#!/usr/bin/env python2
# encoding: utf-8

# Copyright © 2018 Amdocs
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#       http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import sys
import os
import json
import requests
from datetime import datetime

consul_server = "consul-server:8500"
message_router = "message-router:3904"
topic = '{{.Values.config.messageRouterTopic}}'
log_file='/app/monitor.log'
status_file='/app/.health'
logEnabled=False

siteName='sdnc01'
if os.environ.get('SDNC_IS_PRIMARY_CLUSTER', 'true') == 'false':
    siteName='sdnc02'

debug=False
if len(sys.argv) > 1 and sys.argv[1] == '--debug':
    debug=True

def get_state(healthcheck):
    response = requests.get("http://" + consul_server + "/v1/health/checks/" + healthcheck)
    if response.status_code != 200:
        raise RuntimeError("HTTP " + str(response.status_code))
    data = response.json()
    if len(data) == 0:
        raise RuntimeError(healthcheck + " not found")
    if len(data) > 1:
        raise RuntimeError("Multiple states for " + healthcheck + " found")

    return data[0]


def log(message):
    if logEnabled:
        with open(log_file, 'a') as f:
            f.write(str(datetime.now()) + " " + message + "\n")

def healthcheck(checks, failFirst=True):
    if len(checks) == 0:
        return True

    for check in checks:
        if type(check) is list:
            passing = healthcheck(check, False)
        else:
            state = get_state(check)
            status = state['Status']
            passing = status == "passing" or status == "warning"
            log(check + " " + status)
            if debug:
                if status == "passing":
                    color = "\033[32m" # green
                elif status == "warning":
                    color = "\033[33m" # yellow
                else:
                    color = "\033[31m" # red
                print check, color + status + "\033[0m"
                if not passing:
                    print "\tCause:", state['Output']


        if passing:
            if not failFirst:
                # found a passing check so can stop here
                return True
        else:
            if failFirst:
                # found a failing check so can stop here
                return False

    return failFirst


try:
    with open("/app/config/healthchecks.json") as f:
        checks = json.load(f)

    try:
        with open(status_file) as f:
           previous_result = f.read()
    except IOError:
        # file doesn't exist
        previous_result = 'unknown'

    if healthcheck(checks):
        result = "healthy"
    else:
        result = "unhealthy"

    print result

    # save current result to file
    with open(status_file, 'w') as f:
        f.write(result)

    if previous_result != 'unknown' and result != previous_result:
        payload = { 'type' : 'health-change', 'status': result, 'site': siteName, 'deployment': '{{.Values.config.deployment}}', 'timestamp': str(datetime.now())  }
        log("Posting event " + str(payload))
        try:
            requests.post("http://" + message_router + "/events/" + topic, data=json.dumps(payload), headers={ 'Content-Type' : 'application/json' } )
        except Exception:
            # events are best-effort
            pass

except Exception as e:
    sys.exit(str(e))