BlocksWorldActionLanguage

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%%% Class hierachy
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is_subclass(#animate, #thing)
is_subclass(#innimate, #thing)

is_subclass(#person, #animate)
is_subclass(#robot, #animate)

is_subclass(#object, #inanimate)

is_subclass(#door, #inanimate)


%% hierachies of locations
is_subclass(#building, #location)
is_subclass(#floor, #building)
is_subclass(#door, #floor)
is_subclass(#room, #floor)
is_subclass(#area, #room)


%%membership rules
member_of(#object, #class) if is_a(#object, #class)
member_of(#object, #class1) if is_a(#object, #class2)^is_subclass(#class2, #class1)
-member_of(#object, #class) if not member_of(#object, #class)

%% subclass relation rules
-is_subclass(#class1, #class2) if not is_subclass(#class1, #class2)


%% sibling rules
%if both classes have the same parent class, then they are siblings
siblings(C1, C2) if is_subclass(C1, C3), is_subclass(C2, C3)
%% if not defined to be a sibling, then not
-siblings(C1, C2) if not siblings(C1, C2)

%% location membership rules
belongs_to(L1, L2) if is_subclass(L1, L2)
belongs_to(L1, L3) if belongs_to(L1, L2), belongs_to(L2, L3), is_subclass(L2, L3)
-belongs_to(L1, L2) if not belongs_to(L1, L2)


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%%%% AL BEGINS
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%%% Statics
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belongs_to(#location, #location)  %% rooms consist of areas and doors, floors consist of rooms, buildings consist of floors
is_connected(#location, #location)  %% is physically connected

%% Object Predicates
has_size(#real, #size)
has_colour(#real, #colour)
has_shape(#real, #shape)
has_surface(#real, #surface)


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%%% Fluents
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%% Inertial Fluents
has_location(#thing, #location)
has_object(#animate, #inanimate)
is_open(#door)
is_on(#real, #surface)
has_state(#real, #state)

%% Defined Fluents
can_move_to(#animate, #location) 
is_above(#real, #real)


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%%% Actions
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travel(#animate, #location)
pick_up(#animate, #object)
put_down(#animate, #object, #location)
open_door(#animate, #door)


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%%% Causal laws
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%% robot can travel to a location
travel(R, L2) causes has_location(R, L2)
travel(R, L2) causes -has_location(R, L1) @I+1 if has_location(R,L1) @ I

%% robot can pick up an object
pick_up(R, O) causes has_object(R, O)

%% If you pick up an object then it is no longer where it was
pick_up(R,O1) causes -is_on(O1, S2) @ I+1 if is_on(O1, S2) @I, has_surface(O2, S2)

%% robot can put down an object
put_down_object(R, O, L) causes -has_object(R, O)

%% if a robot puts down an object at a location and there is already an object O2 there, O1 is on O2.
put_down_object(R,O, S2) causes is_on(O1,S2) if has_location(Robot, L), has_location(O2, L), has_surface(O2, S2)

%% robot can open a door
open_door(R, D) causes is_open(D)


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%%% State constraints
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%% if a thing is in a specific location, it is also in the locations above it in the hierachy
has_location(Th, L2) if has_location(Th, L1), belongs_to(L1, L2) 

%% an thing can only be in one sort of location at a time
-has_location(Th, L1) if has_location(Th, L2), siblings(L1, L2)

%% if a animate being has an object, the object's location is that of the being
has_location(O,L) if has_location(A,L), has_object(A,O)

%% If areas are in the same room, then they are connected
is_connected(A1, A2) if belongs_to(A1, R1), belongs_to(A2, R1)

%% If rooms have the same door, then they are connected
is_connected(R1, R2) if belongs_to(D1, R1), belongs_to(D2, R2)

%% Locations are not connected unless you explicitly say they are
-is_connected(L1, L2) if not is_connected(L1, L2)

%% Location are communitive
is_connected(L1, L2) if is_connected(L2, L1)

