graded

-module(graded@internal@effect_term).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch, inline]).
-define(FILEPATH, "src/graded/internal/effect_term.gleam").
-export([pure/0, unknown/0, from_effect_set/1, free_vars/1, subst/2, normalize/1, to_effect_set/1, normalize_bounded/2]).

-if(?OTP_RELEASE >= 27).
-define(MODULEDOC(Str), -moduledoc(Str)).
-define(DOC(Str), -doc(Str)).
-else.
-define(MODULEDOC(Str), -compile([])).
-define(DOC(Str), -compile([])).
-endif.

?MODULEDOC(false).

-file("src/graded/internal/effect_term.gleam", 31).
?DOC(false).
-spec pure() -> graded@internal@types:effect_term().
pure() ->
    {t_labels, gleam@set:new()}.

-file("src/graded/internal/effect_term.gleam", 36).
?DOC(false).
-spec unknown() -> graded@internal@types:effect_term().
unknown() ->
    {t_labels, gleam@set:from_list([<<"Unknown"/utf8>>])}.

-file("src/graded/internal/effect_term.gleam", 326).
?DOC(false).
-spec dedup_adjacent(list({binary(), graded@internal@types:effect_term()})) -> list({binary(),
    graded@internal@types:effect_term()}).
dedup_adjacent(Keyed) ->
    _pipe = Keyed,
    _pipe@1 = gleam@list:fold(_pipe, [], fun(Acc, Pair) -> case Acc of
                [{Previous, _} | _] when Previous =:= erlang:element(1, Pair) ->
                    Acc;

                _ ->
                    [Pair | Acc]
            end end),
    lists:reverse(_pipe@1).

-file("src/graded/internal/effect_term.gleam", 343).
?DOC(false).
-spec term_key(graded@internal@types:effect_term()) -> binary().
term_key(Term) ->
    case Term of
        t_top ->
            <<"T"/utf8>>;

        {t_labels, Labels} ->
            <<<<"L["/utf8,
                    (begin
                        _pipe = Labels,
                        _pipe@1 = gleam@set:to_list(_pipe),
                        _pipe@2 = gleam@list:sort(
                            _pipe@1,
                            fun gleam@string:compare/2
                        ),
                        gleam@string:join(_pipe@2, <<","/utf8>>)
                    end)/binary>>/binary,
                "]"/utf8>>;

        {t_var, Name} ->
            <<<<"V("/utf8, Name/binary>>/binary, ")"/utf8>>;

        {t_app, Operator, Arg} ->
            <<<<<<<<"A("/utf8, (term_key(Operator))/binary>>/binary, " "/utf8>>/binary,
                    (term_key(Arg))/binary>>/binary,
                ")"/utf8>>;

        {t_abs, Param, Body} ->
            <<<<<<<<"F("/utf8, Param/binary>>/binary, "."/utf8>>/binary,
                    (term_key(Body))/binary>>/binary,
                ")"/utf8>>;

        {t_union, Terms} ->
            <<<<"U("/utf8,
                    (begin
                        _pipe@3 = Terms,
                        _pipe@4 = gleam@list:map(_pipe@3, fun term_key/1),
                        _pipe@5 = gleam@list:sort(
                            _pipe@4,
                            fun gleam@string:compare/2
                        ),
                        gleam@string:join(_pipe@5, <<"|"/utf8>>)
                    end)/binary>>/binary,
                ")"/utf8>>
    end.

-file("src/graded/internal/effect_term.gleam", 277).
?DOC(false).
-spec flatten_union(list(graded@internal@types:effect_term())) -> graded@internal@types:effect_term().
flatten_union(Members) ->
    Flat = gleam@list:flat_map(Members, fun(Member) -> case Member of
                {t_union, Inner} ->
                    Inner;

                _ ->
                    [Member]
            end end),
    case gleam@list:any(Flat, fun(M) -> M =:= t_top end) of
        true ->
            t_top;

        false ->
            {Label_members, Other_members} = gleam@list:partition(
                Flat,
                fun(M@1) -> case M@1 of
                        {t_labels, _} ->
                            true;

                        _ ->
                            false
                    end end
            ),
            Merged_labels = gleam@list:fold(
                Label_members,
                gleam@set:new(),
                fun(Acc, M@2) -> case M@2 of
                        {t_labels, Labels} ->
                            gleam@set:union(Acc, Labels);

                        _ ->
                            Acc
                    end end
            ),
            Others = begin
                _pipe = Other_members,
                _pipe@1 = gleam@list:map(
                    _pipe,
                    fun(M@3) -> {term_key(M@3), M@3} end
                ),
                _pipe@2 = gleam@list:sort(
                    _pipe@1,
                    fun(A, B) ->
                        gleam@string:compare(
                            erlang:element(1, A),
                            erlang:element(1, B)
                        )
                    end
                ),
                _pipe@3 = dedup_adjacent(_pipe@2),
                gleam@list:map(
                    _pipe@3,
                    fun(Pair) -> erlang:element(2, Pair) end
                )
            end,
            Label_part = case gleam@set:is_empty(Merged_labels) of
                true ->
                    [];

                false ->
                    [{t_labels, Merged_labels}]
            end,
            case lists:append(Label_part, Others) of
                [] ->
                    pure();

                [Single] ->
                    Single;

                All ->
                    {t_union, All}
            end
    end.

