"""
Slide 50: Slide 23
Section 2: LangGraph 1.0
Source: slides/section2-langgraph/section2.pptx

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-050/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 50 ===
  from typing_extensions import TypedDict
  from langgraph.graph import StateGraph, START, END

  class SubState(TypedDict):
      internal: str

  def inner(state: SubState):
      return {"internal": "sub-output"}

  # Собираем subgraph -- у него свой state
> sub = StateGraph(SubState)
> sub.add_node("inner", inner)
> sub.add_edge(START, "inner")
> sub.add_edge("inner", END)
  sub_compiled = sub.compile()

  # Вставляем как обычный узел в родительский граф
  class ParentState(TypedDict):
      out: str

> parent = StateGraph(ParentState)
> parent.add_node("sub_block", sub_compiled)   # <- subgraph целиком
  parent.add_edge(START, "sub_block")
  parent.add_edge("sub_block", END)
  app = parent.compile()
  print(app.invoke({"out": ""}))

// note: snippet has 26 lines, card fits ~18