-module(probly).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch]).

-export([probability_of_event/2, combine_dist/2, normalize/1, combine_dist_normalized/2]).

-file("/home/race/repos/probly/src/probly.gleam", 31).
-spec sum(list(float())) -> float().
sum(Xs) ->
    gleam@list:fold(Xs, +0.0, fun(X, Acc) -> X + Acc end).

-file("/home/race/repos/probly/src/probly.gleam", 23).
-spec probability_of_event(fun((FDC) -> boolean()), list({FDC, float()})) -> float().
probability_of_event(Event, Dist) ->
    _pipe = Dist,
    _pipe@1 = gleam@list:filter(
        _pipe,
        fun(E) -> Event(erlang:element(1, E)) end
    ),
    _pipe@2 = gleam@list:map(_pipe@1, fun(E@1) -> erlang:element(2, E@1) end),
    sum(_pipe@2).

-file("/home/race/repos/probly/src/probly.gleam", 36).
-spec combine_dist(list({FDG, float()}), list({FDI, float()})) -> list({{FDG,
        FDI},
    float()}).
combine_dist(Dist1, Dist2) ->
    _pipe = Dist1,
    gleam@list:flat_map(
        _pipe,
        fun(E1) ->
            Val1 = gleam@pair:first(E1),
            Prob1 = gleam@pair:second(E1),
            _pipe@1 = Dist2,
            gleam@list:map(
                _pipe@1,
                fun(E2) ->
                    Val2 = gleam@pair:first(E2),
                    Prob2 = gleam@pair:second(E2),
                    {{Val1, Val2}, Prob1 * Prob2}
                end
            )
        end
    ).

-file("/home/race/repos/probly/src/probly.gleam", 61).
-spec insert_or_update({FDO, float()}, list({FDO, float()})) -> list({FDO,
    float()}).
insert_or_update(Event, Acc) ->
    Val = gleam@pair:first(Event),
    Prob = gleam@pair:second(Event),
    case Acc of
        [] ->
            [{Val, Prob}];

        [{Existing_val, Existing_prob} | Tail] ->
            case Existing_val =:= Val of
                true ->
                    [{Existing_val, Existing_prob + Prob} | Tail];

                false ->
                    [{Existing_val, Existing_prob} |
                        insert_or_update(Event, Tail)]
            end
    end.

-file("/home/race/repos/probly/src/probly.gleam", 54).
-spec normalize(list({FDL, float()})) -> list({FDL, float()}).
normalize(Dist) ->
    gleam@list:fold(
        Dist,
        [],
        fun(Acc, Event) -> insert_or_update(Event, Acc) end
    ).

-file("/home/race/repos/probly/src/probly.gleam", 79).
-spec combine_dist_normalized(list({FDR, float()}), list({FDT, float()})) -> list({{FDR,
        FDT},
    float()}).
combine_dist_normalized(Dist1, Dist2) ->
    _pipe = combine_dist(Dist1, Dist2),
    normalize(_pipe).