#
# Copyright (C) 2015 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/>.

"""
Dynamips server module.
"""

import sys
import os
import shutil
import socket
import time
import asyncio
import tempfile
import logging
import subprocess
import glob
import re

log = logging.getLogger(__name__)

from gns3server.utils.interfaces import interfaces, is_interface_up
from gns3server.utils.asyncio import wait_run_in_executor, subprocess_check_output
from gns3server.utils import parse_version
from uuid import uuid4
from ..base_manager import BaseManager
from ..port_manager import PortManager
from .dynamips_error import DynamipsError
from .hypervisor import Hypervisor
from .nodes.router import Router
from .dynamips_factory import DynamipsFactory

# NIOs
from .nios.nio_udp import NIOUDP
from .nios.nio_unix import NIOUNIX
from .nios.nio_vde import NIOVDE
from .nios.nio_tap import NIOTAP
from .nios.nio_generic_ethernet import NIOGenericEthernet
from .nios.nio_linux_ethernet import NIOLinuxEthernet
from .nios.nio_null import NIONull

# Adapters
from .adapters.c7200_io_2fe import C7200_IO_2FE
from .adapters.c7200_io_fe import C7200_IO_FE
from .adapters.c7200_io_ge_e import C7200_IO_GE_E
from .adapters.nm_16esw import NM_16ESW
from .adapters.nm_1e import NM_1E
from .adapters.nm_1fe_tx import NM_1FE_TX
from .adapters.nm_4e import NM_4E
from .adapters.nm_4t import NM_4T
from .adapters.pa_2fe_tx import PA_2FE_TX
from .adapters.pa_4e import PA_4E
from .adapters.pa_4t import PA_4T
from .adapters.pa_8e import PA_8E
from .adapters.pa_8t import PA_8T
from .adapters.pa_a1 import PA_A1
from .adapters.pa_fe_tx import PA_FE_TX
from .adapters.pa_ge import PA_GE
from .adapters.pa_pos_oc3 import PA_POS_OC3
from .adapters.wic_1enet import WIC_1ENET
from .adapters.wic_1t import WIC_1T
from .adapters.wic_2t import WIC_2T


ADAPTER_MATRIX = {
    "C7200-IO-2FE": C7200_IO_2FE,
    "C7200-IO-FE": C7200_IO_FE,
    "C7200-IO-GE-E": C7200_IO_GE_E,
    "NM-16ESW": NM_16ESW,
    "NM-1E": NM_1E,
    "NM-1FE-TX": NM_1FE_TX,
    "NM-4E": NM_4E,
    "NM-4T": NM_4T,
    "PA-2FE-TX": PA_2FE_TX,
    "PA-4E": PA_4E,
    "PA-4T+": PA_4T,
    "PA-8E": PA_8E,
    "PA-8T": PA_8T,
    "PA-A1": PA_A1,
    "PA-FE-TX": PA_FE_TX,
    "PA-GE": PA_GE,
    "PA-POS-OC3": PA_POS_OC3,
}

WIC_MATRIX = {"WIC-1ENET": WIC_1ENET, "WIC-1T": WIC_1T, "WIC-2T": WIC_2T}


PLATFORMS_DEFAULT_RAM = {
    "c1700": 160,
    "c2600": 160,
    "c2691": 192,
    "c3600": 192,
    "c3725": 128,
    "c3745": 256,
    "c7200": 512,
}


class Dynamips(BaseManager):

    _NODE_CLASS = DynamipsFactory
    _NODE_TYPE = "dynamips"
    _ghost_ios_lock = None

    def __init__(self):

        super().__init__()
        Dynamips._ghost_ios_lock = asyncio.Lock()
        self._devices = {}
        self._ghost_files = set()
        self._dynamips_path = None
        self._dynamips_ids = {}

    @classmethod
    def node_types(cls):
        """
        :returns: List of node type supported by this class and computer
        """
        return ["dynamips", "frame_relay_switch", "atm_switch"]

    def get_dynamips_id(self, project_id):
        """
        :param project_id: UUID of the project
        :returns: a free dynamips id
        """
        self._dynamips_ids.setdefault(project_id, set())
        for dynamips_id in range(1, 4097):
            if dynamips_id not in self._dynamips_ids[project_id]:
                self._dynamips_ids[project_id].add(dynamips_id)
                return dynamips_id
        raise DynamipsError("Maximum number of Dynamips instances reached")

    def take_dynamips_id(self, project_id, dynamips_id):
        """
        Reserve a dynamips id or raise an error

