import threading
from typing import Any

from sympy.physics.units import temperature

from . import config


_shared_model = None
_lock = threading.Lock()




def _build_openai():
    from strands.models.openai import OpenAIModel
    
    client_args:dict[str, Any] = {"api_key": config.OPENAI_API_KEY}
    if config.OPENAI_API_BASE_URL:
        client_args["base_url"] = config.OPENAI_API_BASE_URL
    
    return OpenAIModel(
        client_args=client_args,
        model_id=config.MODEL_ID,
        params={"max_tokens": config.MAX_TOKENS, "temperature": config.TEMPERATURE},
    )


def _build_anthropic():
    from strands.models.anthropic import AnthropicModel
    
    return AnthropicModel(
        client_args={"api_key": config.ANTHROPIC_API_KEY},
        model_id=config.MODEL_ID,
        max_tokens=config.MAX_TOKENS,
        params={"temperature": config.TEMPERATURE},
    )


def _build_litellm():
    from strands.models.litellm import LiteLLMModel
    
    return LiteLLMModel(
        model_id=config.MODEL_ID,
        
        params={"max_tokens": config.MAX_TOKENS, "temperature": config.TEMPERATURE},
    )


def _build_ollama():
    from strands.models.ollama import OllamaModel
    
    return OllamaModel(
        host=config.OLLAMA_HOST,
        model_id=config.MODEL_ID,
        params={"temperature": config.TEMPERATURE},
    )


def _build_bedrock():
    from strands.models.bedrock import BedrockModel
    
    return BedrockModel(
        model_id=config.MODEL_ID,
        region=config.AWS_REGION,
        max_tokens=config.MAX_TOKENS,
        temperature=config.TEMPERATURE,
    )


_BUILDERS = {
    "openai": _build_openai,
    "anthropic": _build_anthropic,
    "litellm": _build_litellm,
    "ollama": _build_ollama,
    "bedrock": _build_bedrock,
}


def get_model():
    """获取共享的模型实例，根据配置选择不同的模型提供者。

    Returns:
        Any: 模型实例。
    """
    global _shared_model
    if _shared_model is not None:
        return _shared_model
    
    with _lock:
        if _shared_model is not None:
            return _shared_model
        
        builder = _BUILDERS.get(config.MODEL_PROVIDER)
        if builder is None:
            raise ValueError(f"Unsupported model provider: {config.MODEL_PROVIDER}"
                             f"Choose one of: {', '.join(_BUILDERS.keys())}")
        _shared_model = builder()
    return _shared_model


def reset_model() -> None:
    """重置共享的模型实例，通常用于测试或重新加载配置。"""
    global _shared_model
    with _lock:
        _shared_model = None