module Gearman
    class Util
    end
    class << Gearman::Util
        @@cmd = {
            1 =>  [ 'I', "can_do" ],     # from W:  [FUNC]
            23 => [ 'I', "can_do_timeout" ], # from W: FUNC[0]TIMEOUT
            2 =>  [ 'I', "cant_do" ],    # from W:  [FUNC]
            3 =>  [ 'I', "reset_abilities" ],  # from W:  ---
            22 => [ 'I', "set_client_id" ],    # W->J: [RANDOM_STRING_NO_WHITESPACE]
            4 =>  [ 'I', "pre_sleep" ],  # from W: ---
        
            6 =>  [ 'O', "noop" ],        # J->W  ---
            7 =>  [ 'I', "submit_job" ],    # C->J  FUNC[0]UNIQ[0]ARGS
            21 => [ 'I', "submit_job_high" ],    # C->J  FUNC[0]UNIQ[0]ARGS
            18 => [ 'I', "submit_job_bg" ], # C->J     " "   "  " "
        
            8 =>  [ 'O', "job_created" ], # J->C HANDLE
            9 =>  [ 'I', "grab_job" ],    # W->J --
            10 => [ 'O', "no_job" ],      # J->W --
            11 => [ 'O', "job_assign" ],  # J->W HANDLE[0]FUNC[0]ARG
        
            12 => [ 'IO',  "work_status" ],   # W->J/C: HANDLE[0]NUMERATOR[0]DENOMINATOR
            13 => [ 'IO',  "work_complete" ], # W->J/C: HANDLE[0]RES
            14 => [ 'IO',  "work_fail" ],     # W->J/C: HANDLE
        
            15 => [ 'I',  "get_status" ],  # C->J: HANDLE
            20 => [ 'O',  "status_res" ],  # C->J: HANDLE[0]KNOWN[0]RUNNING[0]NUM[0]DENOM
        
            16 => [ 'I',  "echo_req" ],    # ?->J TEXT
            17 => [ 'O',  "echo_res" ],    # J->? TEXT
        
            19 => [ 'O',  "error" ],       # J->? ERRCODE[0]ERR_TEXT
        }

        @@num = {} # name -> num
        @@cmd.each_pair{|key, value|
            @@num[value[1]] = key
        }
        
        def cmd_name(num)
            c = @@cmd[num]
            c ? c[1] : nil
        end
        
        def pack_req_command(type_arg, arg = "")
            type = @@num[type_arg] || type_arg
            len = arg.length
            "\0REQ" + [type, len].pack("NN") + arg
        end
        
        def pack_res_command(type_arg, arg = "")
            type = @@num[type_arg] || type_arg.to_i
            len = arg.length
            "\0RES" + [type, len].pack("NN") + arg
        end
        
        def read_res_packet(sock, err_ref)
            err = Proc.new {|code|
                if err_ref
                    err_ref.replace(code)
                end
                return nil
            }

            buf = ""

            # read the header
            begin
                rv = sock.sysread(12, buf)
            rescue
                warn $!
                rv = nil
            end
            # p buf
            
            return err.call("read_error") if rv.nil?
            return err.call("eof") unless rv
            return err.call("malformed_header") unless rv.size == 12
                
            (magic, type, len) = buf.unpack("a4NN")
            # p [magic, type, len]
            return err.call("malformed_magic") unless magic == "\0RES"
            
            if(len)
                rv = sock.sysread(len, buf)
                return err.call("short_body") unless rv.size == len
            end
            
            
            type = @@cmd[type]
            return err.call("bogus_command") unless type
            return err.call("bugus_command_type") unless type[0].include?("O")
            
            return {
                :type => type[1],
                :len  => len,
                :blobref => buf,
            }
        end
        
        def send_req(sock, req)
            return nil unless sock
            begin
                rv = sock.syswrite(req)
            rescue
                warn $!
                return nil
            end
            # p [rv, req.length]
            return nil unless rv == req.length
            return 1
        end
    
        # given a file descriptor number and a timeout, wait for that descriptor to
        # become readable; returns 0 or 1 on if it did or not
        def wait_for_readability(jss, timeout)
            return nil unless jss && timeout
            nfound = IO.select([jss], nil, nil, timeout)
            nfound ? 1 : nil
        end
    end
end