"""
LangGraph Reducer函数演示 - operator.add Reducer（列表追加）
"""

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

# 3. operator.add Reducer（列表追加）
class ListAddState(TypedDict):
    #data: Annotated[List[int], None]  #默认覆盖
    data: Annotated[List[int], operator.add] # （列表追加）


def producer_1(state: ListAddState) -> dict:
    return {"data": [1, 2]}


def producer_2(state: ListAddState) -> dict:
    return {"data": [3, 4]}


def run_demo():
    builder = StateGraph(ListAddState)
    # 注册节点
    builder.add_node("producer1", producer_1)
    builder.add_node("producer2", producer_2)
    # 顺序执行边
    builder.add_edge(START, "producer1")
    builder.add_edge("producer1", "producer2")
    builder.add_edge("producer2", END)

    graph = builder.compile()
    result = graph.invoke({"data": [0]})
    print(f"初始状态: {{'data': [0]}}")
    print(f"执行结果: {result}\n")


if __name__ == "__main__":
    run_demo()