/*  $Id: stack.pl,v 1.12 2006/11/06 10:36:15 jan Exp $

    Part of XPCE --- The SWI-Prolog GUI toolkit

    Author:        Jan Wielemaker and Anjo Anjewierden
    E-mail:        wielemak@science.uva.nl
    WWW:           http://www.swi.psy.uva.nl/projects/xpce/
    Copyright (C): 1985-2006, University of Amsterdam

    This program is free software; you can redistribute it and/or
    modify it under the terms of the GNU General Public License
    as published by the Free Software Foundation; either version 2
    of the License, or (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

    As a special exception, if you link this library with other files,
    compiled with a Free Software compiler, to produce an executable, this
    library does not by itself cause the resulting executable to be covered
    by the GNU General Public License. This exception does not however
    invalidate any other reasons why the executable file might be covered by
    the GNU General Public License.
*/

:- module(prolog_ide_stack,
	  [ display_stack/3		% +Window, +Call, +Choice
	  ]).
:- use_module(library(lists)).
:- use_module(library(debug)).
:- use_module(library(pce_util)).
:- use_module(util).
:- use_module(gui).
:- use_module(clause).

:- system_module.

%%	display_stack(+StackWindow, +CallList, +ChoiceList) is det.
%
%	Display parent environments and choicepoints.

display_stack(Window, Call, Choice) :-
	assertion(thread_self(main)),
	get(@pce, convert, normal, font, Font),
	get(Font, height, FH),
	merge_choices(Choice, Call, AllFrames),
	in_debug_thread(Window, level_tag_frames(AllFrames, Tagged)),
	keysort(Tagged, SortedByLevel),
	assign_y(SortedByLevel, 0, FH+4, Rows),
	display_levels(Rows, Choice, Window),
	link_parents(Call, Window),
	Call = [Current|_],
	(   Choice = [FirstChoice|_],
	    same_frame(Current, FirstChoice)
	->  link_choices(Choice, Window)
	;   link_choices([Current|Choice], Window)
	),
	send(Window, compute),
	send(Window, scroll_vertical, goto, file, 1000).

same_frame(frame(F, _), frame(F, _)).

merge_choices([], Call, Call).
merge_choices([C0|CT], Call, T) :-
	member(C, Call),
	same_frame(C0, C), !,
	merge_choices(CT, Call, T).
merge_choices([C0|CT], Call, [C0|T]) :-
	merge_choices(CT, Call, T).
	
%%	level_tag_frames(+Frames, -TaggedFrames) is det.
%
%	Tag each frame with its recursion level.  Must run in the context
%	of the debugged thread.

level_tag_frames([], []).
level_tag_frames([H|T], [Level-H|LT]) :-
	frame_level(H, Level),
	level_tag_frames(T, LT).

frame_level(frame(F, _), L) :-
	prolog_frame_attribute(F, level, L).

%%	assign_y(+TaggedFrames, +Y0, +FrameHeight, -Rows) is det.
%
%	Combine all frames (tagged with level) of the same level.
%	
%	@param Rows	List of Y-ListOfFrames

assign_y([], _, _, []).
assign_y([L0-F0|Frames], Y, FH, [Y-[F0|T0]|T]) :-
	same_level(L0, Frames, T0, RFrames),
	NY is Y + FH,
	assign_y(RFrames, NY, FH, T).

same_level(L, [L-F0|T], [F0|FT], R) :- !,
	same_level(L, T, FT, R).
same_level(_, T, [], T).

display_levels([], _, _).
display_levels([Y-Frames|T], Choice, Window) :-
	predsort(cmpframes(Choice), Frames, SortedFrames),
	debug('Sorted frames: ~p~n', [SortedFrames]),
	SortedFrames = [frame(Frame, PC)|_],
	prolog_frame_attribute(Window, Frame, level, Level),
	send(Window, display, text(Level, left, normal), point(5, Y)),
	(   PC == choice
	->  X0 is 30 + 150
	;   X0 is 30
	),
	display_frames(SortedFrames, Window, X0, Y),
	display_levels(T, Choice, Window).


cmpframes(Choice, Result, frame(Fr1, choice), frame(Fr2, choice)) :- !,
	nth1(I1, Choice, frame(Fr1, choice)),
	nth1(I2, Choice, frame(Fr2, choice)),
	compare(Result, I1, I2).
cmpframes(_, <, _, frame(_, choice)) :- !.
cmpframes(_, >, frame(_, choice), _) :- !.
cmpframes(_, Result, F1, F2) :-
	compare(Result, F1, F2).

display_frames([], _, _, _).
display_frames([F|T], Window, X, Y) :-
	v_stack_frame(Window, F, V),
	send(V, set, X, Y),
	send(Window, append, V),
	X2 is X + 150,
	display_frames(T, Window, X2, Y).


