/*  Part of SWI-Prolog

    Author:        Jan Wielemaker
    E-mail:        J.Wielemaker@vu.nl
    WWW:           http://www.swi-prolog.org
    Copyright (c)  2010-2025, University of Amsterdam
			    SWI-Prolog Solutions b.v.
    All rights reserved.

    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions
    are met:

    1. Redistributions of source code must retain the above copyright
       notice, this list of conditions and the following disclaimer.

    2. Redistributions in binary form must reproduce the above copyright
       notice, this list of conditions and the following disclaimer in
       the documentation and/or other materials provided with the
       distribution.

    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
    FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
    COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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*/

:- module(test_hash,
	  [ test_hash/0
	  ]).
:- use_module(library(plunit)).
:- use_module(library(debug)).

test_hash :-
	run_tests([ variant_sha1,
		    variant_hash,
		    term_hash2
		  ]).

:- begin_tests(variant_sha1).

test(atom) :-
	variant_sha1(this_is_an_atom, Hash),
	atom_length(Hash, 40).
test(vars, Hash1 == Hash2) :-
	v(A), v(B),
	variant_sha1(x(A), Hash1),
	variant_sha1(x(B), Hash2).
test(variant, true) :-
	v(A), v(B),
	variant_sha1(x(A,A), Hash1),
	variant_sha1(x(A,B), Hash2),
	assertion(Hash1 \== Hash2).
test(shared, Hash1 == Hash2) :-
	A = x(C),
	variant_sha1(x(A,A), Hash1),
	variant_sha1(x(x(C),x(C)), Hash2).
					% error handling
test(cycle, [sto(rational_trees),error(type_error(acyclic_term, A))]) :-
	A = a(A),
	variant_sha1(A, _).
test(cycle, [sto(rational_trees),error(type_error(acyclic_term, _))]) :-
	A = a(A),
	variant_sha1(x(A), _).
test(attvar, error(_)) :-
	dif(X, 3),
	variant_sha1(X, _).
test(attvar, true) :-
	dif(X, 3), % error(_) fails because subsumes_term does not deal with attvar
	catch(variant_sha1(x(a(X)), _), _, true).
test(float, fail) :-
	variant_sha1(1.0, Hash),
	variant_sha1(2.0, Hash).

v(_).

:- end_tests(variant_sha1).

:- begin_tests(variant_hash).

test(variant, true) :-
	v(A), v(B),
	variant_hash(x(A,A), Hash1),
	variant_hash(x(A,B), Hash2),
	assertion(Hash1 \== Hash2).
test(variant, Hash1 == Hash2) :-
	v(A),
	freeze(B, true),
	variant_hash(x(A,A), Hash1),
	variant_hash(x(B,B), Hash2).
test(variant, Hash1 == Hash2) :-
	v(A),
	freeze(B, true),
	variant_hash(x(A,_), Hash1),
	variant_hash(x(B,_), Hash2).

v(_).

:- end_tests(variant_hash).

:- begin_tests(term_hash2).

                 /*******************************
                 *           TERM-HASH          *
                 *******************************/

% TBD: Big Endian must be updated after change to the
% range in 9.3.2

test(simple_1) :-
    term_hash(aap, X),
    assertion(memberchk(X, [ 3_331_158_974,   % little endian
			     1509846866,      % big endian
			     -963808322	      % WASM
			   ])).

test(simple_2) :-                  % small int
    term_hash(42, X),
    assertion(memberchk(X, [ 1_220_239_556,   % little endian
			     3381815141       % big endian
			   ])).
test(simple_3) :-                  % Big int
    Num is 366454713<<64,
    term_hash(Num, X),
    assertion(
	memberchk(X, [ 347171279,    % little endian (GMP)
		       1214499792,   % big endian (GMP)
		       3784382378,   % LibBF, little endian (HAVE_INT128)
		       3289800483,   % LibBF, big endian (HAVE_INT128)
		       -510584918,   % WASM
		       1902251786,   % LibBF, little endian (no HAVE_INT128)
		       835805437     % 32-bits little endian (GMP)
		     ])).
test(simple_4) :-
    A is pi,
    term_hash(A, X),
    assertion(memberchk(X, [ 4_260_353_184,   % little endian
			     1776496028,      % big endian
			     -34614112	      % WASM
			   ])).
test(simple_5, X == 1_540_712_431) :-
    string_codes(S, "hello world"),
    term_hash(S, X).
test(compound_1) :-
    term_hash(hello(world), X),
    assertion(memberchk(X, [ 3_978_712_206,   % little endian
			     3577832249,      % big endian
			     -316255090	      % WASM
			   ])).
test(compound_2) :-
    A = x(a),
    term_hash(hello(A, A), X),
    assertion(memberchk(X, [ 3_797_822_550,   % little endian
			     1371988747,      % big endian
			     -497144746	      % WASM
			   ])).
test(compound_3) :-
    term_hash(hello(x(a), x(a)), X),
    assertion(memberchk(X, [ 3_797_822_550,   % little endian
			     1371988747,      % big endian
			     -497144746	      % WASM
			   ])).

:- end_tests(term_hash2).
