# -*- 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.
from django.shortcuts import render
from django.http import HttpResponse
from django.http import JsonResponse
from django.views import View
from django.conf import settings
from django.utils.decorators import method_decorator
from django.views.decorators.cache import never_cache
from django.views.decorators.gzip import gzip_page
from django.utils.translation import gettext_lazy as _
from django.core.serializers.json import DjangoJSONEncoder

from .utils import ConfigCache
from .forms import AddByUrlForm
from .forms import AddByConfigForm
from .forms import NotifyForm
from .forms import NotifyByUrlForm
from .forms import CONFIG_FORMATS
from .forms import AUTO_DETECT_CONFIG_KEYWORD

import apprise
import json
import re

# Content-Type Parsing
# application/x-www-form-urlencoded
# application/x-www-form-urlencoded
# multipart/form-data
MIME_IS_FORM = re.compile(
    r'(multipart|application)/(x-www-)?form-(data|urlencoded)', re.I)

# Support JSON formats
# text/json
# text/x-json
# application/json
# application/x-json
MIME_IS_JSON = re.compile(
    r'(text|application)/(x-)?json', re.I)


class JSONEncoder(DjangoJSONEncoder):
    """
    A wrapper to the DjangoJSONEncoder to support
    sets() (converting them to lists).
    """
    def default(self, obj):
        if isinstance(obj, set):
            return list(obj)
        return super().default(obj)


class ResponseCode(object):
    """
    These codes are based on those provided by the requests object
    """
    okay = 200
    no_content = 204
    bad_request = 400
    not_found = 404
    method_not_allowed = 405
    failed_dependency = 424
    internal_server_error = 500


class WelcomeView(View):
    """
    A simple welcome/index page
    """
    template_name = 'welcome.html'

    def get(self, request):
        return render(request, self.template_name, {})


@method_decorator(never_cache, name='dispatch')
class ConfigView(View):
    """
    A Django view used to manage configuration
    """
    template_name = 'config.html'

    def get(self, request, key):
        """
        Handle a GET request
        """
        return render(request, self.template_name, {
            'key': key,
            'form_url': AddByUrlForm(),
            'form_cfg': AddByConfigForm(),
            'form_notify': NotifyForm(),
        })


@method_decorator(never_cache, name='dispatch')
class AddView(View):
    """
    A Django view used to store Apprise configuration
    """

    def post(self, request, key):
        """
        Handle a POST request
        """
        # our content
        content = {}
        if MIME_IS_FORM.match(request.content_type):
            content = {}
            form = AddByConfigForm(request.POST)
            if form.is_valid():
                content.update(form.cleaned_data)

            form = AddByUrlForm(request.POST)
            if form.is_valid():
                content.update(form.cleaned_data)

        elif MIME_IS_JSON.match(request.content_type):
            # Prepare our default response
            try:
                # load our JSON content
                content = json.loads(request.body.decode('utf-8'))

            except (AttributeError, ValueError):
                # could not parse JSON response...
                return HttpResponse(
                    _('Invalid JSON specified.'),
                    status=ResponseCode.bad_request)

        if not content:
            return HttpResponse(
                _('The message format is not supported.'),
                status=ResponseCode.bad_request)

        # Create ourselves an apprise object to work with
        a_obj = apprise.Apprise()
        if 'urls' in content:
            # Load our content
            a_obj.add(content['urls'])
            if not len(a_obj):
                # No URLs were loaded
                return HttpResponse(
                    _('No valid URLs were found.'),
                    status=ResponseCode.bad_request,
                )

            if not ConfigCache.put(
                    key, '\r\n'.join([s.url() for s in a_obj]),
                    apprise.ConfigFormat.TEXT):

                return HttpResponse(
                    _('The configuration could not be saved.'),
                    status=ResponseCode.internal_server_error,
                )

        elif 'config' in content:
            fmt = content.get('format', '').lower()
            if fmt not in [i[0] for i in CONFIG_FORMATS]:
                # Format must be one supported by apprise
                return HttpResponse(
                    _('The format specified is invalid.'),
                    status=ResponseCode.bad_request,
                )

            # prepare our apprise config object
            ac_obj = apprise.AppriseConfig()

            if fmt == AUTO_DETECT_CONFIG_KEYWORD:
                # By setting format to None, it is automatically detected from
                # within the add_config() call
                fmt = None

            # Load our configuration
            if not ac_obj.add_config(content['config'], format=fmt):
                # The format could not be detected
                return HttpResponse(
                    _('The configuration format could not be detected.'),
                    status=ResponseCode.bad_request,
                )

            # Add our configuration
            a_obj.add(ac_obj)

            if not len(a_obj):
                # No specified URL(s) were loaded due to
                # mis-configuration on the caller's part
                return HttpResponse(
                    _('No valid URL(s) were specified.'),
                    status=ResponseCode.bad_request,
                )

            if not ConfigCache.put(
                    key, content['config'], fmt=ac_obj[0].config_format):
                # Something went very wrong; return 500
                return HttpResponse(
                    _('An error occured saving configuration.'),
                    status=ResponseCode.internal_server_error,
                )
        else:
            # No configuration specified; we're done
            return HttpResponse(
                _('No configuration specified.'),
                status=ResponseCode.bad_request,
            )