-file("src/graded/internal/effect_term.gleam", 45).
?DOC(false).
-spec from_effect_set(graded@internal@types:effect_set()) -> graded@internal@types:effect_term().
from_effect_set(Effect_set) ->
    case Effect_set of
        wildcard ->
            t_top;

        {specific, Labels} ->
            {t_labels, Labels};

        {polymorphic, Labels@1, Variables} ->
            Var_terms = begin
                _pipe = Variables,
                _pipe@1 = gleam@set:to_list(_pipe),
                gleam@list:map(_pipe@1, fun(Field@0) -> {t_var, Field@0} end)
            end,
            flatten_union([{t_labels, Labels@1} | Var_terms])
    end.

-file("src/graded/internal/effect_term.gleam", 256).
?DOC(false).
-spec is_abstraction(graded@internal@types:effect_term()) -> boolean().
is_abstraction(Term) ->
    case Term of
        {t_abs, _, _} ->
            true;

        _ ->
            false
    end.

-file("src/graded/internal/effect_term.gleam", 163).
?DOC(false).
-spec fresh_loop(binary(), gleam@set:set(binary()), integer()) -> binary().
fresh_loop(Base, Avoid, N) ->
    Candidate = <<Base/binary, (erlang:integer_to_binary(N))/binary>>,
    case gleam@set:contains(Avoid, Candidate) of
        true ->
            fresh_loop(Base, Avoid, N + 1);

        false ->
            Candidate
    end.

-file("src/graded/internal/effect_term.gleam", 159).
?DOC(false).
-spec fresh(binary(), gleam@set:set(binary())) -> binary().
fresh(Base, Avoid) ->
    fresh_loop(Base, Avoid, 0).

-file("src/graded/internal/effect_term.gleam", 87).
?DOC(false).
-spec free_vars(graded@internal@types:effect_term()) -> gleam@set:set(binary()).
free_vars(Term) ->
    case Term of
        {t_labels, _} ->
            gleam@set:new();

        t_top ->
            gleam@set:new();

        {t_var, Name} ->
            gleam@set:from_list([Name]);

        {t_app, Operator, Arg} ->
            gleam@set:union(free_vars(Operator), free_vars(Arg));

        {t_union, Terms} ->
            gleam@list:fold(
                Terms,
                gleam@set:new(),
                fun(Acc, T) -> gleam@set:union(Acc, free_vars(T)) end
            );

        {t_abs, Param, Body} ->
            gleam@set:delete(free_vars(Body), Param)
    end.

-file("src/graded/internal/effect_term.gleam", 124).
?DOC(false).
-spec subst_abs(
    binary(),
    graded@internal@types:effect_term(),
    gleam@dict:dict(binary(), graded@internal@types:effect_term())
) -> graded@internal@types:effect_term().
subst_abs(Param, Body, Bindings) ->
    Inner = gleam@dict:delete(Bindings, Param),
    gleam@bool:guard(
        gleam@dict:is_empty(Inner),
        {t_abs, Param, Body},
        fun() ->
            Body_fv = free_vars(Body),
            Incoming = gleam@dict:fold(
                Inner,
                gleam@set:new(),
                fun(Acc, Key, Value) -> case gleam@set:contains(Body_fv, Key) of
                        true ->
                            gleam@set:union(Acc, free_vars(Value));

                        false ->
                            Acc
                    end end
            ),
            case gleam@set:contains(Incoming, Param) of
                false ->
                    {t_abs, Param, subst(Body, Inner)};

                true ->
                    Avoid = gleam@set:union(Incoming, Body_fv),
                    Renamed_param = fresh(Param, Avoid),
                    Renamed_body = subst(
                        Body,
                        maps:from_list([{Param, {t_var, Renamed_param}}])
                    ),
                    {t_abs, Renamed_param, subst(Renamed_body, Inner)}
            end
        end
    ).

-file("src/graded/internal/effect_term.gleam", 106).
?DOC(false).
-spec subst(
    graded@internal@types:effect_term(),
    gleam@dict:dict(binary(), graded@internal@types:effect_term())
) -> graded@internal@types:effect_term().
subst(Term, Bindings) ->
    case Term of
        {t_labels, _} ->
            Term;

        t_top ->
            Term;

        {t_var, Name} ->
            case gleam_stdlib:map_get(Bindings, Name) of
                {ok, Replacement} ->
                    Replacement;

                {error, nil} ->
                    Term
            end;

        {t_app, Operator, Arg} ->
            {t_app, subst(Operator, Bindings), subst(Arg, Bindings)};

        {t_union, Terms} ->
            {t_union,
                gleam@list:map(
                    Terms,
                    fun(_capture) -> subst(_capture, Bindings) end
                )};

        {t_abs, Param, Body} ->
            subst_abs(Param, Body, Bindings)
    end.

