from typing import TypedDict

from langgraph.graph import StateGraph, START, END


class State(TypedDict):
    text: str
    length: int


def normalize_text(state: State):
    """清理文本。"""
    normalized = state["text"].strip().lower()
    return {"text": normalized}


def calculate_length(state: State):
    """计算文本长度。"""
    return {"length": len(state["text"])}


builder = StateGraph(State)

builder.add_node("normalize_text", normalize_text)
builder.add_node("calculate_length", calculate_length)

builder.add_edge(START, "normalize_text")
builder.add_edge("normalize_text", "calculate_length")
builder.add_edge("calculate_length", END)

graph = builder.compile()

result = graph.invoke({
    "text": "  Hello LangGraph!  ",
    "length": 0,
})

print(result)