#!/usr/bin/python3
# vim: set fileencoding=utf-8 :
#
# Munin plugin to monitor the temperature values
# of a pellematic/pelletronic touch 2.0
#
# Copyright 2013 Guido Günther <agx@sigxcpu.org>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# 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 General Public License for more details.
#
# You should have received a copy of the GNU 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
#
# depends: python-requests
#
# FIXME: This currently doesn't probe the connected systems
#
#%# capabilities=autoconf
#%# family=contrib

import requests
import os
import re
import sys
import json

username = os.getenv('username', 'oekofen')
password = os.getenv('password', username)
debug = os.getenv('debug')
url = os.getenv('url')

# The items we want to plot:
items = {# Outside temperature sensor (X2)
         "CAPPL:LOCAL.L_aussentemperatur_ist":
          "Outside Temp Act",
         # 1. Pelletronic
         "CAPPL:FA[0].L_kesseltemperatur":
          "Boiler Temp",
         "CAPPL:FA[0].L_kesseltemperatur_soll_anzeige":
          "Boiler Temp Set",
         #"CAPPL:FA[0].L_feuerraumtemperatur",
         #"CAPPL:FA[0].L_feuerraumtemperatur_soll",
         # 1. Buffer
         # TPM (X8)
         "CAPPL:LOCAL.L_pu[0].ausschaltfuehler_ist":
          "TPM Act",
         "CAPPL:LOCAL.L_pu[0].ausschaltfuehler_soll":
          "TPM Set",
         # TPO (X7)
         "CAPPL:LOCAL.L_pu[0].einschaltfuehler_ist":
          "TPO Act",
         "CAPPL:LOCAL.L_pu[0].einschaltfuehler_soll":
          "TPO Set",
         # 1. Heating circuit
         # VL1 (X4)
         "CAPPL:LOCAL.L_hk[0].vorlauftemp_ist":
          "Flow Temp Act",
         "CAPPL:LOCAL.L_hk[0].vorlauftemp_soll":
          "Flow Temp Set",
         "CAPPL:LOCAL.hk[0].raumtemp_heizen":
          "Room Temp Heating",
         "CAPPL:LOCAL.hk[0].raumtemp_absenken":
          "Room Temp Set Back Set",
         "CAPPL:LOCAL.hk[0].heizgrenze_heizen":
          "H Limit Heating",
         "CAPPL:LOCAL.hk[0].heizgrenze_absenken":
          "H Limit Set Back",
         # drinking water
         "CAPPL:LOCAL.L_ww[0].einschaltfuehler_ist":
          "Switch On Sensor Act",
        }

def fixup(name):
    # TPM and TPO are swapped in the returned JSON
    # (compare to /js/config.min.js) so we need
    # to fix it up:
    if name.startswith('TPM'):
        return 'TPO' + name[3:]
    elif name.startswith('TPO'):
        return 'TPM' + name[3:]
    else:
        return name

def canon(name):
    return re.sub(r"[^a-zA-Z0-9_]", "_", name)

def is_preset(name):
    """
    Preset values are inconsistently named so
    so we have to decide manually.
    """
    if name.endswith(' Set'):
        return True
    elif ' Limit ' in name:
        return True
    elif name == 'Room Temp Heating':
        return True
    else:
        return False

def print_config(url):
    print("""graph_title Pellematic Temperature values
graph_vlabel Temperature in Degree Celsius
graph_category Heating
graph_info This graph shows different temperture values as displayed by a Pelletronic Touch 2.0 by Ökofen""")

    out = fetch_raw(url)
    names = []
    for item in out:
        if item['name'] in list(items.keys()):
            names.append(items[item['name']])

    for name in sorted(names):
        print("%s.label %s" % (canon(name), name))
        print("%s.type GAUGE" % canon(name))
        thickness = 1 if is_preset(name) else 2
        print("%s.draw LINE%d" % (canon(name), thickness))

def degree_celsius(val):
    return float(int(val['value'])) / float(val['divisor'])

def fetch_raw(url):
    # Perform authentication and get the cookie
    auth_formdata = {'language': 'en',
                     'username': username,
                     'password': password,
                     'submit': 'Login',
                     }
    r = requests.post(url, data=auth_formdata)

    pksession = r.cookies['pksession']
    cookies = { 'pksession': pksession,
                'language': 'en' }
    params = { 'action': 'get',
               'attr': '1',
             }

    # These are the headers used by the supplied application
    # It mostly doesn't matter what we pass but the backend
    # breaks with a lua error without a Accept-Language header:
    headers = {'Accept': 'application/json',
               'Content-Type': 'application/x-www-form-urlencoded; charset=UTF-8',
               'Accept-Language': 'en',
              }

    # The items to fetch are passed as simple json string
    payload = json.dumps(list(items.keys()))
    r = requests.post(url,
                      data=payload,
                      params=params,
                      cookies=cookies,
                      headers=headers)
    ret = r.json()

    if debug:
        print(ret, file=sys.stderr)

    return ret

def fetch_values(url):
    out = fetch_raw(url)
    for item in out:
        if item['name'] in items:
            name = canon(items[item['name']])
            print("%s.value %.2f" % (name,
                                     degree_celsius(item)))


def main(args):
    if not url:
        print("No url configured", file=sys.stderr)
        return 1
    if len(args) > 1:
        if args[1] in [ 'autoconf', 'detect' ]:
            try:
                fetch_raw(url)
                print("yes")
                return 0
            except:
                print("no")
                return 1
        elif args[1] == 'config':
            try:
                print_config(url)
            except Exception as e:
                print("Failed to fetch config: '%s'" % e, file=sys.stderr)
                return 1
            return 0
    try:
        fetch_values(url)
    except Exception as e:
        print("Failed to fetch values: '%s'" % e, file=sys.stderr)
        return 1
    return 0

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