import hashlib
import json


class DB:
    def __init__(self):
        self.database = {}
        self.emails = []

    def ensure_username(self, data):
        if hasattr(data, 'username'):
            return data.get['username']
        elif hasattr(data, 'email'):
            return self.emails[data.get['username']]

    @staticmethod
    def hash_password(password):
        salt = "your_secret_salt"
        hashed_password = hashlib.sha256((password + salt).encode()).hexdigest()
        return hashed_password

    def add_user(self, data):
        username = data.get['username']
        password = data.get['password']
        email = data.get['email']
        hashed_password = self.hash_password(password)
        user_data = {"hashed_password": hashed_password}
        if username not in self.database:
            self.database[username] = user_data
            self.emails[email] = username
            return True
        return False

    def delete_user(self, data):
        username = self.ensure_username(data)
        data = data.get['data']
        if not self.check_credentials(data):
            return False

        del self.database[username]
        for i in self.emails:
            if i == username:
                del i
        self.save_database()
        return True

    def change_data(self, data):
        username = self.ensure_username(data)
        data = data.get['data']
        if not self.check_credentials(data):
            return False

        self.database[username]['data'] = data
        self.save_database()
        return True

    def update_password(self, data):
        username = self.ensure_username(data)
        new_password = data.get['new_password']
        if not self.check_credentials(data):
            return False

        hashed_new_password = self.hash_password(new_password)
        self.database[username].update({"hashed_password": hashed_new_password})
        self.save_database()
        return True

    def check_credentials(self, data):
        username = self.ensure_username(data)
        password = data.get['password']
        if username not in self.database:
            return False

        stored_hashed_password = self.database[username]["hashed_password"]
        entered_hashed_password = self.hash_password(password)
        return stored_hashed_password == entered_hashed_password

    def get_data(self, data):
        username = self.ensure_username(data)
        if not self.check_credentials(data):
            return None

        send_back = self.database[username].get['data']
        return send_back

    def save_database(self):
        with open("database.json", 'w') as file:
            json.dump(self.database, file)

    def load_database(self):
        try:
            with open("database.json", 'r') as file:
                self.database = json.load(file)
        except FileNotFoundError:
            pass