%% If areas are connected, then you can move between them
can_move_between(A1, A2) if is_connected(A1, A2)

%% If rooms are connected and the door between them is open, you can move between them
can_move_between(R1, R2) if is_connected(R1, R2), is_open(D)

%% If doors belong to the same room, you can move between them
can_move_between(D1, D2) if belongs_to(D1, R1), belongs_to(D2, R1)

%% If an area and a door belong to the same room, you can travel to the door
can_move_to(R, D1) if belongs_to(A1, R1), is_connected(D1, R1), has_location(R, A1)

%% If an room and a door belong to the same room, you can travel to the door
can_move_to(R, D1) if  is_connected(D1, R1), has_location(R, R1)

%% If an area and a door belong to the same room, you can travel between them
can_move_between(A1, D1) if belongs_to(A1, R1), belongs_to(D1, R1)

%% If a room and a door belong to the same room, you can travel from a door
can_move_to(R, R1) if is_connected(D1, R1), has_location(R, D1), is_open(D1)

%% If you are in a room R2 and A1 is directly in R2, you can travel to A1 directly.
can_move_to(R, A1) if belongs_to(A1, R2), has_location(R, R2)

%% Real things can only have 1 state at a time - inertial_fluent
-has_state(R, S1) if has_state(R, S2), S1!=S2

%% If an something O1 is on something O2, then O1 has the location of O2
has_location(O1, L1) if is_on(O1, S2), has_location(O2, L1), has_surface(O2, S2)

%% If an something O1 is on something O2, and O2 is on something O3, then O1 is above O3.
above(O1, O3) if on(O1, O2), on(O2, O3)

%% If O1 is above O2 and O2 is above O3 then O1 is above O3.
above(O1,O3) if above(O1, O2), above(O2, O3)

%% a object cannot be on itself
-is_on(O1, S2) if has_surface(O2, S2), O1 = O2

%% a object cannot be above itself
-above(O1, O2) is O1 = O2

%% only one object can have a surface
-has_surface(O2, S1) if has_surface(O1, S1)


%% Rules to be added in
%% Only can place on block on another block
%% no block can be placed on a triangular block
%% A table is not a movable object?



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%%% Executability constraints
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%% do not plan to travel to where you are
impossible travel(R, L) if has_location(R, L)

%% robot can pick up an object if they are at same location
impossible pick_up(R, O) if has_location(R, L1), has_location(O, L2), L1!=L2

%% robot cannot pick up an object if they have it 
impossible pickup(R,O) if has_object(R,O)

%% cannot put down an object that is not being held
impossible put_down(R,  O, L)if  not has_object(R, O)

%% Cannot open door from a distance
impossible open_door(R, D) if -has_location(R, D)

%%Don't plan to open a door when you don't where the agent is
impossible open_door(R, D) if not has_location(R, D)

%% Do not try to open a door if it is open
impossible open_door(R,D) if is_open(D)

%% We can't travel between areas that you can't move between
impossible travel(R, L2) if -can_move_between(L1, L2), has_location(R, L1)

%% cannot put down an object that is not being held
impossible put_down(R, O, L) if -has_object(R, O)


%% robot can only hold one object at a time
impossible pick_up(R,O1) if has_object(R,O2)

%robot cannot pick up an object if there is something on top of it
impossible pick_up(R,O1) if is_on(O2, O1).



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%%%% AL ENDS
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%%  Not AL but here anyway
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%% CWA for defined fluents and actions
-holds(F, I) :- not holds(F, I), #defined_fluent(F)
-occurs(A, I) :- not occurs(A, I)

%% Inertial axioms
holds(F, I+1) :- holds(F, I), not -holds(F, I+1), #inertial_fluent(F)
-holds(F, I+1) :- -holds(F, I), not holds(F, I+1), #inertial_fluent(F)

%% Any inertial fluent that does not hold initially is set to not hold
-holds(F, 0) :- not holds(F, 0), #inertial_fluent(F)


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