# -*- coding: utf-8 -*-
# BSD 3-Clause License
#
# Apprise - Push Notification Library.
# Copyright (c) 2023, Chris Caron <lead2gold@gmail.com>
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
# 1. Redistributions of source code must retain the above copyright notice,
#    this list of conditions and the following disclaimer.
#
# 2. Redistributions in binary form must reproduce the above copyright notice,
#    this list of conditions and the following disclaimer in the documentation
#    and/or other materials provided with the distribution.
#
# 3. Neither the name of the copyright holder nor the names of its
#    contributors may be used to endorse or promote products derived from
#    this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGE.

# Great sources
# - https://github.com/matrix-org/matrix-python-sdk
# - https://github.com/matrix-org/synapse/blob/master/docs/reverse_proxy.rst
#
import re
import requests
from markdown import markdown
from json import dumps
from json import loads
from time import time

from .NotifyBase import NotifyBase
from ..URLBase import PrivacyMode
from ..common import NotifyType
from ..common import NotifyImageSize
from ..common import NotifyFormat
from ..utils import parse_bool
from ..utils import parse_list
from ..utils import is_hostname
from ..utils import validate_regex
from ..AppriseLocale import gettext_lazy as _

# Define default path
MATRIX_V1_WEBHOOK_PATH = '/api/v1/matrix/hook'
MATRIX_V2_API_PATH = '/_matrix/client/r0'
MATRIX_V3_API_PATH = '/_matrix/client/v3'
MATRIX_V3_MEDIA_PATH = '/_matrix/media/v3'
MATRIX_V2_MEDIA_PATH = '/_matrix/media/r0'

# Extend HTTP Error Messages
MATRIX_HTTP_ERROR_MAP = {
    403: 'Unauthorized - Invalid Token.',
    429: 'Rate limit imposed; wait 2s and try again',
}

# Matrix Room Syntax
IS_ROOM_ALIAS = re.compile(
    r'^\s*(#|%23)?(?P<room>[a-z0-9-]+)((:|%3A)'
    r'(?P<home_server>[a-z0-9.-]+))?\s*$', re.I)

# Room ID MUST start with an exclamation to avoid ambiguity
IS_ROOM_ID = re.compile(
    r'^\s*(!|&#33;|%21)(?P<room>[a-z0-9-]+)((:|%3A)'
    r'(?P<home_server>[a-z0-9.-]+))?\s*$', re.I)


class MatrixMessageType:
    """
    The Matrix Message types
    """
    TEXT = "text"
    NOTICE = "notice"


# matrix message types are placed into this list for validation purposes
MATRIX_MESSAGE_TYPES = (
    MatrixMessageType.TEXT,
    MatrixMessageType.NOTICE,
)


class MatrixVersion:
    # Version 2
    V2 = "2"

    # Version 3
    V3 = "3"


# webhook modes are placed into this list for validation purposes
MATRIX_VERSIONS = (
    MatrixVersion.V2,
    MatrixVersion.V3,
)


class MatrixWebhookMode:
    # Webhook Mode is disabled
    DISABLED = "off"

    # The default webhook mode is to just be set to Matrix
    MATRIX = "matrix"

    # Support the slack webhook plugin
    SLACK = "slack"

    # Support the t2bot webhook plugin
    T2BOT = "t2bot"


# webhook modes are placed into this list for validation purposes
MATRIX_WEBHOOK_MODES = (
    MatrixWebhookMode.DISABLED,
    MatrixWebhookMode.MATRIX,
    MatrixWebhookMode.SLACK,
    MatrixWebhookMode.T2BOT,
)


class NotifyMatrix(NotifyBase):
    """
    A wrapper for Matrix Notifications
    """

    # The default descriptive name associated with the Notification
    service_name = 'Matrix'

    # The services URL
    service_url = 'https://matrix.org/'

    # The default protocol
    protocol = 'matrix'

    # The default secure protocol
    secure_protocol = 'matrixs'

    # Support Attachments
    attachment_support = True

    # A URL that takes you to the setup/help of the specific protocol
    setup_url = 'https://github.com/caronc/apprise/wiki/Notify_matrix'

    # Allows the user to specify the NotifyImageSize object
    image_size = NotifyImageSize.XY_32

    # The maximum allowable characters allowed in the body per message
    # https://spec.matrix.org/v1.6/client-server-api/#size-limits
    # The complete event MUST NOT be larger than 65536 bytes, when formatted
    # with the federation event format, including any signatures, and encoded
    # as Canonical JSON.
    #
    # To gracefully allow for some overhead' we'll define a max body length
    # of just slighty lower then the limit of the full message itself.
    body_maxlen = 65000

    # Throttle a wee-bit to avoid thrashing
    request_rate_per_sec = 0.5

    # Our Matrix API Version
    matrix_api_version = '3'

    # How many retry attempts we'll make in the event the server asks us to
    # throttle back.
    default_retries = 2

    # The number of micro seconds to wait if we get a 429 error code and
    # the server doesn't remind us how long we shoul wait for
    default_wait_ms = 1000

