# -*- coding: utf-8 -*-
#
# Copyright (C) 2013 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/>.

"""
Interface for Dynamips hypervisor management module ("hypervisor")
http://github.com/GNS3/dynamips/blob/master/README.hypervisor#L46
"""

import socket
import errno
import re
import logging
from .dynamips_error import DynamipsError

log = logging.getLogger(__name__)


class DynamipsHypervisor(object):
    """
    Creates a new connection to a Dynamips server (also called hypervisor)

    :param working_dir: working directory
    :param host: the hostname or ip address string of the Dynamips server
    :param port: the tcp port integer (defaults to 7200)
    :param timeout: timeout integer for how long to wait for a response to commands sent to the
    hypervisor (defaults to 30 seconds)
    """

    # Used to parse Dynamips response codes
    error_re = re.compile(r"""^2[0-9]{2}-""")
    success_re = re.compile(r"""^1[0-9]{2}\s{1}""")

    def __init__(self, working_dir, host, port=7200, timeout=30.0):

        self._host = host
        self._port = port

        self._devices = []
        self._ghosts = {}
        self._jitsharing_groups = {}
        self._working_dir = working_dir
        self._baseconsole = 2000
        self._baseaux = 2100
        self._baseudp = 10000
        self._current_udp_port = self._baseudp
        self._version = "N/A"
        self._timeout = 30
        self._socket = None
        self._uuid = None

    def connect(self):
        """
        Connects to the hypervisor.
        """

        # connect to a local address by default
        # if listening to all addresses (IPv4 or IPv6)
        if self._host == "0.0.0.0":
            host = "127.0.0.1"
        elif self._host == "::":
            host = "::1"
        else:
            host = self._host

        try:
            self._socket = socket.create_connection((host,
                                                     self._port),
                                                     self._timeout)
        except OSError as e:
            raise DynamipsError("Could not connect to server: {}".format(e))

        try:
            self._version = self.send("hypervisor version")[0].split("-", 1)[0]
        except IndexError:
            self._version = "Unknown"

        self._uuid = self.send("hypervisor uuid")

    @property
    def version(self):
        """
        Returns Dynamips version.

        :returns: version string
        """

        return self._version

    def module_list(self):
        """
        Returns the modules supported by this hypervisor.

        :returns: module list
        """

        return self.send("hypervisor module_list")

    def cmd_list(self, module):
        """
        Returns commands recognized by the specified module.

        :param module: the module name
        :returns: command list
        """

        return self.send("hypervisor cmd_list {}".format(module))

    def close(self):
        """
        Closes the connection to this hypervisor (but leave it running).
        """

        self.send("hypervisor close")
        self._socket.close()
        self._socket = None

    def stop(self):
        """
        Stops this hypervisor (will no longer run).
        """

        self.send("hypervisor stop")
        self._socket.close()
        self._socket = None

    def reset(self):
        """
        Resets this hypervisor (used to get an empty configuration).
        """

        self.send('hypervisor reset')

    @property
    def working_dir(self):
        """
        Returns current working directory

        :returns: path to the working directory
        """

        return self._working_dir

    @working_dir.setter
    def working_dir(self, working_dir):
        """
        Sets the working directory for this hypervisor.

        :param working_dir: path to the working directory
        """

        # encase working_dir in quotes to protect spaces in the path
        self.send("hypervisor working_dir {}".format('"' + working_dir + '"'))
        self._working_dir = working_dir
        log.debug("working directory set to {}".format(self._working_dir))

    def save_config(self, filename):
        """
        Saves the configuration of all Dynamips instances into the specified file.

        :param filename: path string
        """

        # encase working_dir in quotes to protect spaces in the path
        self.send("hypervisor save_config {}".format('"' + filename + '"'))

    @property
    def uuid(self):
        """
        Returns this hypervisor UUID.

        :Returns: uuid string
        """

        return self._uuid

    @property
    def socket(self):
        """
        Returns the current socket used to communicate with this hypervisor.

        :returns: socket instance
        """

        assert self._socket
        return self._socket

    @property
    def devices(self):
        """
        Returns the list of devices managed by this hypervisor instance.

        :returns: a list of device instances
        """

        return self._devices

    @devices.setter
    def devices(self, devices):
        """
        Sets the list of devices managed by this hypervisor instance.
        This method is for internal use.

        :param devices: a list of device objects
        """

        self._devices = devices

    @property
    def baseconsole(self):
        """
        Returns base console TCP port for this hypervisor.

        :returns: base console value (integer)
        """

        return self._baseconsole

    @baseconsole.setter
    def baseconsole(self, baseconsole):
        """
        Sets the base console TCP port for this hypervisor.

        :param baseconsole: base console value (integer)
        """

        self._baseconsole = baseconsole

    @property
    def baseaux(self):
        """
        Returns base auxiliary port for this hypervisor.

        :returns: base auxiliary port value (integer)
        """

        return self._baseaux

    @baseaux.setter
    def baseaux(self, baseaux):
        """
        Sets the base auxiliary TCP port for this hypervisor.

        :param baseaux: base auxiliary port value (integer)
        """

        self._baseaux = baseaux

    @property
    def baseudp(self):
        """
        Returns the next available UDP port for UDP NIOs.

        :returns: base UDP port value (integer)
        """

        return self._baseudp

    @baseudp.setter
    def baseudp(self, baseudp):
        """
        Sets the next open UDP port for NIOs for this hypervisor.

