class BlueBubblesStreaming:
    streaming_mode = "block"
    preview_stream_throttle_ms = 160
    preview_min_initial_chars = 18

    block_streaming_enabled = True
    block_streaming_break = "text_end"
    block_streaming_chunk_min_chars = 2000
    block_streaming_chunk_max_chars = 4000
    block_streaming_chunk_break_preference = "paragraph"
    block_streaming_coalesce_defaults = {
        "min_chars": 400,
        "max_chars": 4000,
        "idle_ms": 1000,
    }

    def create_draft_stream_session(self, target_id: str) -> object:
        return {"target_id": target_id, "mode": "block"}

    def create_block_chunker(self) -> object:
        return {"mode": "length", "min_chars": 2000, "max_chars": 4000}