v_stack_frame(Window, frame(Frame, choice), V) :- !,
	frame_label(Window, Frame, Label),
	new(V, prolog_stack_frame(Window, Frame, Label, choice, choicepoint)).
v_stack_frame(Window, frame(Frame, PC), V) :-
	frame_label(Window, Frame, Label),
	frame_style(Window, Frame, PC, Style),
	new(V, prolog_stack_frame(Window, Frame, Label, PC, Style)).

frame_label(Window, Frame, Label) :-
	prolog_frame_attribute(Window, Frame, goal,  Goal),
	predicate_name(user:Goal, Label).

frame_style(Window, Frame, PC, Style) :-
	integer(PC), !,
	prolog_frame_attribute(Window, Frame, has_alternatives, A),
	det_style(A, Style).
frame_style(Window, Frame, _, Style) :-
	in_debug_thread(Window, frame_predicate_class(Frame, Style)).

%%	frame_predicate_class(+Frame, -Style) is det.
%
%	Use Style for displaying  Frame.  Computed   as  a  whole in the
%	debugged thread to avoid exchanging the goal between threads.

frame_predicate_class(Frame, Style) :-
	prolog_frame_attribute(Frame, goal, Goal),
	predicate_classification(Goal, Style).

det_style(false, deterministic).
det_style(true,  choicepoint).

link_parents([H1,H2|T], W) :- !,
	H1 = frame(F1, PC1),
	H2 = frame(F2, PC2),
	get(W, member, F1, PC1, V1),
	get(W, member, F2, PC2, V2),
	new(_, hyper(V1, V2, parent, child)),
	link_parents([H2|T], W).
link_parents(_, _).

link_choices([H1,H2|T], W) :- !,
	H1 = frame(F1, _),
	H2 = frame(F2, _),
	get(W, member, F1, V1),
	get(W, member, F2, V2),
	get(V1, pc, PC1),
	get(V2, pc, PC2),
	(   (   PC1 == choice
	    ;   PC2 == choice
	    )
	->  Handle = @default
	;   Handle = east
	),
	new(_, connection(V1, V2, @prolog_choice_link, Handle)),
	link_choices([H2|T], W).
link_choices(_, _).

clean(P) :-
	send(P?graphicals, for_all,
	     if(message(@arg1, instance_of, text),
		message(@prolog, clean_level, @arg1))).

clean_level(Text) :-
	get(@pce, convert, Text?string, int, Level),
	(   get(Text?device?graphicals, find,
		and(message(@arg1, instance_of, prolog_stack_frame),
		    @arg1?level == Level),
		_)
	->  true
	;   free(Text)
	).

		 /*******************************
		 *	 STACK-VIEW WINDOW	*
		 *******************************/

:- pce_begin_class(prolog_stack_view, picture,
		   "Overview of the parent stack-frames").

variable(members,       hash_table,  get, "Frame --> Visualiser table").

initialise(B) :->
	assertion(thread_self(main)),
	get(@pce, convert, normal, font, Font),
	get(Font, ex, Ex),
	send_super(B, initialise, size := size(20 * Ex, 100)),
	send(B, label, 'Stack'),
	send(B, hor_stretch, 100),
	send(B, hor_shrink, 100),
	send(B, slot, members, new(chain_table)).

clean(B) :->
	clean(B).

clear(B) :->
	send(B?graphicals, for_all, message(@arg1, destroy)).


member(B, F:int, PC:[name|int], V:prolog_stack_frame) :<-
	"Find visualiser from frame"::
	get(B, members, Table),
	get(Table, member, F, Chain),
	(   PC == @default
	->  get(Chain, head, V)
	;   get(Chain, find, @arg1?pc == PC, V)
	).


append(B, V:prolog_stack_frame) :->
	send(B, display, V),
	get(V, frame_reference, Frame),
	send(B?members, append, Frame, V).


up(B, Times:[int]) :->
	"Select (Nth) parent"::
	default(Times, 1, N),
	get(B, selection, Fr),
	get(B, member, Fr, V),
	(   N < 0
	->  D is -N,
	    step(D, B, child,  V, V2)
	;   step(N, B, parent, V, V2)
	),
	send(V2, select, @on).
	

step(0, _, _, V, V) :- !.
step(N, B, child, V, V2) :-
	get(V, hypered, child, Ch), !,
	(   get(Ch, frame_reference, Frame),
	    prolog_frame_attribute(B, Frame, goal, Goal),
	    predicate_property(user:Goal, foreign),
	    get(Ch, hypered, child, Ch2)
	->  NN is N - 1,
	    step(NN, B, child, Ch2, V2)
	;   NN is N - 1,
	    step(NN, B, child, Ch, V2)
	).
step(N, B, parent, V, V2) :-
	get(V, frame_reference, Frame),
	in_debug_thread(B, prolog_parent(Frame, Parent, PC)),
	(   debug('Looking for parent ~d, PC=~d~n', [Parent, PC]),
	    get(B, member, Parent, PC, V1)
	->  true
	;   v_stack_frame(B, frame(Parent, PC), V1),
	    send(V1, compute),
	    send(V1, do_set, V?x, V?y - V1?height),
	    new(_, hyper(V, V1, parent, child)),
	    send(V?device, append, V1)
	), !,
	NN is N - 1,
	step(NN, B, parent, V1, V2).
step(_, B, parent, V, V) :- !,
	send(B, report, warning, 'Top frame').
step(_, B, child, V, V) :- !,
	send(B, report, warning, 'Deepest frame').