        :param baseudp: base UDP port value (integer)
        """

        self._baseudp = baseudp
        self._current_udp_port = self._baseudp

        #FIXME
        log.info("hypervisor a new base UDP {}".format(self._baseudp))

    @property
    def ghosts(self):
        """
        Returns a list of the ghosts hosted by this hypervisor.

        :returns: Ghosts dict (image_name -> device)
        """

        return self._ghosts

    def add_ghost(self, image_name, router):
        """
        Adds a ghost name to the list of ghosts created on this hypervisor.

        :param image_name: name of the ghost image
        :param router: Router instance
        """

        self._ghosts[image_name] = router

    @property
    def jitsharing_groups(self):
        """
        Returns a list of the JIT sharing groups hosted by this hypervisor.

        :returns: JIT sharing groups dict (image_name -> group number)
        """

        return self._jitsharing_groups

    def add_jitsharing_group(self, image_name, group_number):
        """
        Adds a JIT blocks sharing group name to the list of groups created on this hypervisor.

        :param image_name: name of the ghost image
        :param group_number: group (integer)
        """

        self._jitsharing_groups[image_name] = group_number

    @property
    def host(self):
        """
        Returns this hypervisor host.

        :returns: host (string)
        """

        return self._host

    @property
    def port(self):
        """
        Returns this hypervisor port.

        :returns: port (integer)
        """

        return self._port

    @staticmethod
    def find_unused_port(start_port, end_port, host='127.0.0.1', socket_type="TCP"):
        """
        Finds an unused port in a range.

        :param start_port: first port in the range
        :param end_port: last port in the range
        :param host: host/address for bind()
        :param socket_type: TCP (default) or UDP
        """

        if socket_type == "UDP":
            socket_type = socket.SOCK_DGRAM
        else:
            socket_type = socket.SOCK_STREAM

        for port in range(start_port, end_port):
            try:
                if ":" in host:
                    # IPv6 address support
                    with socket.socket(socket.AF_INET6, socket_type) as s:
                        s.bind((host, port))  # the port is available if bind is a success
                else:
                    with socket.socket(socket.AF_INET, socket_type) as s:
                        s.bind((host, port))  # the port is available if bind is a success
                return port
            except OSError as e:
                if e.errno == errno.EADDRINUSE:  # socket already in use
                    if port + 1 == end_port:
                        raise DynamipsError("Could not find a free port between {0} and {1}".format(start_port, end_port))
                    else:
                        continue
                else:
                    raise DynamipsError("Could not find an unused port: {}".format(e))

    def allocate_udp_port(self, max_port=100):
        """
        Allocates a new UDP port for creating an UDP NIO.

        :param max_port: maximum number of port to scan in
        order to find one available for use.

        :returns: port number (integer)
        """

        start_port = self._current_udp_port
        end_port = start_port + max_port
        allocated_port = DynamipsHypervisor.find_unused_port(start_port, end_port, self._host, socket_type="UDP")
        if allocated_port - self._current_udp_port > 1:
            self._current_udp_port += allocated_port - self._current_udp_port
        else:
            self._current_udp_port += 1
        return allocated_port

    def send_raw(self, string):
        """
        Sends a raw command to this hypervisor. Use sparingly.

        :param string: command string.

        :returns: command result (string)
        """

        result = self.send(string)
        return result

    def send(self, command):
        """
        Sends commands to this hypervisor.

        :param command: a Dynamips hypervisor command

        :returns: results as a list
        """

        # Dynamips responses are of the form:
        #   1xx yyyyyy\r\n
        #   1xx yyyyyy\r\n
        #   ...
        #   100-yyyy\r\n
        # or
        #   2xx-yyyy\r\n
        #
        # Where 1xx is a code from 100-199 for a success or 200-299 for an error
        # The result might be multiple lines and might be less than the buffer size
        # but still have more data. The only thing we know for sure is the last line
        # will begin with '100-' or a '2xx-' and end with '\r\n'

        if not self._socket:
            raise DynamipsError("Not connected")

        try:
            command = command.strip() + '\n'
            log.debug("sending {}".format(command))
            self.socket.sendall(command.encode('utf-8'))
        except OSError as e:
            raise DynamipsError("Lost communication with {host}:{port} :{error}"
                                   .format(host=self._host, port=self._port, error=e))

        # Now retrieve the result
        data = []
        buf = ''
        while True:
            try:
                chunk = self.socket.recv(1024)  # match to Dynamips' buffer size
                buf += chunk.decode("utf-8")
            except OSError as e:
                raise DynamipsError("Communication timed out with {host}:{port} :{error}"
                                       .format(host=self._host, port=self._port, error=e))

            # If the buffer doesn't end in '\n' then we can't be done
            try:
                if buf[-1] != '\n':
                    continue
            except IndexError:
                raise DynamipsError("Could not communicate with {host}:{port}"
                                    .format(host=self._host, port=self._port))

            data += buf.split('\r\n')
            if data[-1] == '':
                data.pop()
            buf = ''

            if len(data) == 0:
                raise DynamipsError("no data returned from {host}:{port}"
                                    .format(host=self._host, port=self._port))

            # Does it contain an error code?
            if self.error_re.search(data[-1]):
                raise DynamipsError(data[-1][4:])

            # Or does the last line begin with '100-'? Then we are done!
            if data[-1][:4] == '100-':
                data[-1] = data[-1][4:]
                if data[-1] == 'OK':
                    data.pop()
                break

        # Remove success responses codes
        for index in range(len(data)):
            if self.success_re.search(data[index]):
                data[index] = data[index][4:]

        log.debug("returned result {}".format(data))
        return data