#!/usr/bin/env python
# coding: utf-8
#
# Copyright 2010 Alexandre Fiori
# based on the original Tornado by Facebook
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.

import sys
import cyclone.web
import cyclone.auth
import cyclone.escape
from twisted.python import log
from twisted.internet import reactor

import os.path
import uuid


class Application(cyclone.web.Application):
    def __init__(self):
        handlers = [
            (r"/", MainHandler),
            (r"/auth/login", AuthLoginHandler),
            (r"/auth/logout", AuthLogoutHandler),
            (r"/a/message/new", MessageNewHandler),
            (r"/a/message/updates", MessageUpdatesHandler),
        ]
        settings = dict(
            cookie_secret="43oETzKXQAGaYdkL5gEmGeJJFuYh7EQnp2XdTP1o/Vo=",
            login_url="/auth/login",
            template_path=os.path.join(os.path.dirname(__file__), "templates"),
            static_path=os.path.join(os.path.dirname(__file__), "static"),
            xsrf_cookies=True,
            autoescape=None,
        )
        cyclone.web.Application.__init__(self, handlers, **settings)


class BaseHandler(cyclone.web.RequestHandler):
    def get_current_user(self):
        user_json = self.get_secure_cookie("user")
        if not user_json:
            return None
        return cyclone.escape.json_decode(user_json)


class MainHandler(BaseHandler):
    @cyclone.web.authenticated
    def get(self):
        self.render("index.html", messages=MessageMixin.cache)


class MessageMixin(object):
    waiters = []
    cache = []
    cache_size = 200

    def wait_for_messages(self, callback, cursor=None):
        cls = MessageMixin
        if cursor:
            index = 0
            for i in xrange(len(cls.cache)):
                index = len(cls.cache) - i - 1
                if cls.cache[index]["id"] == cursor:
                    break
            recent = cls.cache[index + 1:]
            if recent:
                callback(recent)
                return
        cls.waiters.append(callback)

    def new_messages(self, messages):
        cls = MessageMixin
        log.msg("Sending new message to %r listeners" % len(cls.waiters))
        for callback in cls.waiters:
            try:
                callback(messages)
            except:
                log.err()
        cls.waiters = []
        cls.cache.extend(messages)
        if len(cls.cache) > self.cache_size:
            cls.cache = cls.cache[-self.cache_size:]


class MessageNewHandler(BaseHandler, MessageMixin):
    @cyclone.web.authenticated
    def post(self):
        message = {
            "id": str(uuid.uuid4()),
            "from": self.current_user["first_name"],
            "body": self.get_argument("body"),
        }
        message["html"] = self.render_string("message.html", message=message)
        if self.get_argument("next", None):
            self.redirect(self.get_argument("next"))
        else:
            self.write(message)
        self.new_messages([message])


class MessageUpdatesHandler(BaseHandler, MessageMixin):
    @cyclone.web.authenticated
    @cyclone.web.asynchronous
    def post(self):
        cursor = self.get_argument("cursor", None)
        self.wait_for_messages(self.on_new_messages, cursor=cursor)

    def on_new_messages(self, messages):
        # Closed client connection
        #if self.request.connection.stream.closed():
            #return
        self.finish(dict(messages=messages))


class AuthLoginHandler(BaseHandler, cyclone.auth.GoogleMixin):
    @cyclone.web.asynchronous
    def get(self):
        if self.get_argument("openid.mode", None):
            self.get_authenticated_user(self._on_auth)
            return
        self.authenticate_redirect(ax_attrs=["name"])

    def _on_auth(self, user):
        if not user:
            raise cyclone.web.HTTPError(500, "Google auth failed")
        self.set_secure_cookie("user", cyclone.escape.json_encode(user))
        self.redirect("/")


class AuthLogoutHandler(BaseHandler):
    def get(self):
        self.clear_cookie("user")
        self.write("You are now logged out")


def main():
    reactor.listenTCP(8888, Application())
    reactor.run()


if __name__ == "__main__":
    log.startLogging(sys.stdout)
    main()