Buttons USING [Button, ButtonProc, Create, ReLabel, SetDisplayStyle],
ChoiceButtons,
Containers USING [ChildXBound],
Labels USING [Create, Label, Set],
Rope USING [ROPE, Equal],
ViewerClasses USING [Viewer],
ViewerOps USING [AddProp, EnumProc, EnumerateChildren, FetchProp],
ViewerTools USING [MakeNewTextViewer, SetContents, SetSelection],
VFonts USING [CharWidth, Font, FontHeight, StringWidth, defaultFont];

foundDefault: BOOLEAN ← FALSE;
stateInfo: EnumTypeRef ← NEW[EnumTypeRec];

DefaultFound: PROC[currentName, defaultName: Rope.ROPE] RETURNS [BOOLEAN] = BEGIN

BuildMenuSelection: PROC = BEGIN
  border: INTEGER ← 10;
  startButtons: CARDINAL;
  startX: INTEGER ← 0;    -- keeps a running tally of where the next x position is
  tempButton: Buttons.Button;
  eachButton: ButtonList;
  stateInfo.type ← menuStyle;
  IF title # NIL THEN {
   titleLabel: Labels.Label← Labels.Create[[
    name: title, 
    parent: viewer,
    wx: x,
    wy: y,
    wh: entryHeight,
    border: FALSE
    ]];
   startButtons ← titleLabel.wx + titleLabel.ww + entryHSpace;
   }
  ELSE startButtons ← x;
  startX ← startButtons;
 
  FOR eachButton ← buttonNames, eachButton.rest UNTIL eachButton = NIL DO
   IF ~allInOneRow THEN {
    IF startX + VFonts.StringWidth[eachButton.first, VFonts.defaultFont] +
    border >= maxWidth THEN {
     startX ← startButtons;
     stateInfo.nexty ← stateInfo.nexty + entryHeight;
     };
    };
   tempButton ← Buttons.Create[info: [
    name: eachButton.first,
    wx: startX,
    wy: stateInfo.nexty,
    -- default the width so that it will be computed for us
    wh: entryHeight,   -- specify rather than defaulting so line is uniform
    parent: viewer, 
    border: borderOnButtons
    ],
    proc: MenuSelectionProc,
    clientData: stateInfo
    ];
   ViewerOps.AddProp[tempButton, $ChoiceButtons, stateInfo];
   IF DefaultFound[eachButton.first, default] THEN {
    stateInfo.buttonOn ← tempButton;
    Buttons.SetDisplayStyle[button: tempButton, style: on];
    };
   startX ← tempButton.wx + tempButton.ww;
   ENDLOOP;
  stateInfo.nextx ← startX;
  END;

BuildFlipThru: PROCEDURE = BEGIN
  eachButton: ButtonList;
  titleButton: Buttons.Button;
  nextx: INTEGER ← x;
  IF title # NIL THEN { -- create a title button
   stateInfo.type ← flipThruWithTitle;
   titleButton ← Buttons.Create[
    info: [name: title, 
     parent: viewer,
     wx: nextx,
     wy: y,
     wh: entryHeight,
     border: TRUE
     ],
    proc: FlipThruButtonProc,
    clientData: stateInfo
    ];
   nextx ← titleButton.wx + titleButton.ww + 3;
   }
  ELSE stateInfo.type ← flipThruNoTitle;
  FOR eachButton ← buttonNames, eachButton.rest UNTIL (eachButton = NIL) OR
   DefaultFound[eachButton.first, default] DO -- do nothing
   ENDLOOP;
  -- now set up the initial button
  IF title # NIL THEN stateInfo.flipLabel ← Labels.Create[[
   name: eachButton.first,
   wx: nextx,
   wy: y,
   ww: MaxNameWidth[buttonNames], -- first find the longest name so we can set up the
   -- width properly (unfortunately when re-labeling a button, the width remains the same)
   wh: entryHeight,   
   parent: viewer, 
   border: FALSE
   ]]
  ELSE stateInfo.flipLabel ← Buttons.Create[
   info:  [name: eachButton.first,
     wx: nextx,
     wy: y,
     ww: MaxNameWidth[buttonNames],
     wh: entryHeight,
     parent: viewer, 
     border: borderOnButtons
     ],
   proc: FlipThruButtonProc,
   clientData: stateInfo
   ];
  stateInfo.nextx ← stateInfo.flipLabel.wx + stateInfo.flipLabel.ww;
  END;

stateInfo.nextx ← x;
stateInfo.nexty ← y;
stateInfo.proc ← notifyClientProc;
stateInfo.namesOfButtons ← buttonNames;
stateInfo.clientdata ← clientdata;
stateInfo.permission ← permit;
IF default = NIL THEN -- set it to be the first name of the list of button names
 default ← buttonNames.first;

