from vllm.engine.arg_utils import EngineArgs
from vllm.usage.usage_lib import UsageContext
from typing import Dict, Optional
from vllm.engine.metrics_types import StatLoggerBase

class LLMEngine:

    @classmethod
    def from_engine_args(
        cls,
        engine_args: EngineArgs,
        usage_context: UsageContext = UsageContext.ENGINE_CONTEXT,
        stat_loggers: Optional[Dict[str, StatLoggerBase]] = None,
    ) -> "LLMEngine":
        """Creates an LLM engine from the engine arguments."""
        # Create the engine configs.
        vllm_config = engine_args.create_engine_config(usage_context)
        #patch to prevent num_speculative_tokens > 1
        speculative_mode = hasattr(vllm_config, 'speculative_config')
        if speculative_mode and \
            hasattr(vllm_config.speculative_config, 'num_speculative_tokens') and \
                vllm_config.speculative_config.num_speculative_tokens != 1:
            raise ValueError(f'run_mp_engine: only support num_speculative_tokens == 1, but get {vllm_config.speculative_config.num_speculative_tokens}')
        
        default_model_infos = "default"
        if speculative_mode:
            if hasattr(vllm_config.speculative_config, 'method'):
                default_model_infos = vllm_config.speculative_config.method
                
        from vllm_vacc.vllm.config_manager import vllm_vacc_config_manager
        vllm_vacc_config_manager().update_model_infos(default_model_infos)

        import vllm.envs as envs
        engine_cls = None
        if envs.VLLM_USE_V1:
            from vllm.v1.engine.llm_engine import LLMEngine as V1LLMEngine
            engine_cls = V1LLMEngine
        else:
            from vllm.engine.llm_engine import LLMEngine as DefaultEngine
            engine_cls = DefaultEngine

        assert engine_cls is not None, f"LLMEngine is empty: {engine_cls}"

        return engine_cls.from_vllm_config(
            vllm_config=vllm_config,
            usage_context=usage_context,
            stat_loggers=stat_loggers,
            disable_log_stats=engine_args.disable_log_stats,
        )