# -*- coding: utf-8 -*-
#
# Copyright (C) 2019 Chris Caron <lead2gold@gmail.com>
# All rights reserved.
#
# This code is licensed under the MIT License.
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files(the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions :
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.

# Signup @ https://www.mailgun.com/
#
# Each domain will have an API key associated with it. If you sign up you'll
# get a sandbox domain to use.  Or if you set up your own, they'll have
# api keys associated with them too.  Find your API key out by visiting
#    https://app.mailgun.com/app/domains
#
# From here you can click on the domain you're interested in. You can acquire
# the API Key from here which will look something like:
#    4b4f2918c6c21ba0a26ad2af73c07f4d-dk5f51da-8f91a0df
#
# You'll also need to know the domain that is associated with your API key.
# This will be obvious with a paid account because it will be the domain name
# you've registered with them.   But if you're using a test account, it will
# be name of the sandbox you've set up such as:
#    sandbox74bda3414c06kb5acb946.mailgun.org
#
# Knowing this, you can buid your mailgun url as follows:
#  mailgun://{user}@{domain}/{apikey}
#  mailgun://{user}@{domain}/{apikey}/{email}
#
# You can email as many addresses as you want as:
#  mailgun://{user}@{domain}/{apikey}/{email1}/{email2}/{emailN}
#
#  The {user}@{domain} effectively assembles the 'from' email address
#  the email will be transmitted from.  If no email address is specified
#  then it will also become the 'to' address as well.
#
import re
import requests

from .NotifyBase import NotifyBase
from ..common import NotifyType
from ..utils import parse_list
from ..utils import is_email
from ..AppriseLocale import gettext_lazy as _

# Used to validate your personal access apikey
VALIDATE_API_KEY = re.compile(r'^[a-z0-9]{32}-[a-z0-9]{8}-[a-z0-9]{8}$', re.I)

# Provide some known codes Mailgun uses and what they translate to:
# Based on https://documentation.mailgun.com/en/latest/api-intro.html#errors
MAILGUN_HTTP_ERROR_MAP = {
    400: 'A bad request was made to the server.',
    401: 'The provided API Key was not valid.',
    402: 'The request failed for a reason out of your control.',
    404: 'The requested API query is not valid.',
    413: 'Provided attachment is to big.',
}


# Priorities
class MailgunRegion(object):
    US = 'us'
    EU = 'eu'


# Mailgun APIs
MAILGUN_API_LOOKUP = {
    MailgunRegion.US: 'https://api.mailgun.net/v3/',
    MailgunRegion.EU: 'https://api.eu.mailgun.net/v3/',
}

# A List of our regions we can use for verification
MAILGUN_REGIONS = (
    MailgunRegion.US,
    MailgunRegion.EU,
)


class NotifyMailgun(NotifyBase):
    """
    A wrapper for Mailgun Notifications
    """

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

    # The services URL
    service_url = 'https://www.mailgun.com/'

    # All pushover requests are secure
    secure_protocol = 'mailgun'

    # Mailgun advertises they allow 300 requests per minute.
    # 60/300 = 0.2
    request_rate_per_sec = 0.20

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

    # The default region to use if one isn't otherwise specified
    mailgun_default_region = MailgunRegion.US

    # Define object templates
    templates = (
        '{schema}://{user}@{host}:{apikey}/',
        '{schema}://{user}@{host}:{apikey}/{targets}',
    )

    # Define our template tokens
    template_tokens = dict(NotifyBase.template_tokens, **{
        'user': {
            'name': _('User Name'),
            'type': 'string',
            'required': True,
        },
        'host': {
            'name': _('Domain'),
            'type': 'string',
            'required': True,
        },
        'apikey': {
            'name': _('API Key'),
            'type': 'string',
            'regex': (r'[a-z0-9]{32}-[a-z0-9]{8}-[a-z0-9]{8}', 'i'),
            'private': True,
            'required': True,
        },
        'targets': {
            'name': _('Target Emails'),
            'type': 'list:string',
        },
    })

    # Define our template arguments
    template_args = dict(NotifyBase.template_args, **{
        'name': {
            'name': _('From Name'),
            'type': 'string',
            'map_to': 'from_name',
        },
        'region': {
            'name': _('Region Name'),
            'type': 'choice:string',
            'values': MAILGUN_REGIONS,
            'default': MailgunRegion.US,
            'map_to': 'region_name',
        },
        'to': {
            'alias_of': 'targets',
        },
    })

    def __init__(self, apikey, targets, from_name=None, region_name=None,
                 **kwargs):
        """
        Initialize Mailgun Object
        """
        super(NotifyMailgun, self).__init__(**kwargs)

        try:
            # The personal access apikey associated with the account
            self.apikey = apikey.strip()

        except AttributeError:
            # Token was None
            msg = 'No API Key was specified.'
            self.logger.warning(msg)
            raise TypeError(msg)

        if not VALIDATE_API_KEY.match(self.apikey):
            msg = 'The API Key specified ({}) is invalid.' \
                  .format(apikey)
            self.logger.warning(msg)
            raise TypeError(msg)

