# -*- encoding: UTF-8 -*-
#

import datetime
from models.db import User, session as db_session
from models.forms import LoginForm
from flask import render_template, request, url_for, session, Module, redirect

auth = Module(__name__)

SESSION_KEY = 'auth_session'

UNKNOWN_EMAIL_MESSAGE = 'Unknown e-mail address'
INCORRECT_PASSWORD_MESSAGE = 'Incorrect password'

def check_credentials(email, password):
    """
    Verifies credentials for email and password.
    Returns user id on successful login else returns the error message.
    """
    try:
        user = User.query.filter_by(email=email).one()
    except: # no user found
        return UNKNOWN_EMAIL_MESSAGE
    if user._encrypt_password(password) == user.password: # select the first record and encrypt pass
        return user.id # successful login
    else:
        return INCORRECT_PASSWORD_MESSAGE

def check_auth(func):
    """
    A decorator which checks whether the user is logged in or not.
    """
    def wrap_f(*args, **kwargs):
        if session.get(SESSION_KEY, None): # user is logged in
            func(*args, **kwargs)
        else:
            return redirect(url_for('auth.login', redir=request.url))
    return wrap_f

def auth_conditions(*conditions):
    """
    Specify some conditions for the auth
    """
    def wrap(func):
        def wrap_f(*args, **kwargs):
            for condition in conditions:
                if not condition():
                    abort(403)
            func(*args, **kwargs)
        return wrap_f
    return wrap

def user_id():
    """
    Return the user id
    """
    return session.get(SESSION_KEY) # get userid from session

# Conditions are callables that return True
# if the user fulfills the conditions they define, False otherwise
#

def is_admin():
    """
    Tell if the user is an administrator
    """
    return User.get_by(id=session[SESSION_KEY]).is_admin

def account_not_expired():
    """
    Make sure that the account hasn't yet expired
    """
    return User.get_by(id=session[SESSION_KEY]).days_left() is not 0


### The controller functions

def on_login(user_id):
    """Called on successful login"""
    user = User.get_by(id=user_id)
    user.last_login = datetime.datetime.now() # set the last_login date/time
    db_session.commit()

def on_logout(user_id):
    """Called on logout"""

@auth.route('/login', methods=['POST', 'GET'])
def login():
    """
    Log the user in.
    """
    form = LoginForm()

    if form.validate_on_submit():
        check = check_credentials(form.email.data, form.password.data)
        if check == UNKNOWN_EMAIL_MESSAGE:
            form.email.errors.append(UNKNOWN_EMAIL_MESSAGE)
        elif check == INCORRECT_PASSWORD_MESSAGE:
            form.password.errors.append(INCORRECT_PASSWORD_MESSAGE)
        else:
            session[SESSION_KEY] = check # put the user id

            if form.remember_me.data == True: # if remember_me is set
                session[SESSION_KEY].permanent = True # set cookie for 31 days

            on_login(check)
            return redirect(request.args.get('redir', url_for('site.index')))

    return render_template('auth/login.html', form=form)

@auth.route('/logout')
def logout():
    """
    Log the user out deleting the session key.
    """
    session.pop(SESSION_KEY, None)
    on_logout(user_id)
    return redirect(url_for('site.index')) # redirect to homepage