"""
Slide 21: Краткосрочная память: thread + checkpointer
Section 1: LangChain 1.0
Source: slides/section1-chains/slide-21.js

Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
Паттерн провайдера скопирован из
bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.

Запуск:
  cd langchain-evolution-deck
  cp .env.example .env   # заполни OPENAI_API_KEY
  python examples/slide-021/script.py
"""
import os
from dotenv import load_dotenv
from langchain_openai import ChatOpenAI

load_dotenv()

llm = ChatOpenAI(
    # model="openrouter/free",
    # model="qwen/qwen3.5-35b-a3b",
    model="openai/gpt-oss-20b",
    # model="nvidia/nemotron-3-nano",
    # model="qwen/qwen3.5-9b",
    base_url="https://llm.brojs.ru/v1",
    # base_url="https://api.minimax.io/v1",
    # base_url="http://0.0.0.0:8090/v1",
    # base_url="https://openrouter.ai/api/v1",
    # api_key=os.getenv("MINIMAX_API_KEY"),
    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
    temperature=0.7,
    stream_usage=True,
)


# === Code from slide 21 ===
from langchain.agents import create_agent
from langgraph.checkpoint.memory import InMemorySaver

checkpointer = InMemorySaver()

agent = create_agent(
    model="openai:gpt-4.1-mini",
    tools=[...],
    checkpointer=checkpointer,  # <-- persistent state
)

config = {"configurable": {"thread_id": "user-42"}}

# Первый turn
agent.invoke({"messages": [{"role": "user",
    "content": "My name is Alice."}]}, config=config)

# Второй turn -- модель помнит имя
result = agent.invoke({"messages": [{"role": "user",
    "content": "What is my name?"}]}, config=config)
print(result["messages"][-1].content)  # "Alice"