#!/usr/bin/env python3

# Copyright 2020 Nathaniel Clark <nathaniel.clark@misrule.us>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU Library General Public License as published by
# the Free Software Foundation; version 2 only
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Library General Public License for more details.
#
# You should have received a copy of the GNU Library General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
#

"""
=head1 NAME

arris-sb6183 - Health monitoring plugin for Arris SB6183 Cable Modem

=head1 DESCRIPTION

This provides the following multigraphs:
* upstream and downstream power levels
* downstream signal to noise ratio
* downstream error counts
* uptime

The values are retrieved from the cable modem's status web pages at
192.168.100.1. So, this plugin must be installed on a munin node
which can access those pages.

=head1 CONFIGURATION

Make sure 192.168.100.1 is accessible through your firewall.

To have this register with munin as it's own host set the "env.hostname" in config.
Also ensure that the hostname set is listed in munin.conf.

[arris*]
env.hostname modem

=head1 TESTING

Developed and tested with:
firmware:         D30CM-OSPREY-2.4.0.1-GA-02-NOSH
hardware version: 1

=head1 VERSION

0.0.1

=head1 AUTHOR

Nathaniel Clark <nathaniel.clark@misrule.us>

=head1 LICENSE

GPLv2

=head1 MAGIC MARKERS

 #%# family=contrib
 #%# capabilities=autoconf

=cut
"""

import re
import os
import sys
from urllib import request

HOSTNAME = os.getenv("hostname", None)
STATUS_URL = "http://192.168.100.1/RgConnect.asp"
INFO_URL = "http://192.168.100.1/RgSwInfo.asp"
UPCOUNT = 4
DOWNCOUNT = 16

if len(sys.argv) == 2:
    if sys.argv[1] == "config":
        if HOSTNAME:
            print("host_name {0}\n".format(HOSTNAME))

        # UPTIME
        print(
            """multigraph arris_uptime
graph_title Modem Uptime
graph_category system
graph_args --base 1000 -l 0
graph_vlabel uptime in days
graph_scale no
graph_category system
graph_info This graph shows the number of days that the the host is up and running so far.
uptime.label uptime
uptime.info The system uptime itself in days.
uptime.draw AREA
"""
        )

        # POWER
        print(
            """multigraph arris_power
graph_title Arris Power (dBmV)
graph_vlabel Power (dBmV)
graph_category network"""
        )
        for i in range(1, DOWNCOUNT + 1):
            print("down_{0}.label Down Ch {1}".format(i, i))
            print("down_{0}.type GAUGE".format(i))
            print("down_{0}.draw LINE1".format(i))
        for i in range(1, UPCOUNT + 1):
            print("up_{0}.label Up Ch {1}".format(i, i))
            print("up_{0}.type GAUGE".format(i))
            print("up_{0}.draw LINE1".format(i))

        for i in range(1, DOWNCOUNT + 1):
            name = "down_{0}".format(i)
            print("\nmultigraph arris_power.{0}".format(name))
            print("graph_title Downstream Power for Channel {0} (dBmV)".format(i))
            print("graph_category network")
            print("power.label dBmV")
            print("power.type GAUGE")
            print("power.draw LINE1")
        for i in range(1, UPCOUNT + 1):
            name = "up_{0}".format(i)
            print("\nmultigraph arris_power.{0}".format(name))
            print("graph_title Upstream Power for Channel {0} (dBmV)".format(i))
            print("graph_category network")
            print("power.label dBmV")
            print("power.type GAUGE")
            print("power.draw LINE1")

        # SNR
        print("\nmultigraph arris_snr")
        print("graph_title Arris Signal-to-Noise Ratio (dB)")
        print("graph_vlabel SNR (dB)")
        print("graph_category network")
        for i in range(1, DOWNCOUNT + 1):
            print("down_{0}.label Ch {1}".format(i, i))
            print("down_{0}.type GAUGE".format(i))
            print("down_{0}.draw LINE1".format(i))

        for i in range(1, DOWNCOUNT + 1):
            name = "down_{0}".format(i)
            print("\nmultigraph arris_snr.{0}".format(name))
            print("graph_title SNR on Channel {0} (dB)".format(i))
            print("graph_vlabel SNR (dB)")
            print("graph_category network")
            print("snr.label dB")
            print("snr.type GAUGE")
            print("snr.draw LINE1")

        # ERRORS
        print(
            """
multigraph arris_error
graph_title Arris Channel Errors
graph_category network
graph_args --base 1000
graph_vlabel errors/sec
graph_category network
corr.label Corrected
corr.type DERIVE
corr.min 0
uncr.label Uncorrectable
uncr.type DERIVE
uncr.min 0
uncr.warning 1"""
        )

        for i in range(1, DOWNCOUNT + 1):
            name = "down_{0}".format(i)
            print("\nmultigraph arris_error.{0}".format(name))
            print("graph_title Channel {0} Errors".format(i))
            print("graph_args --base 1000")
            print("graph_vlabel errors/sec")
            print("graph_category network")
            print("corr.label Correctable")
            print("corr.type DERIVE")
            print("corr.min 0")
            print("uncr.label Uncorrectable")
            print("uncr.type DERIVE")
            print("uncr.min 0")
            print("uncr.warning 1")

        sys.exit(0)

