:- initialization(main, main).

% --- Global State ---
:- dynamic gdispstr/1, gfnumenting/1, gax/1, gbx/1, gbinop/1.

gdispstr("0").
gfnumenting(false).
gax(0.0).
gbx(0.0).
gbinop(11).

% --- Key Definition Table & Mappings ---
kbd(0, "Off", 2628095).  kbd(1, "C", 2628095).    kbd(2, "<x]", 2628095). kbd(3, "*", 1015567).
kbd(4, "7", 986895).    kbd(5, "8", 986895).     kbd(6, "9", 986895).   kbd(7, "/", 1015567).
kbd(8, "4", 986895).    kbd(9, "5", 986895).     kbd(10, "6", 986895).  kbd(11, "+", 986895).
kbd(12, "1", 986895).   kbd(13, "2", 986895).    kbd(14, "3", 986895).  kbd(15, "-", 1015567).
kbd(16, "0", 986895).   kbd(17, ".", 986895).    kbd(18, "+/-", 986895). kbd(19, "=", 1015567).

keymap(111, 0). keymap(79, 0). keymap(99, 1).  keymap(67, 1). 
keymap(8, 2).   keymap(42, 3).  keymap(55, 4).  keymap(56, 5).  
keymap(57, 6).  keymap(47, 7).  keymap(52, 8).  keymap(53, 9).  
keymap(54, 10). keymap(43, 11). keymap(49, 12). keymap(50, 13). 
keymap(51, 14). keymap(45, 15). keymap(48, 16). keymap(46, 17). 
keymap(105, 18). keymap(73, 18). keymap(61, 19).

% --- Utilities & IO ---
myputs(Str) :- format('~w', [Str]), flush_output.

dispstr(Psz, Color) :-
    (Psz == "" -> Text = "0" ; Text = Psz),
    format('F 0 16777215~nFR 0 0 0 9900 600~nF 0 ~d~nR 0 100 100 9800 500~nR$ 0 9800 520"~w"~n', [Color, Text]),
    flush_output.

itorect(Pref, BX, BY, EX, EY, I) :-
    X_Off is (I mod 4) * 2000, Y_Off is (I // 4) * 1200,
    X1 is X_Off + BX, Y1 is Y_Off + BY,
    X2 is X_Off + EX, Y2 is Y_Off + EY,
    format('~w 0 ~d ~d ~d ~d~n', [Pref, X1, Y1, X2, Y2]).

% --- UI Rendering ---
drawapp :-
    myputs("Fo 0 611 3\nFo 2 140 3\n"),
    myputs("F 0 16777215\nFR 0 0 0 10000 10000\n"),
    gdispstr(D), dispstr(D, 6052991),
    forall(between(0, 19, I), (
        kbd(I, Label, Color),
        itorect("F 0 10526880\nFR", 220, 1220, 2080, 2280, I),
        itorect("F 0 986895\nR", 200, 1200, 2100, 2300, I),
        format('F 0 ~d~n', [Color]),
        X_Text is (I mod 4) * 2000 + 1100,
        Y_Text is (I // 4) * 1200 + 1700,
        format('C$ 0 ~d ~d "~w"~n', [X_Text, Y_Text, Label])
    )),
    myputs("F 0 255\nC$ 0 5000 800 \"Prolog cloud app shell\"\n"),
    myputs("F 2 255\nC$ 2 5000 7200 \"Corrie Zucker Technologies LLC.\"\n"),
    myputs("C$ 2 5000 7340 \"d/b/a CZ Technologies\"\nZ \n"),
    flush_output.

% --- Calculator Engine ---
key_to_exe(0) :- myputs("O 0 0 0\n"), halt.
key_to_exe(1) :- 
    retractall(gdispstr(_)), assertz(gdispstr("")),
    retractall(gfnumenting(_)), assertz(gfnumenting(false)),
    dispstr("0", 6052991).
key_to_exe(2) :- 
    gdispstr(Current),
    (string_length(Current, L), L > 0 ->
        (L == 1 -> New = "" ; sub_string(Current, 1, _, 0, New)),
        retractall(gdispstr(_)), assertz(gdispstr(New)),
        dispstr(New, 6052991)
    ; true).
key_to_exe(RC) :- member(RC, [4,5,6,8,9,10,12,13,14,16,17]), !,
    kbd(RC, Digit, _), numappend(Digit).
key_to_exe(RC) :- member(RC, [3,7,11,15]), !,
    gdispstr(D), (D == "" -> V = 0.0 ; atom_number(D, V)),
    retractall(gax(_)), assertz(gax(V)),
    retractall(gdispstr(_)), assertz(gdispstr("")),
    retractall(gfnumenting(_)), assertz(gfnumenting(false)),
    retractall(gbinop(_)), assertz(gbinop(RC)).
key_to_exe(18) :- 
    gdispstr(D), string_length(D, L), L > 0,
    (sub_string(D, 0, 1, _, "-") -> sub_string(D, 1, _, 0, New) ; string_concat("-", D, New)),
    retractall(gdispstr(_)), assertz(gdispstr(New)),
    dispstr(New, 6052991).
key_to_exe(19) :- !, 
    gfnumenting(Flag),
    (Flag == true -> 
        gdispstr(D), (D == "" -> V = 0.0 ; atom_number(D, V)),
        retractall(gbx(_)), assertz(gbx(V)),
        retractall(gfnumenting(_)), assertz(gfnumenting(false))
    ; true),
    gax(A), gbx(B), gbinop(Op),
    (Op == 3 -> Res is A * B ; Op == 7 -> Res is A / B ; Op == 11 -> Res is A + B ; Op == 15 -> Res is A - B ; Res = A),
    atom_string(Res, S),
    retractall(gax(_)), assertz(gax(Res)),
    retractall(gdispstr(_)), assertz(gdispstr(S)),
    dispstr(S, 6052991).

numappend(Digit) :-
    gfnumenting(Flag), gdispstr(Current),
    (Flag == true -> string_concat(Current, Digit, New) ; New = Digit),
    retractall(gdispstr(_)), assertz(gdispstr(New)),
    retractall(gfnumenting(_)), assertz(gfnumenting(true)),
    dispstr(New, 6052991).

% --- Main Controller & Loop ---
main :- 
    prompt(_, ''), % Set prompt to empty string to silence |:
    loop.

loop :-
    read_line_to_string(user_input, Line),
    (Line == end_of_file -> true ; process_line(Line), loop).

process_line("drawapp") :- !, drawapp.
process_line(Line) :-
    split_string(Line, " ", " ", [BtnS, XS, YS]),
    atom_number(BtnS, B), atom_number(XS, X), atom_number(YS, Y), !,
    handle_input(B, X, Y).
process_line(_).

handle_input(Btn, -2, _) :- !, (keymap(Btn, RC) -> key_to_exe(RC) ; true).
handle_input(Btn, -4, Y) :- !, format('Rz ~d ~d~n', [Btn, Y]).
handle_input(Btn, -5, Y) :- !, format('Mv ~d ~d~n', [Btn, Y]).
handle_input(1, X, Y) :- X >= 0, !,
    Row is (Y - 1200) // 1200, Col is (X - 200) // 2000,
    RC is Row * 4 + Col, key_to_exe(RC).
handle_input(_, _, _).