import threading
from datetime import timedelta
import time

import flask
from flask import Flask, Response, redirect, url_for, request, session, abort
from flask.ext.login import LoginManager, UserMixin,
                                login_required, login_user, logout_user

class ResettableTimer(threading.Timer):
    """Call a function after a specified number of seconds:

            t = Timer(30.0, f, args=None, kwargs=None)
            t.start()
            t.reset()      # after starting, it reset the time back to 0
            t.cancel()     # stop the timer's action if it's still waiting


    """

    def __init__(self, interval, function, args=None, kwargs=None):
        super().__init__(interval, function, args, kwargs)
        self.daemon = True
        self.time_to_wait_per_cycle = 0.3
        self.time_to_wait = interval

    def reset(self):
        if not self.finished.is_set():
            self.time_to_wait = self.interval

    def run(self):
        while self.time_to_wait > 0 and not self.finished.is_set():
            s = time.perf_counter()
            self.finished.wait(self.time_to_wait_per_cycle)
            self.time_to_wait -= time.perf_counter() - s

        if not self.finished.is_set():
            self.function(*self.args, **self.kwargs)
        self.finished.set()

app = Flask(__name__)

# config
app.config.update(
    DEBUG = True,
    SECRET_KEY = 'secret_xxx'
)

# flask-login
login_manager = LoginManager()
login_manager.init_app(app)


# silly user model
class User(UserMixin):

    def __init__(self, id):
        self.id = id
        self.name = "user" + str(id)
        self.password = self.name + "_secret"

    def __repr__(self):
        return "%d/%s/%s" % (self.id, self.name, self.password)


# create some users with ids 1 to 20
users = [User(id) for id in range(1, 21)]

# some protected url
@app.route('/')
@login_required
def home():
    return Response("Hello World!")

@app.route("/foo")
@login_required
def foo():
    try:
        session['counter'] += 1
    except Exception:
        session['counter'] = 1
    return Response("Hello world %d" % (session['counter'],))

# somewhere to login
@app.route("/login", methods=["GET", "POST"])
def login():

    user = User(1)
    login_user(user)

    @flask.copy_current_request_context
    def auto_logout():
        print("auto logout")
        logout_user()
        flask.session.clear()

    auto_logout_timer = ResettableTimer(10, auto_logout)
    auto_logout_timer.start()
    return "<p>OK</p>", 200#redirect(request.args.get("next"))


# somewhere to logout
@app.route("/logout")
@login_required
def logout():
    logout_user()
    return Response('<p>Logged out</p>')


# callback to reload the user object
@login_manager.user_loader
def load_user(userid):
    return User(userid)


if __name__ == "__main__":
    app.run()