#!/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-sb8200 - Health monitoring plugin for Arris SB8200 Cable Modem

=head1 DESCRIPTION

This provides the following multigraphs:

=over 4

=item upstream and downstream power levels

=item downstream signal to noise ratio

=item downstream error counts

=item uptime

=back

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.

Password is required to be set, user will default to "admin" if left unset.

 [arris*]
 env.hostname modem
 env.user     admin
 env.password UserConfiguredPassword

=head1 REQUIRES

This requires the following non-default python plug-ins:

=over4

=item requests - for HTTPS processing with cookies

=item lxml - for HTML processing

=back

=head1 TESTING

Developed and tested with:
firmware:         AB01.02.053.05_051921_193.0A.NSH
hardware version: 7

=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
import base64

# SB8200 has bad SSL cert, ignore warnings
import urllib3

urllib3.disable_warnings()

# Extra Packages
import requests
from lxml import html


# Auth Flow
# AUTH = base64("{user}:{password}")
# GET $STATUS_URL + "login_"+AUTH -> TEXTBLOB
# GET $URL + "ct_" + TEXTBLOB -> Status page

HOSTNAME = os.getenv("hostname", None)


class Modem:
    STATUS_URL = "https://192.168.100.1/cmconnectionstatus.html?"
    INFO_URL = "https://192.168.100.1/cmswinfo.html?"
    login_key = None

    def __init__(self):
        # save cookies in Session
        self.session = requests.Session()
        user = os.getenv("user", "admin")
        password = os.getenv("password", None)
        auth = base64.b64encode(bytes(user + ":" + password, "utf-8"))
        try:
            resp = self.session.get(
                self.STATUS_URL + "login_" + auth.decode("utf-8"), verify=False
            )
        except OSError as e:
            print("failed to contact router", file=sys.stderr)
            raise (e)
        if not resp.ok:
            print(
                "failed to get status page %d: %s" % (resp.status, resp.reason),
                file=sys.stderr,
            )
            return
        self.rxblank = re.compile(r"[\x00\n\r\t ]+", re.MULTILINE)
        self.rxcomment = re.compile(r"<!--.*?-->")
        self.rxscript = re.compile(r"<script.*?</script>", re.MULTILINE)
        self.login_key = resp.text

    def _process_url(self, url):
        """
        Extract simpleTables from page at URL
        """
        if self.login_key is None:
            return []
        try:
            resp = self.session.get(url + "ct_" + self.login_key, verify=False)
        except OSError:
            print("failed to contact router", file=sys.stderr)
            return []
        if not resp.ok:
            print(
                "failed to get status page %d: %s" % (resp.status, resp.reason),
                file=sys.stderr,
            )
            return []
        data = self.rxscript.sub(
            "", self.rxcomment.sub("", self.rxblank.sub(" ", resp.text))
        )
        dom = html.fromstring(data)
        return dom.xpath('//table[contains(@class, "simpleTable")]')

    def status(self):
        return self._process_url(self.STATUS_URL)

    def info(self):
        return self._process_url(self.INFO_URL)


# Sets maximum number of channels
UPCOUNT = 8
DOWNCOUNT = 33
# DOWNCOUNT should be 32, but I have observed 33

if os.getenv("password", None) is None:
    print("Set password.", file=sys.stderr)

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)


print("multigraph arris_uptime")
modem = Modem()
arr = modem.info()
if not arr:
    # login doesn't work first time?
    modem = Modem()
    arr = modem.info()
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(float(hms[2]))
    print("uptime.value {0}".format(seconds / 86400.0))
else:
    print("uptime.value U")


arr = modem.status()
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")]
    # SB8200 FW AB01.02.053.05_051921_193.0A.NSH
    # outputs BAD html in that the there is not second <tr> for th table
    #    <table class='simpleTable'>
    # <tr><th colspan=8><strong>Downstream Bonded Channels</strong></th></tr>
    #  <td><strong>Channel ID</strong></td>
    #  <td><strong>Lock Status</strong></td>
    #  <td><strong>Modulation</strong></td>
    #  <td><strong>Frequency</strong></td>
    #  <td><strong>Power</strong></td>
    #  <td><strong>SNR/MER</strong></td>
    #  <td><strong>Corrected</strong></td>
    #  <td><strong>Uncorrectables</strong></td>
    # </tr>
    if not headings:
        headings = [
            "Channel ID",
            "Lock Status",
            "Modulation",
            "Frequency",
            "Power",
            "SNR/MER",
            "Corrected",
            "Uncorrectables",
        ]
else:
    trs = []
    headings = []

# Summation Graphs
correct = 0
uncorr = 0
power = {"up": ["U"] * UPCOUNT, "down": ["U"] * DOWNCOUNT}
snr = ["U"] * DOWNCOUNT
channel = 0
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"])

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

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

    print("multigraph arris_error.down_{0}".format(channel + 1))
    print("corr.value {0}".format(data["Corrected"]))
    print("uncr.value {0}".format(data["Uncorrectables"]))
    channel += 1

# 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")]

    # Same issue as above
    #    <table class='simpleTable'>
    # <tr><th colspan=7><strong>Upstream Bonded Channels</strong></th></tr>
    #       <td><strong>Channel</strong></td>
    #       <td><strong>Channel ID</strong></td>
    #       <td><strong>Lock Status</strong></td>
    #       <td><strong>US Channel Type</td>
    #       <td><strong>Frequency</strong></td>
    #       <td><strong>Width</strong></td>
    #       <td><strong>Power</strong></td>
    #    </tr>
    headings = [
        "Channel",
        "Channel ID",
        "Lock Status",
        "US Channel Type",
        "Frequency",
        "Width",
        "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]))