#!/usr/bin/python
# vim: set fileencoding=utf-8 :
#
# Munin plugin to monitor the temperature values
# of the pellematic burning chamber
#
# 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
#
#%# 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 = {
    "CAPPL:FA[0].L_feuerraumtemperatur":
    'Combustion Chamber Temp',
    "CAPPL:FA[0].L_feuerraumtemperatur_soll":
    'Combustion Chamber Temp Set',
    "CAPPL:FA[0].L_agt_zuend_flammueb":
    'Flue Gas Temp Ignition Control',
}

def fixup(name):
    return name

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

def get_name(item):
    if item['shortText'] != '???':
        return fixup(item['shortText'])
    else:
        return items[item['name']]

def print_config(url):
    print """graph_title Pellematic Combustion Chamber Temperature values
graph_vlabel Temperature in Degree Celsius
graph_category Heating
graph_info This graph shows the temperature values of the combustion chamber of a pellematic"""

    out = fetch_raw(url)
    for item in out:
        name = get_name(item)
        if name:
            print "%s.label %s" % (canon(name), name)
            print "%s.type GAUGE" % canon(name)
            thickness = 1 if name.endswith(' Set') 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(items.keys())
    r = requests.post(url,
                      data=payload,
                      params=params,
                      cookies=cookies,
                      headers=headers)

    if hasattr(r.json, '__call__'):
        ret = r.json()
    else: # in requests 0.12 json isn't a callable
        ret = r.json

    if debug:
        print >>sys.stderr, ret

    return ret

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


def main(args):
    if not url:
        print >>sys.stderr, "No url< configured"
        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 >>sys.stderr, "Failed to fetch config: '%s'" % e
                return 1
            return 0
    try:
        fetch_values(url)
    except Exception as e:
        print >>sys.stderr, "Failed to fetch values: '%s'" % e
        return 1
    return 0

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