    if sys.argv[1] == "autoconfig":

        def check(url):
            from lxml import html

            resp = request.urlopen(url)
            html.fromstring("<html>")
            return resp

        try:
            resp = check(STATUS_URL)
        except ImportError:
            print("no (missing lxml module)")
        except OSError:
            print("no (no router)")
        else:
            if resp.status == 200:
                print("yes")
            else:
                print("no (Bad status code: %d)" % resp.status_code)
        sys.exit(0)

rxblank = re.compile(r"[\x00\n\r\t ]+", re.MULTILINE)
rxcomment = re.compile(r"<!--.*?-->")
rxscript = re.compile(r"<script.*?</script>", re.MULTILINE)


def process_url(url):
    """
    Extract simpleTables from page at URL
    """
    from lxml import html

    try:
        resp = request.urlopen(url)
    except OSError:
        print("failed to contact router", file=sys.stderr)
        return []
    if resp.status != 200:
        print(
            "failed to get status page %d: %s" % (resp.status, resp.reason),
            file=sys.stderr,
        )
        return []
    data = rxscript.sub(
        "",
        rxcomment.sub(
            "",
            rxblank.sub(
                " ", "".join(map(lambda x: x.decode("utf-8"), resp.readlines()))
            ),
        ),
    )
    dom = html.fromstring(data)

    return dom.xpath('//table[contains(@class, "simpleTable")]')


print("multi_graph arris_uptime")
arr = process_url(INFO_URL)
if arr:
    trs = arr[1].findall("tr")
    # drop title
    trs.pop(0)

    date = "".join(trs[0].findall("td")[1].itertext()).strip()

    arr = date.split(" ")
    rx = re.compile(r"[hms]")
    days = int(arr[0])
    hms = rx.sub("", arr[2]).split(":")

    seconds = ((days * 24 + int(hms[0])) * 60 + int(hms[1])) * 60 + int(hms[2])
    print("uptime.value {0}".format(seconds / 86400.0))
else:
    print("uptime.value U")


arr = process_url(STATUS_URL)
if arr:
    downstream = arr[1]
    upstream = arr[2]

    trs = downstream.findall("tr")
    # drop title
    trs.pop(0)

    headings = ["".join(x.itertext()).strip() for x in trs.pop(0).findall("td")]
    # ['Channel', 'Lock Status', 'Modulation', 'Channel ID', 'Frequency', 'Power', 'SNR',
    # 'Corrected', 'Uncorrectables']
else:
    trs = []
    headings = []

# Summation Graphs
correct = 0
uncorr = 0
power = {"up": ["U"] * UPCOUNT, "down": ["U"] * DOWNCOUNT}
snr = ["U"] * DOWNCOUNT
for row in trs:
    data = dict(
        zip(headings, ["".join(x.itertext()).strip() for x in row.findall("td")])
    )
    uncorr += int(data["Uncorrectables"])
    correct += int(data["Corrected"])

    channel = int(data["Channel"])

    print("\nmultigraph arris_power.down_{0}".format(channel))
    value = data["Power"].split(" ")[0]
    print("power.value {0}".format(value))
    power["down"][channel - 1] = value

    print("multigraph arris_snr.down_{0}".format(channel))
    value = data["SNR"].split(" ")[0]
    print("snr.value {0}".format(value))
    snr[channel - 1] = value

    print("multigraph arris_error.down_{0}".format(channel))
    print("corr.value {0}".format(data["Corrected"]))
    print("uncr.value {0}".format(data["Uncorrectables"]))

# Fill missing
for i in range(len(trs), DOWNCOUNT):
    print("\nmultigraph arris_power.down_{0}".format(i + 1))
    print("power.value U")

    print("multigraph arris_snr.down_{0}".format(i + 1))
    print("snr.value U")

    print("multigraph arris_error.down_{0}".format(i + 1))
    print("corr.value U")
    print("uncr.value U")

print("multigraph arris_error")
if arr:
    print("corr.value {0}".format(correct))
    print("uncr.value {0}".format(uncorr))
else:
    print("corr.value U")
    print("uncr.value U")

print("multigraph arris_snr")
for i in range(0, DOWNCOUNT):
    print("down_{0}.value {1}".format(i + 1, snr[i]))

if arr:
    trs = upstream.findall("tr")
    # drop title
    trs.pop(0)

    headings = ["".join(x.itertext()).strip() for x in trs.pop(0).findall("td")]
    # ['Channel', 'Lock Status', 'US Channel Type', 'Channel ID', 'Symbol Rate',
    # 'Frequency', 'Power']

for row in trs:
    data = dict(
        zip(headings, ["".join(x.itertext()).strip() for x in row.findall("td")])
    )
    channel = int(data["Channel"])
    print("multigraph arris_power.up_{0}".format(channel))
    value = data["Power"].split(" ")[0]
    print("power.value {0}".format(value))
    power["up"][channel - 1] = value

# Fill missing
for i in range(len(trs), UPCOUNT):
    print("multigraph arris_power.up_{0}".format(i + 1))
    print("power.value U")

print("multigraph arris_power")
for i in range(0, DOWNCOUNT):
    print("down_{0}.value {1}".format(i + 1, power["down"][i]))
for i in range(0, UPCOUNT):
    print("up_{0}.value {1}".format(i + 1, power["up"][i]))