#!/usr/bin/env python
"""Contains Users class which represents the users database"""

from botly.db import Db


class Users(Db):
    
    def __init__(self):
        assert self.is_loaded(), "Db is not loaded upon Users object creation."
        self.userCache = []
        self.root = self.get_node('/BotDb/Knowledge')

    # Shortcut higher level methods:

    def is_master(self, userid):
        """Returns whether or not this user can control the bot."""
        user = self.get(userid)
        if user is not None:
            if user['IsMaster'] == '1':
                return True
        return False

    def affinity(self, userid):
        """Returns the bot affinity to the user."""
        user = self.get(userid)
        if user is not None:
            return int(user['BotAffinity'])
        return 0

    def change_affinity(self, userid, delta):
        """Increase or decrease the affinity with the user."""
        curr = self.affinity(userid)
        return self.set(userid, 'BotAffinity', str(curr + delta))

    # Low level methods:

    def get(self, userid):
        """Returns the user with given ID or None if it does not exist."""
        user = self._get_cached_user(userid)
        if user is None:
            user = self.query_object('Users', userid)
        return user

    def set(self, userid, valueName, value):
        """Modify the user valueName with given value."""
        user = self.get(userid)
        if user is not None:
            user[valueName] = value
            return self.store_object('Users', user) 
        return False

    def get_all(self):
        """Returns all users from the database."""
        users = self.query_object_list('Users')
        self.userCache.clear()
        self.userCache = users
        return users

    # Internal methods

    def _new_user(self, userid):
        # TODO
        pass

    def _get_cached_user(self, userid):
        """Returns the cached user if it exists, None otherwise."""
        for user in self.userCache:
            if user['Id'] == userid:
                return user
        return None