        :param project_id: UUID of the project
        :param dynamips_id: Asked id
        """
        self._dynamips_ids.setdefault(project_id, set())
        if dynamips_id in self._dynamips_ids[project_id]:
            raise DynamipsError(f"Dynamips identifier {dynamips_id} is already used by another router")
        self._dynamips_ids[project_id].add(dynamips_id)

    def release_dynamips_id(self, project_id, dynamips_id):
        """
        A Dynamips id can be reused by another VM

        :param project_id: UUID of the project
        :param dynamips_id: Asked id
        """
        self._dynamips_ids.setdefault(project_id, set())
        if dynamips_id in self._dynamips_ids[project_id]:
            self._dynamips_ids[project_id].remove(dynamips_id)

    async def unload(self):

        await BaseManager.unload(self)

        tasks = []
        for device in self._devices.values():
            tasks.append(asyncio.ensure_future(device.hypervisor.stop()))

        if tasks:
            done, _ = await asyncio.wait(tasks)
            for future in done:
                try:
                    future.result()
                except (Exception, GeneratorExit) as e:
                    log.error(f"Could not stop device hypervisor {e}", exc_info=1)
                    continue

    async def project_closing(self, project):
        """
        Called when a project is about to be closed.

        :param project: Project instance
        """

        await super().project_closing(project)
        # delete the Dynamips devices corresponding to the project
        tasks = []
        for device in self._devices.values():
            if device.project.id == project.id:
                tasks.append(asyncio.ensure_future(device.delete()))

        if tasks:
            done, _ = await asyncio.wait(tasks)
            for future in done:
                try:
                    future.result()
                except (Exception, GeneratorExit) as e:
                    log.error(f"Could not delete device {e}", exc_info=1)

    async def project_closed(self, project):
        """
        Called when a project is closed.

        :param project: Project instance
        """
        await super().project_closed(project)
        # delete useless Dynamips files
        project_dir = project.module_working_path(self.module_name.lower())

        files = glob.glob(os.path.join(glob.escape(project_dir), "*.ghost"))
        files += glob.glob(os.path.join(glob.escape(project_dir), "*", "*_lock"))
        files += glob.glob(os.path.join(glob.escape(project_dir), "*_log.txt"))
        files += glob.glob(os.path.join(glob.escape(project_dir), "*_stdout.txt"))
        files += glob.glob(os.path.join(glob.escape(project_dir), "ilt_*"))
        files += glob.glob(os.path.join(glob.escape(project_dir), "*", "c[0-9][0-9][0-9][0-9]_i[0-9]*_rommon_vars"))
        files += glob.glob(os.path.join(glob.escape(project_dir), "*", "c[0-9][0-9][0-9][0-9]_i[0-9]*_log.txt"))
        for file in files:
            try:
                log.debug(f"Deleting file {file}")
                if file in self._ghost_files:
                    self._ghost_files.remove(file)
                await wait_run_in_executor(os.remove, file)
            except OSError as e:
                log.warning(f"Could not delete file {file}: {e}")
                continue

        # Release the dynamips ids if we want to reload the same project
        # later
        if project.id in self._dynamips_ids:
            del self._dynamips_ids[project.id]

    @property
    def dynamips_path(self):
        """
        Returns the path to Dynamips.

        :returns: path
        """

        return self._dynamips_path

    def find_dynamips(self):

        # look for Dynamips
        dynamips_path = self.config.settings.Dynamips.dynamips_path
        if not os.path.isabs(dynamips_path):
            dynamips_path = shutil.which(dynamips_path)

        if not dynamips_path:
            raise DynamipsError("Could not find Dynamips")
        if not os.path.isfile(dynamips_path):
            raise DynamipsError(f"Dynamips {dynamips_path} is not accessible")
        if not os.access(dynamips_path, os.X_OK):
            raise DynamipsError(f"Dynamips {dynamips_path} is not executable")

        self._dynamips_path = dynamips_path
        return dynamips_path

    @staticmethod
    async def dynamips_version(dynamips_path):
        """
        Gets the Dynamips version

        :param dynamips_path: path to Dynamips executable.
        """

        try:
            output = await subprocess_check_output(dynamips_path, "-P", "none")
            match = re.search(r"Cisco Router Simulation Platform \(version\s+([\d.]+)", output)
            if match:
                version = match.group(1)
                return version
            else:
                raise DynamipsError("Could not determine the Dynamips version for {}".format(dynamips_path))
        except (OSError, subprocess.SubprocessError) as e:
            raise DynamipsError("Error while looking for the Dynamips version: {}".format(e))

    async def start_new_hypervisor(self, working_dir=None):
        """
        Creates a new Dynamips process and start it.

