#!/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 shutil
import asyncio
import aiohttp

from ..config import Config
from .project import Project
from .appliance import Appliance
from .appliance_template import ApplianceTemplate
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 ..utils.get_resource import get_resource
from ..utils.asyncio import locking
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()

        # FIXME: store settings shared by the different GUI will be replace by dedicated API later
        self._settings = None
        self._appliances = {}
        self._appliance_templates = {}
        self._appliance_templates_etag = None

        self._config_file = os.path.join(Config.instance().config_dir, "gns3_controller.conf")
        log.info("Load controller configuration file {}".format(self._config_file))

    @locking
    async def download_appliance_templates(self):

        try:
            headers = {}
            if self._appliance_templates_etag:
                log.info("Checking if appliance templates are up-to-date (ETag {})".format(self._appliance_templates_etag))
                headers["If-None-Match"] = self._appliance_templates_etag
            async with aiohttp.ClientSession() as session:
                async with session.get('https://api.github.com/repos/GNS3/gns3-registry/contents/appliances', headers=headers) as response:
                    if response.status == 304:
                        log.info("Appliance templates are already up-to-date (ETag {})".format(self._appliance_templates_etag))
                        return
                    elif response.status != 200:
                        raise aiohttp.web.HTTPConflict(text="Could not retrieve appliance templates on GitHub due to HTTP error code {}".format(response.status))
                    etag = response.headers.get("ETag")
                    if etag:
                        self._appliance_templates_etag = etag
                        self.save()
                    json_data = await response.json()
                appliances_dir = get_resource('appliances')
                for appliance in json_data:
                    if appliance["type"] == "file":
                        appliance_name = appliance["name"]
                        log.info("Download appliance template file from '{}'".format(appliance["download_url"]))
                        async with session.get(appliance["download_url"]) as response:
                            if response.status != 200:
                                log.warning("Could not download '{}' due to HTTP error code {}".format(appliance["download_url"], response.status))
                                continue
                            try:
                                appliance_data = await response.read()
                            except asyncio.TimeoutError:
                                log.warning("Timeout while downloading '{}'".format(appliance["download_url"]))
                                continue
                            path = os.path.join(appliances_dir, appliance_name)
                            try:
                                log.info("Saving {} file to {}".format(appliance_name, path))
                                with open(path, 'wb') as f:
                                    f.write(appliance_data)
                            except OSError as e:
                                raise aiohttp.web.HTTPConflict(text="Could not write appliance template file '{}': {}".format(path, e))
        except ValueError as e:
            raise aiohttp.web.HTTPConflict(text="Could not read appliance templates information from GitHub: {}".format(e))

    def load_appliance_templates(self):

        self._appliance_templates = {}
        for directory, builtin in ((get_resource('appliances'), True,), (self.appliances_path(), False,)):
            if directory and os.path.isdir(directory):
                for file in os.listdir(directory):
                    if not file.endswith('.gns3a') and not file.endswith('.gns3appliance'):
                        continue
                    path = os.path.join(directory, file)
                    appliance_id = uuid.uuid3(uuid.NAMESPACE_URL, path)  # Generate UUID from path to avoid change between reboots
                    try:
                        with open(path, 'r', encoding='utf-8') as f:
                            appliance = ApplianceTemplate(appliance_id, json.load(f), builtin=builtin)
                            appliance.__json__()  # Check if loaded without error
                        if appliance.status != 'broken':
                            self._appliance_templates[appliance.id] = appliance
                    except (ValueError, OSError, KeyError) as e:
                        log.warning("Cannot load appliance template file '%s': %s", path, str(e))
                        continue

    def load_appliances(self):