        # If we reach here; we successfully loaded the configuration so we can
        # go ahead and write it to disk and alert our caller of the success.
        return HttpResponse(
            _('Successfully saved configuration.'),
            status=ResponseCode.okay,
        )


@method_decorator(never_cache, name='dispatch')
class DelView(View):
    """
    A Django view for removing content associated with a key
    """
    def post(self, request, key):
        """
        Handle a POST request
        """
        # Clear the key
        result = ConfigCache.clear(key)
        if result is None:
            return HttpResponse(
                _('There was no configuration to remove.'),
                status=ResponseCode.no_content,
            )

        elif result is False:
            # There was a failure at the os level
            return HttpResponse(
                _('The configuration could not be removed.'),
                status=ResponseCode.internal_server_error,
            )

        # Removed content
        return HttpResponse(
            _('Successfully removed configuration.'),
            status=ResponseCode.okay,
        )


@method_decorator((gzip_page, never_cache), name='dispatch')
class GetView(View):
    """
    A Django view used to retrieve previously stored Apprise configuration
    """
    def post(self, request, key):
        """
        Handle a POST request
        """

        # Detect the format our response should be in
        json_response = MIME_IS_JSON.match(request.content_type) is not None

        config, format = ConfigCache.get(key)
        if config is None:
            # The returned value of config and format tell a rather cryptic
            # story; this portion could probably be updated in the future.
            # but for now it reads like this:
            #   config == None and format == None: We had an internal error
            #   config == None and format != None: we simply have no data
            #   config != None: we simply have no data
            if format is not None:
                # no content to return
                return HttpResponse(
                    _('There was no configuration found.'),
                    status=ResponseCode.no_content,
                ) if not json_response else JsonResponse({
                        'error': _('There was no configuration found.')
                    },
                    encoder=JSONEncoder,
                    safe=False,
                    status=ResponseCode.no_content,
                )

            # Something went very wrong; return 500
            return HttpResponse(
                _('An error occured accessing configuration.'),
                status=ResponseCode.internal_server_error,
            ) if not json_response else JsonResponse({
                    'error': _('There was no configuration found.')
                },
                encoder=JSONEncoder,
                safe=False,
                status=ResponseCode.internal_server_error,
            )

        # Our configuration was retrieved; now our response varies on whether
        # we are a YAML configuration or a TEXT based one.  This allows us to
        # be compatible with those using the AppriseConfig() library or the
        # reference to it through the --config (-c) option in the CLI.
        content_type = 'text/yaml; charset=utf-8' \
            if format == apprise.ConfigFormat.YAML \
            else 'text/html; charset=utf-8'

        # Return our retrieved content
        return HttpResponse(
            config,
            content_type=content_type,
            status=ResponseCode.okay,
        ) if not json_response else JsonResponse({
                'format': format,
                'config': config,
            },
            encoder=JSONEncoder,
            safe=False,
            status=ResponseCode.okay,
        )


@method_decorator((gzip_page, never_cache), name='dispatch')
class NotifyView(View):
    """
    A Django view for sending a notification
    """
    def post(self, request, key):
        """
        Handle a POST request
        """
        # our content
        content = {}
        if MIME_IS_FORM.match(request.content_type):
            content = {}
            form = NotifyForm(request.POST)
            if form.is_valid():
                content.update(form.cleaned_data)

        elif MIME_IS_JSON.match(request.content_type):
            # Prepare our default response
            try:
                # load our JSON content
                content = json.loads(request.body.decode('utf-8'))

            except (AttributeError, ValueError):
                # could not parse JSON response...
                return HttpResponse(
                    _('Invalid JSON specified.'),
                    status=ResponseCode.bad_request)

        if not content:
            # We could not handle the Content-Type
            return HttpResponse(
                _('The message format is not supported.'),
                status=ResponseCode.bad_request)

        # Some basic error checking
        if not content.get('body') or \
                content.get('type', apprise.NotifyType.INFO) \
                not in apprise.NOTIFY_TYPES:

            return HttpResponse(
                _('An invalid payload was specified.'),
                status=ResponseCode.bad_request)

        # If we get here, we have enough information to generate a notification
        # with.
        config, format = ConfigCache.get(key)
        if config is None:
            # The returned value of config and format tell a rather cryptic
            # story; this portion could probably be updated in the future.
            # but for now it reads like this:
            #   config == None and format == None: We had an internal error
            #   config == None and format != None: we simply have no data
            #   config != None: we simply have no data
            if format is not None:
                # no content to return
                return HttpResponse(
                    _('There was no configuration found.'),
                    status=ResponseCode.no_content,
                )

            # Something went very wrong; return 500
            return HttpResponse(
                _('An error occured accessing configuration.'),
                status=ResponseCode.internal_server_error,
            )

