-module(webls@rss).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch]).

-export([to_string/1]).
-export_type([rss_channel/0, rss_item/0]).

-type rss_channel() :: {rss_channel,
        binary(),
        binary(),
        binary(),
        list(rss_item())}.

-type rss_item() :: {rss_item,
        binary(),
        binary(),
        binary(),
        birl:time(),
        gleam@option:option(binary()),
        {binary(), gleam@option:option(boolean())}}.

-spec rss_item_to_string(rss_item()) -> binary().
rss_item_to_string(Item) ->
    <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<"<item>\n"/utf8, "<title>"/utf8>>/binary,
                                                            (erlang:element(
                                                                2,
                                                                Item
                                                            ))/binary>>/binary,
                                                        "</title>\n"/utf8>>/binary,
                                                    "<link>"/utf8>>/binary,
                                                (erlang:element(3, Item))/binary>>/binary,
                                            "</link>\n"/utf8>>/binary,
                                        "<description>"/utf8>>/binary,
                                    (erlang:element(4, Item))/binary>>/binary,
                                "</description>\n"/utf8>>/binary,
                            "<pubDate>"/utf8>>/binary,
                        (begin
                            _pipe = erlang:element(5, Item),
                            birl:to_iso8601(_pipe)
                        end)/binary>>/binary,
                    "</pubDate>\n"/utf8>>/binary,
                (case erlang:element(6, Item) of
                    {some, Author} ->
                        <<<<"<author>"/utf8, Author/binary>>/binary,
                            "</author>\n"/utf8>>;

                    _ ->
                        <<""/utf8>>
                end)/binary>>/binary,
            (case erlang:element(7, Item) of
                {Guid, {some, Is_permalink}} ->
                    <<<<<<<<"<guid isPermaLink=\""/utf8, (case Is_permalink of
                                        true ->
                                            <<"true"/utf8>>;

                                        false ->
                                            <<"false"/utf8>>
                                    end)/binary>>/binary, "\">"/utf8>>/binary, Guid/binary>>/binary, "</guid>\n"/utf8>>;

                _ ->
                    <<""/utf8>>
            end)/binary>>/binary,
        "</item>"/utf8>>.

-spec channel_to_string(rss_channel()) -> binary().
channel_to_string(Channel) ->
    Channel_items = begin
        _pipe = erlang:element(5, Channel),
        _pipe@2 = gleam@list:map(_pipe, fun(Rss_item) -> _pipe@1 = Rss_item,
                rss_item_to_string(_pipe@1) end),
        _pipe@3 = gleam@list:reduce(
            _pipe@2,
            fun(Acc, Rss_item_string) ->
                <<<<Acc/binary, "\n"/utf8>>/binary, Rss_item_string/binary>>
            end
        ),
        gleam@result:unwrap(_pipe@3, <<""/utf8>>)
    end,
    <<<<<<<<<<<<<<<<<<<<<<"\n<channel>\n"/utf8, "<title>"/utf8>>/binary,
                                            (erlang:element(2, Channel))/binary>>/binary,
                                        "</title>\n"/utf8>>/binary,
                                    "<description>"/utf8>>/binary,
                                (erlang:element(3, Channel))/binary>>/binary,
                            "</description>\n"/utf8>>/binary,
                        "<link>"/utf8>>/binary,
                    (erlang:element(4, Channel))/binary>>/binary,
                "</link>\n"/utf8>>/binary,
            Channel_items/binary>>/binary,
        "</channel>"/utf8>>.

-spec to_string(list(rss_channel())) -> binary().
to_string(Channels) ->
    Channel_content = begin
        _pipe = Channels,
        _pipe@2 = gleam@list:map(_pipe, fun(Channel) -> _pipe@1 = Channel,
                channel_to_string(_pipe@1) end),
        _pipe@3 = gleam@list:reduce(
            _pipe@2,
            fun(Acc, Channel_string) ->
                <<<<Acc/binary, "\n"/utf8>>/binary, Channel_string/binary>>
            end
        ),
        gleam@result:unwrap(_pipe@3, <<""/utf8>>)
    end,
    <<<<"<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n<rss version=\"2.0\">"/utf8,
            Channel_content/binary>>/binary,
        "\n</rss>"/utf8>>.