% GPS route-planning example translated from Eyeling's gps.n3.
% The map is stored as quoted formula data and projected with ordinary term
% traversal and =../2. Route
% paths accumulate action sequence, duration, cost, belief, and comfort; table
% keeps repeated comparison and explanation queries from recomputing paths.

%% goal: recommendedRoute(X0, X1)

%% goal: outcome(X0, X1)

%% goal: statement(X0, X1, X2)

%% goal: label(X0, X1)

%% goal: actionSequence(X0, X1)

%% goal: durationSeconds(X0, X1)

%% goal: cost(X0, X1)

%% goal: belief(X0, X1)

%% goal: comfort(X0, X1)

%% goal: selectedRoute(X0, X1)

%% goal: comparison(X0, X1)



case_graph(caseGraph, (
  location(i1, gent),
  text(question, "Which route should we take from Gent to Oostende?"),
  label(routeDirect, "Gent -> Brugge -> Oostende"),
  label(routeViaKortrijk, "Gent -> Kortrijk -> Brugge -> Oostende")
)).

map_graph(mapBE, (
  gps_description(mapBE, description(location(S, gent), true, location(S, brugge), drive_gent_brugge, 1500.0, 0.006, 0.96, 0.99)),
  gps_description(mapBE, description(location(S, gent), true, location(S, kortrijk), drive_gent_kortrijk, 1600.0, 0.007, 0.96, 0.99)),
  gps_description(mapBE, description(location(S, kortrijk), true, location(S, brugge), drive_kortrijk_brugge, 1600.0, 0.007, 0.96, 0.99)),
  gps_description(mapBE, description(location(S, brugge), true, location(S, oostende), drive_brugge_oostende, 900.0, 0.004, 0.98, 1.0))
)).

context_member((Left, _right), Member) :- context_member(Left, Member).
context_member((_left, Right), Member) :- context_member(Right, Member).
context_member(Member, Member) :- Member \= (_left, _right).

case_statement(S, P, O) :-
  case_graph(caseGraph, Context),
  context_member(Context, Statement),
  (Statement =.. [P, S, O]).

map_description(From, To, Action, Duration, Cost, Belief, Comfort) :-
  map_graph(mapBE, Context),
  context_member(Context, gps_description(mapBE, description(From, true, To, Action, Duration, Cost, Belief, Comfort))).

path(From, To, [Action], Duration, Cost, Belief, Comfort) :-
  map_description(From, To, Action, Duration, Cost, Belief, Comfort).

path(From, To, Actions, Duration, Cost, Belief, Comfort) :-
  map_description(From, Mid, Action, D1, C1, B1, F1),
  path(Mid, To, Restactions, D2, C2, B2, F2),
  append([Action], Restactions, Actions),
  (Duration is D1 + D2),
  (Cost is C1 + C2),
  (Belief is B1 * B2),
  (Comfort is F1 * F2).

traveller_start(i1, location(i1, gent)).
traveller_goal(i1, location(i1, oostende)).

traveller_path(Traveller, Actions, Duration, Cost, Belief, Comfort) :-
  traveller_start(Traveller, From),
  traveller_goal(Traveller, To),
  path(From, To, Actions, Duration, Cost, Belief, Comfort).

route_metrics(routeDirect, Duration, Cost, Belief, Comfort) :-
  traveller_path(i1, [drive_gent_brugge, drive_brugge_oostende], Duration, Cost, Belief, Comfort).

route_metrics(routeViaKortrijk, Duration, Cost, Belief, Comfort) :-
  traveller_path(i1, [drive_gent_kortrijk, drive_kortrijk_brugge, drive_brugge_oostende], Duration, Cost, Belief, Comfort).

recommended_route(routeDirect) :-
  route_metrics(routeDirect, Directduration, Directcost, Directbelief, Directcomfort),
  route_metrics(routeViaKortrijk, Viaduration, Viacost, Viabelief, Viacomfort),
  (Directduration < Viaduration),
  (Directcost < Viacost),
  (Directbelief > Viabelief),
  (Directcomfort > Viacomfort).

outcome(routeDirect, "Take the direct route via Brugge.").

% Verification checks, analogous to the false-producing guards in gps.n3.
check(c1, true) :-
  traveller_path(i1, [drive_gent_brugge, drive_brugge_oostende], _, _, _, _).

check(c2, true) :-
  traveller_path(i1, [drive_gent_kortrijk, drive_kortrijk_brugge, drive_brugge_oostende], _, _, _, _).

check(c3, true) :-
  route_metrics(routeDirect, D1, _, _, _),
  route_metrics(routeViaKortrijk, D2, _, _, _),
  (D1 < D2).

check(c4, true) :-
  route_metrics(routeDirect, _, C1, _, _),
  route_metrics(routeViaKortrijk, _, C2, _, _),
  (C1 < C2).

check(c5, true) :-
  route_metrics(routeDirect, _, _, B1, F1),
  route_metrics(routeViaKortrijk, _, _, B2, F2),
  (B1 > B2),
  (F1 > F2).

recommendedRoute(decision, Route) :-
  recommended_route(Route).

outcome(decision, Outcome) :-
  recommended_route(Route),
  outcome(Route, Outcome).

statement(check, Check, true) :-
  check(Check, true).

route_actions(routeDirect, [drive_gent_brugge, drive_brugge_oostende]).
route_actions(routeViaKortrijk, [drive_gent_kortrijk, drive_kortrijk_brugge, drive_brugge_oostende]).

% Derived route and report relations.  These are consequences of the route search
% and comparison, not pre-written markdown output.
label(Route, Label) :-
  case_statement(Route, label, Label),
  route_metrics(Route, _duration, _cost, _belief, _comfort).

actionSequence(Route, Actions) :-
  route_actions(Route, Actions),
  route_metrics(Route, _duration, _cost, _belief, _comfort).

durationSeconds(Route, Duration) :-
  route_metrics(Route, Duration, _cost, _belief, _comfort).

cost(Route, Cost) :-
  route_metrics(Route, _duration, Cost, _belief, _comfort).

belief(Route, Belief) :-
  route_metrics(Route, _duration, _cost, Belief, _comfort).

comfort(Route, Comfort) :-
  route_metrics(Route, _duration, _cost, _belief, Comfort).

selectedRoute(report, route(Route, Actions, Duration, Cost, Belief, Comfort)) :-
  recommended_route(Route),
  route_actions(Route, Actions),
  route_metrics(Route, Duration, Cost, Belief, Comfort).

comparison(report, dominates(routeDirect, routeViaKortrijk)) :-
  recommended_route(routeDirect),
  check(c3, true),
  check(c4, true),
  check(c5, true).