-module(squirrel@internal@gleam).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch]).

-export([contains_option/1, identifier/1, identifier_to_string/1, identifier_to_type_name/1, similar_identifier_string/1]).
-export_type([type/0, field/0, value_identifier/0]).

-type type() :: {list, type()} | {option, type()} | int | float | bool | string.

-type field() :: {field, value_identifier(), type()}.

-opaque value_identifier() :: {value_identifier, binary()}.

-spec contains_option(type()) -> boolean().
contains_option(Type_) ->
    case Type_ of
        int ->
            false;

        float ->
            false;

        bool ->
            false;

        string ->
            false;

        {option, _} ->
            true;

        {list, Type_@1} ->
            contains_option(Type_@1)
    end.

-spec to_identifier_rest(binary(), binary(), integer()) -> {ok,
        value_identifier()} |
    {error, squirrel@internal@error:value_identifier_error()}.
to_identifier_rest(Name, Rest, Position) ->
    case Rest of
        <<"a"/utf8, Rest@1/binary>> ->
            to_identifier_rest(Name, Rest@1, Position + 1);

        <<"b"/utf8, Rest@1/binary>> ->
            to_identifier_rest(Name, Rest@1, Position + 1);

        <<"c"/utf8, Rest@1/binary>> ->
            to_identifier_rest(Name, Rest@1, Position + 1);

        <<"d"/utf8, Rest@1/binary>> ->
            to_identifier_rest(Name, Rest@1, Position + 1);

        <<"e"/utf8, Rest@1/binary>> ->
            to_identifier_rest(Name, Rest@1, Position + 1);

        <<"f"/utf8, Rest@1/binary>> ->
            to_identifier_rest(Name, Rest@1, Position + 1);

        <<"g"/utf8, Rest@1/binary>> ->
            to_identifier_rest(Name, Rest@1, Position + 1);

        <<"h"/utf8, Rest@1/binary>> ->
            to_identifier_rest(Name, Rest@1, Position + 1);

        <<"i"/utf8, Rest@1/binary>> ->
            to_identifier_rest(Name, Rest@1, Position + 1);

        <<"j"/utf8, Rest@1/binary>> ->
            to_identifier_rest(Name, Rest@1, Position + 1);

        <<"k"/utf8, Rest@1/binary>> ->
            to_identifier_rest(Name, Rest@1, Position + 1);

        <<"l"/utf8, Rest@1/binary>> ->
            to_identifier_rest(Name, Rest@1, Position + 1);

        <<"m"/utf8, Rest@1/binary>> ->
            to_identifier_rest(Name, Rest@1, Position + 1);

        <<"n"/utf8, Rest@1/binary>> ->
            to_identifier_rest(Name, Rest@1, Position + 1);

        <<"o"/utf8, Rest@1/binary>> ->
            to_identifier_rest(Name, Rest@1, Position + 1);

        <<"p"/utf8, Rest@1/binary>> ->
            to_identifier_rest(Name, Rest@1, Position + 1);

        <<"q"/utf8, Rest@1/binary>> ->
            to_identifier_rest(Name, Rest@1, Position + 1);

        <<"r"/utf8, Rest@1/binary>> ->
            to_identifier_rest(Name, Rest@1, Position + 1);

        <<"s"/utf8, Rest@1/binary>> ->
            to_identifier_rest(Name, Rest@1, Position + 1);

        <<"t"/utf8, Rest@1/binary>> ->
            to_identifier_rest(Name, Rest@1, Position + 1);

        <<"u"/utf8, Rest@1/binary>> ->
            to_identifier_rest(Name, Rest@1, Position + 1);

        <<"v"/utf8, Rest@1/binary>> ->
            to_identifier_rest(Name, Rest@1, Position + 1);

        <<"w"/utf8, Rest@1/binary>> ->
            to_identifier_rest(Name, Rest@1, Position + 1);

        <<"x"/utf8, Rest@1/binary>> ->
            to_identifier_rest(Name, Rest@1, Position + 1);

        <<"y"/utf8, Rest@1/binary>> ->
            to_identifier_rest(Name, Rest@1, Position + 1);

        <<"z"/utf8, Rest@1/binary>> ->
            to_identifier_rest(Name, Rest@1, Position + 1);

        <<"_"/utf8, Rest@1/binary>> ->
            to_identifier_rest(Name, Rest@1, Position + 1);

        <<"0"/utf8, Rest@1/binary>> ->
            to_identifier_rest(Name, Rest@1, Position + 1);