    # Define object templates
    templates = (
        # Targets are ignored when using t2bot mode; only a token is required
        '{schema}://{token}',
        '{schema}://{user}@{token}',

        # Disabled webhook
        '{schema}://{user}:{password}@{host}/{targets}',
        '{schema}://{user}:{password}@{host}:{port}/{targets}',

        # Webhook mode
        '{schema}://{user}:{token}@{host}/{targets}',
        '{schema}://{user}:{token}@{host}:{port}/{targets}',
    )

    # Define our template tokens
    template_tokens = dict(NotifyBase.template_tokens, **{
        'host': {
            'name': _('Hostname'),
            'type': 'string',
        },
        'port': {
            'name': _('Port'),
            'type': 'int',
            'min': 1,
            'max': 65535,
        },
        'user': {
            'name': _('Username'),
            'type': 'string',
        },
        'password': {
            'name': _('Password'),
            'type': 'string',
            'private': True,
        },
        'token': {
            'name': _('Access Token'),
            'private': True,
            'map_to': 'password',
        },
        'target_user': {
            'name': _('Target User'),
            'type': 'string',
            'prefix': '@',
            'map_to': 'targets',
        },
        'target_room_id': {
            'name': _('Target Room ID'),
            'type': 'string',
            'prefix': '!',
            'map_to': 'targets',
        },
        'target_room_alias': {
            'name': _('Target Room Alias'),
            'type': 'string',
            'prefix': '!',
            'map_to': 'targets',
        },
        'targets': {
            'name': _('Targets'),
            'type': 'list:string',
        },
    })

    # Define our template arguments
    template_args = dict(NotifyBase.template_args, **{
        'image': {
            'name': _('Include Image'),
            'type': 'bool',
            'default': False,
            'map_to': 'include_image',
        },
        'mode': {
            'name': _('Webhook Mode'),
            'type': 'choice:string',
            'values': MATRIX_WEBHOOK_MODES,
            'default': MatrixWebhookMode.DISABLED,
        },
        'version': {
            'name': _('Matrix API Verion'),
            'type': 'choice:string',
            'values': MATRIX_VERSIONS,
            'default': MatrixVersion.V3,
        },
        'msgtype': {
            'name': _('Message Type'),
            'type': 'choice:string',
            'values': MATRIX_MESSAGE_TYPES,
            'default': MatrixMessageType.TEXT,
        },
        'to': {
            'alias_of': 'targets',
        },
        'token': {
            'alias_of': 'token',
        },
    })

    def __init__(self, targets=None, mode=None, msgtype=None, version=None,
                 include_image=False, **kwargs):
        """
        Initialize Matrix Object
        """
        super().__init__(**kwargs)

        # Prepare a list of rooms to connect and notify
        self.rooms = parse_list(targets)

        # our home server gets populated after a login/registration
        self.home_server = None

        # our user_id gets populated after a login/registration
        self.user_id = None

        # This gets initialized after a login/registration
        self.access_token = None

        # Place an image inline with the message body
        self.include_image = include_image

        # maintain a lookup of room alias's we already paired with their id
        # to speed up future requests
        self._room_cache = {}

        # Setup our mode
        self.mode = self.template_args['mode']['default'] \
            if not isinstance(mode, str) else mode.lower()
        if self.mode and self.mode not in MATRIX_WEBHOOK_MODES:
            msg = 'The mode specified ({}) is invalid.'.format(mode)
            self.logger.warning(msg)
            raise TypeError(msg)

        # Setup our version
        self.version = self.template_args['version']['default'] \
            if not isinstance(version, str) else version
        if self.version not in MATRIX_VERSIONS:
            msg = 'The version specified ({}) is invalid.'.format(version)
            self.logger.warning(msg)
            raise TypeError(msg)

        # Setup our message type
        self.msgtype = self.template_args['msgtype']['default'] \
            if not isinstance(msgtype, str) else msgtype.lower()
        if self.msgtype and self.msgtype not in MATRIX_MESSAGE_TYPES:
            msg = 'The msgtype specified ({}) is invalid.'.format(msgtype)
            self.logger.warning(msg)
            raise TypeError(msg)

        if self.mode == MatrixWebhookMode.T2BOT:
            # t2bot configuration requires that a webhook id is specified
            self.access_token = validate_regex(
                self.password, r'^[a-z0-9]{64}$', 'i')
            if not self.access_token:
                msg = 'An invalid T2Bot/Matrix Webhook ID ' \
                      '({}) was specified.'.format(self.password)
                self.logger.warning(msg)
                raise TypeError(msg)

        elif not is_hostname(self.host):
            msg = 'An invalid Matrix Hostname ({}) was specified'\
                  .format(self.host)
            self.logger.warning(msg)
            raise TypeError(msg)
        else:
            # Verify port if specified
            if self.port is not None and not (
                    isinstance(self.port, int)
                    and self.port >= self.template_tokens['port']['min']
                    and self.port <= self.template_tokens['port']['max']):
                msg = 'An invalid Matrix Port ({}) was specified'\
                      .format(self.port)
                self.logger.warning(msg)
                raise TypeError(msg)

    def send(self, body, title='', notify_type=NotifyType.INFO, **kwargs):
        """
        Perform Matrix Notification
        """

