"""LLM 模型枚举与实例获取。

Usage:
    from app.ai.models import LLM

    llm = LLM.DOUBAO_SEED_LITE.create(temperature=0)
    llm = LLM.CLAUDE_OPUS.create(temperature=0)
"""

from enum import Enum
from typing import Callable

from langchain_anthropic import ChatAnthropic
from langchain_core.language_models import BaseChatModel
from langchain_openai import ChatOpenAI

from app.config import settings

ConfigGetter = Callable[[], str]

# 供应商连接配置 = (api_key函数, base_url函数)
_VOLCENGINE = (
    lambda: settings.volcengine_api_key,
    lambda: settings.volcengine_base_url,
)
_ANTHROPIC = (
    lambda: settings.anthropic_api_key,
    lambda: settings.anthropic_base_url,
)


class LLM(Enum):
    """所有可用模型，每个枚举值 = (模型名, 封装类, api_key函数, base_url函数)。"""

    # 火山引擎（OpenAI 兼容）
    DOUBAO_PRO_32K = ("doubao-1-5-pro-32k-250115", ChatOpenAI, *_VOLCENGINE)
    DOUBAO_LITE_32K = ("doubao-1-5-lite-32k-250115", ChatOpenAI, *_VOLCENGINE)
    DOUBAO_SEED_LITE = ("doubao-seed-2-0-lite-260215", ChatOpenAI, *_VOLCENGINE)
    DOUBAO_SEED_PRO = ("doubao-seed-2-0-pro-260215", ChatOpenAI, *_VOLCENGINE)
    DEEPSEEK_V4_FLASH = ("deepseek-v4-flash-260425", ChatOpenAI, *_VOLCENGINE)

    # Claude（Anthropic 风格）
    CLAUDE_OPUS = ("claude-opus-4-6", ChatAnthropic, *_ANTHROPIC)

    def __init__(
        self,
        model_name: str,
        model_class: type[BaseChatModel],
        api_key_getter: ConfigGetter,
        base_url_getter: ConfigGetter,
    ) -> None:
        self.model_name = model_name
        self._model_class = model_class
        self._api_key_getter = api_key_getter
        self._base_url_getter = base_url_getter

    def create(self, **kwargs) -> BaseChatModel:
        """创建模型实例，其他参数透传给 LangChain 模型类。"""
        return self._model_class(
            model=self.model_name,
            api_key=self._api_key_getter(),
            base_url=self._base_url_getter(),
            **kwargs,
        )