#!/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 uuid
import socket
import asyncio
import aiohttp

from ..config import Config
from .project import Project
from .compute import Compute, ComputeError
from .notification import Notification
from .symbols import Symbols
from ..version import __version__
from .topology import load_topology
from .gns3vm import GNS3VM
from .gns3vm.gns3_vm_error import GNS3VMError

import logging
log = logging.getLogger(__name__)


class Controller:
    """The controller is responsible to manage one or more compute servers"""

    def __init__(self):
        self._computes = {}
        self._projects = {}
        self._notification = Notification(self)
        self.gns3vm = GNS3VM(self)
        self.symbols = Symbols()
        # Store settings shared by the different GUI will be replace by dedicated API later
        self._settings = None
        self._local_server = None
        self._config_file = os.path.join(Config.instance().config_dir, "gns3_controller.conf")
        log.info("Load controller configuration file {}".format(self._config_file))

    @asyncio.coroutine
    def start(self):
        log.info("Start controller")

        server_config = Config.instance().get_section_config("Server")
        Config.instance().listen_for_config_changes(self._update_config)
        host = server_config.get("host", "localhost")

        # If console_host is 0.0.0.0 client will use the ip they use
        # to connect to the controller
        console_host = host
        if host == "0.0.0.0":
            host = "127.0.0.1"

        name = socket.gethostname()
        if name == "gns3vm":
            name = "Main server"

        computes = yield from self._load_controller_settings()
        try:
            self._local_server = yield from self.add_compute(compute_id="local",
                                                             name=name,
                                                             protocol=server_config.get("protocol", "http"),
                                                             host=host,
                                                             console_host=console_host,
                                                             port=server_config.getint("port", 3080),
                                                             user=server_config.get("user", ""),
                                                             password=server_config.get("password", ""),
                                                             force=True)
        except aiohttp.web_exceptions.HTTPConflict as e:
            log.fatal("Can't acces to the local server, make sure anything else is not running on the same port")
            sys.exit(1)
        for c in computes:
            try:
                yield from self.add_compute(**c)
            except (aiohttp.web_exceptions.HTTPConflict):
                pass  # Skip not available servers at loading
        yield from self.load_projects()
        try:
            yield from self.gns3vm.auto_start_vm()
        except GNS3VMError as e:
            log.warn(str(e))
        yield from self._project_auto_open()

    def _update_config(self):
        """
        Call this when the server configuration file
        change
        """
        if self._local_server:
            server_config = Config.instance().get_section_config("Server")
            self._local_server.user = server_config.get("user")
            self._local_server.password = server_config.get("password")

    @asyncio.coroutine
    def stop(self):
        log.info("Stop controller")
        for project in self._projects.values():
            yield from project.close()
        for compute in self._computes.values():
            try:
                yield from compute.close()
            # We don't care if a compute is down at this step
            except (ComputeError, aiohttp.web_exceptions.HTTPError, OSError):
                pass
        yield from self.gns3vm.exit_vm()
        self._computes = {}
        self._projects = {}

    def save(self):
        """
        Save the controller configuration on disk
        """
        # We don't save during the loading otherwise we could lost stuff
        if self._settings is None:
            return
        data = {
            "computes": [],
            "settings": self._settings,
            "gns3vm": self.gns3vm.__json__(),
            "version": __version__
        }

        for c in self._computes.values():
            if c.id != "local" and c.id != "vm":
                data["computes"].append({
                    "host": c.host,
                    "name": c.name,
                    "port": c.port,
                    "protocol": c.protocol,
                    "user": c.user,
                    "password": c.password,
                    "compute_id": c.id
                })
        try:
            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)
        except OSError as e:
            log.error("Can't write the configuration {}: {}".format(self._config_file, str(e)))

    @asyncio.coroutine
    def _load_controller_settings(self):
        """
        Reload the controller configuration from disk
        """
        try:
            if not os.path.exists(self._config_file):
                yield from self._import_gns3_gui_conf()
                self.save()
            with open(self._config_file) as f:
                data = json.load(f)
        except (OSError, ValueError) as e:
            log.critical("Cannot load %s: %s", self._config_file, str(e))
            self._settings = {}
            return []

        if "settings" in data and data["settings"] is not None:
            self._settings = data["settings"]
        else:
            self._settings = {}
        if "gns3vm" in data:
            self.gns3vm.settings = data["gns3vm"]

        return data["computes"]

