGH_PRIORITY_CLASS         => :high,
      IDLE_PRIORITY_CLASS         => :idle,
      NORMAL_PRIORITY_CLASS       => :normal,
      REALTIME_PRIORITY_CLASS     => :realtime,
    }
    SYM_PRIO_MAP = PRIO_SYM_MAP.invert

    def getpriority(pid)
      if (hp = OpenProcess(PROCESS_ALL_ACCESS, 0, $$)) != 0
        begin
          r = GetPriorityClass(hp)
          PRIO_SYM_MAP[r] || r
        ensure
          CloseHandle(hp)
        end
      else
        false
      end
    end

    def setpriority(pid, prio)
      if (hp = OpenProcess(PROCESS_ALL_ACCESS, 0, $$)) != 0
        begin
          case prio
          when Integer
            PRIO_SYM_MAP[prio] or prio = nil
          when Symbol
            prio = SYM_PRIO_MAP[prio]
          else
            prio = nil
          end
          prio and SetPriorityClass(hp, prio) != 0
        ensure
          CloseHandle(hp)
        end
      else
        false
      end
    end
  end
end
p Process.setpriority($$, :high)
p Process.getpriority($$)