        # Call the _send_ function applicable to whatever mode we're in
        # - calls _send_webhook_notification if the mode variable is set
        # - calls _send_server_notification if the mode variable is not set
        return getattr(self, '_send_{}_notification'.format(
            'webhook' if self.mode != MatrixWebhookMode.DISABLED
            else 'server'))(
                body=body, title=title, notify_type=notify_type, **kwargs)

    def _send_webhook_notification(self, body, title='',
                                   notify_type=NotifyType.INFO, **kwargs):
        """
        Perform Matrix Notification as a webhook
        """

        headers = {
            'User-Agent': self.app_id,
            'Content-Type': 'application/json',
        }

        if self.mode != MatrixWebhookMode.T2BOT:
            # Acquire our access token from our URL
            access_token = self.password if self.password else self.user

            default_port = 443 if self.secure else 80

            # Prepare our URL
            url = '{schema}://{hostname}:{port}{webhook_path}/{token}'.format(
                schema='https' if self.secure else 'http',
                hostname=self.host,
                port='' if self.port is None
                or self.port == default_port else self.port,
                webhook_path=MATRIX_V1_WEBHOOK_PATH,
                token=access_token,
            )

        else:
            #
            # t2bot Setup
            #

            # Prepare our URL
            url = 'https://webhooks.t2bot.io/api/v1/matrix/hook/' \
                '{token}'.format(token=self.access_token)

        # Retrieve our payload
        payload = getattr(self, '_{}_webhook_payload'.format(self.mode))(
            body=body, title=title, notify_type=notify_type, **kwargs)

        self.logger.debug('Matrix POST URL: %s (cert_verify=%r)' % (
            url, self.verify_certificate,
        ))
        self.logger.debug('Matrix Payload: %s' % str(payload))

        # Always call throttle before any remote server i/o is made
        self.throttle()

        try:
            r = requests.post(
                url,
                data=dumps(payload),
                headers=headers,
                verify=self.verify_certificate,
                timeout=self.request_timeout,
            )
            if r.status_code != requests.codes.ok:
                # We had a problem
                status_str = \
                    NotifyMatrix.http_response_code_lookup(
                        r.status_code, MATRIX_HTTP_ERROR_MAP)

                self.logger.warning(
                    'Failed to send Matrix notification: '
                    '{}{}error={}.'.format(
                        status_str,
                        ', ' if status_str else '',
                        r.status_code))

                self.logger.debug('Response Details:\r\n{}'.format(r.content))

                # Return; we're done
                return False

            else:
                self.logger.info('Sent Matrix notification.')

        except requests.RequestException as e:
            self.logger.warning(
                'A Connection error occurred sending Matrix notification.'
            )
            self.logger.debug('Socket Exception: %s' % str(e))
            # Return; we're done
            return False

        return True

    def _slack_webhook_payload(self, body, title='',
                               notify_type=NotifyType.INFO, **kwargs):
        """
        Format the payload for a Slack based message

        """

        if not hasattr(self, '_re_slack_formatting_rules'):
            # Prepare some one-time slack formatting variables

            self._re_slack_formatting_map = {
                # New lines must become the string version
                r'\r\*\n': '\\n',
                # Escape other special characters
                r'&': '&amp;',
                r'<': '&lt;',
                r'>': '&gt;',
            }

            # Iterate over above list and store content accordingly
            self._re_slack_formatting_rules = re.compile(
                r'(' + '|'.join(self._re_slack_formatting_map.keys()) + r')',
                re.IGNORECASE,
            )

        # Perform Formatting
        title = self._re_slack_formatting_rules.sub(  # pragma: no branch
            lambda x: self._re_slack_formatting_map[x.group()], title,
        )

        body = self._re_slack_formatting_rules.sub(  # pragma: no branch
            lambda x: self._re_slack_formatting_map[x.group()], body,
        )

        # prepare JSON Object
        payload = {
            'username': self.user if self.user else self.app_id,
            # Use Markdown language
            'mrkdwn': (self.notify_format == NotifyFormat.MARKDOWN),
            'attachments': [{
                'title': title,
                'text': body,
                'color': self.color(notify_type),
                'ts': time(),
                'footer': self.app_id,
            }],
        }

        return payload

    def _matrix_webhook_payload(self, body, title='',
                                notify_type=NotifyType.INFO, **kwargs):
        """
        Format the payload for a Matrix based message