%%	prolog_parent(+Frame, -Parent, -PC)
%
%	Find parent executing Prolog. If our  direct parent is a foreign
%	frame, keep walking up. Same  if  the   parent  appears  to be a
%	hidden frame, we keep walking up for   a user-frame. Must run in
%	debugged thread.

prolog_parent(Frame, Parent, PC) :-
	prolog_frame_attribute(Frame, pc, PC0), !,
	prolog_frame_attribute(Frame, parent, MyParent),
	(   prolog_frame_attribute(MyParent, hidden, false)
	->  Parent = MyParent,
	    PC = PC0
	;   prolog_parent(MyParent, Parent, PC)
	).
prolog_parent(Frame, Parent, PC) :-
	prolog_frame_attribute(Frame, parent, Super),
	prolog_parent(Super, Parent, PC).

down(B, Times:[int]) :->
	"Select (Nth) child"::
	default(Times, 1, N),
	NN is -N,
	send(B, up, NN).

selection(B, What:'int|prolog_stack_frame', PC:[int|name]) :->
	"Select the given frame"::
	(   integer(What)
	->  (   get(B, member, What, PC, V)
	    ->  send_super(B, selection, V)
	    ;   send_super(B, selection, @nil)
	    )
	;   send_super(B, selection, What)
	).

selection(B, Fr:int) :<-
	"Return selected frame visualiser"::
	get_super(B, selection, Chain),
	get(Chain, size, 1),
	get(Chain, head, Gr),
	get(Gr, frame_reference, Fr).

frame_finished(B, Fr:int) :->
	get(B, members, Table),
	get(Table, member, Fr, Frames),
	(   send(Frames, empty)
	->  true
	;   send(Frames, for_all, message(@arg1, destroy)),
	    clean(B)
	).

:- pce_end_class.


		 /*******************************
		 *	 FRAME VISUALISER	*
		 *******************************/

:- pce_global(@prolog_choice_link,
	      new(link(link, link, line(arrows := second)))).

:- pce_begin_class(prolog_stack_frame, figure,
		   "Frame of the stack-view").

handle(-5,  h/2, link, east).
handle(w+5, h/2, link, west).

style_image(deterministic,	'det.xpm').
style_image(choicepoint,	'ndet.xpm').
style_image(built_in,		'builtin.xpm').
style_image(foreign,		'foreign.xpm').
style_image(dynamic,		'dynamic.xpm').
style_image(undefined,		'undefined.xpm').
style_image(transparent,	'meta.xpm').
style_image(user,		'user.xpm').

variable(frame_reference,  int,		get, "Reference of Prolog frame").
variable(pc,		   'int|name',	get, "Location in the frame").
variable(frame_level,	   int,		get, "Nesting of the frame").

:- pce_global(@prolog_stack_frame_recogniser,
	      new(click_gesture(left, '', single,
				message(@receiver, select)))).

initialise(D, Window:window, Frame:int, Label:char_array,
	   PC:'int|name', Style:name) :->
	send_super(D, initialise),
	send(D, border, 3),
	send(D, shadow, 1),
	send(D, pen, 1),
	send(D, background, colour(white)),
	style_image(Style, Image),
	send(D, display, new(B, bitmap(Image))),
	send(D, display, text(Label, left, normal), point(B?right_side, 0)),
	send(D, slot, frame_reference, Frame),
	send(D, slot, pc, PC),
	prolog_frame_attribute(Window, Frame, level, Level),
	send(D, slot, frame_level, Level).

unlink(D) :->
	(   get(D, device, Dev),
	    Dev \== @nil,
	    get(Dev, members, Table),
	    send(Table, delete, D?frame_reference)
	->  true
	;   true
	),
	send_super(D, unlink).


event(D, Ev:event) :->
	(   send_super(D, event, Ev)
	;   send(@prolog_stack_frame_recogniser, event, Ev)
	).


select(D, Show:[bool]) :->
	"Make this frame the selected one"::
	send(D?device, selection, D),
	(   Show \== @off
	->  get(D, frame_reference, Frame),
	    get(D, pc, PC),
	    debug('~p: select ~p at PC=~w~n', [D, Frame, PC]),
	    send(D?frame, show_frame, Frame, PC)
	;   true
	).

help_message(D, _What:{tag,summary}, _Ev:[event], Msg:string) :<-
	"Fetch associated help message"::
	get(D, frame_reference, FR),
	get(D, pc, PC),
	new(Msg, string('Frame #%d at PC = %s', FR, PC)).

:- pce_end_class.
