import os
import tornado.ioloop
import tornado.web
import tornado.websocket
import tornado.escape
import tornado.gen
import webbrowser

import yaml
import logging

import logging
import threading
import io
from datetime import timedelta
from contextlib import contextmanager

logger = logging.getLogger(__name__)
logger.setLevel(logging.INFO)

class VisualizationElement:
	"""
    Defines an element of the visualization.
    Attributes:
        package_includes: A list of external JavaScript files to include that
                          are part of the packages.
        local_includes: A list of JavaScript files that are local to the
                        directory that the server is being run in.
        js_code: A JavaScript code string to instantiate the element.
    Methods:
        render: Takes a model object, and produces JSON data which can be sent
                to the client.
    """

	package_includes = []
	local_includes = []
	js_code = ''
	render_args = {}

	def __init__(self):
		pass

	def render(self, model):
		return '<b>VisualizationElement goes here</b>.'


class PageHandler(tornado.web.RequestHandler):
	""" Handler for the HTML template which holds the visualization. """

	def get(self):
		self.render('index.html', port=self.application.port,
					model_name=self.application.model_name,
					package_includes=self.application.package_includes,
					local_includes=self.application.local_includes,
					scripts=self.application.js_code)


class SocketHandler(tornado.websocket.WebSocketHandler):

	def open(self):
		if self.application.verbose:
			logger.info('Socket opened!')
		

	def check_origin(self, origin):
		return True

	def on_message(self, message):
		""" Receiving a message from the websocket, parse, and act accordingly. """

		msg = tornado.escape.json_decode(message)

		if msg['type'] == 'config_file':

			if self.application.verbose:
				print(msg['data'])

			config = list(yaml.load_all(msg['data']))

			if len(config) > 1:
				error = 'Please, provide only one configuration.'
				if self.application.verbose:
					logger.error(error)
				self.write_message({'type': 'error',
					'error': error})
				return
			else:
				config = config[0]
				self.send_log('INFO.soil', 'Using config: {name}'.format(name=config['name']))

			self.name = config['name']
			
			with self.logging(self.application.model.name):
				self.application.model.run(config)

			trials = []
			for i in range(config['num_trials']):
				trials.append('{}_trial_{}'.format(self.name, i))
			self.write_message({'type': 'trials',
				'data': trials })

		elif msg['type'] == 'get_trial':
			if self.application.verbose:
				logger.info('Trial {} requested!'.format(msg['data']))
			self.send_log('INFO.user', 'Trial {} requested!'.format(msg['data']))
			self.write_message({'type': 'get_trial',
				'data': self.application.model.get_trial(self.name, msg['data']) })

		else:
			if self.application.verbose:
				logger.info('Unexpected message!')

	def update_logging(self):
		try:
			if (not self.log_capture_string.closed and self.log_capture_string.getvalue()):
				self.send_log('INFO.soil', self.log_capture_string.getvalue())
				self.log_capture_string.truncate(0)
				self.log_capture_string.seek(0)
		finally:
			if self.capture_logging:
				thread = threading.Timer(0.01, self.update_logging)
				thread.start()

	def on_close(self):
		logger.info('Socket closed!')

	def send_log(self, logger, logging):
		self.write_message({'type': 'log',
			'logger': logger,
			'logging': logging })

	@contextmanager
	def logging(self, logger):
		self.capture_logging = True
		self.logger_application = logging.getLogger(logger)
		self.log_capture_string = io.StringIO()
		ch = logging.StreamHandler(self.log_capture_string)
		self.logger_application.addHandler(ch)
		self.update_logging()
		yield self.capture_logging

		self.capture_logging = False
		self.log_capture_string.close()
		self.logger_application.removeHandler(ch)
		return self.capture_logging
	


class ModularServer(tornado.web.Application):
	""" Main visualization application. """

	portrayal_method = None
	port = 8001
	model_args = ()
	model_kwargs = {}
	page_handler = (r'/', PageHandler)
	socket_handler = (r'/ws', SocketHandler)
	static_handler = (r'/(.*)', tornado.web.StaticFileHandler,
					  {'path': 'templates'})
	local_handler = (r'/local/(.*)', tornado.web.StaticFileHandler,
					 {'path': ''})

	handlers = [page_handler, socket_handler, static_handler, local_handler]
	settings = {'debug': True,
				'template_path': os.path.dirname(__file__) + '/templates'}

	def __init__(self, model, visualization_element, name='SOIL Model', verbose=True,
				 *args, **kwargs):
		
		self.verbose = verbose
		self.package_includes = set()
		self.local_includes = set()
		self.js_code = []
		
		self.visualization_element = visualization_element

		self.model_name = name
		self.model = model
		self.model_args = args
		self.model_kwargs = kwargs
		#self.reset_model()

		# Initializing the application itself:
		super().__init__(self.handlers, **self.settings)

	'''
	def reset_model(self):
		self.model = self.model_cls(*self.model_args, **self.model_kwargs)
	'''

	def render_model(self):
		return self.visualization_element.render(self.model)

	def launch(self, port=None):
		""" Run the app. """
		
		if port is not None:
			self.port = port
		url = 'http://127.0.0.1:{PORT}'.format(PORT=self.port)
		print('Interface starting at {url}'.format(url=url))
		self.listen(self.port)
		# webbrowser.open(url)
		tornado.ioloop.IOLoop.instance().start()