        self._appliances = {}
        vms = []
        for vm in self._settings.get("Qemu", {}).get("vms", []):
            vm["node_type"] = "qemu"
            vms.append(vm)
        for vm in self._settings.get("IOU", {}).get("devices", []):
            vm["node_type"] = "iou"
            vms.append(vm)
        for vm in self._settings.get("Docker", {}).get("containers", []):
            vm["node_type"] = "docker"
            vms.append(vm)
        for vm in self._settings.get("Builtin", {}).get("cloud_nodes", []):
            vm["node_type"] = "cloud"
            vms.append(vm)
        for vm in self._settings.get("Builtin", {}).get("ethernet_switches", []):
            vm["node_type"] = "ethernet_switch"
            vms.append(vm)
        for vm in self._settings.get("Builtin", {}).get("ethernet_hubs", []):
            vm["node_type"] = "ethernet_hub"
            vms.append(vm)
        for vm in self._settings.get("Dynamips", {}).get("routers", []):
            vm["node_type"] = "dynamips"
            vms.append(vm)
        for vm in self._settings.get("VMware", {}).get("vms", []):
            vm["node_type"] = "vmware"
            vms.append(vm)
        for vm in self._settings.get("VirtualBox", {}).get("vms", []):
            vm["node_type"] = "virtualbox"
            vms.append(vm)
        for vm in self._settings.get("VPCS", {}).get("nodes", []):
            vm["node_type"] = "vpcs"
            vms.append(vm)
        for vm in self._settings.get("TraceNG", {}).get("nodes", []):
            vm["node_type"] = "traceng"
            vms.append(vm)

        for vm in vms:
            # remove deprecated properties
            for prop in vm.copy():
                if prop in ["enable_remote_console", "use_ubridge", "acpi_shutdown"]:
                    del vm[prop]

            # remove deprecated default_symbol and hover_symbol
            # and set symbol if not present
            deprecated = ["default_symbol", "hover_symbol"]
            if len([prop for prop in vm.keys() if prop in deprecated]) > 0:
                if "default_symbol" in vm.keys():
                    del vm["default_symbol"]
                if "hover_symbol" in vm.keys():
                    del vm["hover_symbol"]

                if "symbol" not in vm.keys():
                    vm["symbol"] = ":/symbols/computer.svg"

            vm.setdefault("appliance_id", str(uuid.uuid4()))
            try:
                appliance = Appliance(vm["appliance_id"], vm)
                appliance.__json__()  # Check if loaded without error
                self._appliances[appliance.id] = appliance
            except KeyError as e:
                # appliance data is not complete (missing name or type)
                log.warning("Cannot load appliance template {} ('{}'): missing key {}".format(vm["appliance_id"], vm.get("name", "unknown"), e))
                continue

        # Add builtins
        builtins = []
        builtins.append(Appliance(uuid.uuid3(uuid.NAMESPACE_DNS, "cloud"), {"node_type": "cloud", "name": "Cloud", "category": 2, "symbol": ":/symbols/cloud.svg"}, builtin=True))
        builtins.append(Appliance(uuid.uuid3(uuid.NAMESPACE_DNS, "nat"), {"node_type": "nat", "name": "NAT", "category": 2, "symbol": ":/symbols/cloud.svg"}, builtin=True))
        builtins.append(Appliance(uuid.uuid3(uuid.NAMESPACE_DNS, "vpcs"), {"node_type": "vpcs", "name": "VPCS", "default_name_format": "PC-{0}", "category": 2, "symbol": ":/symbols/vpcs_guest.svg", "properties": {"base_script_file": "vpcs_base_config.txt"}}, builtin=True))
        builtins.append(Appliance(uuid.uuid3(uuid.NAMESPACE_DNS, "ethernet_switch"), {"node_type": "ethernet_switch", "console_type": "telnet", "name": "Ethernet switch", "category": 1, "symbol": ":/symbols/ethernet_switch.svg"}, builtin=True))
        builtins.append(Appliance(uuid.uuid3(uuid.NAMESPACE_DNS, "ethernet_hub"), {"node_type": "ethernet_hub", "name": "Ethernet hub", "category": 1, "symbol": ":/symbols/hub.svg"}, builtin=True))
        builtins.append(Appliance(uuid.uuid3(uuid.NAMESPACE_DNS, "frame_relay_switch"), {"node_type": "frame_relay_switch", "name": "Frame Relay switch", "category": 1, "symbol": ":/symbols/frame_relay_switch.svg"}, builtin=True))
        builtins.append(Appliance(uuid.uuid3(uuid.NAMESPACE_DNS, "atm_switch"), {"node_type": "atm_switch", "name": "ATM switch", "category": 1, "symbol": ":/symbols/atm_switch.svg"}, builtin=True))

