#!/usr/bin/env python
# -*- coding: utf-8 -*-

"""Displays network traffic
   * No extra configuration needed
"""

import psutil
import netifaces

import core.module
import core.widget

import util.format

WIDGET_NAME = 'network_traffic'

class Module(core.module.Module):
    def __init__(self, config, theme):
        widgets = [
            core.widget.Widget(module=self, name='{0}.rx'.format(WIDGET_NAME), full_text=self.download_rate),
            core.widget.Widget(module=self, name='{0}.tx'.format(WIDGET_NAME), full_text=self.upload_rate)
        ]
        super().__init__(config, theme, widgets)

        self.widgets()[0].set('theme.minwidth', '0000000KiB/s')
        self.widgets()[1].set('theme.minwidth', '0000000KiB/s')

        try:
            self._bandwidth = BandwidthInfo()

            self._rate_recv = '?'
            self._rate_sent = '?'
            self._bytes_recv = self._bandwidth.bytes_recv()
            self._bytes_sent = self._bandwidth.bytes_sent()
        except Exception:
            """ We do not want do explode anything """
            pass

    def state(self, widget):
        """Return the widget state"""

        if widget.name == '{}.rx'.format(WIDGET_NAME):
            return 'rx'
        elif widget.name == '{}.tx'.format(WIDGET_NAME):
            return 'tx'

        return None

    def update(self):
        try:
            bytes_recv = self._bandwidth.bytes_recv()
            bytes_sent = self._bandwidth.bytes_sent()

            self._rate_recv = (bytes_recv - self._bytes_recv)
            self._rate_sent = (bytes_sent - self._bytes_sent)

            self._bytes_recv, self._bytes_sent = bytes_recv, bytes_sent
        except Exception:
            """ We do not want do explode anything """
            pass

    def download_rate(self, _):
        return '{}/s'.format(util.format.byte(self._rate_recv))

    def upload_rate(self, _):
        return '{}/s'.format(util.format.byte(self._rate_sent))

class BandwidthInfo(object):
    """Get received/sent bytes from network adapter"""

    def bytes_recv(self):
        """Return received bytes"""
        return self.bandwidth().bytes_recv

    def bytes_sent(self):
        """Return sent bytes"""
        return self.bandwidth().bytes_sent

    def bandwidth(self):
        """Return bandwidth information"""
        io_counters = self.io_counters()
        return io_counters[self.default_network_adapter()]

    @classmethod
    def default_network_adapter(cls):
        """Return default active network adapter"""
        gateway = netifaces.gateways()['default']

        if not gateway:
            raise 'No default gateway found'

        return gateway[netifaces.AF_INET][1]

    @classmethod
    def io_counters(cls):
        """Return IO counters"""
        return psutil.net_io_counters(pernic=True)

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