#!/usr/bin/env python
#
# Copyright (C) 2016 GNS3 Technologies Inc.
#
# 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 3 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, see <http://www.gnu.org/licenses/>.

import os
import sys
import json
import asyncio

import logging
log = logging.getLogger(__name__)


class BaseGNS3VM:

    def __init__(self):

        self._vmname = None
        self._auto_start = False
        self._auto_stop = False
        self._ip_address = None
        self._port = 3080
        self._headless = False
        self._vcpus = 1
        self._ram = 1024
        self._running = False

        if sys.platform.startswith("win"):
            config_path = os.path.join(os.path.expandvars("%APPDATA%"), "GNS3")
        else:
            config_path = os.path.join(os.path.expanduser("~"), ".config", "GNS3")
        self._config_file = os.path.join(config_path, "gns3_vm.conf")
        self.load()

    def __json__(self):

        settings = {"vmname": self._vmname,
                    "ip_address": self._ip_address,
                    "port": self._port,
                    "headless": self._headless,
                    "vcpus": self._vcpus,
                    "ram": self._ram,
                    "auto_start": self._auto_start,
                    "auto_stop": self._auto_stop,
                    "engine": self._engine}

        return settings

    def load(self):
        """
        Reload the GNS3 VM configuration from disk
        """

        if not os.path.exists(self._config_file):
            self.save()
        try:
            with open(self._config_file) as f:
                data = json.load(f)
        except OSError as e:
            log.critical("Cannot load %s: %s", self._config_file, str(e))
            return
        if "gns3vm" in data:
            for name, value in data["gns3vm"].items():
                if hasattr(self, name) and getattr(self, name) != value:
                    log.debug("GNS3 VM: set {} to {}".format(name, value))
                    setattr(self, name, value)

    def save(self):
        """
        Save the GNS3 VM configuration on disk
        """

        data = {"gns3vm": self.__json__()}
        os.makedirs(os.path.dirname(self._config_file), exist_ok=True)
        with open(self._config_file, 'w+') as f:
            json.dump(data, f, indent=4)

    @property
    def vmname(self):
        """
        Returns the GNS3 VM name.

        :returns: VM name
        """

        return self._vmname

    @vmname.setter
    def vmname(self, new_name):
        """
        Sets the GNS3 VM name

        :param new_name: new VM name
        """

        self._vmname = new_name

    @property
    def port(self):
        """
        Returns the GNS3 VM port.

        :returns: VM port
        """

        return self._port

    @port.setter
    def port(self, new_port):
        """
        Sets the GNS3 VM port

        :param new_port: new VM port
        """

        self._port = new_port

    @property
    def ip_address(self):
        """
        Returns the GNS3 VM IP address.

        :returns: VM IP address
        """

        return self._ip_address

    @ip_address.setter
    def ip_address(self, new_ip_address):
        """
        Sets the GNS3 VM IP address.

        :param new_ip_address: new VM IP address
        """

        self._ip_address = new_ip_address

    @property
    def running(self):
        """
        Returns whether the GNS3 VM is running or not.

        :returns: boolean
        """

        return self._running

    @running.setter
    def running(self, value):
        """
        Sets whether the GNS3 VM is running or not.

        :param value: boolean
        """

        self._running = value

    @property
    def headless(self):
        """
        Returns whether the GNS3 VM is headless or not.

        :returns: boolean
        """

        return self._headless

    @headless.setter
    def headless(self, value):
        """
        Sets whether the GNS3 VM is headless or not.

        :param value: boolean
        """

        self._headless = value

    @property
    def vcpus(self):
        """
        Returns the number of allocated vCPUs.

        :returns: number of vCPUs.
        """

        return self._vcpus

    @vcpus.setter
    def vcpus(self, new_vcpus):
        """
        Sets the number of allocated vCPUs.

        :param new_vcpus: new number of vCPUs.
        """

        self._vcpus = new_vcpus

    @property
    def ram(self):
        """
        Returns the amount of allocated RAM.

        :returns: number of vCPUs.
        """

        return self._ram

    @ram.setter
    def ram(self, new_ram):
        """
        Sets the amount of allocated RAM.

        :param new_ram: new amount of RAM.
        """

        self._ram = new_ram

    @property
    def auto_start(self):
        """
        Returns whether the VM should automatically be started when GNS3 is launched

        :returns: boolean
        """

        return self._auto_start

    @auto_start.setter
    def auto_start(self, new_auto_start):
        """
        Set whether the VM should automatically be started when GNS3 is launched

        :param new_auto_start: boolean
        """

        self._auto_start = new_auto_start

    @property
    def auto_stop(self):
        """
        Returns whether the VM should automatically be started when GNS3 is launched

        :returns: boolean
        """

        return self._auto_start

    @auto_stop.setter
    def auto_stop(self, new_auto_stop):
        """
        Set whether the VM should automatically be stopped when GNS3 is launched

        :param new_auto_stop: boolean
        """

        self._auto_stop = new_auto_stop

    @property
    def engine(self):
        """
        Returns the engine (virtualization technology used to run the GNS3 VM).

        :returns: engine name
        """

        return self._engine

    @asyncio.coroutine
    def list(self):
        """
        List all VMs
        """

        raise NotImplementedError

    @asyncio.coroutine
    def start(self):
        """
        Starts the GNS3 VM.
        """

        raise NotImplementedError

    @asyncio.coroutine
    def stop(self, force=False):
        """
        Stops the GNS3 VM.
        """

        raise NotImplementedError

    @classmethod
    def instance(cls):
        """
        Singleton to return only one instance of BaseGNS3VM.

        :returns: instance of BaseGNS3VM
        """

        if not hasattr(cls, "_instance") or cls._instance is None:
            cls._instance = cls()
        return cls._instance