import django
import threading
from django.core.management.commands.runserver import Command as RunserverCommand
from django.core.management import CommandError
from django.core.handlers.wsgi import WSGIHandler
from django.http import HttpResponse
from channels import Channel, channel_backends, DEFAULT_CHANNEL_BACKEND
from channels.worker import Worker
from channels.utils import auto_import_consumers
from channels.adapters import UrlConsumer


class Command(RunserverCommand):

    def get_handler(self, *args, **options):
        """
        Returns the default WSGI handler for the runner.
        """
        django.setup()
        return WSGIInterfaceHandler()

    def run(self, *args, **options):
        # Force disable reloader for now
        options['use_reloader'] = False
        # Check a handler is registered for http reqs
        channel_backend = channel_backends[DEFAULT_CHANNEL_BACKEND]
        auto_import_consumers()
        if not channel_backend.registry.consumer_for_channel("django.wsgi.request"):
            # Register the default one
            channel_backend.registry.add_consumer(UrlConsumer(), ["django.wsgi.request"])
        # Launch a worker thread
        worker = WorkerThread(channel_backend)
        worker.daemon = True
        worker.start()
        # Run the rest
        return super(Command, self).run(*args, **options)


class WSGIInterfaceHandler(WSGIHandler):
    """
    New WSGI handler that pushes requests to channels.
    """

    def get_response(self, request):
        request.response_channel = Channel.new_name("django.wsgi.response")
        Channel("django.wsgi.request").send(**request.channel_encode())
        channel, message = channel_backends[DEFAULT_CHANNEL_BACKEND].receive_many([request.response_channel])
        return HttpResponse.channel_decode(message)


class WorkerThread(threading.Thread):
    """
    Class that runs a worker
    """

    def __init__(self, channel_backend):
        super(WorkerThread, self).__init__()
        self.channel_backend = channel_backend

    def run(self):
        Worker(channel_backend=self.channel_backend).run()