#!/usr/bin/env python
from json import dumps, loads
import os,sys,argparse, urllib.request, urllib.error, urllib.parse
import websocket
import time
import uuid
import logging
import threading
from kombu import Connection, Exchange, Queue

class Umbra:
	logger = logging.getLogger('umbra.Umbra')
	def __init__(self, websocket_url, amqp_url):
		self.cmd_id = 0
		self.producer = None
		self.browser_lock = threading.Lock()
		self.amqp_url = amqp_url
		self.producer_lock = threading.Lock()
		self.websocket_url = websocket_url
		self.websock = websocket.WebSocketApp(websocket_url, on_message = self.handle_message)
		self.amqp_thread = threading.Thread(target=self.consume_amqp)
		self.amqp_stop = threading.Event()
		self.websock.on_open = lambda ws: self.amqp_thread.start()
		threading.Thread(target=self.websock.run_forever).start()

	def shutdown(self):
		self.logger.info("shutting down amqp consumer {}".format(self.amqp_url))
		self.amqp_stop.set()
		self.logger.info("shutting down websocket {}".format(self.websocket_url))
		self.websock.close()
		self.amqp_thread.join()

	def handle_message(self, ws, message):
		# self.logger.debug("handling message from websocket {} - {}".format(ws, message))
		message = loads(message)
		if "method" in message.keys() and message["method"] == "Network.requestWillBeSent":
			request_queue = Queue('requests',  routing_key='request', 
					exchange=self.umbra_exchange)
			with self.producer_lock:
				self.producer.publish(message['params']['request'], 
						routing_key='request', exchange=self.umbra_exchange, 
						declare=[request_queue])

	def consume_amqp(self):
		self.umbra_exchange = Exchange('umbra', 'direct', durable=True)
		url_queue = Queue('urls', routing_key='url', exchange=self.umbra_exchange)
		self.logger.info("connecting to amqp {} at {}".format(repr(self.umbra_exchange), self.amqp_url))
		with Connection(self.amqp_url) as conn:
			self.producer = conn.Producer(serializer='json')
			with conn.Consumer(url_queue, callbacks=[self.fetch_url]) as consumer:
				import socket
				while not self.amqp_stop.is_set():
					try:
						conn.drain_events(timeout=0.5)
					except socket.timeout:
						pass

	def send_command(self, **kwargs):
		self.logger.debug("sending command kwargs={}".format(kwargs))
		command = {}
		command.update(kwargs)
		self.cmd_id += 1
		command['id'] = self.cmd_id
		self.websock.send(dumps(command))

	def fetch_url(self, body, message):
		self.logger.debug("body={} message={} message.headers={} message.payload={}".format(body, message, message.headers, message.payload))

		url = body['url']

		with self.browser_lock:
			self.send_command(method="Network.enable")
			self.send_command(method="Runtime.evaluate", params={"expression":"document.location = '%s';" % url})

			# XXX more logic goes here
			time.sleep(10)

			message.ack()

class Chrome():
	logger = logging.getLogger('umbra.Chrome')

	def __init__(self, port, executable, browser_wait):
		self.port = port
		self.executable = executable
		self.browser_wait = browser_wait

	def fetch_debugging_json():
		raw_json = urllib.request.urlopen("http://localhost:%s/json" % self.port).read()
		json = raw_json.decode('utf-8')
		return loads(json)

	def __enter__(self):
		import subprocess
		chrome_args = [self.executable, "--temp-profile",
				"--remote-debugging-port=%s" % self.port,
				"--disable-web-sockets", "--disable-cache",
				"--window-size=1100,900", "--enable-logging"
				"--homepage=about:blank", "about:blank"]
		self.logger.info("running {}".format(chrome_args))
		self.chrome_process = subprocess.Popen(chrome_args)
		self.logger.info("chrome running, pid {}".format(self.chrome_process.pid))
		start = time.time()

		json_url = "http://localhost:%s/json" % self.port
		while True:
			try:
				raw_json = urllib.request.urlopen(json_url).read()
				all_debug_info = loads(raw_json.decode('utf-8'))
				debug_info = [x for x in all_debug_info if x['url'] == 'about:blank']

				if debug_info and 'webSocketDebuggerUrl' in debug_info[0]:
					self.logger.debug("{} returned {}".format(json_url, raw_json))
					url = debug_info[0]['webSocketDebuggerUrl']
					self.logger.info('got chrome window websocket debug url {} from {}'.format(url, json_url))
					return url
			except:
				pass
			finally:
				if time.time() - start > float(self.browser_wait):
					raise Exception("failed to retrieve {} after {} seconds".format(json_url, time.time() - start))
				else:
					time.sleep(0.5)

	def __exit__(self, *args):
		self.logger.info("killing chrome pid {}".format(self.chrome_process.pid))
		self.chrome_process.kill()

def main():
	# logging.basicConfig(stream=sys.stdout, level=logging.INFO,
	logging.basicConfig(stream=sys.stdout, level=logging.DEBUG,
			format='%(asctime)s %(process)d %(levelname)s %(threadName)s %(name)s.%(funcName)s(%(filename)s:%(lineno)d) %(message)s')

	arg_parser = argparse.ArgumentParser(prog=os.path.basename(sys.argv[0]),
			description='umbra - Browser automation tool',
			formatter_class=argparse.ArgumentDefaultsHelpFormatter)
	arg_parser.add_argument('-w', '--browser-wait', dest='browser_wait', default='10',
			help='Seconds to wait for browser initialization')
	arg_parser.add_argument('-e', '--executable', dest='executable', default='chromium-browser',
			help='Executable to use to invoke chrome')
	arg_parser.add_argument('-p', '--port', dest='port', default='9222',
			help='Port to have invoked chrome listen on for debugging connections')
	arg_parser.add_argument('-u', '--url', dest='amqp_url', default='amqp://guest:guest@localhost:5672//',
			help='URL identifying the amqp server to talk to')
	args = arg_parser.parse_args(args=sys.argv[1:])
	with Chrome(args.port, args.executable, args.browser_wait) as websocket_url:
		umbra = Umbra(websocket_url, args.amqp_url)
		try:
			while True:
				time.sleep(0.5)
		except:
			pass
		finally:
			umbra.shutdown()


if __name__ == "__main__":
	main()