MODULE editor;

(* based on the kilo editor building course*)

(* Step 21 *)

(*** IMPORTS ***)

IMPORT IO, termios, FIO, libc, CharClass, NumberIO, ASCII ;
IMPORT STextIO, Strings;

(*** data ***)

VAR 
    c           : CHAR;
    theTermios  : termios.TERMIOS;
    TCSAFLUSH   : INTEGER;
    i           : CARDINAL;

(*** Terminal ***)

    PROCEDURE CtrlKey(c: CHAR) : CARDINAL;

        VAR
            n : BITSET;

    BEGIN
        n := BITSET(ORD(c));
        n := n * BITSET(1FH);
        RETURN CARDINAL(n)
    END CtrlKey;

    PROCEDURE die (s : ARRAY OF CHAR);
    BEGIN
        libc.perror(s);
        FOR i := 0 TO Strings.Length(s) DO
            IO.Write(s[i])
        END;
        HALT
    END die;

    PROCEDURE disablerawMode() : INTEGER;

        VAR
            result : INTEGER;
    BEGIN
        IO.BufferedMode(0,TRUE);
        IO.BufferedMode(1,TRUE);
        result := termios.tcsetattr(FIO.StdIn, TCSAFLUSH, theTermios);
        IF result = -1 THEN
            theTermios := termios.KillTermios(theTermios);
            die("tcsetattr")
        ELSE 
            RETURN result
        END;
    END disablerawMode;

    PROCEDURE enablerawMode;
    BEGIN
        libc.atexit(disablerawMode);
        theTermios := termios.InitTermios();
        IF termios.tcgetattr(FIO.StdIn, theTermios) = -1 THEN
            die("tcgetattr")
        END;

        IO.UnBufferedMode(0,TRUE);
        IO.UnBufferedMode(1,TRUE);
    END enablerawMode;

    PROCEDURE  editorReadKey() : CHAR;
        VAR
            c : CHAR;
    BEGIN
        IO.Read(c);
        RETURN c
    END editorReadKey; 
    
(*** Input ***)

  PROCEDURE editorProcessKeypress;
        VAR
            c       : CHAR;
    BEGIN
        c := editorReadKey();
        CASE ORD(c) OF
          17 : HALT;
        END
    END editorProcessKeypress;

(*** Init ***)

BEGIN
    TCSAFLUSH := termios.tcsflush (); 
    enablerawMode;
    LOOP
       editorProcessKeypress;
    END;
END editor.