import json
import os

STATE_FILE = "plant_state.json"


def save_state(ps_id=None, ps_key=None, device_name=None):
    state = load_state() or {}

    if device_name is not None:
        state["device_name"] = device_name
    if ps_id is not None:
        state["ps_id"] = ps_id
    if ps_key is not None:
        state["ps_key"] = ps_key


    with open(STATE_FILE, "w") as f:
        json.dump(state, f, indent=4)


def load_state():
    if not os.path.exists(STATE_FILE):
        return None
    with open(STATE_FILE) as f:
        return json.load(f)


def load_ps_id():
    state = load_state()
    return state.get("ps_id") if state else None


def load_ps_key():
    state = load_state()
    return state.get("ps_key") if state else None


def load_device_name():
    state = load_state()
    return state.get("device_name") if state else None