        #FIXME: disable TraceNG
        #if sys.platform.startswith("win"):
        #    builtins.append(Appliance(uuid.uuid3(uuid.NAMESPACE_DNS, "traceng"), {"node_type": "traceng", "name": "TraceNG", "default_name_format": "TraceNG-{0}", "category": 2, "symbol": ":/symbols/traceng.svg", "properties": {}}, builtin=True))
        for b in builtins:
            self._appliances[b.id] = b

    async def start(self):

        log.info("Controller is starting")
        self.load_base_files()
        server_config = Config.instance().get_section_config("Server")
        Config.instance().listen_for_config_changes(self._update_config)
        host = server_config.get("host", "localhost")
        port = server_config.getint("port", 3080)

        # clients will use the IP they use to connect to
        # the controller if console_host is 0.0.0.0
        console_host = host
        if host == "0.0.0.0":
            host = "127.0.0.1"

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

        computes = await self._load_controller_settings()
        try:
            self._local_server = await self.add_compute(compute_id="local",
                                                             name=name,
                                                             protocol=server_config.get("protocol", "http"),
                                                             host=host,
                                                             console_host=console_host,
                                                             port=port,
                                                             user=server_config.get("user", ""),
                                                             password=server_config.get("password", ""),
                                                             force=True)
        except aiohttp.web.HTTPConflict as e:
            log.fatal("Cannot access to the local server, make sure something else is not running on the TCP port {}".format(port))
            sys.exit(1)
        for c in computes:
            try:
                await self.add_compute(**c)
            except (aiohttp.web.HTTPError, KeyError):
                pass  # Skip not available servers at loading
        await self.load_projects()
        try:
            await self.gns3vm.auto_start_vm()
        except GNS3VMError as e:
            log.warning(str(e))
        await self._project_auto_open()

    def _update_config(self):
        """
        Call this when the server configuration file changes.
        """

        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")

    async def stop(self):

        log.info("Controller is Stopping")
        for project in self._projects.values():
            await project.close()
        for compute in self._computes.values():
            try:
                await compute.close()
            # We don't care if a compute is down at this step
            except (ComputeError, aiohttp.web.HTTPError, OSError):
                pass
        await 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__(),
            "appliance_templates_etag": self._appliance_templates_etag,
            "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("Cannnot write configuration file '{}': {}".format(self._config_file, e))

    async def _load_controller_settings(self):
        """
        Reload the controller configuration from disk
        """

        try:
            if not os.path.exists(self._config_file):
                await 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 configuration file '{}': {}".format(self._config_file, 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"]

        self._appliance_templates_etag = data.get("appliance_templates_etag")
        self.load_appliance_templates()
        self.load_appliances()
        return data.get("computes", [])

    async 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:
                                await self.load_project(os.path.join(project_dir, file), load=False)
                            except (aiohttp.web.HTTPConflict, NotImplementedError):
                                pass  # Skip not compatible projects
        except OSError as e:
            log.error(str(e))

    def load_base_files(self):
        """
        At startup we copy base file to the user location to allow
        them to customize it
        """

        dst_path = self.configs_path()
        src_path = get_resource('configs')
        try:
            for file in os.listdir(src_path):
                if not os.path.exists(os.path.join(dst_path, file)):
                    shutil.copy(os.path.join(src_path, file), os.path.join(dst_path, file))
        except OSError:
            pass

