# !/usr/bin/env python3

# SPDX-FileCopyrightText: 2020 The Magma Authors.
# SPDX-FileCopyrightText: 2022 Open Networking Foundation <support@opennetworking.org>
#
# SPDX-License-Identifier: BSD-3-Clause

import asyncio
import os
import subprocess
from datetime import datetime

import apt
from dateutil import tz
from common.health.entities import (
    ActiveState,
    Errors,
    HealthStatus,
    HealthSummary,
    RestartFrequency,
    ServiceHealth,
    Version,
)
from common.service import MagmaService
from common.service_registry import ServiceRegistry
from configuration.mconfig_managers import load_service_mconfig_as_json
from magmad.metrics import UNEXPECTED_SERVICE_RESTARTS
from magmad.service_poller import ServicePoller
from orc8r.protos import common_pb2, magmad_pb2
from orc8r.protos.magmad_pb2_grpc import MagmadStub
from orc8r.protos.mconfig import mconfigs_pb2
from pystemd.systemd1 import Unit


class GenericHealthChecker:

    def ping(self, host, num_packets=4):
        chan = ServiceRegistry.get_rpc_channel('magmad', ServiceRegistry.LOCAL)
        client = MagmadStub(chan)

        response = client.RunNetworkTests(
            magmad_pb2.NetworkTestRequest(
                pings=[
                    magmad_pb2.PingParams(
                        host_or_ip=host,
                        num_packets=num_packets,
                    ),
                ],
            ),
        )
        return response.pings

    def ping_status(self, host):
        pings = self.ping(host=host, num_packets=4)[0]
        if pings.error:
            return HealthStatus.DOWN
        if pings.avg_response_ms:
            return HealthStatus.UP
        return HealthStatus.UNKNOWN

    def get_error_summary(self, service_names):
        """Get the list of services with the error count.

        Args:
            service_names: List of service names.

        Returns:
            A dictionary with service name as a key and the Errors object
            as a value.

        Raises:
            PermissionError: User has no permision to exectue the command
        """
        configs = {
            service_name: load_service_mconfig_as_json(service_name)
            for service_name in service_names
        }
        res = {
            service_name: Errors(
            log_level=configs[service_name].get('logLevel', 'INFO'),
            error_count=0,
            )
            for service_name in service_names
        }

        syslog_path = '/var/log/syslog'
        if not os.access(syslog_path, os.R_OK):
            raise PermissionError(
                'syslog is not readable. '
                'Try `sudo chmod a+r {}`. '
                'Or execute the command with sudo '
                'permissions: `venvsudo`'.format(syslog_path),
            )
        with open(syslog_path, 'r', encoding='utf-8') as f:
            for line in f:
                for service_name in service_names:
                    if service_name not in line:
                        continue
                    # Reset the counter for restart/start
                    if 'Starting {}...'.format(service_name) in line:
                        res[service_name].error_count = 0
                    elif 'ERROR' in line:
                        res[service_name].error_count += 1
        return res

    def get_magma_services_summary(self):
        """ Get health for all the running services """
        services_health_summary = []

        # DBus objects: https://www.freedesktop.org/wiki/Software/systemd/dbus/
        chan = ServiceRegistry.get_rpc_channel('magmad', ServiceRegistry.LOCAL)
        client = MagmadStub(chan)

        configs = client.GetConfigs(common_pb2.Void())

        service_names = [str(name) for name in configs.configs_by_key]
        services_errors = self.get_error_summary(service_names=service_names)

        for service_name in service_names:
            unit = Unit(
                'magma@{}.service'.format(service_name),
                _autoload=True,
            )
            active_state = ActiveState.dbus2state[unit.Unit.ActiveState]
            sub_state = str(unit.Unit.SubState, 'utf-8')
            if active_state == ActiveState.ACTIVE:
                pid = unit.Service.MainPID
                process = subprocess.Popen(
                    'ps -o etime= -p {}'.format(pid).split(),
                    stdout=subprocess.PIPE,
                )

                time_running, error = process.communicate()
                if error:
                    raise ValueError(
                        'Cannot get time running for the service '
                        '{} `ps -o etime= -p {}`'
                        .format(service_name, pid),
                    )
            else:
                time_running = b'00'

            services_health_summary.append(
                ServiceHealth(
                    service_name=service_name,
                    active_state=active_state, sub_state=sub_state,
                    time_running=str(time_running, 'utf-8').strip(),
                    errors=services_errors[service_name],
                ),
            )
        return services_health_summary

    def get_unexpected_restart_summary(self):
        service = MagmaService('magmad', mconfigs_pb2.MagmaD())
        service_poller = ServicePoller(service.loop, service.config)
        service_poller.start()

        asyncio.set_event_loop(service.loop)

        # noinspection PyProtectedMember
        # pylint: disable=protected-access
        async def fetch_info():
            restart_frequencies = {}
            await service_poller._get_service_info()
            for service_name in service_poller.service_info.keys():
                restarts = int(
                    UNEXPECTED_SERVICE_RESTARTS
                    .labels(service_name=service_name)
                    ._value.get(),
                )
                restart_frequencies[service_name] = RestartFrequency(
                    count=restarts,
                    time_interval='',
                )

            return restart_frequencies

        return service.loop.run_until_complete(fetch_info())

    def get_kernel_version(self):
        info, error = subprocess.Popen(
            'uname -a'.split(),
            stdout=subprocess.PIPE,
        ).communicate()

        if error:
            raise ValueError('Cannot get the kernel version')
        return str(info, 'utf-8')

    def get_magma_version(self):
        cache = apt.Cache()

        # Return the python version if magma is not there
        if 'magma' not in cache:
            return Version(
                version_code=cache['python3'].versions[0],
                last_update_time='-',
            )

        pkg = str(cache['magma'].versions[0])
        version = pkg.split('-')[0].split('=')[-1]
        timestamp = int(pkg.split('-')[1])

        return Version(
            version_code=version,
            last_update_time=datetime.utcfromtimestamp(timestamp)
            .replace(tzinfo=tz.tzutc())
            .astimezone(tz=tz.tzlocal())
            .strftime('%Y-%m-%d %H:%M:%S'),
        )

    def get_health_summary(self):

        return HealthSummary(
            version=self.get_magma_version(),
            platform=self.get_kernel_version(),
            services_health=self.get_magma_services_summary(),
            internet_health=self.ping_status(host='8.8.8.8'),
            dns_health=self.ping_status(host='google.com'),
            unexpected_restarts=self.get_unexpected_restart_summary(),
        )