# Copyright 2021-2023 H2020 TeraFlow (https://www.teraflow-h2020.eu/)
#
# 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 logging, signal, sys, threading, socket

from common.Settings import get_setting, wait_for_environment_variables
from context.client.ContextClient import ContextClient
from monitoring.Config import (
    GRPC_SERVICE_PORT, GRPC_MAX_WORKERS, GRPC_GRACE_PERIOD, LOG_LEVEL, METRICS_PORT, CONTEXT_GRPC_SERVICE_PORT,
    CONTEXT_SERVICE_HOST)

from monitoring.client.monitoring_client import MonitoringClient
from monitoring.proto import monitoring_pb2
from monitoring.service.EventTools import EventsDeviceCollector
from monitoring.service.MonitoringService import MonitoringService

from prometheus_client import start_http_server

terminate = threading.Event()
LOGGER = None
LOCALHOST = '127.0.0.1'

def signal_handler(signal, frame):
    LOGGER.warning('Terminate signal received')
    terminate.set()

def start_monitoring():
    LOGGER.info('Start Monitoring...',)

    grpc_service_port    = get_setting('MONITORINGSERVICE_SERVICE_PORT_GRPC', default=GRPC_SERVICE_PORT        )
    context_service_host = get_setting('CONTEXTSERVICE_SERVICE_HOST',         default=CONTEXT_SERVICE_HOST     )
    context_service_port = get_setting('CONTEXTSERVICE_SERVICE_PORT_GRPC',    default=CONTEXT_GRPC_SERVICE_PORT)

    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    if s.connect_ex((context_service_host, int(context_service_port))) != 0:
        LOGGER.info('Context service is not reachable')
        return

    context_client_grpc = ContextClient(address=context_service_host, port=context_service_port)
    monitoring_client = MonitoringClient(server=LOCALHOST, port=grpc_service_port)  # instantiate the client
    events_collector = EventsDeviceCollector(context_client_grpc, monitoring_client)
    events_collector.start()

    # Iterate while terminate is not set
    while not terminate.is_set():
        list_new_kpi_ids = events_collector.listen_events()

        # Monitor Kpis
        if bool(list_new_kpi_ids):
            for kpi_id in list_new_kpi_ids:
                # Create Monitor Kpi Requests
                monitor_kpi_request = monitoring_pb2.MonitorKpiRequest()
                monitor_kpi_request.kpi_id.CopyFrom(kpi_id)
                monitor_kpi_request.sampling_duration_s = 300
                monitor_kpi_request.sampling_interval_s = 15

                monitoring_client.MonitorKpi(monitor_kpi_request)
    else:
        # Terminate is set, looping terminates
        LOGGER.warning("Stopping execution...")

    events_collector.start()

def main():
    global LOGGER

    grpc_service_port = get_setting('MONITORINGSERVICE_SERVICE_PORT_GRPC', default=GRPC_SERVICE_PORT)
    max_workers       = get_setting('MAX_WORKERS',                         default=GRPC_MAX_WORKERS )
    grace_period      = get_setting('GRACE_PERIOD',                        default=GRPC_GRACE_PERIOD)
    log_level         = get_setting('LOG_LEVEL',                           default=LOG_LEVEL        )
    metrics_port      = get_setting('METRICS_PORT',                        default=METRICS_PORT     )

    logging.basicConfig(level=log_level)
    LOGGER = logging.getLogger(__name__)

    wait_for_environment_variables([
        'CONTEXTSERVICE_SERVICE_HOST', 'CONTEXTSERVICE_SERVICE_PORT_GRPC',
        'DEVICESERVICE_SERVICE_HOST', 'DEVICESERVICE_SERVICE_PORT_GRPC'
    ])

    signal.signal(signal.SIGINT,  signal_handler)
    signal.signal(signal.SIGTERM, signal_handler)

    LOGGER.info('Starting...')
    # Start metrics server
    start_http_server(metrics_port)

    # Starting monitoring service
    grpc_service = MonitoringService(port=grpc_service_port, max_workers=max_workers, grace_period=grace_period)
    grpc_service.start()

    start_monitoring()

    # Wait for Ctrl+C or termination signal
    while not terminate.wait(timeout=0.1): pass

    LOGGER.info('Terminating...')
    grpc_service.stop()

    LOGGER.info('Bye')
    return 0

if __name__ == '__main__':
    sys.exit(main())