"""
LangGraph Reducer函数演示 - 数值累加Reducer
"""

import operator
from typing import Annotated
from typing_extensions import TypedDict
from langgraph.graph import StateGraph, START, END


# 7. 数值累加Reducer
class NumberAddState(TypedDict):
    count: Annotated[int, operator.add]


def increment_1(state: NumberAddState) -> dict:
    return {"count": 5}


def increment_2(state: NumberAddState) -> dict:
    return {"count": 3}


def run_demo():
    print("3.3 数值累加Reducer演示:")
    builder = StateGraph(NumberAddState)
    builder.add_node("increment_1", increment_1)
    builder.add_node("increment_2", increment_2)
    # 顺序执行边
    builder.add_edge(START, "increment_1")
    builder.add_edge("increment_1", "increment_2")
    builder.add_edge("increment_2", END)

    graph = builder.compile()

    result = graph.invoke({"count": 10})
    print(f"初始状态: {{'count': 10}}")
    print(f"执行结果: {result}\n")


if __name__ == "__main__":
    run_demo()