        :param working_dir: working directory

        :returns: the new hypervisor instance
        """

        if not self._dynamips_path:
            self.find_dynamips()

        if not working_dir:
            working_dir = tempfile.gettempdir()

        server_host = self.config.settings.Server.host
        bind_console_host = False

        dynamips_version = await self.dynamips_version(self.dynamips_path)
        if parse_version(dynamips_version) < parse_version('0.2.11'):
            raise DynamipsError("Dynamips version must be >= 0.2.11, detected version is {}".format(dynamips_version))

        if not sys.platform.startswith("win"):
            # Hypervisor should always listen to 127.0.0.1
            # See https://github.com/GNS3/dynamips/issues/62
            # This was fixed in Dynamips v0.2.23 which hasn't been built for Windows
            if parse_version(dynamips_version) >= parse_version('0.2.23'):
                server_host = "127.0.0.1"
                bind_console_host = True

        try:
            info = socket.getaddrinfo(server_host, 0, socket.AF_UNSPEC, socket.SOCK_STREAM, 0, socket.AI_PASSIVE)
            if not info:
                raise DynamipsError(f"getaddrinfo returns an empty list on {server_host}")
            for res in info:
                af, socktype, proto, _, sa = res
                # let the OS find an unused port for the Dynamips hypervisor
                with socket.socket(af, socktype, proto) as sock:
                    sock.bind(sa)
                    port = sock.getsockname()[1]
                    break
        except OSError as e:
            raise DynamipsError(f"Could not find free port for the Dynamips hypervisor: {e}")

        port_manager = PortManager.instance()
        hypervisor = Hypervisor(self._dynamips_path, working_dir, server_host, port, port_manager.console_host, bind_console_host)

        log.info(f"Creating new hypervisor {hypervisor.host}:{hypervisor.port} with working directory {working_dir}")
        await hypervisor.start()
        log.info(f"Hypervisor {hypervisor.host}:{hypervisor.port} has successfully started")
        await hypervisor.connect()
        return hypervisor

    async def ghost_ios_support(self, vm):

        ghost_ios_support = self.config.settings.Dynamips.ghost_ios_support
        if ghost_ios_support:
            async with Dynamips._ghost_ios_lock:
                try:
                    await self._set_ghost_ios(vm)
                except GeneratorExit:
                    log.warning(f"Could not create ghost IOS image {vm.name} (GeneratorExit)")

    async def create_nio(self, node, nio_settings):
        """
        Creates a new NIO.

        :param node: Dynamips node instance
        :param nio_settings: information to create the NIO

        :returns: a NIO object
        """

        nio = None
        if nio_settings["type"] == "nio_udp":
            lport = nio_settings["lport"]
            rhost = nio_settings["rhost"]
            rport = nio_settings["rport"]
            try:
                info = socket.getaddrinfo(rhost, rport, socket.AF_UNSPEC, socket.SOCK_DGRAM, 0, socket.AI_PASSIVE)
                if not info:
                    raise DynamipsError(f"getaddrinfo returns an empty list on {rhost}:{rport}")
                for res in info:
                    af, socktype, proto, _, sa = res
                    with socket.socket(af, socktype, proto) as sock:
                        sock.connect(sa)
            except OSError as e:
                raise DynamipsError(f"Could not create an UDP connection to {rhost}:{rport}: {e}")
            nio = NIOUDP(node, lport, rhost, rport)
            nio.filters = nio_settings.get("filters", {})
            nio.suspend = nio_settings.get("suspend", False)
        elif nio_settings["type"] == "nio_generic_ethernet":
            ethernet_device = nio_settings["ethernet_device"]
            if not is_interface_up(ethernet_device):
                raise DynamipsError(f"Ethernet interface {ethernet_device} is down")
            nio = NIOGenericEthernet(node.hypervisor, ethernet_device)
        elif nio_settings["type"] == "nio_linux_ethernet":
            ethernet_device = nio_settings["ethernet_device"]
            nio = NIOLinuxEthernet(node.hypervisor, ethernet_device)
        elif nio_settings["type"] == "nio_tap":
            tap_device = nio_settings["tap_device"]
            nio = NIOTAP(node.hypervisor, tap_device)
            if not is_interface_up(tap_device):
                # test after the TAP interface has been created (if it doesn't exist yet)
                raise DynamipsError(f"TAP interface {tap_device} is down")
        elif nio_settings["type"] == "nio_unix":
            local_file = nio_settings["local_file"]
            remote_file = nio_settings["remote_file"]
            nio = NIOUNIX(node.hypervisor, local_file, remote_file)
        elif nio_settings["type"] == "nio_vde":
            control_file = nio_settings["control_file"]
            local_file = nio_settings["local_file"]
            nio = NIOVDE(node.hypervisor, control_file, local_file)
        elif nio_settings["type"] == "nio_null":
            nio = NIONull(node.hypervisor)
        else:
            raise DynamipsError("NIO of type {} is not supported".format(nio_settings["type"]))

        await nio.create()
        return nio

    async def _set_ghost_ios(self, vm):
        """
        Manages Ghost IOS support.

