AKPlan/templatetags/color_gradients.py

+# gradients based on http://bsou.io/posts/color-gradients-with-python
+
+
+def hex_to_rgb(hex): #pylint: disable=redefined-builtin
+    """
+    Convert hex color to RGB color code
+    :param hex: hex encoded color
+    :type hex: str
+    :return: rgb encoded version of given color
+    :rtype: list[int]
+    """
+    # Pass 16 to the integer function for change of base
+    return [int(hex[i:i+2], 16) for i in range(1,6,2)]
+
+
+def rgb_to_hex(rgb):
+    """
+    Convert rgb color (list) to hex encoding (str)
+    :param rgb: rgb encoded color
+    :type rgb: list[int]
+    :return: hex encoded version of given color
+    :rtype: str
+    """
+    # Components need to be integers for hex to make sense
+    rgb = [int(x) for x in rgb]
+    return "#"+"".join([f"0{v:x}" if v < 16 else f"{v:x}" for v in rgb])
+
+
+def linear_blend(start_hex, end_hex, position):
+    """
+    Create a linear blend between two colors and return color code on given position of the range from 0 to 1
+    :param start_hex: hex representation of start color
+    :type start_hex: str
+    :param end_hex: hex representation of end color
+    :type end_hex: str
+    :param position: position in range from 0 to 1
+    :type position: float
+    :return: hex encoded interpolated color
+    :rtype: str
+    """
+    s = hex_to_rgb(start_hex)
+    f = hex_to_rgb(end_hex)
+    blended = [int(s[j] + position * (f[j] - s[j])) for j in range(3)]
+    return rgb_to_hex(blended)
+
+
+def darken(start_hex, amount):
+    """
+    Darken the given color by the given amount (sensitivity will be cut in half)
+
+    :param start_hex: original color
+    :type start_hex: str
+    :param amount: how much to darken (1.0 -> 50% darker)
+    :type amount: float
+    :return: darker version of color
+    :rtype: str
+    """
+    start_rbg = hex_to_rgb(start_hex)
+    darker = [int(s * (1 - amount * .5)) for s in start_rbg]
+    return rgb_to_hex(darker)

AKPlan/templatetags/tags_AKPlan.py

+from datetime import datetime
+
+from django import template
+from django.utils.formats import date_format
+
+from AKPlan.templatetags.color_gradients import darken
+from AKPlanning import settings
+
+register = template.Library()
+
+
+@register.filter
+def highlight_change_colors(akslot):
+    """
+    Adjust color to highlight recent changes if needed
+
+    :param akslot: akslot to determine color for
+    :type akslot: AKSlot
+    :return: color that should be used (either default color of the category or some kind of red)
+    :rtype: str
+    """
+    # Do not highlight in preview mode or when changes occurred before the plan was published
+    if akslot.event.plan_hidden or (akslot.event.plan_published_at is not None
+                                    and akslot.event.plan_published_at > akslot.updated):
+        return akslot.ak.category.color
+
+    seconds_since_update = akslot.seconds_since_last_update
+
+    # Last change long ago? Use default color
+    if seconds_since_update > settings.PLAN_MAX_HIGHLIGHT_UPDATE_SECONDS:
+        return akslot.ak.category.color
+
+    # Recent change? Calculate gradient blend between red and
+    recentness = seconds_since_update / settings.PLAN_MAX_HIGHLIGHT_UPDATE_SECONDS
+    return darken("#b71540", recentness)
+
+
+@register.simple_tag
+def timestamp_now(tz):
+    """
+    Get the current timestamp for the given timezone
+
+    :param tz: timezone to be used for the timestamp
+    :return: current timestamp in given timezone
+    """
+    return date_format(datetime.now().astimezone(tz), "c")

AKPlan/tests.py

+from django.test import TestCase
+
+from AKModel.tests import BasicViewTests
+
+
+class PlanViewTests(BasicViewTests, TestCase):
+    """
+    Tests for AKPlan
+    """
+    fixtures = ['model.json']
+    APP_NAME = 'plan'
+
+    VIEWS = [
+        ('plan_overview', {'event_slug': 'kif42'}),
+        ('plan_wall', {'event_slug': 'kif42'}),
+        ('plan_room', {'event_slug': 'kif42', 'pk': 2}),
+        ('plan_track', {'event_slug': 'kif42', 'pk': 1}),
+    ]
+
+    def test_plan_hidden(self):
+        """
+        Test correct handling of plan visibility
+        """
+        _, url = self._name_and_url(('plan_overview', {'event_slug': 'kif23'}))
+
+        self.client.logout()
+        response = self.client.get(url)
+        self.assertContains(response, "Plan is not visible (yet).",
+                            msg_prefix="Plan is visible even though it shouldn't be")
+
+        self.client.force_login(self.staff_user)
+        response = self.client.get(url)
+        self.assertNotContains(response, "Plan is not visible (yet).",
+                               msg_prefix="Plan is not visible for staff user")
+
+    def test_wall_redirect(self):
+        """
+        Test: Make sure that user is redirected from wall to overview when plan is hidden
+        """
+        _, url_wall = self._name_and_url(('plan_wall', {'event_slug': 'kif23'}))
+        _, url_plan = self._name_and_url(('plan_overview', {'event_slug': 'kif23'}))
+
+        response = self.client.get(url_wall)
+        self.assertRedirects(response, url_plan,
+                             msg_prefix=f"Redirect away from wall not working ({url_wall} -> {url_plan})")

