#!/usr/bin/python
"""
Copyright (C) 2012 struktur AG
http://www.strukturag.com

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 tornado.httpserver
import tornado.websocket
import tornado.ioloop
import tornado.web

import os
import sys

try:
    import json
except ImportError:
    import simplejson as json

# Globals
dataGrabbers = {}
dataGrabbed = {}
CLIENT_ROOT = os.path.abspath(os.path.normpath(os.path.join(os.path.dirname(__file__), "..", "client")))


class Grabber(object):

    keys = [
    "collisions",
    "multicast",
    "rx_bytes",
    "rx_compressed",
    "rx_crc_errors",
    "rx_dropped",
    "rx_errors",
    "rx_fifo_errors",
    "rx_frame_errors",
    "rx_length_errors",
    "rx_missed_errors",
    "rx_over_errors",
    "rx_packets",
    "tx_aborted_errors",
    "tx_bytes",
    "tx_carrier_errors",
    "tx_compressed",
    "tx_dropped",
    "tx_errors",
    "tx_fifo_errors",
    "tx_heartbeat_errors",
    "tx_packets",
    "tx_window_errors"
    ]

    def __init__(self, interface):
        self.interface = interface
        self.base = "/sys/class/net/%s/statistics" % interface

    def grab(self):

        data = {}
        for k in self.keys:
            data[k] = self.read(k)

        dataGrabbed[self.interface]=data

    def read(self, key):
        data = 0
        fn = os.path.join(self.base, key)
        if os.path.exists(fn):
            fp = file(fn, "rb")
            try:
                data = fp.read()
            finally:
                fp.close()
            data = int(data.strip())
        return data


class WSHandler(tornado.websocket.WebSocketHandler):

    dataSender = None
    dataInterface = None

    def open(self):

        interface = self.dataInterface = self.get_argument("if", "eth0").lower()

        grabber = dataGrabbers.get(interface, None)
        if grabber is None:
            # create new grabber
            print >>sys.stdout, "Starting grabber for %s." % interface
            callback = Grabber(interface)
            grabber = tornado.ioloop.PeriodicCallback(callback.grab, 240)
            grabber.start()
            dataGrabbers[interface]=[1, grabber]
        else:
            dataGrabbers[interface][0] = grabber[0]+1

        sender = self.dataSender = tornado.ioloop.PeriodicCallback(self.doSendData, 500)
        sender.start()

    def on_message(self, message):
        pass

    def on_close(self):

        self.dataSender.stop()
        self.dataSender = None

        grabber = dataGrabbers.get(self.dataInterface, None)
        if grabber is not None:
            dataGrabbers[self.dataInterface][0] = grabber[0]-1
            if grabber[0] <= 0:
                print >>sys.stdout, "Stopping grabber for %s." % self.dataInterface
                grabber[1].stop()
                del dataGrabbers[self.dataInterface]

    def doSendData(self):

        data = {
            self.dataInterface: dataGrabbed.get(self.dataInterface, {})
        }
        self.write_message(json.dumps(data))


class ClientHandler(tornado.web.RequestHandler):

    def get(self, filename):

        if not filename or filename == "index.html":
            filename = "realtimetraffic.html"

        fn = os.path.abspath(os.path.join(CLIENT_ROOT, os.path.normpath(filename)))
        if not fn.startswith(CLIENT_ROOT):
            raise tornado.web.HTTPError(404)
        if not os.path.isfile(fn):
            raise tornado.web.HTTPError(404)
        fp = file(fn, "rb")
        try:
            self.write(fp.read())
        finally:
            fp.close()


def main(listen="127.0.0.1:8088"):

    from optparse import OptionParser

    parser = OptionParser()
    parser.add_option("-l", "--listen", dest="listen", help="listen address (default: [%s])" % listen, default=listen)
    parser.add_option("--ssl_keyfile", dest="ssl_keyfile", help="SSL key file", metavar="FILE")
    parser.add_option("--ssl_certfile", dest="ssl_certfile", help="SSL certificate file", metavar="FILE")

    (options, args) = parser.parse_args()

    if ":" in options.listen:
        address, port = options.listen.split(":", 1)
        port = int(port)
        listen = options.listen
    else:
        address = options.listen
        port = 8088
        listen = "%s:%s" % (address, port)

    application = tornado.web.Application([
        (r'^/realtimetraffic$', WSHandler),
        (r'^/css/(.*)$', tornado.web.StaticFileHandler, {'path': os.path.join(CLIENT_ROOT, 'css')}),
        (r'^/scripts/(.*)$', tornado.web.StaticFileHandler, {'path': os.path.join(CLIENT_ROOT, 'scripts')}),
        (r'^/img/(.*)$', tornado.web.StaticFileHandler, {'path': os.path.join(CLIENT_ROOT, 'img')}),
        (r'^/(.*)$', ClientHandler)
    ], debug=False, static_path=CLIENT_ROOT)

    params = {}
    ssl = False
    if options.ssl_keyfile and options.ssl_certfile:
        if not os.path.isfile(options.ssl_keyfile):
            print >>sys.stderr, "SSL key file not found: %s" % options.ssl_keyfile
            return 1
        if not os.path.isfile(options.ssl_certfile):
            print >>sys.stderr, "SSL certificate file not found: %s" % options.ssl_certfile
            return 1
        params["ssl_options"] = {
            "keyfile": options.ssl_keyfile,
            "certfile": options.ssl_certfile
        }
        ssl = True

    http_server = tornado.httpserver.HTTPServer(application, **params)
    http_server.listen(port=port, address=address)
    print >>sys.stdout, "Server running on %s (ssl:%r) ..." % (listen, ssl)
    try:
        tornado.ioloop.IOLoop.instance().start()
    except KeyboardInterrupt:
        pass
    print >>sys.stdout, "Server stopped."
    return 0

if __name__ == "__main__":
    status = main()
    sys.exit(status)