# main.py

from typing import NamedTuple

import pydepot


class State(NamedTuple):
    counter: int


class AddToCounterAction(pydepot.Action):
    def __init__(self, value: int):
        self.value: int = value


class AddToCounterReducer(pydepot.Reducer[AddToCounterAction, State]):
    @property
    def action_type(self) -> type[AddToCounterAction]:
        return AddToCounterAction

    def apply(self, action: AddToCounterAction, state: State) -> State:
        return State(counter=state.counter + action.value)


class CounterSubscriber(pydepot.StoreSubscriber[State]):
    def on_state(self, state: State) -> None:
        print(f"The counter has changed to {state.counter}.")


def main() -> None:
    store = pydepot.Store(initial_state=State(counter=0))
    store.register(AddToCounterReducer())

    subscriber = CounterSubscriber()
    store.subscribe(subscriber)

    store.dispatch(AddToCounterAction(value=42))


if __name__ == "__main__":
    main()