AKPlan/urls.py

+from csp.decorators import csp_replace
+from django.urls import path, include
+
+from . import views
+
+app_name = "plan"
+
+urlpatterns = [
+    path(
+        '<slug:event_slug>/plan/',
+        include([
+            path('', views.PlanIndexView.as_view(), name='plan_overview'),
+            path('wall/', csp_replace(FRAME_ANCESTORS="*")(views.PlanScreenView.as_view()), name='plan_wall'),
+            path('room/<int:pk>/', views.PlanRoomView.as_view(), name='plan_room'),
+            path('track/<int:pk>/', views.PlanTrackView.as_view(), name='plan_track'),
+        ])
+    ),
+]

AKPlan/views.py

+from datetime import datetime, timedelta
+
+from django.conf import settings
+from django.shortcuts import redirect
+from django.urls import reverse_lazy
+from django.views.generic import DetailView, ListView
+
+from AKModel.metaviews.admin import FilterByEventSlugMixin
+from AKModel.models import AKSlot, AKTrack, Room
+
+
+class PlanIndexView(FilterByEventSlugMixin, ListView):
+    """
+    Default plan view
+
+    Shows two lists of current and upcoming AKs and a graphical full plan below
+    """
+    model = AKSlot
+    template_name = "AKPlan/plan_index.html"
+    context_object_name = "akslots"
+    ordering = "start"
+
+    def get_queryset(self):
+        # Ignore slots not scheduled yet
+        return super().get_queryset().filter(start__isnull=False).select_related('ak', 'room', 'ak__category')
+
+    def get_context_data(self, *, object_list=None, **kwargs):
+        context = super().get_context_data(object_list=object_list, **kwargs)
+
+        context["event"] = self.event
+
+        current_timestamp = datetime.now().astimezone(self.event.timezone)
+
+        context["akslots_now"] = []
+        context["akslots_next"] = []
+        rooms = set()
+        buildings = set()
+
+        # Get list of current and next slots
+        for akslot in context["akslots"]:
+            # Construct a list of all rooms used by these slots on the fly
+            if akslot.room is not None:
+                rooms.add(akslot.room)
+                # Store buildings for hierarchical view
+                if akslot.room.location != '':
+                    buildings.add(akslot.room.location)
+
+            # Recent AKs: Started but not ended yet
+            if akslot.start <= current_timestamp <= akslot.end:
+                context["akslots_now"].append(akslot)
+            # Next AKs: Not started yet, list will be filled in order until threshold is reached
+            elif akslot.start > current_timestamp:
+                if len(context["akslots_next"]) < settings.PLAN_MAX_NEXT_AKS:
+                    context["akslots_next"].append(akslot)
+
+        # Sort list of rooms by title
+        context["rooms"] = sorted(rooms, key=lambda x: x.title)
+        if settings.PLAN_SHOW_HIERARCHY:
+            context["buildings"] = sorted(buildings)
+
+        context["tracks"] = self.event.aktrack_set.all()
+
+        return context
+
+
+class PlanScreenView(PlanIndexView):
+    """
+    Plan view optimized for screens and projectors
+
+    This again shows current and upcoming AKs as well as a graphical plan,
+    but no navigation elements and trys to use the available space as best as possible
+    such that no scrolling is needed.
+
+    The view contains a frontend functionality for auto-reload.
+    """
+    template_name = "AKPlan/plan_wall.html"
+
+    def get(self, request, *args, **kwargs):
+        s = super().get(request, *args, **kwargs)
+        # Don't show wall when event is not active -> redirect to normal schedule
+        if not self.event.active or (self.event.plan_hidden and not request.user.is_staff):
+            return redirect(reverse_lazy("plan:plan_overview", kwargs={"event_slug": self.event.slug}))
+        return s
+
+    # pylint: disable=attribute-defined-outside-init
+    def get_queryset(self):
+        now = datetime.now().astimezone(self.event.timezone)
+        # Wall during event: Adjust, show only parts in the future
+        if self.event.start < now < self.event.end:
+            # Determine interesting range (some hours ago until some hours in the future as specified in the settings)
+            self.start = now - timedelta(hours=settings.PLAN_WALL_HOURS_RETROSPECT)
+        else:
+            self.start = self.event.start
+        self.end = self.event.end
+
+        # Restrict AK slots to relevant ones
+        # This will automatically filter all rooms not needed for the selected range in the orginal get_context method
+        akslots = super().get_queryset().filter(start__gt=self.start)
+
+        # Find the earliest hour AKs start and end (handle 00:00 as 24:00)
+        self.earliest_start_hour = 23
+        self.latest_end_hour = 1
+        for akslot in akslots.all():
+            start_hour = akslot.start.astimezone(self.event.timezone).hour
+            if start_hour < self.earliest_start_hour:
+                # Use hour - 1 to improve visibility of date change
+                self.earliest_start_hour = max(start_hour - 1, 0)
+            end_hour = akslot.end.astimezone(self.event.timezone).hour
+            # Special case: AK starts before but ends after midnight -- show until midnight
+            if end_hour < start_hour:
+                self.latest_end_hour = 24
+            elif end_hour > self.latest_end_hour:
+                # Always use hour + 1, since AK may end at :xy and not always at :00
+                self.latest_end_hour = min(end_hour + 1, 24)
+        return akslots
+
+    def get_context_data(self, *, object_list=None, **kwargs):
+        context = super().get_context_data(object_list=object_list, **kwargs)
+        context["start"] = self.start
+        context["end"] = self.event.end
+        context["earliest_start_hour"] = self.earliest_start_hour
+        context["latest_end_hour"] = self.latest_end_hour
+        return context
+
+
+class PlanRoomView(FilterByEventSlugMixin, DetailView):
+    """
+    Plan view for a single room
+    """
+    template_name = "AKPlan/plan_room.html"
+    model = Room
+    context_object_name = "room"
+
+    def get_context_data(self, *, object_list=None, **kwargs):
+        context = super().get_context_data(object_list=object_list, **kwargs)
+        # Restrict AKSlot list to the given room
+        # while joining AK, room and category information to reduce the amount of necessary SQL queries
+        context["slots"] = AKSlot.objects.filter(room=context['room']).select_related('ak', 'ak__category', 'ak__track')
+        return context
+
+
+class PlanTrackView(FilterByEventSlugMixin, DetailView):
+    """
+    Plan view for a single track
+    """
+    template_name = "AKPlan/plan_track.html"
+    model = AKTrack
+    context_object_name = "track"
+
+    def get_context_data(self, *, object_list=None, **kwargs):
+        context = super().get_context_data(object_list=object_list, **kwargs)
+        # Restrict AKSlot list to given track
+        # while joining AK, room and category information to reduce the amount of necessary SQL queries
+        context["slots"] = AKSlot.objects. \
+            filter(event=self.event, ak__track=context['track']). \
+            select_related('ak', 'room', 'ak__category')
+        return context

