"""
Agent Service 配置模块 - 配置构建和解析
"""

from typing import Dict, Any, Tuple, Optional
from langchain_core.messages import HumanMessage
from backend.app.logger import warning


class ServiceConfig:
    """配置构建器"""

    def __init__(self, chat_services: dict):
        self.chat_services = chat_services

    def resolve_model(self, model: Optional[str]) -> str:
        """
        解析并验证模型名称，不可用时回退到第一个可用模型
        """
        if not model or model not in self.chat_services:
            fallback = next(iter(self.chat_services.keys()))
            warning(f"模型 '{model}' 不可用，回退到 '{fallback}'")
            return fallback
        return model

    def build_invocation(
        self, message: str, thread_id: str, model: str, user_id: str
    ) -> Tuple[Dict[str, Any], Dict[str, Any]]:
        """
        构建图调用所需的 config 和 input_state

        Returns:
            (config, input_state) 元组
        """
        config = {
            "configurable": {
                "thread_id": thread_id,
            },
            "metadata": {"user_id": user_id}
        }

        input_state = {
            "messages": [HumanMessage(content=message)],
            "user_id": user_id,
        }
        return config, input_state