    @asyncio.coroutine
    def load_projects(self):
        """
        Preload the list of projects from disk
        """
        server_config = Config.instance().get_section_config("Server")
        projects_path = os.path.expanduser(server_config.get("projects_path", "~/GNS3/projects"))
        os.makedirs(projects_path, exist_ok=True)
        try:
            for project_path in os.listdir(projects_path):
                project_dir = os.path.join(projects_path, project_path)
                if os.path.isdir(project_dir):
                    for file in os.listdir(project_dir):
                        if file.endswith(".gns3"):
                            try:
                                yield from self.load_project(os.path.join(project_dir, file), load=False)
                            except (aiohttp.web_exceptions.HTTPConflict, NotImplementedError):
                                pass  # Skip not compatible projects
        except OSError as e:
            log.error(str(e))

    def images_path(self):
        """
        Get the image storage directory
        """
        server_config = Config.instance().get_section_config("Server")
        images_path = os.path.expanduser(server_config.get("images_path", "~/GNS3/projects"))
        os.makedirs(images_path, exist_ok=True)
        return images_path

    @asyncio.coroutine
    def _import_gns3_gui_conf(self):
        """
        Import old config from GNS3 GUI
        """
        config_file = os.path.join(os.path.dirname(self._config_file), "gns3_gui.conf")
        if os.path.exists(config_file):
            with open(config_file) as f:
                data = json.load(f)
                server_settings = data.get("Servers", {})
                for remote in server_settings.get("remote_servers", []):
                    try:
                        yield from self.add_compute(
                            host=remote.get("host", "localhost"),
                            port=remote.get("port", 3080),
                            protocol=remote.get("protocol", "http"),
                            name=remote.get("url"),
                            user=remote.get("user"),
                            password=remote.get("password")
                        )
                    except aiohttp.web.HTTPConflict:
                        pass  # if the server is broken we skip it
                if "vm" in server_settings:
                    vmname = None
                    vm_settings = server_settings["vm"]
                    if vm_settings["virtualization"] == "VMware":
                        engine = "vmware"
                        vmname = vm_settings.get("vmname", "")
                    elif vm_settings["virtualization"] == "VirtualBox":
                        engine = "virtualbox"
                        vmname = vm_settings.get("vmname", "")
                    else:
                        engine = "remote"
                        # In case of remote server we match the compute with url parameter
                        for compute in self._computes.values():
                            if compute.host == vm_settings.get("remote_vm_host") and compute.port == vm_settings.get("remote_vm_port"):
                                vmname = compute.name

                    if vm_settings.get("auto_stop", True):
                        when_exit = "stop"
                    else:
                        when_exit = "keep"

                    self.gns3vm.settings = {
                        "engine": engine,
                        "enable": vm_settings.get("auto_start", False),
                        "when_exit": when_exit,
                        "headless": vm_settings.get("headless", False),
                        "vmname": vmname
                    }
                self._settings = {}

    @property
    def settings(self):
        """
        Store settings shared by the different GUI will be replace by dedicated API later. Dictionnary
        """
        return self._settings

    @settings.setter
    def settings(self, val):
        self._settings = val
        self._settings["modification_uuid"] = str(uuid.uuid4())  # We add a modification id to the settings it's help the gui to detect changes
        self.save()
        self.notification.emit("settings.updated", val)

    @asyncio.coroutine
    def add_compute(self, compute_id=None, name=None, force=False, connect=True, **kwargs):
        """
        Add a server to the dictionary of compute servers controlled by this controller

        :param compute_id: Compute server identifier
        :param name: Compute name
        :param force: True skip security check
        :param connect: True connect to the compute immediately
        :param kwargs: See the documentation of Compute
        """
        if compute_id not in self._computes:

            # We disallow to create from the outside the local and VM server
            if (compute_id == 'local' or compute_id == 'vm') and not force:
                return None

            # It seem we have error with a gns3vm imported as a remote server and conflict
            # with GNS3 VM settings. That's why we ignore server name gns3vm
            if name == 'gns3vm':
                return None

            for compute in self._computes.values():
                if name and compute.name == name and not force:
                    raise aiohttp.web.HTTPConflict(text='Compute name "{}" already exists'.format(name))

            compute = Compute(compute_id=compute_id, controller=self, name=name, **kwargs)
            self._computes[compute.id] = compute
            self.save()
            if connect:
                yield from compute.connect()
            self.notification.emit("compute.created", compute.__json__())
            return compute
        else:
            if connect:
                yield from self._computes[compute_id].connect()
            self.notification.emit("compute.updated", self._computes[compute_id].__json__())
            return self._computes[compute_id]