        <<"1"/utf8, Rest@1/binary>> ->
            to_identifier_rest(Name, Rest@1, Position + 1);

        <<"2"/utf8, Rest@1/binary>> ->
            to_identifier_rest(Name, Rest@1, Position + 1);

        <<"3"/utf8, Rest@1/binary>> ->
            to_identifier_rest(Name, Rest@1, Position + 1);

        <<"4"/utf8, Rest@1/binary>> ->
            to_identifier_rest(Name, Rest@1, Position + 1);

        <<"5"/utf8, Rest@1/binary>> ->
            to_identifier_rest(Name, Rest@1, Position + 1);

        <<"6"/utf8, Rest@1/binary>> ->
            to_identifier_rest(Name, Rest@1, Position + 1);

        <<"7"/utf8, Rest@1/binary>> ->
            to_identifier_rest(Name, Rest@1, Position + 1);

        <<"8"/utf8, Rest@1/binary>> ->
            to_identifier_rest(Name, Rest@1, Position + 1);

        <<"9"/utf8, Rest@1/binary>> ->
            to_identifier_rest(Name, Rest@1, Position + 1);

        <<""/utf8>> ->
            {ok, {value_identifier, Name}};

        _ ->
            case gleam@string:pop_grapheme(Rest) of
                {ok, {G, _}} ->
                    {error, {contains_invalid_grapheme, Position, G}};

                {error, _} ->
                    erlang:error(#{gleam_error => panic,
                            message => <<"unreachable: empty identifier rest should be ok"/utf8>>,
                            module => <<"squirrel/internal/gleam"/utf8>>,
                            function => <<"to_identifier_rest"/utf8>>,
                            line => 140})
            end
    end.

-spec identifier(binary()) -> {ok, value_identifier()} |
    {error, squirrel@internal@error:value_identifier_error()}.
identifier(Name) ->
    case Name of
        <<"a"/utf8, Rest/binary>> ->
            to_identifier_rest(Name, Rest, 1);

        <<"b"/utf8, Rest/binary>> ->
            to_identifier_rest(Name, Rest, 1);

        <<"c"/utf8, Rest/binary>> ->
            to_identifier_rest(Name, Rest, 1);

        <<"d"/utf8, Rest/binary>> ->
            to_identifier_rest(Name, Rest, 1);

        <<"e"/utf8, Rest/binary>> ->
            to_identifier_rest(Name, Rest, 1);

        <<"f"/utf8, Rest/binary>> ->
            to_identifier_rest(Name, Rest, 1);

        <<"g"/utf8, Rest/binary>> ->
            to_identifier_rest(Name, Rest, 1);

        <<"h"/utf8, Rest/binary>> ->
            to_identifier_rest(Name, Rest, 1);

        <<"i"/utf8, Rest/binary>> ->
            to_identifier_rest(Name, Rest, 1);

        <<"j"/utf8, Rest/binary>> ->
            to_identifier_rest(Name, Rest, 1);

        <<"k"/utf8, Rest/binary>> ->
            to_identifier_rest(Name, Rest, 1);

        <<"l"/utf8, Rest/binary>> ->
            to_identifier_rest(Name, Rest, 1);

        <<"m"/utf8, Rest/binary>> ->
            to_identifier_rest(Name, Rest, 1);

        <<"n"/utf8, Rest/binary>> ->
            to_identifier_rest(Name, Rest, 1);

        <<"o"/utf8, Rest/binary>> ->
            to_identifier_rest(Name, Rest, 1);

        <<"p"/utf8, Rest/binary>> ->
            to_identifier_rest(Name, Rest, 1);

        <<"q"/utf8, Rest/binary>> ->
            to_identifier_rest(Name, Rest, 1);

        <<"r"/utf8, Rest/binary>> ->
            to_identifier_rest(Name, Rest, 1);

        <<"s"/utf8, Rest/binary>> ->
            to_identifier_rest(Name, Rest, 1);

        <<"t"/utf8, Rest/binary>> ->
            to_identifier_rest(Name, Rest, 1);

        <<"u"/utf8, Rest/binary>> ->
            to_identifier_rest(Name, Rest, 1);

        <<"v"/utf8, Rest/binary>> ->
            to_identifier_rest(Name, Rest, 1);

        <<"w"/utf8, Rest/binary>> ->
            to_identifier_rest(Name, Rest, 1);

        <<"x"/utf8, Rest/binary>> ->
            to_identifier_rest(Name, Rest, 1);

        <<"y"/utf8, Rest/binary>> ->
            to_identifier_rest(Name, Rest, 1);

        <<"z"/utf8, Rest/binary>> ->
            to_identifier_rest(Name, Rest, 1);

        _ ->
            case gleam@string:pop_grapheme(Name) of
                {ok, {G, _}} ->
                    {error, {contains_invalid_grapheme, 0, G}};

                {error, _} ->
                    {error, is_empty}
            end
    end.

