-module(sprocket@internal@render@html).
-compile([no_auto_import, nowarn_unused_vars]).

-export([renderer/0, preflight_renderer/2]).
-export_type([inject_element_operation/0]).

-type inject_element_operation() :: append | prepend.

-spec text(binary()) -> gleam@string_builder:string_builder().
text(T) ->
    gleam@string_builder:from_string(T).

-spec inject_element(
    sprocket@render:rendered_element(),
    binary(),
    sprocket@render:rendered_element(),
    inject_element_operation()
) -> sprocket@render:rendered_element().
inject_element(Root, Target_tag, Inject_element, Insert_op) ->
    sprocket@render:traverse(Root, fun(El) -> case El of
                {rendered_element, Tag, Key, Attrs, Children} when Tag =:= Target_tag ->
                    {rendered_element, Target_tag, Key, Attrs, case Insert_op of
                            append ->
                                gleam@list:append(Children, [Inject_element]);

                            prepend ->
                                [Inject_element | Children]
                        end};

                _ ->
                    El
            end end).

-spec element(
    binary(),
    gleam@option:option(binary()),
    list(sprocket@render:rendered_attribute()),
    list(sprocket@render:rendered_element())
) -> gleam@string_builder:string_builder().
element(Tag, Key, Attrs, Children) ->
    Rendered_attrs = begin
        _pipe = Attrs,
        gleam@list:fold(
            _pipe,
            gleam@string_builder:new(),
            fun(Acc, Attr) -> case Attr of
                    {rendered_attribute, Name, Value} ->
                        gleam@string_builder:append_builder(
                            Acc,
                            gleam@string_builder:from_strings(
                                [<<" "/utf8>>,
                                    Name,
                                    <<"=\""/utf8>>,
                                    Value,
                                    <<"\""/utf8>>]
                            )
                        );

                    {rendered_event_handler, Kind, Id} ->
                        gleam@string_builder:append_builder(
                            Acc,
                            gleam@string_builder:from_strings(
                                [<<" "/utf8>>,
                                    sprocket@internal@constants:constant(
                                        event_attr_prefix
                                    ),
                                    <<"-"/utf8>>,
                                    Kind,
                                    <<"=\""/utf8>>,
                                    Id,
                                    <<"\""/utf8>>]
                            )
                        )
                end end
        )
    end,
    Rendered_attrs@1 = case Key of
        {some, K} ->
            gleam@string_builder:append_builder(
                Rendered_attrs,
                gleam@string_builder:from_strings(
                    [<<" "/utf8>>,
                        sprocket@internal@constants:constant(key_attr),
                        <<"=\""/utf8>>,
                        K,
                        <<"\""/utf8>>]
                )
            );

        none ->
            Rendered_attrs
    end,
    Inner_html = begin
        _pipe@1 = Children,
        gleam@list:fold(
            _pipe@1,
            gleam@string_builder:new(),
            fun(Acc@1, Child) ->
                gleam@string_builder:append_builder(Acc@1, render(Child))
            end
        )
    end,
    gleam@string_builder:concat(
        [gleam@string_builder:from_string(<<"<"/utf8>>),
            gleam@string_builder:from_string(Tag),
            Rendered_attrs@1,
            gleam@string_builder:from_string(<<">"/utf8>>),
            Inner_html,
            gleam@string_builder:from_string(<<"</"/utf8>>),
            gleam@string_builder:from_string(Tag),
            gleam@string_builder:from_string(<<">"/utf8>>)]
    ).

-spec render(sprocket@render:rendered_element()) -> gleam@string_builder:string_builder().
render(El) ->
    case El of
        {rendered_element, Tag, Key, Attrs, Children} ->
            element(Tag, Key, Attrs, Children);

        {rendered_component, _, _, _, _, Children@1} ->
            component(Children@1);

        {rendered_text, T} ->
            text(T)
    end.

-spec renderer() -> sprocket@render:renderer(binary()).
renderer() ->
    {renderer, fun(El) -> gleam@string_builder:to_string(render(El)) end}.

-spec preflight_renderer(
    gleam@erlang@process:subject(sprocket@cassette:message()),
    sprocket@element:element()
) -> sprocket@render:renderer(binary()).
preflight_renderer(Ca, View) ->
    _assert_subject = sprocket@internal@utils@uuid:v4(),
    {ok, Preflight_id} = case _assert_subject of
        {ok, _} -> _assert_subject;
        _assert_fail ->
            erlang:error(#{gleam_error => assert,
                        message => <<"Assertion pattern match failed"/utf8>>,
                        value => _assert_fail,
                        module => <<"sprocket/internal/render/html"/utf8>>,
                        function => <<"preflight_renderer"/utf8>>,
                        line => 25})
    end,
    Csrf_token = sprocket@internal@csrf:generate(),
    sprocket@cassette:push_preflight(
        Ca,
        {preflight, Preflight_id, View, Csrf_token, os:system_time(millisecond)}
    ),
    Preflight_meta = begin
        _pipe = sprocket@html:meta(
            [sprocket@html@attributes:name(
                    sprocket@internal@constants:constant(meta_preflight_id)
                ),
                sprocket@html@attributes:content(Preflight_id)]
        ),
        sprocket@render:render_element(_pipe)
    end,
    Csrf_meta = begin
        _pipe@1 = sprocket@html:meta(
            [sprocket@html@attributes:name(
                    sprocket@internal@constants:constant(meta_crsf_token)
                ),
                sprocket@html@attributes:content(Csrf_token)]
        ),
        sprocket@render:render_element(_pipe@1)
    end,
    Sprocket_client = begin
        _pipe@2 = sprocket@html:script(
            [sprocket@html@attributes:src(
                    sprocket@internal@constants:constant(client_script)
                )],
            none
        ),
        sprocket@render:render_element(_pipe@2)
    end,
    {renderer, fun(El) -> _pipe@3 = El,
            _pipe@4 = inject_element(
                _pipe@3,
                <<"head"/utf8>>,
                Preflight_meta,
                append
            ),
            _pipe@5 = inject_element(
                _pipe@4,
                <<"head"/utf8>>,
                Csrf_meta,
                append
            ),
            _pipe@6 = inject_element(
                _pipe@5,
                <<"body"/utf8>>,
                Sprocket_client,
                append
            ),
            _pipe@7 = render(_pipe@6),
            gleam@string_builder:to_string(_pipe@7) end}.

-spec component(list(sprocket@render:rendered_element())) -> gleam@string_builder:string_builder().
component(Children) ->
    _pipe = Children,
    gleam@list:fold(
        _pipe,
        gleam@string_builder:new(),
        fun(Acc, Child) ->
            gleam@string_builder:append_builder(Acc, render(Child))
        end
    ).