        """

        payload = {
            'displayName':
                self.user if self.user else self.app_id,
            'format': 'plain' if self.notify_format == NotifyFormat.TEXT
            else 'html',
            'text': '',
        }

        if self.notify_format == NotifyFormat.HTML:
            payload['text'] = '{title}{body}'.format(
                title='' if not title else '<h1>{}</h1>'.format(
                    NotifyMatrix.escape_html(title)),
                body=body)

        elif self.notify_format == NotifyFormat.MARKDOWN:
            payload['text'] = '{title}{body}'.format(
                title='' if not title else '<h1>{}</h1>'.format(
                    NotifyMatrix.escape_html(title)),
                body=markdown(body))

        else:  # NotifyFormat.TEXT
            payload['text'] = \
                body if not title else '{}\r\n{}'.format(title, body)

        return payload

    def _t2bot_webhook_payload(self, body, title='',
                               notify_type=NotifyType.INFO, **kwargs):
        """
        Format the payload for a T2Bot Matrix based messages

        """

        # Retrieve our payload
        payload = self._matrix_webhook_payload(
            body=body, title=title, notify_type=notify_type, **kwargs)

        # Acquire our image url if we're configured to do so
        image_url = None if not self.include_image else \
            self.image_url(notify_type)

        if image_url:
            # t2bot can take an avatarUrl Entry
            payload['avatarUrl'] = image_url

        return payload

    def _send_server_notification(self, body, title='',
                                  notify_type=NotifyType.INFO, attach=None,
                                  **kwargs):
        """
        Perform Direct Matrix Server Notification (no webhook)
        """

        if self.access_token is None:
            # We need to register
            if not self._login():
                if not self._register():
                    return False

        if len(self.rooms) == 0:
            # Attempt to retrieve a list of already joined channels
            self.rooms = self._joined_rooms()

            if len(self.rooms) == 0:
                # Nothing to notify
                self.logger.warning(
                    'There were no Matrix rooms specified to notify.')
                return False

        # Create a copy of our rooms to join and message
        rooms = list(self.rooms)

        # Initiaize our error tracking
        has_error = False

        attachments = None
        if attach and self.attachment_support:
            attachments = self._send_attachments(attach)
            if not attachments:
                # take an early exit
                return False

        while len(rooms) > 0:

            # Get our room
            room = rooms.pop(0)

            # Get our room_id from our response
            room_id = self._room_join(room)
            if not room_id:
                # Notify our user about our failure
                self.logger.warning(
                    'Could not join Matrix room {}.'.format((room)))

                # Mark our failure
                has_error = True
                continue

            # Acquire our image url if we're configured to do so
            image_url = None if not self.include_image else \
                self.image_url(notify_type)

            # Build our path
            path = '/rooms/{}/send/m.room.message'.format(
                NotifyMatrix.quote(room_id))

            if image_url:
                # Define our payload
                image_payload = {
                    'msgtype': 'm.image',
                    'url': image_url,
                    'body': '{}'.format(notify_type if not title else title),
                }

                # Post our content
                postokay, response = self._fetch(path, payload=image_payload)
                if not postokay:
                    # Mark our failure
                    has_error = True
                    continue

            if attachments:
                for attachment in attachments:
                    postokay, response = self._fetch(path, payload=attachment)
                if not postokay:
                    # Mark our failure
                    has_error = True
                    continue

            # Define our payload
            payload = {
                'msgtype': 'm.{}'.format(self.msgtype),
                'body': '{title}{body}'.format(
                    title='' if not title else '# {}\r\n'.format(title),
                    body=body),
            }

            # Update our payload advance formatting for the services that
            # support them.
            if self.notify_format == NotifyFormat.HTML:
                payload.update({
                    'format': 'org.matrix.custom.html',
                    'formatted_body': '{title}{body}'.format(
                        title='' if not title else '<h1>{}</h1>'.format(title),
                        body=body,
                    )
                })

            elif self.notify_format == NotifyFormat.MARKDOWN:
                payload.update({
                    'format': 'org.matrix.custom.html',
                    'formatted_body': '{title}{body}'.format(
                        title='' if not title else '<h1>{}</h1>'.format(
                            NotifyMatrix.escape_html(title, whitespace=False)),
                        body=markdown(body),
                    )
                })

            # Post our content
            postokay, response = self._fetch(path, payload=payload)
            if not postokay:
                # Notify our user
                self.logger.warning(
                    'Could not send notification Matrix room {}.'.format(room))

                # Mark our failure
                has_error = True
                continue

        return not has_error

    def _send_attachments(self, attach):
        """
        Posts all of the provided attachments
        """

        payloads = []
        for attachment in attach:
            if not attachment:
                # invalid attachment (bad file)
                return False

            if not re.match(r'^image/', attachment.mimetype, re.I):
                # unsuppored at this time
                continue

            postokay, response = \
                self._fetch('/upload', attachment=attachment)
            if not (postokay and isinstance(response, dict)):
                # Failed to perform upload
                return False