        # Validate our username
        if not self.user:
            msg = 'No username was specified.'
            self.logger.warning(msg)
            raise TypeError(msg)

        # Parse our targets
        self.targets = parse_list(targets)

        # Store our region
        try:
            self.region_name = self.mailgun_default_region \
                if region_name is None else region_name.lower()

            if self.region_name not in MAILGUN_REGIONS:
                # allow the outer except to handle this common response
                raise
        except:
            # Invalid region specified
            msg = 'The region specified ({}) is invalid.' \
                  .format(region_name)
            self.logger.warning(msg)
            raise TypeError(msg)

        # Get our From username (if specified)
        self.from_name = from_name

        # Get our from email address
        self.from_addr = '{user}@{host}'.format(user=self.user, host=self.host)

        if not is_email(self.from_addr):
            # Parse Source domain based on from_addr
            msg = 'Invalid ~From~ email format: {}'.format(self.from_addr)
            self.logger.warning(msg)
            raise TypeError(msg)

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

        # error tracking (used for function return)
        has_error = False

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

        # Prepare our payload
        payload = {
            'from': '{name} <{addr}>'.format(
                name=self.app_id if not self.from_name else self.from_name,
                addr=self.from_addr),
            'subject': title,
            'text': body,
        }

        # Prepare our URL as it's based on our hostname
        url = '{}{}/messages'.format(
            MAILGUN_API_LOOKUP[self.region_name], self.host)

        # Create a copy of the targets list
        emails = list(self.targets)

        if len(emails) == 0:
            # No email specified; use the from
            emails.append(self.from_addr)

        while len(emails):
            # Get our email to notify
            email = emails.pop(0)

            # Prepare our user
            payload['to'] = '{} <{}>'.format(email, email)

            # Some Debug Logging
            self.logger.debug('Mailgun POST URL: {} (cert_verify={})'.format(
                url, self.verify_certificate))
            self.logger.debug('Mailgun Payload: {}' .format(payload))

            # Always call throttle before any remote server i/o is made
            self.throttle()
            try:
                r = requests.post(
                    url,
                    auth=("api", self.apikey),
                    data=payload,
                    headers=headers,
                    verify=self.verify_certificate,
                )

                if r.status_code != requests.codes.ok:
                    # We had a problem
                    status_str = \
                        NotifyBase.http_response_code_lookup(
                            r.status_code, MAILGUN_API_LOOKUP)

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

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

                    # Mark our failure
                    has_error = True
                    continue

                else:
                    self.logger.info(
                        'Sent Mailgun notification to {}.'.format(email))

            except requests.RequestException as e:
                self.logger.warning(
                    'A Connection error occured sending Mailgun:%s ' % (
                        email) + 'notification.'
                )
                self.logger.debug('Socket Exception: %s' % str(e))

                # Mark our failure
                has_error = True
                continue

        return not has_error

    def url(self):
        """
        Returns the URL built dynamically based on specified arguments.
        """

        # Define any arguments set
        args = {
            'format': self.notify_format,
            'overflow': self.overflow_mode,
            'verify': 'yes' if self.verify_certificate else 'no',
            'region': self.region_name,
        }

        if self.from_name is not None:
            # from_name specified; pass it back on the url
            args['name'] = self.from_name

        return '{schema}://{user}@{host}/{apikey}/{targets}/?{args}'.format(
            schema=self.secure_protocol,
            host=self.host,
            user=NotifyMailgun.quote(self.user, safe=''),
            apikey=NotifyMailgun.quote(self.apikey, safe=''),
            targets='/'.join(
                [NotifyMailgun.quote(x, safe='') for x in self.targets]),
            args=NotifyMailgun.urlencode(args))

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

        """
        results = NotifyBase.parse_url(url)

        if not results:
            # We're done early as we couldn't load the results
            return results

        # Get our entries; split_path() looks after unquoting content for us
        # by default
        results['targets'] = NotifyMailgun.split_path(results['fullpath'])

        # Our very first entry is reserved for our api key
        try:
            results['apikey'] = results['targets'].pop(0)

        except IndexError:
            # We're done - no API Key found
            results['apikey'] = None

        if 'name' in results['qsd'] and len(results['qsd']['name']):
            # Extract from name to associate with from address
            results['from_name'] = \
                NotifyMailgun.unquote(results['qsd']['name'])

        if 'region' in results['qsd'] and len(results['qsd']['region']):
            # Extract from name to associate with from address
            results['region_name'] = \
                NotifyMailgun.unquote(results['qsd']['region'])

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

        return results