DEFINITION MODULE tv;

(* A small TVision/Turbo-Vision style character-cell UI toolkit in ISO
   GNU Modula-2 (gm2 -fiso), terminal backend.

   It provides a tiny retained view tree (groups/windows containing widgets)
   with clipping and z-order, a diffed ANSI cell screen, keyboard and mouse
   decoding (xterm SGR mouse reports), and widgets: static text, frame,
   input line, button, check box, radio buttons, list box and scroll bar.

   Compile (from this directory):
       gm2 -fiso -c tvtty.def
       gm2 -fiso -I. -c tv.mod
       gm2 -fiso -I. tv.o demo.mod -o demo

   The only non-Modula-2 part is tvtty.def (libc termios/ioctl/read/write). *)

FROM SYSTEM IMPORT ADDRESS;

CONST
    (* 16 terminal colours *)
    Black = 0;  Blue = 1;  Green = 2;  Cyan = 3;
    Red = 4;  Magenta = 5;  Brown = 6;  LightGray = 7;
    DarkGray = 8;  LightBlue = 9;  LightGreen = 10;  LightCyan = 11;
    LightRed = 12;  LightMagenta = 13;  Yellow = 14;  White = 15;

    SingleFrame = 1;
    DoubleFrame = 2;

    (* key codes *)
    kNone  = 0;  kChar  = 1;  kUp    = 2;  kDown  = 3;
    kLeft  = 4;  kRight = 5;  kHome  = 6;  kEnd   = 7;
    kPgUp  = 8;  kPgDn  = 9;  kEnter = 10; kEsc   = 11;
    kTab   = 12; kBack  = 13; kDel   = 14; kIns   = 15;
    kF1    = 20; kF2    = 21; kF3    = 22; kF4    = 23; kF5  = 24;
    kF6    = 25; kF7    = 26; kF8    = 27; kF9    = 28; kF10 = 29;
    kCtrlC = 30; kF11   = 31; kF12   = 32; kSpace = 33;

    (* built-in commands (button tags) *)
    cmNone   = 0;
    cmClose  = 1;
    cmOK     = 2;
    cmCancel = 3;
    cmYes    = 4;
    cmNo     = 5;

    (* view flags *)
    vfDisabled = 1;
    vfSelected = 2;
    vfFramed   = 4;

    MAXLINE  = 128;
    MAXVIEWS = 128;

TYPE
    Attr  = CARDINAL;
    Point = RECORD x, y : INTEGER; END;
    Rect  = RECORD x, y, w, h : INTEGER; END;

    EventKind = (evNone, evKey, evMouse);

    Event = RECORD
                kind  : EventKind;
                key   : INTEGER;
                ch    : CARDINAL;
                ctrl  : BOOLEAN;
                mx, my : INTEGER;
                mbtn  : INTEGER;     (* 1 left, 2 middle, 3 right *)
                mpressed, mreleased : BOOLEAN;
                mwheel : INTEGER;    (* -1 up, +1 down *)
            END;

(* ---- screen ------------------------------------------------------------ *)

PROCEDURE Init() : BOOLEAN;
PROCEDURE Done;
PROCEDURE Cols() : INTEGER;
PROCEDURE Rows() : INTEGER;
PROCEDURE Resized() : BOOLEAN;

PROCEDURE A (fg, bg : INTEGER; blink : BOOLEAN) : Attr;
PROCEDURE Clear (attr : Attr);
PROCEDURE Fill (x, y, w, h : INTEGER; cp : CARDINAL; attr : Attr);
PROCEDURE DrawCh (x, y : INTEGER; cp : CARDINAL; attr : Attr);
PROCEDURE DrawText (x, y : INTEGER; s : ARRAY OF CHAR; attr : Attr);
PROCEDURE DrawBox (r : Rect; style : INTEGER; attr : Attr);
PROCEDURE DrawShadow (r : Rect; attr : Attr);
PROCEDURE SetCursor (x, y : INTEGER);
PROCEDURE HideCursor;
PROCEDURE Present;

PROCEDURE ReadEvent (VAR e : Event) : BOOLEAN;

(* ---- text helpers ------------------------------------------------------ *)

PROCEDURE TextLen (s : ARRAY OF CHAR) : INTEGER;
PROCEDURE CopyText (VAR dest : ARRAY OF CHAR; s : ARRAY OF CHAR);
PROCEDURE AppendText (VAR dest : ARRAY OF CHAR; s : ARRAY OF CHAR);
PROCEDURE PadText (VAR dest : ARRAY OF CHAR; s : ARRAY OF CHAR; width : INTEGER);
PROCEDURE IntToText (VAR dest : ARRAY OF CHAR; n : INTEGER; width : INTEGER);

(* ---- view tree --------------------------------------------------------- *)

TYPE
    VKind = (VGroup, VWindow, VText, VFrame, VInput, VButton,
             VCheck, VRadio, VList, VScroll);

    ListData = RECORD
                   items : ARRAY [0..255] OF ARRAY [0..63] OF CHAR;
                   count : INTEGER;
               END;
    ListDataPtr = POINTER TO ListData;

    ViewPtr = POINTER TO View;
    View = RECORD
               kind   : VKind;
               rect   : Rect;
               parent, next, prev, first, last, focus : ViewPtr;
               clipKids : BOOLEAN;
               text   : ARRAY [0..MAXLINE - 1] OF CHAR;
               len, pos : INTEGER;
               value, minv, maxv, tag : INTEGER;
               flags  : CARDINAL;
               list   : ListDataPtr;
           END;

PROCEDURE NewView (kind : VKind; x, y, w, h : INTEGER) : ViewPtr;
PROCEDURE FreeView (v : ViewPtr);
PROCEDURE AddView (parent, child : ViewPtr);
PROCEDURE DelView (v : ViewPtr);
PROCEDURE SetText (v : ViewPtr; s : ARRAY OF CHAR);
PROCEDURE SetTag (v : ViewPtr; t : INTEGER);
PROCEDURE Desk () : ViewPtr;

PROCEDURE DrawTree;                   (* draw desktop + all views *)
PROCEDURE Finish;                     (* DrawTree + Present *)

PROCEDURE HandleEvent (e : Event) : INTEGER;   (* returns a command *)
PROCEDURE Sender () : ViewPtr;                (* view that produced it *)

PROCEDURE BringToFront (v : ViewPtr);
PROCEDURE FocusView (v : ViewPtr);
PROCEDURE FocusNext (backwards : BOOLEAN);
PROCEDURE MoveViewBy (v : ViewPtr; dx, dy : INTEGER);

(* Menu bar + drop-down menus.  Typical use:
     MenuBarInit;
     MenuAdd("File"); MenuItemAdd("New", cNew); MenuItemAdd("Quit", cQuit);
     MenuAdd("Help"); MenuItemAdd("About", cAbout);
   Selecting an item makes HandleEvent return its tag. *)
PROCEDURE MenuBarInit;
PROCEDURE MenuAdd (title : ARRAY OF CHAR);
PROCEDURE MenuItemAdd (text : ARRAY OF CHAR; tag : INTEGER);
PROCEDURE MenuSep;
PROCEDURE MenuBar (show : BOOLEAN);

(* Modal helper: shows a small centered box with the text and an OK button. *)
PROCEDURE Message (title : ARRAY OF CHAR; text : ARRAY OF CHAR);

END tv.