            # If we get here, we'll have a response that looks like:
            # {
            #     "content_uri": "mxc://example.com/a-unique-key"
            # }

            # Prepare our payload
            payloads.append({
                "info": {
                    "mimetype": attachment.mimetype,
                },
                "msgtype": "m.image",
                "body": "tta.webp",
                "url": response.get('content_uri'),
            })

        return payloads

    def _register(self):
        """
        Register with the service if possible.
        """

        # Prepare our Registration Payload. This will only work if registration
        # is enabled for the public
        payload = {
            'kind': 'user',
            'auth': {'type': 'm.login.dummy'},
        }

        # parameters
        params = {
            'kind': 'user',
        }

        # If a user is not specified, one will be randomly generated for you.
        # If you do not specify a password, you will be unable to login to the
        # account if you forget the access_token.
        if self.user:
            payload['username'] = self.user

        if self.password:
            payload['password'] = self.password

        # Register
        postokay, response = \
            self._fetch('/register', payload=payload, params=params)
        if not (postokay and isinstance(response, dict)):
            # Failed to register
            return False

        # Pull the response details
        self.access_token = response.get('access_token')
        self.home_server = response.get('home_server')
        self.user_id = response.get('user_id')

        if self.access_token is not None:
            self.logger.debug(
                'Registered successfully with Matrix server.')
            return True

        return False

    def _login(self):
        """
        Acquires the matrix token required for making future requests. If we
        fail we return False, otherwise we return True
        """

        if self.access_token:
            # Login not required; silently skip-over
            return True

        if not (self.user and self.password):
            # It's not possible to register since we need these 2 values to
            # make the action possible.
            self.logger.warning(
                'Failed to login to Matrix server: '
                'user/pass combo is missing.')
            return False

        # Prepare our Registration Payload
        payload = {
            'type': 'm.login.password',
            'user': self.user,
            'password': self.password,
        }

        # Build our URL
        postokay, response = self._fetch('/login', payload=payload)
        if not (postokay and isinstance(response, dict)):
            # Failed to login
            return False

        # Pull the response details
        self.access_token = response.get('access_token')
        self.home_server = response.get('home_server')
        self.user_id = response.get('user_id')

        if not self.access_token:
            return False

        self.logger.debug(
            'Authenticated successfully with Matrix server.')
        return True

    def _logout(self):
        """
        Relinquishes token from remote server
        """

        if not self.access_token:
            # Login not required; silently skip-over
            return True

        # Prepare our Registration Payload
        payload = {}

        # Expire our token
        postokay, response = self._fetch('/logout', payload=payload)
        if not postokay:
            # If we get here, the token was declared as having already
            # been expired.  The response looks like this:
            # {
            #    u'errcode': u'M_UNKNOWN_TOKEN',
            #    u'error': u'Access Token unknown or expired',
            # }
            #
            # In this case it's okay to safely return True because
            # we're logged out in this case.
            if response.get('errcode') != u'M_UNKNOWN_TOKEN':
                return False

        # else: The response object looks like this if we were successful:
        #  {}

        # Pull the response details
        self.access_token = None
        self.home_server = None
        self.user_id = None

        # Clear our room cache
        self._room_cache = {}

        self.logger.debug(
            'Unauthenticated successfully with Matrix server.')

        return True

    def _room_join(self, room):
        """
        Joins a matrix room if we're not already in it. Otherwise it attempts
        to create it if it doesn't exist and always returns
        the room_id if it was successful, otherwise it returns None

        """

        if not self.access_token:
            # We can't join a room if we're not logged in
            return None

        if not isinstance(room, str):
            # Not a supported string
            return None

        # Prepare our Join Payload
        payload = {}

        # Check if it's a room id...
        result = IS_ROOM_ID.match(room)
        if result:
            # We detected ourselves the home_server
            home_server = result.group('home_server') \
                if result.group('home_server') else self.home_server

            # It was a room ID; simple mapping:
            room_id = "!{}:{}".format(
                result.group('room'),
                home_server,
            )

            # Check our cache for speed:
            if room_id in self._room_cache:
                # We're done as we've already joined the channel
                return self._room_cache[room_id]['id']

            # Build our URL
            path = '/join/{}'.format(NotifyMatrix.quote(room_id))

            # Make our query
            postokay, _ = self._fetch(path, payload=payload)
            if postokay:
                # Cache our entry for fast access later
                self._room_cache[room_id] = {
                    'id': room_id,
                    'home_server': home_server,
                }

            return room_id if postokay else None

        # Try to see if it's an alias then...
        result = IS_ROOM_ALIAS.match(room)
        if not result:
            # There is nothing else it could be
            self.logger.warning(
                'Ignoring illegally formed room {} '
                'from Matrix server list.'.format(room))
            return None