-file("src/graded/internal/effect_term.gleam", 263).
?DOC(false).
-spec reduce_each(list(graded@internal@types:effect_term()), integer()) -> {list(graded@internal@types:effect_term()),
    integer()}.
reduce_each(Terms, Fuel) ->
    {Acc, Final_fuel} = gleam@list:fold(
        Terms,
        {[], Fuel},
        fun(State, T) ->
            {Done, Remaining} = State,
            {Reduced, Remaining1} = reduce(T, Remaining),
            {[Reduced | Done], Remaining1}
        end
    ),
    {lists:reverse(Acc), Final_fuel}.

-file("src/graded/internal/effect_term.gleam", 218).
?DOC(false).
-spec reduce_app(
    graded@internal@types:effect_term(),
    graded@internal@types:effect_term(),
    integer()
) -> {graded@internal@types:effect_term(), integer()}.
reduce_app(Operator, Arg, Fuel) ->
    {Reduced_fn, Fuel1} = reduce(Operator, Fuel - 1),
    {Reduced_arg, Fuel2} = reduce(Arg, Fuel1),
    case Reduced_fn of
        {t_abs, Param, Body} ->
            reduce(
                subst(Body, maps:from_list([{Param, Reduced_arg}])),
                Fuel2 - 1
            );

        {t_union, Members} ->
            case gleam@list:all(Members, fun is_abstraction/1) of
                true ->
                    Applied = {t_union,
                        gleam@list:map(
                            Members,
                            fun(M) -> {t_app, M, Reduced_arg} end
                        )},
                    reduce(Applied, Fuel2 - 1);

                false ->
                    {{t_app, Reduced_fn, Reduced_arg}, Fuel2}
            end;

        _ ->
            {{t_app, Reduced_fn, Reduced_arg}, Fuel2}
    end.

-file("src/graded/internal/effect_term.gleam", 196).
?DOC(false).
-spec reduce(graded@internal@types:effect_term(), integer()) -> {graded@internal@types:effect_term(),
    integer()}.
reduce(Term, Fuel) ->
    gleam@bool:guard(Fuel =< 0, {unknown(), -1}, fun() -> case Term of
                {t_labels, _} ->
                    {Term, Fuel};

                t_top ->
                    {Term, Fuel};

                {t_var, _} ->
                    {Term, Fuel};

                {t_abs, Param, Body} ->
                    {Reduced_body, Fuel1} = reduce(Body, Fuel),
                    {{t_abs, Param, Reduced_body}, Fuel1};

                {t_app, Operator, Arg} ->
                    reduce_app(Operator, Arg, Fuel);

                {t_union, Terms} ->
                    {Reduced, Fuel1@1} = reduce_each(Terms, Fuel),
                    {flatten_union(Reduced), Fuel1@1}
            end end).

-file("src/graded/internal/effect_term.gleam", 177).
?DOC(false).
-spec normalize(graded@internal@types:effect_term()) -> graded@internal@types:effect_term().
normalize(Term) ->
    {Result, _} = reduce(Term, 1000000),
    Result.

-file("src/graded/internal/effect_term.gleam", 66).
?DOC(false).
-spec term_to_set(graded@internal@types:effect_term()) -> graded@internal@types:effect_set().
term_to_set(Normalized) ->
    case Normalized of
        t_top ->
            wildcard;

        {t_labels, Labels} ->
            {specific, Labels};

        {t_var, Name} ->
            {polymorphic, gleam@set:new(), gleam@set:from_list([Name])};

        {t_app, _, _} ->
            {specific, gleam@set:from_list([<<"Unknown"/utf8>>])};

        {t_abs, _, _} ->
            {specific, gleam@set:from_list([<<"Unknown"/utf8>>])};

        {t_union, Members} ->
            gleam@list:fold(
                Members,
                graded@internal@types:empty(),
                fun(Acc, Member) ->
                    graded@internal@types:union(Acc, term_to_set(Member))
                end
            )
    end.

-file("src/graded/internal/effect_term.gleam", 62).
?DOC(false).
-spec to_effect_set(graded@internal@types:effect_term()) -> graded@internal@types:effect_set().
to_effect_set(Term) ->
    term_to_set(normalize(Term)).

-file("src/graded/internal/effect_term.gleam", 185).
?DOC(false).
-spec normalize_bounded(graded@internal@types:effect_term(), integer()) -> {ok,
        graded@internal@types:effect_term()} |
    {error, nil}.
normalize_bounded(Term, Fuel) ->
    {Result, Remaining} = reduce(Term, Fuel),
    case Remaining < 0 of
        true ->
            {error, nil};

        false ->
            {ok, Result}
    end.