-module(claude@streaming).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch, inline]).
-define(FILEPATH, "src/claude/streaming.gleam").
-export([parse_event/2, parse_sse/1]).
-export_type([delta/0, delta_usage/0, stream_event/0]).

-if(?OTP_RELEASE >= 27).
-define(MODULEDOC(Str), -moduledoc(Str)).
-define(DOC(Str), -doc(Str)).
-else.
-define(MODULEDOC(Str), -compile([])).
-define(DOC(Str), -compile([])).
-endif.

-type delta() :: {text_delta, binary()} |
    {input_json_delta, binary()} |
    {thinking_delta, binary()}.

-type delta_usage() :: {delta_usage, integer()}.

-type stream_event() :: {message_start, claude@types@message:message()} |
    {content_block_start, integer(), claude@types@content:content_block()} |
    {content_block_delta, integer(), delta()} |
    {content_block_stop, integer()} |
    {message_delta,
        gleam@option:option(claude@types@message:stop_reason()),
        delta_usage()} |
    message_stop |
    ping |
    {unknown_event, binary(), binary()}.

-file("src/claude/streaming.gleam", 65).
?DOC(" Extract the value after a field prefix (e.g. \"event:\" or \"data:\") from SSE lines.\n").
-spec find_field(list(binary()), binary()) -> {ok, binary()} | {error, nil}.
find_field(Lines, Prefix) ->
    gleam@list:find_map(
        Lines,
        fun(Line) ->
            Trimmed = gleam@string:trim(Line),
            case gleam_stdlib:string_starts_with(Trimmed, Prefix) of
                true ->
                    Value = gleam@string:drop_start(
                        Trimmed,
                        string:length(Prefix)
                    ),
                    {ok, gleam@string:trim(Value)};

                false ->
                    {error, nil}
            end
        end
    ).

-file("src/claude/streaming.gleam", 94).
-spec parse_message_start(binary()) -> stream_event().
parse_message_start(Data) ->
    Decoder = begin
        gleam@dynamic@decode:field(
            <<"message"/utf8>>,
            claude@json@decode:message_decoder(),
            fun(Message) ->
                gleam@dynamic@decode:success({message_start, Message})
            end
        )
    end,
    case gleam@json:parse(Data, Decoder) of
        {ok, Event} ->
            Event;

        {error, _} ->
            {unknown_event, <<"message_start"/utf8>>, Data}
    end.

-file("src/claude/streaming.gleam", 129).
-spec parse_content_block_stop(binary()) -> stream_event().
parse_content_block_stop(Data) ->
    Decoder = begin
        gleam@dynamic@decode:field(
            <<"index"/utf8>>,
            {decoder, fun gleam@dynamic@decode:decode_int/1},
            fun(Index) ->
                gleam@dynamic@decode:success({content_block_stop, Index})
            end
        )
    end,
    case gleam@json:parse(Data, Decoder) of
        {ok, Event} ->
            Event;

        {error, _} ->
            {unknown_event, <<"content_block_stop"/utf8>>, Data}
    end.

-file("src/claude/streaming.gleam", 140).
-spec parse_message_delta(binary()) -> stream_event().
parse_message_delta(Data) ->
    Decoder = begin
        gleam@dynamic@decode:subfield(
            [<<"delta"/utf8>>, <<"stop_reason"/utf8>>],
            gleam@dynamic@decode:optional(
                claude@json@decode:stop_reason_decoder()
            ),
            fun(Stop_reason) ->
                gleam@dynamic@decode:subfield(
                    [<<"usage"/utf8>>, <<"output_tokens"/utf8>>],
                    {decoder, fun gleam@dynamic@decode:decode_int/1},
                    fun(Output_tokens) ->
                        gleam@dynamic@decode:success(
                            {message_delta,
                                Stop_reason,
                                {delta_usage, Output_tokens}}
                        )
                    end
                )
            end
        )
    end,
    case gleam@json:parse(Data, Decoder) of
        {ok, Event} ->
            Event;

        {error, _} ->
            {unknown_event, <<"message_delta"/utf8>>, Data}
    end.

-file("src/claude/streaming.gleam", 165).
?DOC(
    " Decoder for a content block in content_block_start events.\n"
    " Handles \"text\" and \"tool_use\" types.\n"
).
-spec content_block_start_decoder() -> gleam@dynamic@decode:decoder(claude@types@content:content_block()).
content_block_start_decoder() ->
    gleam@dynamic@decode:field(
        <<"type"/utf8>>,
        {decoder, fun gleam@dynamic@decode:decode_string/1},
        fun(Block_type) -> case Block_type of
                <<"text"/utf8>> ->
                    gleam@dynamic@decode:field(
                        <<"text"/utf8>>,
                        {decoder, fun gleam@dynamic@decode:decode_string/1},
                        fun(Text) ->
                            gleam@dynamic@decode:success({text, Text, []})
                        end
                    );

                <<"tool_use"/utf8>> ->
                    gleam@dynamic@decode:field(
                        <<"id"/utf8>>,
                        {decoder, fun gleam@dynamic@decode:decode_string/1},
                        fun(Id) ->
                            gleam@dynamic@decode:field(
                                <<"name"/utf8>>,
                                {decoder,
                                    fun gleam@dynamic@decode:decode_string/1},
                                fun(Name) ->
                                    gleam@dynamic@decode:success(
                                        {tool_use, Id, Name, <<""/utf8>>}
                                    )
                                end
                            )
                        end
                    );

                _ ->
                    gleam@dynamic@decode:success({text, <<""/utf8>>, []})
            end end
    ).

