#-*- coding: utf-8 -*-
import os
import copy
import binascii

from lodel import logger
from lodel.settings import Settings
from lodel.auth.exceptions import *

__sessions = dict()

def __generate_token():
    return binascii.hexlify(os.urandom(Settings.sessions.tokensize//2))

def _check_token(token):
    if len(token) != Settings.sessions.tokensize:
        raise ClientAuthenticationFailure("Malformed session token")
    if token not in __sessions:
        raise ClientAuthenticationFailure("No session with this token")

def start_session():
    token = __generate_token()
    __sessions[token] = dict()
    _check_token(token)
    logger.debug("New session created")
    return token

def destroy_session(token):
    _check_token(token)
    del(__sessions[token])
    logger.debug("Session %s destroyed" % token)

def restore_session(token):
    _check_token(token)
    logger.debug("Restoring session : %s" %__sessions[token])
    return __sessions[token]

def save_session(token, datas):
    _check_token(token)
    __sessions[token] = copy.copy(datas)
    logger.debug("Session saved")