SELECT style FROM
 menuSelection => BuildMenuSelection;
 flipThru => BuildFlipThru;
 ENDCASE => ERROR;

-- signal that the default didn't exist if necessary
IF ~foundDefault THEN SIGNAL DefaultDoesntExist;

stateInfo.nexty ← stateInfo.nexty + entryHeight;  
RETURN[stateInfo];
END;

info: EnumTypeRef ← NARROW[clientData];
viewer: ViewerClasses.Viewer ← NARROW[parent];
IF info.permission # NIL THEN {
 IF info.permission[info] THEN { -- don't do anything without permission first
  SwitchButtons[info.buttonOn, viewer]; -- viewer is the button which was just selected
  info.buttonOn ← viewer;
  -- Notify client that change has taken place if the client provided a proc for doing this
  IF info.proc # NIL THEN info.proc[viewer.name, info.clientdata];
  }}
ELSE {
 SwitchButtons[info.buttonOn, viewer]; -- viewer is the button which was just selected
 info.buttonOn ← viewer;
 -- Notify client that change has taken place if the client provided a proc for doing this
 IF info.proc # NIL THEN info.proc[viewer.name, info.clientdata];
 };
END;

-- merely changes the physical appearance of the buttons
-- Switch off the previously selected button
Buttons.SetDisplayStyle[button: oldButton, style: off];
-- switch "on" the newly selected button
Buttons.SetDisplayStyle[button: newButton, style: on];
END;

info: EnumTypeRef ← NARROW[clientData];
IF info.permission # NIL THEN {
 IF info.permission[info] THEN { -- don't do anything without permission first
  IF mouseButton=red THEN
  -- Display the next name in succession
   ViewerTools.SetContents[viewer: info.flipLabel, contents:
    GetNextName[info.namesOfButtons, info.flipLabel.name]]
  ELSE -- Display the previous name
   ViewerTools.SetContents[viewer: info.flipLabel, contents:
    GetPrevName[info.namesOfButtons, info.flipLabel.name]];
  -- Notify client that change has taken place if the client provided a proc for doing this
  IF info.proc # NIL THEN info.proc[info.flipLabel.name, info.clientdata];
  }}
ELSE {
 IF mouseButton=red THEN
  -- Display the next name in succession
  ViewerTools.SetContents[viewer: info.flipLabel, contents:
   GetNextName[info.namesOfButtons, info.flipLabel.name]]
 ELSE -- display the previous name
  ViewerTools.SetContents[viewer: info.flipLabel, contents:
   GetPrevName[info.namesOfButtons, info.flipLabel.name]];
 -- Notify client that change has taken place if the client provided a procedure for doing this
 IF info.proc # NIL THEN info.proc[info.flipLabel.name, info.clientdata];
 };
END;

newButton: Buttons.Button ← NIL;

GetDesiredButton: ViewerOps.EnumProc = BEGIN
 IF (Rope.Equal[v.name, newName, FALSE]) AND
     (ViewerOps.FetchProp[v, $ChoiceButtons] = enumTypeInfo) THEN {
  newButton ← v;
  RETURN [FALSE];
  };
 END;

IF enumTypeInfo = NIL THEN SIGNAL ButtonsCannotBeUpdated;
SELECT enumTypeInfo.type FROM
 menuStyle   => {ViewerOps.EnumerateChildren[viewer, GetDesiredButton];
       IF newButton # NIL THEN {
        SwitchButtons[enumTypeInfo.buttonOn, newButton];
        enumTypeInfo.buttonOn ← newButton;
        }
       ELSE SIGNAL ChoiceDoesntExist;
       };
 flipThruWithTitle => Labels.Set[label: enumTypeInfo.flipLabel, value: newName];
 flipThruNoTitle  => Buttons.ReLabel[button: enumTypeInfo.flipLabel, newName: newName];
 ENDCASE => ERROR;
END;