        :param vm: VM instance
        """

        if not vm.mmap:
            raise DynamipsError("mmap support is required to enable ghost IOS support")

        if vm.platform == "c7200" and vm.npe == "npe-g2":
            log.warning("Ghost IOS is not supported for c7200 with NPE-G2")
            return

        ghost_file = vm.formatted_ghost_file()

        module_workdir = vm.project.module_working_directory(self.module_name.lower())
        ghost_file_path = os.path.join(module_workdir, ghost_file)
        if ghost_file_path not in self._ghost_files:
            # create a new ghost IOS instance
            ghost_id = str(uuid4())
            ghost = Router(
                "ghost-" + ghost_file,
                ghost_id,
                vm.project,
                vm.manager,
                platform=vm.platform,
                hypervisor=vm.hypervisor,
                ghost_flag=True,
            )
            try:
                await ghost.create()
                await ghost.set_image(vm.image)
                await ghost.set_ghost_status(1)
                await ghost.set_ghost_file(ghost_file_path)
                await ghost.set_ram(vm.ram)
                try:
                    await ghost.start()
                    await ghost.stop()
                    self._ghost_files.add(ghost_file_path)
                except DynamipsError:
                    raise
                finally:
                    await ghost.clean_delete()
            except DynamipsError as e:
                log.warning(f"Could not create ghost instance: {e}")

        if vm.ghost_file != ghost_file and os.path.isfile(ghost_file_path):
            # set the ghost file to the router
            await vm.set_ghost_status(2)
            await vm.set_ghost_file(ghost_file_path)

    async def update_vm_settings(self, vm, settings):
        """
        Updates the VM settings.

        :param vm: VM instance
        :param settings: settings to update (dict)
        """

        for name, value in settings.items():
            if hasattr(vm, name) and getattr(vm, name) != value:
                if hasattr(vm, f"set_{name}"):
                    setter = getattr(vm, f"set_{name}")
                    await setter(value)
            elif name.startswith("slot") and value in ADAPTER_MATRIX:
                slot_id = int(name[-1])
                adapter_name = value
                adapter = ADAPTER_MATRIX[adapter_name]()
                try:
                    if vm.slots[slot_id] and not isinstance(vm.slots[slot_id], type(adapter)):
                        await vm.slot_remove_binding(slot_id)
                    if not isinstance(vm.slots[slot_id], type(adapter)):
                        await vm.slot_add_binding(slot_id, adapter)
                except IndexError:
                    raise DynamipsError(f"Slot {slot_id} doesn't exist on this router")
            elif name.startswith("slot") and (value is None or value == ""):
                slot_id = int(name[-1])
                try:
                    if vm.slots[slot_id]:
                        await vm.slot_remove_binding(slot_id)
                except IndexError:
                    raise DynamipsError(f"Slot {slot_id} doesn't exist on this router")
            elif name.startswith("wic") and value in WIC_MATRIX:
                wic_slot_id = int(name[-1])
                wic_name = value
                wic = WIC_MATRIX[wic_name]()
                try:
                    if vm.slots[0].wics[wic_slot_id] and not isinstance(vm.slots[0].wics[wic_slot_id], type(wic)):
                        await vm.uninstall_wic(wic_slot_id)
                    if not isinstance(vm.slots[0].wics[wic_slot_id], type(wic)):
                        await vm.install_wic(wic_slot_id, wic)
                except IndexError:
                    raise DynamipsError(f"WIC slot {wic_slot_id} doesn't exist on this router")
            elif name.startswith("wic") and (value is None or value == ""):
                wic_slot_id = int(name[-1])
                try:
                    if vm.slots[0].wics and vm.slots[0].wics[wic_slot_id]:
                        await vm.uninstall_wic(wic_slot_id)
                except IndexError:
                    raise DynamipsError(f"WIC slot {wic_slot_id} doesn't exist on this router")

        mmap_support = self.config.settings.Dynamips.mmap_support
        if mmap_support is False:
            await vm.set_mmap(False)

        sparse_memory_support = self.config.settings.Dynamips.sparse_memory_support
        if sparse_memory_support is False:
            await vm.set_sparsemem(False)

        usage = settings.get("usage")
        if usage is not None and usage != vm.usage:
            vm.usage = usage

        # update the configs if needed
        await self.set_vm_configs(vm, settings)

    async def set_vm_configs(self, vm, settings):
        """
        Set VM configs from pushed content or existing config files.