        # If we reach here, we're dealing with a channel alias
        home_server = self.home_server \
            if not result.group('home_server') \
            else result.group('home_server')

        # tidy our room (alias) identifier
        room = '#{}:{}'.format(result.group('room'), home_server)

        # Check our cache for speed:
        if room in self._room_cache:
            # We're done as we've already joined the channel
            return self._room_cache[room]['id']

        # If we reach here, we need to join the channel

        # Build our URL
        path = '/join/{}'.format(NotifyMatrix.quote(room))

        # Attempt to join the channel
        postokay, response = self._fetch(path, payload=payload)
        if postokay:
            # Cache our entry for fast access later
            self._room_cache[room] = {
                'id': response.get('room_id'),
                'home_server': home_server,
            }
            return self._room_cache[room]['id']

        # Try to create the channel
        return self._room_create(room)

    def _room_create(self, room):
        """
        Creates a matrix room and return it's room_id if successful
        otherwise None is returned.
        """
        if not self.access_token:
            # We can't create a room if we're not logged in
            return None

        if not isinstance(room, str):
            # Not a supported string
            return None

        # Build our room if we have to:
        result = IS_ROOM_ALIAS.match(room)
        if not result:
            # Illegally formed room
            return None

        # Our home_server
        home_server = result.group('home_server') \
            if result.group('home_server') else self.home_server

        # update our room details
        room = '#{}:{}'.format(result.group('room'), home_server)

        # Prepare our Create Payload
        payload = {
            'room_alias_name': result.group('room'),
            # Set our channel name
            'name': '#{} - {}'.format(result.group('room'), self.app_desc),
            # hide the room by default; let the user open it up if they wish
            # to others.
            'visibility': 'private',
            'preset': 'trusted_private_chat',
        }

        postokay, response = self._fetch('/createRoom', payload=payload)
        if not postokay:
            # Failed to create channel
            # Typical responses:
            #   - {u'errcode': u'M_ROOM_IN_USE',
            #      u'error': u'Room alias already taken'}
            #   - {u'errcode': u'M_UNKNOWN',
            #      u'error': u'Internal server error'}
            if (response and response.get('errcode') == 'M_ROOM_IN_USE'):
                return self._room_id(room)
            return None

        # Cache our entry for fast access later
        self._room_cache[response.get('room_alias')] = {
            'id': response.get('room_id'),
            'home_server': home_server,
        }

        return response.get('room_id')

    def _joined_rooms(self):
        """
        Returns a list of the current rooms the logged in user
        is a part of.
        """

        if not self.access_token:
            # No list is possible
            return list()

        postokay, response = self._fetch(
            '/joined_rooms', payload=None, method='GET')
        if not postokay:
            # Failed to retrieve listings
            return list()

        # Return our list of rooms
        return response.get('joined_rooms', list())

    def _room_id(self, room):
        """Get room id from its alias.
        Args:
            room (str): The room alias name.

        Returns:
            returns the room id if it can, otherwise it returns None
        """

        if not self.access_token:
            # We can't get a room id if we're not logged in
            return None

        if not isinstance(room, str):
            # Not a supported string
            return None

        # Build our room if we have to:
        result = IS_ROOM_ALIAS.match(room)
        if not result:
            # Illegally formed room
            return None

        # Our home_server
        home_server = result.group('home_server') \
            if result.group('home_server') else self.home_server

        # update our room details
        room = '#{}:{}'.format(result.group('room'), home_server)

        # Make our request
        postokay, response = self._fetch(
            "/directory/room/{}".format(
                NotifyMatrix.quote(room)), payload=None, method='GET')

        if postokay:
            return response.get("room_id")

        return None

    def _fetch(self, path, payload=None, params=None, attachment=None,
               method='POST'):
        """
        Wrapper to request.post() to manage it's response better and make
        the send() function cleaner and easier to maintain.

        This function returns True if the _post was successful and False
        if it wasn't.
        """

        # Define our headers
        headers = {
            'User-Agent': self.app_id,
            'Content-Type': 'application/json',
            'Accept': 'application/json',
        }

        if self.access_token is not None:
            headers["Authorization"] = 'Bearer %s' % self.access_token

        default_port = 443 if self.secure else 80

        url = \
            '{schema}://{hostname}{port}'.format(
                schema='https' if self.secure else 'http',
                hostname=self.host,
                port='' if self.port is None
                or self.port == default_port else f':{self.port}')

        if path == '/upload':
            if self.version == MatrixVersion.V3:
                url += MATRIX_V3_MEDIA_PATH + path

            else:
                url += MATRIX_V2_MEDIA_PATH + path

            params = {'filename': attachment.name}
            with open(attachment.path, 'rb') as fp:
                payload = fp.read()

