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

-export([calculate/2]).

-spec filter_requirement(boolean(), fun(() -> integer()), fun(() -> integer())) -> integer().
filter_requirement(Condition, Return, Apply) ->
    case Condition of
        true ->
            Return();

        false ->
            Apply()
    end.

-spec get_operation_results(list(binary()), list(binary()), integer()) -> list(integer()).
get_operation_results(Word1, Word2, Distance) ->
    [calculate_levenshtein_distance(gleam@list:drop(Word1, 1), Word2, Distance),
        calculate_levenshtein_distance(
            Word1,
            gleam@list:drop(Word2, 1),
            Distance
        ),
        calculate_levenshtein_distance(
            gleam@list:drop(Word1, 1),
            gleam@list:drop(Word2, 1),
            Distance
        )].

-spec calculate_levenshtein_distance(list(binary()), list(binary()), integer()) -> integer().
calculate_levenshtein_distance(Word1, Word2, Distance) ->
    filter_requirement(
        gleam@list:is_empty(Word1),
        fun() -> erlang:length(Word2) end,
        fun() ->
            filter_requirement(
                gleam@list:is_empty(Word2),
                fun() -> erlang:length(Word1) end,
                fun() ->
                    filter_requirement(
                        begin
                            _pipe = gleam@list:first(Word1),
                            gleam@result:unwrap(_pipe, <<""/utf8>>)
                        end
                        =:= begin
                            _pipe@1 = gleam@list:first(Word2),
                            gleam@result:unwrap(_pipe@1, <<""/utf8>>)
                        end,
                        fun() ->
                            calculate_levenshtein_distance(
                                gleam@list:drop(Word1, 1),
                                gleam@list:drop(Word2, 1),
                                Distance
                            )
                        end,
                        fun() ->
                            _pipe@2 = get_operation_results(
                                Word1,
                                Word2,
                                Distance
                            ),
                            _pipe@3 = gleam@list:reduce(
                                _pipe@2,
                                fun gleam@int:min/2
                            ),
                            _pipe@4 = gleam@result:unwrap(_pipe@3, Distance),
                            gleam@int:add(_pipe@4, 1)
                        end
                    )
                end
            )
        end
    ).

-spec calculate(binary(), binary()) -> integer().
calculate(Word1, Word2) ->
    Word1@1 = begin
        _pipe = Word1,
        gleam@string:lowercase(_pipe)
    end,
    Word2@1 = begin
        _pipe@1 = Word2,
        gleam@string:lowercase(_pipe@1)
    end,
    calculate_levenshtein_distance(
        begin
            _pipe@2 = Word1@1,
            gleam@string:to_graphemes(_pipe@2)
        end,
        begin
            _pipe@3 = Word2@1,
            gleam@string:to_graphemes(_pipe@3)
        end,
        0
    ).