        :param vm: VM instance
        :param settings: VM settings
        """

        startup_config_content = settings.get("startup_config_content")
        if startup_config_content:
            self._create_config(vm, vm.startup_config_path, startup_config_content)
        private_config_content = settings.get("private_config_content")
        if private_config_content:
            self._create_config(vm, vm.private_config_path, private_config_content)

    def _create_config(self, vm, path, content=None):
        """
        Creates a config file.

        :param vm: VM instance
        :param path: path to the destination config file
        :param content: config content

        :returns: relative path to the created config file
        """

        log.info(f"Creating config file {path}")
        config_dir = os.path.dirname(path)
        try:
            os.makedirs(config_dir, exist_ok=True)
        except OSError as e:
            raise DynamipsError(f"Could not create Dynamips configs directory: {e}")

        if content is None or len(content) == 0:
            content = "!\n"
            if os.path.exists(path):
                return

        try:
            with open(path, "wb") as f:
                if content:
                    content = "!\n" + content.replace("\r", "")
                    content = content.replace("%h", vm.name)
                    f.write(content.encode("utf-8"))
        except OSError as e:
            raise DynamipsError(f"Could not create config file '{path}': {e}")

        return os.path.join("configs", os.path.basename(path))

    async def auto_idlepc(self, vm):
        """
        Try to find the best possible idle-pc value.

        :param vm: VM instance
        """

        await vm.set_idlepc("0x0")
        was_auto_started = False
        try:
            status = await vm.get_status()
            if status != "running":
                await vm.start()
                was_auto_started = True
                await asyncio.sleep(20)  # leave time to the router to boot
            validated_idlepc = None
            idlepcs = await vm.get_idle_pc_prop()
            if not idlepcs:
                raise DynamipsError("No Idle-PC values found")

            for idlepc in idlepcs:
                match = re.search(r"^0x[0-9a-f]{8}$", idlepc.split()[0])
                if not match:
                    continue
                await vm.set_idlepc(idlepc.split()[0])
                log.debug(f"Auto Idle-PC: trying idle-PC value {vm.idlepc}")
                start_time = time.time()
                initial_cpu_usage = await vm.get_cpu_usage()
                log.debug(f"Auto Idle-PC: initial CPU usage is {initial_cpu_usage}%")
                await asyncio.sleep(3)  # wait 3 seconds to probe the cpu again
                elapsed_time = time.time() - start_time
                cpu_usage = await vm.get_cpu_usage()
                cpu_elapsed_usage = cpu_usage - initial_cpu_usage
                cpu_usage = abs(cpu_elapsed_usage * 100.0 / elapsed_time)
                if cpu_usage > 100:
                    cpu_usage = 100
                log.debug(f"Auto Idle-PC: CPU usage is {cpu_usage}% after {elapsed_time:.2} seconds")
                if cpu_usage < 70:
                    validated_idlepc = vm.idlepc
                    log.debug(f"Auto Idle-PC: idle-PC value {validated_idlepc} has been validated")
                    break

            if validated_idlepc is None:
                raise DynamipsError("Sorry, no idle-pc value was suitable")

        except DynamipsError:
            raise
        finally:
            if was_auto_started:
                await vm.stop()
        return validated_idlepc

    async def duplicate_node(self, source_node_id, destination_node_id):
        """
        Duplicate a node

        :param node_id: Node identifier
        :returns: New node instance
        """

        source_node = self.get_node(source_node_id)
        destination_node = self.get_node(destination_node_id)

        # Not a Dynamips router
        if not hasattr(source_node, "startup_config_path"):
            return await super().duplicate_node(source_node_id, destination_node_id)

        try:
            with open(source_node.startup_config_path) as f:
                startup_config = f.read()
        except OSError:
            startup_config = None
        try:
            with open(source_node.private_config_path) as f:
                private_config = f.read()
        except OSError:
            private_config = None
        await self.set_vm_configs(
            destination_node, {"startup_config_content": startup_config, "private_config_content": private_config}
        )

        # Force refresh of the name in configuration files
        new_name = destination_node.name
        await destination_node.set_name(source_node.name)
        await destination_node.set_name(new_name)
        return destination_node