html_parser

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

-export([get_attrs/1, get_first_element/1, as_list/1, as_tree/1]).
-export_type([element/0, attribute/0, current_element_type/0]).

-type element() :: empty_element |
    {start_element, binary(), list(attribute()), list(element())} |
    {end_element, binary()} |
    {content, binary()}.

-type attribute() :: {attribute, binary(), binary()}.

-type current_element_type() :: start | 'end' | none.

-spec trim_space_to_elem_begin(binary()) -> binary().
trim_space_to_elem_begin(In) ->
    case In of
        <<" "/utf8, Remain/binary>> ->
            trim_space_to_elem_begin(Remain);

        <<"\n"/utf8, Remain/binary>> ->
            trim_space_to_elem_begin(Remain);

        <<"\t"/utf8, Remain/binary>> ->
            trim_space_to_elem_begin(Remain);

        <<"<"/utf8, Remain@1/binary>> ->
            <<"<"/utf8, Remain@1/binary>>;

        _ ->
            In
    end.

-spec remove_quotes(binary()) -> binary().
remove_quotes(In) ->
    Remove_first_quote = fun(Str) -> case Str of
            <<"\""/utf8, Remain/binary>> ->
                Remain;

            _ ->
                Str
        end end,
    _pipe = In,
    _pipe@1 = Remove_first_quote(_pipe),
    _pipe@2 = gleam@string:reverse(_pipe@1),
    _pipe@3 = Remove_first_quote(_pipe@2),
    gleam@string:reverse(_pipe@3).

-spec do_get_attrs(binary(), binary(), binary(), boolean()) -> {list(attribute()),
    binary()}.
do_get_attrs(In, Key, Val, Finding_value) ->
    case In of
        <<""/utf8>> ->
            case {Key, Val} of
                {<<""/utf8>>, <<""/utf8>>} ->
                    {[], <<""/utf8>>};

                {_, <<""/utf8>>} ->
                    {[], Key};

                {_, _} ->
                    {[{attribute, Key, remove_quotes(Val)}], <<""/utf8>>}
            end;

        <<">"/utf8>> ->
            case {Key, Val} of
                {<<""/utf8>>, <<""/utf8>>} ->
                    {[], <<""/utf8>>};

                {_, <<""/utf8>>} ->
                    {[], Key};

                {_, _} ->
                    {[{attribute, Key, remove_quotes(Val)}], <<""/utf8>>}
            end;

        <<">"/utf8, Remain/binary>> ->
            case {Key, Val} of
                {<<""/utf8>>, <<""/utf8>>} ->
                    {[], Remain};

                {_, _} ->
                    {[{attribute, Key, remove_quotes(Val)}], Remain}
            end;

        <<" "/utf8, Remain@1/binary>> when not Finding_value ->
            do_get_attrs(Remain@1, Key, Val, Finding_value);

        <<"\n"/utf8, Remain@1/binary>> when not Finding_value ->
            do_get_attrs(Remain@1, Key, Val, Finding_value);

        <<"\t"/utf8, Remain@1/binary>> when not Finding_value ->
            do_get_attrs(Remain@1, Key, Val, Finding_value);

        <<" "/utf8, Remain@2/binary>> ->
            {Attrs, Remain_after_attr} = do_get_attrs(
                Remain@2,
                <<""/utf8>>,
                <<""/utf8>>,
                false
            ),
            {[{attribute, Key, remove_quotes(Val)} | Attrs], Remain_after_attr};

        <<"\n"/utf8, Remain@2/binary>> ->
            {Attrs, Remain_after_attr} = do_get_attrs(
                Remain@2,
                <<""/utf8>>,
                <<""/utf8>>,
                false
            ),
            {[{attribute, Key, remove_quotes(Val)} | Attrs], Remain_after_attr};

        <<"\t"/utf8, Remain@2/binary>> ->
            {Attrs, Remain_after_attr} = do_get_attrs(
                Remain@2,
                <<""/utf8>>,
                <<""/utf8>>,
                false
            ),
            {[{attribute, Key, remove_quotes(Val)} | Attrs], Remain_after_attr};

        <<"="/utf8, Remain@3/binary>> ->
            do_get_attrs(Remain@3, Key, <<""/utf8>>, true);

        _ ->
            _assert_subject = gleam@string:pop_grapheme(In),
            {ok, {Head, Remain@4}} = case _assert_subject of
                {ok, {_, _}} -> _assert_subject;
                _assert_fail ->
                    erlang:error(#{gleam_error => let_assert,
                                message => <<"Assertion pattern match failed"/utf8>>,
                                value => _assert_fail,
                                module => <<"html_parser"/utf8>>,
                                function => <<"do_get_attrs"/utf8>>,
                                line => 120})
            end,
            case Finding_value of
                true ->
                    do_get_attrs(
                        Remain@4,
                        Key,
                        <<Val/binary, Head/binary>>,
                        Finding_value
                    );

                false ->
                    do_get_attrs(
                        Remain@4,
                        <<Key/binary, Head/binary>>,
                        <<""/utf8>>,
                        Finding_value
                    )
            end
    end.