    @asyncio.coroutine
    def close_compute_projects(self, compute):
        """
        Close projects running on a compute
        """
        for project in self._projects.values():
            if compute in project.computes:
                yield from project.close()

    @asyncio.coroutine
    def delete_compute(self, compute_id):
        """
        Delete a compute node. Project using this compute will be close

        :param compute_id: Compute server identifier
        """
        try:
            compute = self.get_compute(compute_id)
        except aiohttp.web.HTTPNotFound:
            return
        yield from self.close_compute_projects(compute)
        yield from compute.close()
        del self._computes[compute_id]
        self.save()
        self.notification.emit("compute.deleted", compute.__json__())

    @property
    def notification(self):
        """
        The notification system
        """
        return self._notification

    @property
    def computes(self):
        """
        :returns: The dictionary of compute server managed by this controller
        """
        return self._computes

    def get_compute(self, compute_id):
        """
        Returns a compute server or raise a 404 error.
        """
        try:
            return self._computes[compute_id]
        except KeyError:
            if compute_id == "vm":
                raise aiohttp.web.HTTPNotFound(text="You try to use a node on the GNS3 VM server but the GNS3 VM is not configured")
            raise aiohttp.web.HTTPNotFound(text="Compute ID {} doesn't exist".format(compute_id))

    def has_compute(self, compute_id):
        """
        Return True if the compute exist in the controller
        """
        return compute_id in self._computes

    @asyncio.coroutine
    def add_project(self, project_id=None, name=None, **kwargs):
        """
        Creates a project or returns an existing project

        :param project_id: Project ID
        :param name: Project name
        :param kwargs: See the documentation of Project
        """
        if project_id not in self._projects:

            for project in self._projects.values():
                if name and project.name == name:
                    raise aiohttp.web.HTTPConflict(text='Project name "{}" already exists'.format(name))
            project = Project(project_id=project_id, controller=self, name=name, **kwargs)
            self._projects[project.id] = project
            return self._projects[project.id]
        return self._projects[project_id]

    def get_project(self, project_id):
        """
        Returns a project or raise a 404 error.
        """
        try:
            return self._projects[project_id]
        except KeyError:
            raise aiohttp.web.HTTPNotFound(text="Project ID {} doesn't exist".format(project_id))

    @asyncio.coroutine
    def get_loaded_project(self, project_id):
        """
        Returns a project or raise a 404 error.

        If project is not finished to load wait for it
        """
        project = self.get_project(project_id)
        yield from project.wait_loaded()
        return project

    def remove_project(self, project):
        if project.id in self._projects:
            del self._projects[project.id]

    @asyncio.coroutine
    def load_project(self, path, load=True):
        """
        Load a project from a .gns3

        :param path: Path of the .gns3
        :param load: Load the topology
        """
        topo_data = load_topology(path)
        topo_data.pop("topology")
        topo_data.pop("version")
        topo_data.pop("revision")
        topo_data.pop("type")

        if topo_data["project_id"] in self._projects:
            project = self._projects[topo_data["project_id"]]
        else:
            project = yield from self.add_project(path=os.path.dirname(path), status="closed", filename=os.path.basename(path), **topo_data)
        if load or project.auto_open:
            yield from project.open()
        return project

    @asyncio.coroutine
    def _project_auto_open(self):
        """
        Auto open the project with auto open enable
        """
        for project in self._projects.values():
            if project.auto_open:
                yield from project.open()

    def get_free_project_name(self, base_name):
        """
        Generate a free project name base on the base name
        """
        names = [p.name for p in self._projects.values()]
        if base_name not in names:
            return base_name
        i = 1

        projects_path = self.projects_directory()

        while True:
            new_name = "{}-{}".format(base_name, i)
            if new_name not in names and not os.path.exists(os.path.join(projects_path, new_name)):
                break
            i += 1
            if i > 1000000:
                raise aiohttp.web.HTTPConflict(text="A project name could not be allocated (node limit reached?)")
        return new_name

    @property
    def projects(self):
        """
        :returns: The dictionary of computes managed by GNS3
        """
        return self._projects

    def projects_directory(self):
        server_config = Config.instance().get_section_config("Server")
        return os.path.expanduser(server_config.get("projects_path", "~/GNS3/projects"))

    @staticmethod
    def instance():
        """
        Singleton to return only on instance of Controller.

        :returns: instance of Controller
        """

        if not hasattr(Controller, '_instance') or Controller._instance is None:
            Controller._instance = Controller()
        return Controller._instance
