'''
# PYTHONPATH="$HOME/evserver:$HOME/amqplib-0.6" 
 ./manage.py runevserver

or
 PYTHONPATH="$HOME/amqplib-0.6:.." DJANGO_SETTINGS_MODULE=django_agentpush.settings
 evserver --listen 127.0.0.1:8080 --framework=django

Beware, static files are served from ./static directory! (relative to current!)
'''

from django.http import HttpResponse
from django.conf import settings

import socket
import datetime
import sys
import time
import os.path
import socket
import evserver.transports
import logging
import cgi
import amqplib.client_0_8 as amqp

logging.getLogger('amqplib').setLevel(logging.INFO) # ignore msgs from there
log = logging.getLogger(os.path.basename(__file__))


def send_amqp_message(msg_body):
    # conn should be cached
    conn = amqp.Connection('localhost', userid='guest', password='guest')
    ch = conn.channel()
    ch.access_request('/data', active=True, write=True)
    ch.exchange_declare('myfan', 'fanout', auto_delete=True)

    cached_publisher_connection = conn
    cached_publisher_channel = ch

    msg = amqp.Message(msg_body, content_type='text/plain')
    cached_publisher_channel.basic_publish(msg, 'myfan')

    ch.close()
    conn.close()

    ch.connection = None
    conn.channels = {}
    conn.connection = None
    conn.transport = None


# that is a raw hack that doesn't scale!
counter = 0
state_cache = []

def index(request):
    global counter
    counter += 1

    referer = request.META.get('HTTP_REFERER', '')
    agent = request.META.get('HTTP_USER_AGENT', '')
    msg = cgi.escape('#%i %s: %r %r' % (counter, datetime.datetime.now().strftime('%Y-%m-%d %H:%M:%S'), agent, referer))
    send_amqp_message(msg)
    state_cache.append(msg)
    if len(state_cache) > 30: state_cache.pop(0) # remove first element

    f = open(os.path.join(settings.STATIC_DIR, 'index.html'), 'rb')
    data = f.read()
    f.close()

    return HttpResponse(data, mimetype="text/html")




def set_ridiculously_high_buffers(sd):
    for flag in [socket.SO_SNDBUF, socket.SO_RCVBUF]:
        for i in range(10):
            bef = sd.getsockopt(socket.SOL_SOCKET, flag)
            sd.setsockopt(socket.SOL_SOCKET, flag, bef*2)
            aft = sd.getsockopt(socket.SOL_SOCKET, flag)
            if aft <= bef or aft >= 16777216: # 16M
                break

def comet(request):
    t = evserver.transports.get_transport(request.GET.get('transport','basic'),
                                      callback=request.GET.get('callback','c0'),
                                      domain=request.GET.get('domain',''))

    # setup the amqp subscriber
    msgs = []
    def callback(msg):
        msgs.append(msg.body)
        msg.channel.basic_ack(msg.delivery_tag)

    t0 = time.time()
    conn = amqp.Connection('localhost', userid='guest', password='guest')

    ch = conn.channel()
    ch.access_request('/data', active=True, read=True)

    ch.exchange_declare('myfan', 'fanout', auto_delete=True)
    qname, _, _ = ch.queue_declare()
    ch.queue_bind(qname, 'myfan')
    ch.basic_consume(qname, callback=callback)

    sd = conn.transport.sock
    sd.setblocking(False)
    set_ridiculously_high_buffers(sd)

    def iterator():
        try:
            yield t.start()
            for msg in state_cache:# feed with the initial state
                yield t.write(msg)

            while ch.callbacks:
                try:
                    while True: # until exception
                        ch.wait()
                except (TypeError,), e:
                    pass

                if not msgs:
                    yield t.write('ping')
                while msgs:
                    msg = msgs.pop(0)
                    yield t.write(msg)

                yield request.environ['x-wsgiorg.fdevent.readable'](conn.transport.sock, 60)
        except GeneratorExit:
            pass

        try:
            ch.close()
        except Exception:
            pass
        try:
            conn.close()
        except Exception:
            pass

        ch.connection = None
        conn.channels = {}
        conn.connection = None
        conn.transport = None

    # build the response
    response = HttpResponse(iterator())
    for k, v in t.get_headers():
        response[k] = v
    return response



def empty(request):
    return HttpResponse('', mimetype="text/html")