module tut10_4_2

// ********************************************************************************
// Clean tutorial example program.
//
// This program defines a Controls component that implements a manually settable
// counter. A receiver is used to add a reset option.
// ********************************************************************************

import StdEnv, StdIO

Start :: *World -> *World
Start world = startIO NDI Void initialise [] world
where
    initialise pst
    # (displayId, pst)  = accPIO openId pst
    # (resetId, pst)    = accPIO openRId pst
    # (error, pst)      = openDialog Void (dialog displayId resetId) pst
    | error <> NoError  = abort "Counter could not open Dialog."
    | otherwise         = pst

dialog displayId resetId = Dialog "Counter" (counter :+: resetButton) [WindowClose (noLS closeProcess)]
where
    counter = { newLS = initcount,
                newDef = LayoutControl (EditControl (toString initcount) (PixelWidth (hmm 50.0)) 1 [ControlId displayId, ControlSelectState Unable] :+:
                                        ButtonControl "-" [ControlFunction (count(-1)), ControlWidth (PixelWidth (hmm 25.0)), ControlPos (BelowPrev, zero)] :+:
                                        ButtonControl "+" [ControlFunction (count  1 ), ControlWidth (PixelWidth (hmm 25.0))] :+:
                                        Receiver resetId reset [])
                                       [ControlPos (Center, zero), ControlHMargin 0 0, ControlVMargin 0 0, ControlItemSpace 0 0] }
    where
        initcount = 0

        count :: Int (Int, PSt .l) -> (Int, PSt .l)
        count dx (count, pst) = (count + dx, appPIO (setControlText displayId (toString (count+dx))) pst)

        reset :: m (Int, PSt .l) -> (Int, PSt .l)
        reset _ (_, pst) = (initcount, appPIO (setControlText displayId (toString initcount)) pst)

    resetButton = ButtonControl "Reset" [ControlFunction (noLS (snd o syncSend resetId undef)), ControlPos (Center, zero)]