import asyncio
import copy
from deepmerge import always_merger

STATE = {"initialized": 0}
state_lock = asyncio.Lock()

NOTIFY_CALLBACKS = []

def register_callback(callback):
    global NOTIFY_CALLBACKS
    NOTIFY_CALLBACKS = NOTIFY_CALLBACKS + [callback]

def unregister_callback(callback):
    NOTIFY_CALLBACK = [ x for x in NOTIFY_CALLBACKS if x != callback ]

async def mutate(delta):
    global STATE
    async with state_lock:
        old_state = copy.deepcopy(STATE)
        STATE = always_merger.merge(STATE, delta)
        for callback in NOTIFY_CALLBACKS:
            await callback(old_state, STATE)

async def get_data():
    global STATE
    async with state_lock:
        return STATE

async def inc_initialized():
    global STATE
    async with state_lock:
        STATE["initialized"] += 1