IF handle.type = menuStyle THEN {
 IF handle.buttonOn = NIL THEN ERROR
 ELSE RETURN [handle.buttonOn.name]
 }
ELSE {
 IF handle.flipLabel = NIL THEN ERROR
 ELSE RETURN[handle.flipLabel.name]
 };
};

eachButton: ButtonList ← listOfNames;
WHILE (eachButton # NIL) AND (eachButton.first # currentName) DO 
 eachButton ← eachButton.rest;
 ENDLOOP;
IF eachButton = NIL THEN ERROR; -- This shouldn't happen; we should always be able to
           -- find the current button name in list of button names
IF eachButton.rest = NIL THEN
 -- we are at the end of our list, cycle around to the beginning
 RETURN [listOfNames.first]
ELSE RETURN [(eachButton.rest).first];
END;

prev: Rope.ROPE ← listOfNames.first;
eachName: ChoiceButtons.ButtonList ← listOfNames.rest;
WHILE (eachName # NIL) AND ~Rope.Equal[eachName.first, currentName, FALSE] DO
 prev ← eachName.first;
 eachName ← eachName.rest;
 ENDLOOP;
RETURN[prev];
END;

eachButton: ButtonList ← listOfNames;
maxWidth: CARDINAL;
IF eachButton # NIL THEN {
 maxWidth ← VFonts.StringWidth[string: eachButton.first, font: VFonts.defaultFont];
 eachButton ← eachButton.rest }
ELSE RETURN [0];
WHILE (eachButton # NIL) DO
 IF VFonts.StringWidth[string: eachButton.first, font: VFonts.defaultFont] > maxWidth THEN
  maxWidth ← VFonts.StringWidth[string: eachButton.first, font: VFonts.defaultFont]; 
 eachButton ← eachButton.rest;
 ENDLOOP;
maxWidth ← maxWidth + VFonts.CharWidth['M]; -- add on a little extra just to be sure
RETURN[maxWidth];
END;

tempButton: Buttons.Button;
stateInfo ← NEW[ThreeState];
tempButton ← Buttons.Create[
info: [name: name,
  wx: x,
  wy: y,
  -- default the width so that it will be computed for us
  wh: entryHeight,   -- specify rather than defaulting so line is uniform
  parent: viewer, 
  border: TRUE
  ],
 proc: TriSwitchProc,
 clientData: stateInfo  -- this will be passed to our button proc
 ];
stateInfo.button ← tempButton;
nextX ← tempButton.wx + tempButton.ww + 4;
};

SELECT state FROM
 on => Buttons.SetDisplayStyle[button: buttonSelected, style: $WhiteOnBlack];
 off => Buttons.SetDisplayStyle[button: buttonSelected, style: $BlackOnWhite];
 default => Buttons.SetDisplayStyle[button: buttonSelected, style: $BlackOnGrey];
 ENDCASE => ERROR;
END;

IF state = LAST[StateType] THEN RETURN[FIRST[StateType]]
ELSE RETURN[SUCC[state]];
END;

handle: ThreeStateRef ← NARROW[clientData];
handle.state ← NextState[handle.state];
-- Indicate which state this button is in.
SetButtonState[handle.button, handle.state];
END;

force the selection into the user input field (the text viewer). Depending on which mouse button this viewer button was selected with, do different things

handle: PromptDataRef ← NARROW[clientData];
viewer: ViewerClasses.Viewer ← NARROW[parent];
IF handle.permission # NIL THEN {
 IF handle.permission[handle] THEN { -- dont do anything without permission
  IF mouseButton=red THEN -- make pending delete
   ViewerTools.SetSelection[handle.textViewer]
  ELSE -- notify the client if proc provided.
   IF handle.notify # NIL THEN handle.notify[viewer.name, handle.clientdata];
  }}
ELSE {
 IF mouseButton=red THEN -- make pending delete
  ViewerTools.SetSelection[handle.textViewer]
 ELSE -- notify the client if proc provided.
  IF handle.notify # NIL THEN handle.notify[viewer.name, handle.clientdata];
 }  
END;