%
% xml_API.pl
%
% Copyright 2008,5 by Wojciech Szymanski
%
% XML API

% some basics
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

add(A, B, [A|B]).

add2end(X,[H|T],[H|NewT]):-add2end(X,T,NewT).
add2end(X,[],[X]).

append([], A, A).
append([A|B], C, [A|D]) :-
        append(B, C, D).

remove(A, [A|B], B).
remove(B, [A|C], [A|D]) :-
        remove(B, C, D).

belongs(*,[]).
belongs(X,[X|_]).
belongs(X,[_|Yogon]) :-
	belongs(X,Yogon).

first(_,L):- 
	L == [],!. 
first(E,L) :-
	L \= [],
	append([],[E|_],L).

max([], A, A).
max([H|T], A, M) :- 
	H > A, 
	max(T, H, M).
max([H|T], A, M) :- 
	H =< A, 
	max(T, A, M). 

% id handling
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

:- dynamic element/3.
:- dynamic current_id/2.

current_id(*,0).

create_id(X,ID):-
	current_id(X,N),
	N1 is N + 1,
	retractall(current_id(X,_)),
	assert(current_id(X,N1)),
	string_concat(X,'_',ID1),
	string_concat(ID1,N1,ID2),
	string_to_atom(ID2,ID).
	
create_id(X,ID):-
	assert(current_id(X,0)),
	string_concat(X,'_',ID1),
	string_concat(ID1,0,ID2),
	string_to_atom(ID2,ID).


% API 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

create_root(Name,ID_name):-
	create_id(ID_name,ID),
	assert(element(Name,[id=ID],[])).

app_child(Parent,P_id,Child,ChildIdName):-
	Parent\=Child,
	assert(need_build(0)),
	search(Parent,A,L,1,P_id),
	create_id(ChildIdName,ID),
	add2end(element(Child,[id=ID],[]),L,L1),
	retract(element(Parent,A,L)),
	assert(element(Parent,A,L1)),
	need_build(Q),
	check_need_build(Q,Parent,A,L,L1,1).

app_child(_,_,_,_,0).
app_child(Parent,P_id,Child,ChildIdName,How_much):-
	How_much > 0,
	app_child(Parent,P_id,Child,ChildIdName),
	New is How_much - 1,
	app_child(Parent,P_id,Child,ChildIdName,New).	 

add_attribute(Parent,P_id,Attr):-
	assert(need_build(0)),
	search(Parent,AttL,L,1,P_id),
	add2end(Attr,AttL,A1),
	retract(element(Parent,AttL,L)),
	assert(element(Parent,A1,L)),
	need_build(Q),
	check_need_build(Q,Parent,AttL,A1,L,2).


% search and build handling
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

check_need_build(X,_,_,_,_,_):-
	X == 0,!.	

check_need_build(X,P,P1,P2,L,W):-
	X == 1,
	W == 1,
	retract(pair(element(P,P1,P2),Z,Z1)),
	assert(pair(element(P,P1,L),Z,Z1)),
	retractall(element(_,_,_)),
	maxo(I),
	build1(I),
	retractall(pair(_,_,_)),
	retractall(need_build(_)).

check_need_build(X,P,P1,P2,L,W):-
	X == 1,
	W == 2,
	retract(pair(element(P,P1,L),Z,Z1)),
	assert(pair(element(P,P2,L),Z,Z1)),
	retractall(element(_,_,_)),
	maxo(I),
	build1(I),
	retractall(pair(_,_,_)),
	retractall(need_build(_)).

search(N,LA,LN,_,P_id):-
	element(N,LA,LN),
	%bagof(N,element(N,LA,LN),_),
	belongs(P_id,LA).

search(N,LA,LN,P1,P_id):-
	element(X,X1,L),
	X\=N,
	member3(element(_,_,_),L,element(X,X1,[]),P1,P2),!,
	Pn is P2,
	retract(element(X,X1,L)),
	assert(element(X,X1,[])),
	search(N,LA,LN,Pn,P_id).

maxo(X):-
	findall(X,pair(_,_,X),L),
	max(L,0,X).

check_pair(X,Y,N,L):-
	pair(_,element(X,Y,_),Q),
	Q \= 1,
	retract(pair(element(X,Y,_),element(R,R1,R2),R4)),
	assert(pair(element(X,Y,N),element(R,R1,R2),R4)),
	Ln is L-1,
	build(Ln).

check_pair(X,Y,_,L):-
	pair(_,element(X,Y,_),Q),
	Q == 1,
	Ln is L-1,
	build(Ln).
	
check_id2(X,Y,A,B,C,_,_,_,W,W1,W2,L):-
	X == Y,
	add(element(A,B,C),W2,New),
	assert(element(W,W1,New)),
	retract(element(W,W1,W2)),
	check_pair(W,W1,New,L).
 
check_id2(X,Y,A,B,C,A1,B1,C1,W,W1,W2,L):-
	X \= Y,
	add(element(A,B,C),C1,New),
	assert(element(A1,B1,New)),
	retract(element(W,W1,W2)),
	check_pair(A1,B1,New,L).

check_id1(X,Y,_,_,_,_,A1,B1,C1,W,W1,W2,L):-
	X == Y,
	add(element(W,W1,W2),C1,NL),
	assert(element(A1,B1,NL)),
	retract(element(W,W1,W2)),
	Ln is L-1,
	build(Ln).

check_id1(X,Y,Z,A,B,C,A1,B1,C1,W,W1,W2,L):-
	X \= Y,
	check_id2(X,Z,A,B,C,A1,B1,C1,W,W1,W2,L).

build(0):-!.	
build(L):-
	pair(element(A,B,C),element(A1,B1,C1),L),
	element(W,W1,W2),
	first(ID1,W1),
	first(ID2,B1),
	first(ID3,B),
	check_id1(ID1,ID3,ID2,A,B,C,A1,B1,C1,W,W1,W2,L).

build1(X):-
	assert(element(*,[id=0],[])),
	build(X).

member3(_,L,_,P,P3):-L == [],P3 is P,!.
member3(D,L,O,P,P3):-
	L\=[],
	belongs(D,L),
	assert(D),
	assert(pair(D,O,P)),
	P2 is P + 1,
	remove(D,L,Ln),
	retractall(need_build(_)),
	assert(need_build(1)),
	first(E,Ln),
	member3(E,Ln,O,P2,P3).

% save, create xml file
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

make_list(List) :-
	bagof(A,element(A,B,C),A),
	L=..A,
	add(element(L,B,C),[],List).

save(File) :-
	tell(File),
	listing(element),
	listing(current_id),
	told.

prolog2xml(File):-
	make_list(List),
	tell(File),
	open(File,write,S),
	xml_write(S,List,[]),
	told,
	close(S).