            # Update our content type
            headers['Content-Type'] = attachment.mimetype

        else:
            if self.version == MatrixVersion.V3:
                url += MATRIX_V3_API_PATH + path

            else:
                url += MATRIX_V2_API_PATH + path

        # Our response object
        response = {}

        # fetch function
        fn = requests.post if method == 'POST' else requests.get

        # Define how many attempts we'll make if we get caught in a throttle
        # event
        retries = self.default_retries if self.default_retries > 0 else 1
        while retries > 0:

            # Decrement our throttle retry count
            retries -= 1

            self.logger.debug('Matrix POST URL: %s (cert_verify=%r)' % (
                url, self.verify_certificate,
            ))
            self.logger.debug('Matrix Payload: %s' % str(payload))

            # Initialize our response object
            r = None

            try:
                r = fn(
                    url,
                    data=dumps(payload) if not attachment else payload,
                    params=params,
                    headers=headers,
                    verify=self.verify_certificate,
                    timeout=self.request_timeout,
                )

                self.logger.debug('Matrix Response: %s' % str(r.content))
                response = loads(r.content)

                if r.status_code == 429:
                    wait = self.default_wait_ms / 1000
                    try:
                        wait = response['retry_after_ms'] / 1000

                    except KeyError:
                        try:
                            errordata = response['error']
                            wait = errordata['retry_after_ms'] / 1000
                        except KeyError:
                            pass

                    self.logger.warning(
                        'Matrix server requested we throttle back {}ms; '
                        'retries left {}.'.format(wait, retries))
                    self.logger.debug(
                        'Response Details:\r\n{}'.format(r.content))

                    # Throttle for specified wait
                    self.throttle(wait=wait)

                    # Try again
                    continue

                elif r.status_code != requests.codes.ok:
                    # We had a problem
                    status_str = \
                        NotifyMatrix.http_response_code_lookup(
                            r.status_code, MATRIX_HTTP_ERROR_MAP)

                    self.logger.warning(
                        'Failed to handshake with Matrix server: '
                        '{}{}error={}.'.format(
                            status_str,
                            ', ' if status_str else '',
                            r.status_code))

                    self.logger.debug(
                        'Response Details:\r\n{}'.format(r.content))

                    # Return; we're done
                    return (False, response)

            except (AttributeError, TypeError, ValueError):
                # This gets thrown if we can't parse our JSON Response
                #  - ValueError = r.content is Unparsable
                #  - TypeError = r.content is None
                #  - AttributeError = r is None
                self.logger.warning('Invalid response from Matrix server.')
                self.logger.debug(
                    'Response Details:\r\n{}'.format(r.content))
                return (False, {})

            except requests.RequestException as e:
                self.logger.warning(
                    'A Connection error occurred while registering with Matrix'
                    ' server.')
                self.logger.debug('Socket Exception: %s' % str(e))
                # Return; we're done
                return (False, response)

            except (OSError, IOError) as e:
                self.logger.warning(
                    'An I/O error occurred while reading {}.'.format(
                        attachment.name if attachment else 'unknown file'))
                self.logger.debug('I/O Exception: %s' % str(e))
                return (False, {})

            return (True, response)

        # If we get here, we ran out of retries
        return (False, {})

    def __del__(self):
        """
        Ensure we relinquish our token
        """
        if self.mode == MatrixWebhookMode.T2BOT:
            # nothing to do
            return

        try:
            self._logout()

        except LookupError:  # pragma: no cover
            # Python v3.5 call to requests can sometimes throw the exception
            #   "/usr/lib64/python3.7/socket.py", line 748, in getaddrinfo
            #   LookupError: unknown encoding: idna
            #
            # This occurs every time when running unit-tests against Apprise:
            # LANG=C.UTF-8 PYTHONPATH=$(pwd) py.test-3.7
            #
            # There has been an open issue on this since Jan 2017.
            #   - https://bugs.python.org/issue29288
            #
            # A ~similar~ issue can be identified here in the requests
            # ticket system as unresolved and has provided workarounds
            #   - https://github.com/kennethreitz/requests/issues/3578
            pass

        except ImportError:  # pragma: no cover
            # The actual exception is `ModuleNotFoundError` however ImportError
            # grants us backwards compatibility with versions of Python older
            # than v3.6

            # Python code that makes early calls to sys.exit() can cause
            # the __del__() code to run. However, in some newer versions of
            # Python, this causes the `sys` library to no longer be
            # available. The stack overflow also goes on to suggest that
            # it's not wise to use the __del__() as a destructor
            # which is the case here.