    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

    def configs_path(self):
        """
        Get the configs storage directory
        """

        server_config = Config.instance().get_section_config("Server")
        images_path = os.path.expanduser(server_config.get("configs_path", "~/GNS3/projects"))
        os.makedirs(images_path, exist_ok=True)
        return images_path

    def appliances_path(self):
        """
        Get the image storage directory
        """

        server_config = Config.instance().get_section_config("Server")
        appliances_path = os.path.expanduser(server_config.get("appliances_path", "~/GNS3/projects"))
        os.makedirs(appliances_path, exist_ok=True)
        return appliances_path

    async 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:
                        await 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 to help the gui to detect changes
        self.save()
        self.load_appliance_templates()
        self.load_appliances()
        self.notification.controller_emit("settings.updated", val)

    async 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:
                await compute.connect()
            self.notification.controller_emit("compute.created", compute.__json__())
            return compute
        else:
            if connect:
                await self._computes[compute_id].connect()
            self.notification.controller_emit("compute.updated", self._computes[compute_id].__json__())
            return self._computes[compute_id]

    async def close_compute_projects(self, compute):
        """
        Close projects running on a compute
        """

        for project in self._projects.values():
            if compute in project.computes:
                await project.close()

    def compute_has_open_project(self, compute):
        """
        Check is compute has a project opened.

        :returns: True if a project is open
        """

        for project in self._projects.values():
            if compute in project.computes and project.status == "opened":
                return True
        return False

    async 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
        await self.close_compute_projects(compute)
        await compute.close()
        del self._computes[compute_id]
        self.save()
        self.notification.controller_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="Cannot use a node on the GNS3 VM server with the GNS3 VM 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

    async def add_project(self, project_id=None, name=None, path=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:
                    if path and path == project.path:
                        raise aiohttp.web.HTTPConflict(text='Project "{}" already exists in location "{}"'.format(name, path))
                    else:
                        raise aiohttp.web.HTTPConflict(text='Project "{}" already exists'.format(name))
            project = Project(project_id=project_id, controller=self, name=name, path=path, **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))

    async 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)
        await project.wait_loaded()
        return project

    def remove_project(self, project):

        if project.id in self._projects:
            del self._projects[project.id]

    async 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 = await self.add_project(path=os.path.dirname(path), status="closed", filename=os.path.basename(path), **topo_data)
        if load or project.auto_open:
            await project.open()
        return project

    async def _project_auto_open(self):
        """
        Auto open the project with auto open enable
        """

        for project in self._projects.values():
            if project.auto_open:
                await 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 projects managed by GNS3
        """

        return self._projects

    @property
    def appliance_templates(self):
        """
        :returns: The dictionary of appliances templates managed by GNS3
        """

        return self._appliance_templates

    @property
    def appliances(self):
        """
        :returns: The dictionary of appliances managed by GNS3
        """

        return self._appliances

    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

    async def autoidlepc(self, compute_id, platform, image, ram):
        """
        Compute and IDLE PC value for an image

        :param compute_id: ID of the compute where the idlepc operation need to run
        :param platform: Platform type
        :param image: Image to use
        :param ram: amount of RAM to use
        """

        compute = self.get_compute(compute_id)
        for project in list(self._projects.values()):
            if project.name == "AUTOIDLEPC":
                await project.delete()
                self.remove_project(project)
        project = await self.add_project(name="AUTOIDLEPC")
        node = await project.add_node(compute, "AUTOIDLEPC", str(uuid.uuid4()), node_type="dynamips", platform=platform, image=image, ram=ram)
        res = await node.dynamips_auto_idlepc()
        await project.delete()
        self.remove_project(project)
        return res

    async def compute_ports(self, compute_id):
        """
        Get the ports used by a compute.

        :param compute_id: ID of the compute
        """

        compute = self.get_compute(compute_id)
        response = await compute.get("/network/ports")
        return response.json