-file("src/claude/streaming.gleam", 105).
-spec parse_content_block_start(binary()) -> stream_event().
parse_content_block_start(Data) ->
    Decoder = begin
        gleam@dynamic@decode:field(
            <<"index"/utf8>>,
            {decoder, fun gleam@dynamic@decode:decode_int/1},
            fun(Index) ->
                gleam@dynamic@decode:field(
                    <<"content_block"/utf8>>,
                    content_block_start_decoder(),
                    fun(Block) ->
                        gleam@dynamic@decode:success(
                            {content_block_start, Index, Block}
                        )
                    end
                )
            end
        )
    end,
    case gleam@json:parse(Data, Decoder) of
        {ok, Event} ->
            Event;

        {error, _} ->
            {unknown_event, <<"content_block_start"/utf8>>, Data}
    end.

-file("src/claude/streaming.gleam", 183).
?DOC(" Decoder for the delta object in content_block_delta events.\n").
-spec delta_decoder() -> gleam@dynamic@decode:decoder(delta()).
delta_decoder() ->
    gleam@dynamic@decode:field(
        <<"type"/utf8>>,
        {decoder, fun gleam@dynamic@decode:decode_string/1},
        fun(Delta_type) -> case Delta_type of
                <<"text_delta"/utf8>> ->
                    gleam@dynamic@decode:field(
                        <<"text"/utf8>>,
                        {decoder, fun gleam@dynamic@decode:decode_string/1},
                        fun(Text) ->
                            gleam@dynamic@decode:success({text_delta, Text})
                        end
                    );

                <<"input_json_delta"/utf8>> ->
                    gleam@dynamic@decode:field(
                        <<"partial_json"/utf8>>,
                        {decoder, fun gleam@dynamic@decode:decode_string/1},
                        fun(Partial_json) ->
                            gleam@dynamic@decode:success(
                                {input_json_delta, Partial_json}
                            )
                        end
                    );

                <<"thinking_delta"/utf8>> ->
                    gleam@dynamic@decode:field(
                        <<"thinking"/utf8>>,
                        {decoder, fun gleam@dynamic@decode:decode_string/1},
                        fun(Thinking) ->
                            gleam@dynamic@decode:success(
                                {thinking_delta, Thinking}
                            )
                        end
                    );

                _ ->
                    gleam@dynamic@decode:success({text_delta, <<""/utf8>>})
            end end
    ).

-file("src/claude/streaming.gleam", 117).
-spec parse_content_block_delta(binary()) -> stream_event().
parse_content_block_delta(Data) ->
    Decoder = begin
        gleam@dynamic@decode:field(
            <<"index"/utf8>>,
            {decoder, fun gleam@dynamic@decode:decode_int/1},
            fun(Index) ->
                gleam@dynamic@decode:field(
                    <<"delta"/utf8>>,
                    delta_decoder(),
                    fun(Delta) ->
                        gleam@dynamic@decode:success(
                            {content_block_delta, Index, Delta}
                        )
                    end
                )
            end
        )
    end,
    case gleam@json:parse(Data, Decoder) of
        {ok, Event} ->
            Event;

        {error, _} ->
            {unknown_event, <<"content_block_delta"/utf8>>, Data}
    end.

-file("src/claude/streaming.gleam", 79).
?DOC(" Parse a single event given its type and JSON data string.\n").
-spec parse_event(binary(), binary()) -> stream_event().
parse_event(Event_type, Data) ->
    case Event_type of
        <<"message_start"/utf8>> ->
            parse_message_start(Data);

        <<"content_block_start"/utf8>> ->
            parse_content_block_start(Data);

        <<"content_block_delta"/utf8>> ->
            parse_content_block_delta(Data);

        <<"content_block_stop"/utf8>> ->
            parse_content_block_stop(Data);

        <<"message_delta"/utf8>> ->
            parse_message_delta(Data);

        <<"message_stop"/utf8>> ->
            message_stop;

        <<"ping"/utf8>> ->
            ping;

        _ ->
            {unknown_event, Event_type, Data}
    end.

-file("src/claude/streaming.gleam", 48).
?DOC(
    " Parse a single SSE block into a StreamEvent.\n"
    " Returns Error(Nil) if the block cannot be parsed.\n"
).
-spec parse_block(binary()) -> {ok, stream_event()} | {error, nil}.
parse_block(Block) ->
    Lines = gleam@string:split(Block, <<"\n"/utf8>>),
    Event_type = find_field(Lines, <<"event:"/utf8>>),
    Data = find_field(Lines, <<"data:"/utf8>>),
    case {Event_type, Data} of
        {{ok, Evt}, {ok, D}} ->
            {ok, parse_event(Evt, D)};

        {{ok, Evt@1}, {error, _}} ->
            case Evt@1 of
                <<"ping"/utf8>> ->
                    {ok, ping};

                _ ->
                    {ok, {unknown_event, Evt@1, <<""/utf8>>}}
            end;

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

-file("src/claude/streaming.gleam", 39).
?DOC(
    " Parse a full SSE text payload into a list of StreamEvents.\n"
    "\n"
    " SSE events are separated by blank lines (\"\\n\\n\"). Each event block\n"
    " contains an `event:` line and a `data:` line.\n"
).
-spec parse_sse(binary()) -> list(stream_event()).
parse_sse(Text) ->
    _pipe = Text,
    _pipe@1 = gleam@string:split(_pipe, <<"\n\n"/utf8>>),
    _pipe@2 = gleam@list:filter(
        _pipe@1,
        fun(Block) -> not gleam@string:is_empty(gleam@string:trim(Block)) end
    ),
    gleam@list:filter_map(_pipe@2, fun parse_block/1).