{- 
   This program models the digital watch found in Bilung Lee's PhD thesis
   as a (fairly low-level) FSM model and which has also been modelled
   in Esterel.

-}

data LightState = Lon | Loff;

-- Used to indicate that an event has occurred
--data Event = Event;

--constant LIGHT_TIMEOUT = 3s;

{-
  There should be a way of handling timeouts here, so that if the
  mode button is pressed only once, there is no mode change.
-}

--port clock from "null" timeout 1s raise Event;

-- User Buttons
data Button = Adjust | Select | Update | Mode;

type TDMode = bool;
data TUMode = USecond | UMinute | UHour | UDay;
type ADMode = (bool,bool);
type AUMode = bool;

-- Possible System Modes
data SysMode = TimeDisplay | TimeUpdate TUMode | AlarmDisplay | AlarmUpdate AUMode;

type ModeState = (Time,TDMode,ADMode);

-- Actions for the status keeper
data Action = ResetSec | IncrMin | IncrHr | IncrDay | IncrAlarmMin | IncrAlarmHr;

-- Actions for the display unit
data DisplayAction = ToggleDisplay | ToggleDisplayUpd |  ToggleTimeMode | ToggleAlarmUpd | ToggleAlarmMode;

-- Types for time
type Seconds = int 8; type Minutes = int 8; type Hours = int 7; type Days = int 3;
type Time = (Seconds,Minutes,Hours,Days);


box Button
in ( bi :: Button )
out ( bo1, bo2 :: Button )
match
  b -> (b, nextB b);

nextB Adjust = Mode;
nextB Mode = Select;
nextB Select = Update;
nextB Update = Adjust;

wire Button ( Button.bo2 initially Adjust ) (mode_control.b, Button.bi);

wire mode_control (mode_control.mode' initially TimeDisplay, Button.bo1, 
		   mode_control.s'    initially ((0,0,0,0),false,(false,false)))
                  (Display.act, Display.dact, mode_control.mode, mode_control.s);

--stream stdin from "std_in";
stream stdout to "std_out";


--data AAction = ResetSec | IncrMin | IncrHr | IncrDay | IncrAlarmMin | IncrAlarmHr;

--adjustStatus :: TUMode -> Action;
adjustStatus USecond = ResetSec;
adjustStatus UMinute = IncrMin;
adjustStatus UHour =   IncrHr;
adjustStatus UDay =    IncrDay;

-- The mode control box
-- The coster has a problem with act :: Action/AAction for some reason!
box mode_control
in  ( mode :: SysMode, b :: a, s :: ModeState )
out ( act  :: Action, dact :: DisplayAction, mode' :: SysMode, s' :: ModeState )
match

-- TimeDisplay section of FSM
  ( TimeDisplay, Mode, s ) ->   ( *, ToggleDisplay,    AlarmDisplay, s )
| ( TimeDisplay, Update, s ) -> ( *, ToggleDisplayUpd, TimeUpdate USecond, s )
| ( TimeDisplay, Adjust, s ) -> ( *, ToggleTimeMode,   TimeDisplay, toggleTD s )

-- TimeUpdate section of FSM
--| ( t @ (TimeUpdate u), Adjust, s ) -> ( adjustStatus u, *, t, s )
| ( TimeUpdate u, Adjust, s ) -> ( adjustStatus u, *, TimeUpdate u, s )
| ( TimeUpdate u, Select, s ) ->      ( *, ToggleTimeMode, TimeUpdate (nextTU u), s )

-- AlarmDisplay section of FSM
| ( AlarmDisplay, Mode, s ) ->   ( *, ToggleDisplay,    TimeDisplay, s  )
| ( AlarmDisplay, Update, s ) -> ( *, ToggleDisplayUpd, AlarmUpdate false, s  )
| ( AlarmDisplay, Adjust, s ) -> ( *, ToggleAlarmMode,   AlarmDisplay, nextAD s )

-- AlarmUpdate section of FSM
--| ( a @ (AlarmUpdate u), Adjust, s ) -> ( if u then IncrAlarmHr else IncrAlarmMin, *, a, s )
| ( AlarmUpdate u, Adjust, s ) -> ( if u then IncrAlarmHr else IncrAlarmMin, *, AlarmUpdate u, s )
| ( AlarmUpdate u, Select, s ) -> ( *, ToggleAlarmUpd,   AlarmUpdate (not u), s )

-- Ignore all other actions
| ( *, _, * ) -> ( *, *, *, * )
;

nextADM :: ADMode -> ADMode;
nextADM (false,false) = (true,false);
nextADM (true,false) =  (false,true);
nextADM (false,true) =  (true,true);
nextADM (true,true) =   (false,false);

nextAD :: ModeState -> ModeState;
nextAD (t,td,ad) = (t,td,nextADM ad);

toggleTD :: ModeState -> ModeState;
toggleTD (t,td,ad) = (t,not td,ad);

nextTU :: TUMode -> TUMode;
nextTU USecond = UMinute; nextTU UMinute = UHour; nextTU UHour = UDay; nextTU UDay = USecond;

--not true = false;
--not false = True;

showAct ResetSec = "ResetSec";
showAct IncrMin =  "IncrMin";
showAct IncrHr =   "IncrHr";
showAct IncrDay =  "IncrDay";
showAct IncrAlarmMin = "IncrAlarmMin";
showAct IncrAlarmHr = "IncrAlarmHr";

--showDAct DisplayAction = "DisplayAction";
showDAct ToggleDisplay = "ToggleDisplay";
showDAct ToggleDisplayUpd = "ToggleDisplayUpd";
showDAct ToggleTimeMode = "ToggleTimeMode";
showDAct ToggleAlarmUpd = "ToggleTimeMode";
showDAct ToggleAlarmMode = "ToggleAlarmMode";

box Display
in ( act :: Action, dact :: DisplayAction )
out ( s :: string )
fair
  (s, *) -> showAct s ++ "\n"
| (*, s) -> showDAct s ++ "\n"
;

wire Display ( mode_control.act, mode_control.dact)(stdout);