-spec identifier_to_string(value_identifier()) -> binary().
identifier_to_string(Identifier) ->
    {value_identifier, Name} = Identifier,
    Name.

-spec identifier_to_type_name(value_identifier()) -> binary().
identifier_to_type_name(Identifier) ->
    {value_identifier, Name} = Identifier,
    _pipe = justin:pascal_case(Name),
    _pipe@1 = gleam@string:to_graphemes(_pipe),
    _pipe@2 = gleam@list:filter(_pipe@1, fun(C) -> C /= <<"_"/utf8>> end),
    gleam@string:join(_pipe@2, <<""/utf8>>).

-spec is_digit(binary()) -> boolean().
is_digit(Char) ->
    case Char of
        <<"0"/utf8>> ->
            true;

        <<"1"/utf8>> ->
            true;

        <<"2"/utf8>> ->
            true;

        <<"3"/utf8>> ->
            true;

        <<"4"/utf8>> ->
            true;

        <<"5"/utf8>> ->
            true;

        <<"6"/utf8>> ->
            true;

        <<"7"/utf8>> ->
            true;

        <<"8"/utf8>> ->
            true;

        <<"9"/utf8>> ->
            true;

        _ ->
            false
    end.

-spec is_identifier_char(binary()) -> boolean().
is_identifier_char(Char) ->
    case Char of
        <<"a"/utf8>> ->
            true;

        <<"b"/utf8>> ->
            true;

        <<"c"/utf8>> ->
            true;

        <<"d"/utf8>> ->
            true;

        <<"e"/utf8>> ->
            true;

        <<"f"/utf8>> ->
            true;

        <<"g"/utf8>> ->
            true;

        <<"h"/utf8>> ->
            true;

        <<"i"/utf8>> ->
            true;

        <<"j"/utf8>> ->
            true;

        <<"k"/utf8>> ->
            true;

        <<"l"/utf8>> ->
            true;

        <<"m"/utf8>> ->
            true;

        <<"n"/utf8>> ->
            true;

        <<"o"/utf8>> ->
            true;

        <<"p"/utf8>> ->
            true;

        <<"q"/utf8>> ->
            true;

        <<"r"/utf8>> ->
            true;

        <<"s"/utf8>> ->
            true;

        <<"t"/utf8>> ->
            true;

        <<"u"/utf8>> ->
            true;

        <<"v"/utf8>> ->
            true;

        <<"w"/utf8>> ->
            true;

        <<"x"/utf8>> ->
            true;

        <<"y"/utf8>> ->
            true;

        <<"z"/utf8>> ->
            true;

        <<"_"/utf8>> ->
            true;

        <<"0"/utf8>> ->
            true;

        <<"1"/utf8>> ->
            true;

        <<"2"/utf8>> ->
            true;

        <<"3"/utf8>> ->
            true;

        <<"4"/utf8>> ->
            true;

        <<"5"/utf8>> ->
            true;

        <<"6"/utf8>> ->
            true;

        <<"7"/utf8>> ->
            true;

        <<"8"/utf8>> ->
            true;

        <<"9"/utf8>> ->
            true;

        _ ->
            false
    end.

-spec similar_identifier_string(binary()) -> {ok, binary()} | {error, nil}.
similar_identifier_string(String) ->
    Proposal = begin
        _pipe = gleam@string:trim(String),
        _pipe@1 = justin:snake_case(_pipe),
        _pipe@2 = gleam@string:to_graphemes(_pipe@1),
        _pipe@3 = gleam@list:drop_while(
            _pipe@2,
            fun(G) -> (G =:= <<"_"/utf8>>) orelse is_digit(G) end
        ),
        _pipe@4 = gleam@list:filter(_pipe@3, fun is_identifier_char/1),
        gleam@string:join(_pipe@4, <<""/utf8>>)
    end,
    case Proposal of
        <<""/utf8>> ->
            {error, nil};

        _ ->
            {ok, Proposal}
    end.