activity.py

from tinydb import TinyDB, Query
from threading import Lock
# Programs and Activities databases
class Activities():
    _instance = None

    @classmethod
    def get_instance(cls):
        if cls._instance is None:
            cls._instance = Activities()
        return cls._instance

    def __init__(self):
        self.activities = TinyDB("data/activities.json")
        self.query = Query()
        self.lock = Lock()

    def load(self, name, default):
        with self.lock: 
            if name and default is None:
                activities = self.activities.search(self.query.name == name)
                if len(activities) > 0:
                    return activities[0]
            elif default is not None:
                if len(self.activities.search(self.query.default == True)) > 0:
                    return self.activities.search(self.query.default == True)[0]
                return None
            return None

    def save(self, name, activity):
        with self.lock: 
            # if saved activity is "default", reset existing default activity to "non-default"
            if activity.get("default", False) is True:
                self.activities.update({'default': False})
            if self.activities.search(self.query.name == name) == []:
                self.activities.insert(activity)
            else:
                self.activities.update(activity, self.query.name == activity["name"])

    def delete(self, name):
        with self.lock: 
            activities = self.activities.search(self.query.name == name)
            if len(activities) > 0:
                activity = activities[0]
                if activity.get("default", False) is True:
                    self.activities.update({'default': True}, self.query.stock == True)
                self.activities.remove(self.query.name == activity["name"])

    def list(self):
        with self.lock: 
            return self.activities.all()