# SPDX-FileCopyrightText: Copyright (c) 2025-2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
# SPDX-License-Identifier: Apache-2.0

"""Worker initialization modules for TensorRT-LLM backend.

This package contains worker initialization functions for different modalities:
- llm_worker: Text and multimodal LLM inference
- video_diffusion_worker: Video generation using diffusion models

The init_worker() function dispatches to the appropriate worker based on modality.

Note on import strategy:
- llm_worker is imported eagerly (standard dependency, always available)
- video_diffusion_worker is imported lazily because it depends on visual_gen,
  an optional package only available on TensorRT-LLM's feat/visual_gen branch.
  Eager import would break text/multimodal users who don't have it installed.
"""

import asyncio
import logging
from typing import Optional

from dynamo.runtime import DistributedRuntime
from dynamo.trtllm.args import Config
from dynamo.trtllm.constants import Modality
from dynamo.trtllm.workers.llm_worker import init_llm_worker


async def init_worker(
    runtime: DistributedRuntime,
    config: Config,
    shutdown_event: asyncio.Event,
    shutdown_endpoints: Optional[list] = None,
    engine_holder: Optional[list] = None,
) -> None:
    """Initialize the appropriate worker based on modality.

    Dispatches to the correct worker initialization function based on the
    configured modality (text, multimodal, video_diffusion, etc.).

    Args:
        runtime: The Dynamo distributed runtime.
        config: Configuration parsed from command line.
        shutdown_event: Event to signal shutdown.
        shutdown_endpoints: Optional list to populate with endpoints for graceful shutdown.
        engine_holder: Optional mutable list; when provided, init_llm_worker will
            append the TensorRTLLMEngine instance so that the drain callback
            (installed earlier by main.py) can access it at signal time.
    """
    logging.info(f"Initializing worker with modality={config.modality}")

    modality = config.modality

    if Modality.is_diffusion(modality):
        if modality == Modality.VIDEO_DIFFUSION:
            from dynamo.trtllm.workers.video_diffusion_worker import (
                init_video_diffusion_worker,
            )

            await init_video_diffusion_worker(
                runtime, config, shutdown_event, shutdown_endpoints
            )
            return
        # TODO: Add IMAGE_DIFFUSION support in follow-up PR
        raise ValueError(f"Unsupported diffusion modality: {modality}")

    # LLM modalities (text, multimodal)
    await init_llm_worker(
        runtime,
        config,
        shutdown_event,
        shutdown_endpoints,
        engine_holder=engine_holder,
    )


__all__ = ["init_worker"]