        # Prepare our apprise object
        a_obj = apprise.Apprise()

        # Create an apprise config object
        ac_obj = apprise.AppriseConfig()

        # Load our configuration
        ac_obj.add_config(config, format=format)

        # Add our configuration
        a_obj.add(ac_obj)

        # Perform our notification at this point
        result = a_obj.notify(
            content.get('body'),
            title=content.get('title', ''),
            notify_type=content.get('type', apprise.NotifyType.INFO),
            tag=content.get('tag'),
        )

        if not result:
            # If at least one notification couldn't be sent; change up
            # the response to a 424 error code
            return HttpResponse(
                _('One or more notification could not be sent.'),
                status=ResponseCode.failed_dependency)

        # Return our retrieved content
        return HttpResponse(
            _('Notification(s) sent.'),
            status=ResponseCode.okay
        )


@method_decorator((gzip_page, never_cache), name='dispatch')
class StatelessNotifyView(View):
    """
    A Django view for sending a stateless notification
    """
    def post(self, request):
        """
        Handle a POST request
        """
        # our content
        content = {}
        if MIME_IS_FORM.match(request.content_type):
            content = {}
            form = NotifyByUrlForm(request.POST)
            if form.is_valid():
                content.update(form.cleaned_data)

        elif MIME_IS_JSON.match(request.content_type):
            # Prepare our default response
            try:
                # load our JSON content
                content = json.loads(request.body.decode('utf-8'))

            except (AttributeError, ValueError):
                # could not parse JSON response...
                return HttpResponse(
                    _('Invalid JSON specified.'),
                    status=ResponseCode.bad_request)

        if not content:
            # We could not handle the Content-Type
            return HttpResponse(
                _('The message format is not supported.'),
                status=ResponseCode.bad_request)

        if not content.get('urls') and settings.APPRISE_STATELESS_URLS:
            # fallback to settings.APPRISE_STATELESS_URLS if no urls were
            # defined
            content['urls'] = settings.APPRISE_STATELESS_URLS

        # Some basic error checking
        if not content.get('body') or \
                content.get('type', apprise.NotifyType.INFO) \
                not in apprise.NOTIFY_TYPES:

            return HttpResponse(
                _('An invalid payload was specified.'),
                status=ResponseCode.bad_request)

        # Prepare our apprise object
        a_obj = apprise.Apprise()

        # Add URLs
        a_obj.add(content.get('urls'))
        if not len(a_obj):
            return HttpResponse(
                _('There was no services to notify.'),
                status=ResponseCode.no_content,
            )

        # Perform our notification at this point
        result = a_obj.notify(
            content.get('body'),
            title=content.get('title', ''),
            notify_type=content.get('type', apprise.NotifyType.INFO),
            tag='all',
        )

        if not result:
            # If at least one notification couldn't be sent; change up the
            # response to a 424 error code
            return HttpResponse(
                _('One or more notification could not be sent.'),
                status=ResponseCode.failed_dependency)

        # Return our retrieved content
        return HttpResponse(
            _('Notification(s) sent.'),
            status=ResponseCode.okay,
        )


@method_decorator((gzip_page, never_cache), name='dispatch')
class JsonUrlView(View):
    """
    A Django view that lists all loaded tags and URLs for a given key
    """
    def get(self, request, key):
        """
        Handle a POST request
        """

        # Now build our tag response that identifies all of the tags
        # and the URL's they're associated with
        #  {
        #    "tags": ["tag1', "tag2", "tag3"],
        #    "urls": [
        #       {
        #          "url": "windows://",
        #          "tags": [],
        #       },
        #       {
        #          "url": "mailto://user:pass@gmail.com"
        #          "tags": ["tag1", "tag2", "tag3"]
        #       }
        #    ]
        #  }
        response = {
            'tags': set(),
            'urls': [],
        }

        # Privacy flag
        privacy = bool(request.GET.get('privacy', False))

        config, format = ConfigCache.get(key)
        if config is None:
            # The returned value of config and format tell a rather cryptic
            # story; this portion could probably be updated in the future.
            # but for now it reads like this:
            #   config == None and format == None: We had an internal error
            #   config == None and format != None: we simply have no data
            #   config != None: we simply have no data
            if format is not None:
                # no content to return
                return JsonResponse(
                    response,
                    encoder=JSONEncoder,
                    safe=False,
                    status=ResponseCode.no_content,
                )

            # Something went very wrong; return 500
            response['error'] = _('There was no configuration found.')
            return JsonResponse(
                response,
                encoder=JSONEncoder,
                safe=False,
                status=ResponseCode.internal_server_error,
            )

        # Prepare our apprise object
        a_obj = apprise.Apprise()

        # Create an apprise config object
        ac_obj = apprise.AppriseConfig()

        # Load our configuration
        ac_obj.add_config(config, format=format)

        # Add our configuration
        a_obj.add(ac_obj)

        for notification in a_obj:
            # Set Notification
            response['urls'].append({
                'url': notification.url(privacy=privacy),
                'tags': notification.tags,
            })

            # Store Tags
            response['tags'] |= notification.tags

        # Return our retrieved content
        return JsonResponse(
            response,
            encoder=JSONEncoder,
            safe=False,
            status=ResponseCode.okay
        )