-spec get_attrs(binary()) -> {list(attribute()), binary()}.
get_attrs(In) ->
    _pipe = In,
    _pipe@1 = trim_space_to_elem_begin(_pipe),
    do_get_attrs(_pipe@1, <<""/utf8>>, <<""/utf8>>, false).

-spec do_get_first_element(binary(), binary(), current_element_type()) -> {element(),
    binary()}.
do_get_first_element(In, Out, Currently_parsing) ->
    case In of
        <<"</"/utf8, Remain/binary>> ->
            case Out of
                <<""/utf8>> ->
                    do_get_first_element(Remain, Out, 'end');

                _ ->
                    {{content, Out}, <<"</"/utf8, Remain/binary>>}
            end;

        <<"<"/utf8, Remain@1/binary>> ->
            case Out of
                <<""/utf8>> ->
                    do_get_first_element(Remain@1, Out, start);

                _ ->
                    {{content, Out}, <<"<"/utf8, Remain@1/binary>>}
            end;

        <<">"/utf8, Remain@2/binary>> ->
            case Currently_parsing of
                start ->
                    {{start_element, Out, [], []}, Remain@2};

                'end' ->
                    {{end_element, Out}, Remain@2};

                none ->
                    {{content, Out}, Remain@2}
            end;

        <<" "/utf8, Remain@3/binary>> when Currently_parsing =:= start ->
            {Attrs, Remain_after_attr} = get_attrs(Remain@3),
            {{start_element, Out, Attrs, []}, Remain_after_attr};

        <<"\n"/utf8, Remain@3/binary>> when Currently_parsing =:= start ->
            {Attrs, Remain_after_attr} = get_attrs(Remain@3),
            {{start_element, Out, Attrs, []}, Remain_after_attr};

        <<"\t"/utf8, Remain@3/binary>> when Currently_parsing =:= start ->
            {Attrs, Remain_after_attr} = get_attrs(Remain@3),
            {{start_element, Out, Attrs, []}, Remain_after_attr};

        <<""/utf8>> ->
            {empty_element, <<""/utf8>>};

        _ ->
            _assert_subject = gleam@string:pop_grapheme(In),
            {ok, {Head, Remain@4}} = case _assert_subject of
                {ok, {_, _}} -> _assert_subject;
                _assert_fail ->
                    erlang:error(#{gleam_error => let_assert,
                                message => <<"Assertion pattern match failed"/utf8>>,
                                value => _assert_fail,
                                module => <<"html_parser"/utf8>>,
                                function => <<"do_get_first_element"/utf8>>,
                                line => 81})
            end,
            do_get_first_element(
                Remain@4,
                <<Out/binary, Head/binary>>,
                Currently_parsing
            )
    end.

-spec get_first_element(binary()) -> {element(), binary()}.
get_first_element(In) ->
    _pipe = In,
    _pipe@1 = trim_space_to_elem_begin(_pipe),
    do_get_first_element(_pipe@1, <<""/utf8>>, none).

-spec as_list(binary()) -> list(element()).
as_list(In) ->
    case In of
        <<""/utf8>> ->
            [];

        _ ->
            {First, Remain} = get_first_element(In),
            [First | as_list(Remain)]
    end.

-spec do_as_tree(binary(), element()) -> {element(), binary()}.
do_as_tree(In, Current) ->
    {Next, Remain} = get_first_element(In),
    {start_element, Cur_name, Cur_attrs, Cur_children} = case Current of
        {start_element, _, _, _} -> Current;
        _assert_fail ->
            erlang:error(#{gleam_error => let_assert,
                        message => <<"Assertion pattern match failed"/utf8>>,
                        value => _assert_fail,
                        module => <<"html_parser"/utf8>>,
                        function => <<"do_as_tree"/utf8>>,
                        line => 164})
    end,
    case Next of
        {end_element, Name} when Name =:= Cur_name ->
            {{start_element,
                    Cur_name,
                    Cur_attrs,
                    begin
                        _pipe = Cur_children,
                        lists:reverse(_pipe)
                    end},
                Remain};

        {end_element, _} ->
            do_as_tree(Remain, Current);

        _ ->
            {Child_tree, Remain_after_child} = do_as_tree(Remain, Next),
            do_as_tree(
                Remain_after_child,
                {start_element,
                    Cur_name,
                    Cur_attrs,
                    [Child_tree | Cur_children]}
            )
    end.

-spec as_tree(binary()) -> element().
as_tree(In) ->
    {First, Remain} = get_first_element(In),
    {Result, _} = do_as_tree(Remain, First),
    Result.