import asyncio
import logging
import platform

from typing import Optional

import api
import grpc
import systemd
import storage

from google.protobuf.empty_pb2 import Empty

class AgentApi(api.AgentServicer):
    def __init__(self) -> None:
        super().__init__()

        self._systemd_monitor: Optional[systemd.Monitor] = None
        self._storage_monitor: Optional[storage.Monitor] = None

    async def Configure(self,
                        request: api.AgentConfiguration,
                        context: grpc.aio.ServicerContext) -> api.AgentConfigurationResponse:
        
        if self._systemd_monitor:
            del self._systemd_monitor
            self._systemd_monitor = None
        if self._storage_monitor:
            del self._storage_monitor
            self._storage_monitor = None

        try:
            if len(request.services_to_monitor) > 0:
                self._systemd_monitor = systemd.Monitor(request.services_to_monitor)
                await self._systemd_monitor.initialize()

            if len(request.storage_to_monitor) > 0:
                self._storage_monitor = storage.Monitor(request.storage_to_monitor)
                await self._storage_monitor.initialize()
        except Exception as e:
            context.set_code(grpc.StatusCode.INTERNAL)
            context.set_details(f"{e}")
            raise RuntimeWarning("Error encountered while servicing API.")

        return api.AgentConfigurationResponse(hostname=platform.node())

    async def Poll(self,
                   request: Empty,
                   context: grpc.aio.ServicerContext) -> api.MonitoringStats:
        
        try:
            if self._systemd_monitor:
                services = await self._systemd_monitor.poll()
            else:
                services = None

            if self._storage_monitor:
                storage = await self._storage_monitor.poll()
            else:
                storage = None

            return api.MonitoringStats(services=services, storage=storage)
        except Exception as e:
            context.set_code(grpc.StatusCode.INTERNAL)
            context.set_details(f"{e}")
            raise RuntimeWarning("Error encountered while servicing API.")