            # https://stackoverflow.com/questions/67218341/\
            #       modulenotfounderror-import-of-time-halted-none-in-sys-\
            #           modules-occured-when-obj?noredirect=1&lq=1
            #
            #
            # Also see: https://stackoverflow.com/questions\
            #       /1481488/what-is-the-del-method-and-how-do-i-call-it

            # At this time it seems clean to try to log out (if we can)
            # but not throw any unnecessary exceptions (like this one) to
            # the end user if we don't have to.
            pass

    def url(self, privacy=False, *args, **kwargs):
        """
        Returns the URL built dynamically based on specified arguments.
        """

        # Define any URL parameters
        params = {
            'image': 'yes' if self.include_image else 'no',
            'mode': self.mode,
            'version': self.version,
            'msgtype': self.msgtype,
        }

        # Extend our parameters
        params.update(self.url_parameters(privacy=privacy, *args, **kwargs))

        auth = ''
        if self.mode != MatrixWebhookMode.T2BOT:
            # Determine Authentication
            if self.user and self.password:
                auth = '{user}:{password}@'.format(
                    user=NotifyMatrix.quote(self.user, safe=''),
                    password=self.pprint(
                        self.password, privacy, mode=PrivacyMode.Secret,
                        safe=''),
                )

            elif self.user:
                auth = '{user}@'.format(
                    user=NotifyMatrix.quote(self.user, safe=''),
                )

        default_port = 443 if self.secure else 80

        return '{schema}://{auth}{hostname}{port}/{rooms}?{params}'.format(
            schema=self.secure_protocol if self.secure else self.protocol,
            auth=auth,
            hostname=NotifyMatrix.quote(self.host, safe='')
            if self.mode != MatrixWebhookMode.T2BOT
            else self.pprint(self.access_token, privacy, safe=''),
            port='' if self.port is None
            or self.port == default_port else ':{}'.format(self.port),
            rooms=NotifyMatrix.quote('/'.join(self.rooms)),
            params=NotifyMatrix.urlencode(params),
        )

    def __len__(self):
        """
        Returns the number of targets associated with this notification
        """
        targets = len(self.rooms)
        return targets if targets > 0 else 1

    @staticmethod
    def parse_url(url):
        """
        Parses the URL and returns enough arguments that can allow
        us to re-instantiate this object.

        """
        results = NotifyBase.parse_url(url, verify_host=False)
        if not results:
            # We're done early as we couldn't load the results
            return results

        if not results.get('host'):
            return None

        # Get our rooms
        results['targets'] = NotifyMatrix.split_path(results['fullpath'])

        # Support the 'to' variable so that we can support rooms this way too
        # The 'to' makes it easier to use yaml configuration
        if 'to' in results['qsd'] and len(results['qsd']['to']):
            results['targets'] += NotifyMatrix.parse_list(results['qsd']['to'])

        # Boolean to include an image or not
        results['include_image'] = parse_bool(results['qsd'].get(
            'image', NotifyMatrix.template_args['image']['default']))

        # Get our mode
        results['mode'] = results['qsd'].get('mode')

        # t2bot detection... look for just a hostname, and/or just a user/host
        # if we match this; we can go ahead and set the mode (but only if
        # it was otherwise not set)
        if results['mode'] is None \
                and not results['password'] \
                and not results['targets']:

            # Default mode to t2bot
            results['mode'] = MatrixWebhookMode.T2BOT

        if results['mode'] and \
                results['mode'].lower() == MatrixWebhookMode.T2BOT:
            # unquote our hostname and pass it in as the password/token
            results['password'] = NotifyMatrix.unquote(results['host'])

        # Support the message type keyword
        if 'msgtype' in results['qsd'] and len(results['qsd']['msgtype']):
            results['msgtype'] = \
                NotifyMatrix.unquote(results['qsd']['msgtype'])

        # Support the use of the token= keyword
        if 'token' in results['qsd'] and len(results['qsd']['token']):
            results['password'] = NotifyMatrix.unquote(results['qsd']['token'])

        # Support the use of the version= or v= keyword
        if 'version' in results['qsd'] and len(results['qsd']['version']):
            results['version'] = \
                NotifyMatrix.unquote(results['qsd']['version'])

        elif 'v' in results['qsd'] and len(results['qsd']['v']):
            results['version'] = NotifyMatrix.unquote(results['qsd']['v'])

        return results

    @staticmethod
    def parse_native_url(url):
        """
        Support https://webhooks.t2bot.io/api/v1/matrix/hook/WEBHOOK_TOKEN/
        """

        result = re.match(
            r'^https?://webhooks\.t2bot\.io/api/v[0-9]+/matrix/hook/'
            r'(?P<webhook_token>[A-Z0-9_-]+)/?'
            r'(?P<params>\?.+)?$', url, re.I)

        if result:
            mode = 'mode={}'.format(MatrixWebhookMode.T2BOT)

            return NotifyMatrix.parse_url(
                '{schema}://{webhook_token}/{params}'.format(
                    schema=NotifyMatrix.secure_protocol,
                    webhook_token=result.group('webhook_token'),
                    params='?{}'.format(mode) if not result.group('params')
                    else '{}&{}'.format(result.group('params'), mode)))

        return None
