import subprocess
import datetime

import parse
from timeout_decorator import timeout, TimeoutError
import pandas
from bokeh.plotting import figure, ColumnDataSource, curdoc

MAX_PING = 500
MAX_TABLE_LENGTH = 20


@timeout(seconds=MAX_PING/1e3)
def _ping(host='google.com'):
    r = subprocess.run(['ping', '-c', '1', host], stdout=subprocess.PIPE)
    time_str = r.stdout.decode('utf-8').split('\n')[1].split(' ')[-2]
    return float(parse.parse('time={}', time_str)[0])


def ping(**kwargs):
    try:
        p = _ping(**kwargs)
    except TimeoutError:
        p = 'NaN'
    return p


def make_doc(doc):
    source = ColumnDataSource(
        pandas.DataFrame({
            'time': [],
            'latency': []}))

    def update():
        new = {'time': [datetime.datetime.now()],
               'latency': [ping()]}
        source.stream(pandas.DataFrame(new))

    # Setup line figure
    fig_1 = figure(sizing_mode='scale_width',
                   x_axis_type='datetime')
    fig_1.line(
        source=source,
        x='time',
        y='latency',
        color='black',
        line_width=2,)
    fig_1.xaxis.axis_label = 'Time'
    fig_1.yaxis.axis_label = 'Round-Trip Time to google.com [ms]'
    fig_1.x_range.follow = "end"
    fig_1.x_range.follow_interval = 6e4
    fig_1.x_range.range_padding = 0

    # Setup Document
    doc.title = "High Street Ping"
    doc.add_periodic_callback(update, 200)
    doc.add_root(fig_1)


# Create document
make_doc(curdoc())