AKPlanning/locale/de_DE/LC_MESSAGES/django.po

+# SOME DESCRIPTIVE TITLE.
+# Copyright (C) YEAR THE PACKAGE'S COPYRIGHT HOLDER
+# This file is distributed under the same license as the PACKAGE package.
+# FIRST AUTHOR <EMAIL@ADDRESS>, YEAR.
+#
+#, fuzzy
+msgid ""
+msgstr ""
+"Project-Id-Version: PACKAGE VERSION\n"
+"Report-Msgid-Bugs-To: \n"
+"POT-Creation-Date: 2023-08-16 16:30+0200\n"
+"PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
+"Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
+"Language-Team: LANGUAGE <LL@li.org>\n"
+"Language: \n"
+"MIME-Version: 1.0\n"
+"Content-Type: text/plain; charset=UTF-8\n"
+"Content-Transfer-Encoding: 8bit\n"
+
+#: AKPlanning/settings.py:148
+msgid "German"
+msgstr "Deutsch"
+
+#: AKPlanning/settings.py:149
+msgid "English"
+msgstr "Englisch"

AKPlanning/settings.py

+"""
+Django settings for AKPlanning project.
+
+Generated by 'django-admin startproject' using Django 2.2.6.
+
+For more information on this file, see
+https://docs.djangoproject.com/en/2.2/topics/settings/
+
+For the full list of settings and their values, see
+https://docs.djangoproject.com/en/2.2/ref/settings/
+"""
+
+import os
+
+from django.utils.translation import gettext_lazy as _
+# Build paths inside the project like this: os.path.join(BASE_DIR, ...)
+from split_settings.tools import optional, include
+
+BASE_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
+
+# Quick-start development settings - unsuitable for production
+# See https://docs.djangoproject.com/en/2.2/howto/deployment/checklist/
+
+# SECURITY WARNING: keep the secret key used in production secret!
+SECRET_KEY = '+7#&=$grg7^x62m#3cuv)k$)tqx!xkj_o&y9sm)@@sgj7_7-!+'
+
+# SECURITY WARNING: don't run with debug turned on in production!
+DEBUG = True
+
+ALLOWED_HOSTS = []
+
+# Application definition
+
+INSTALLED_APPS = [
+    'AKModel.apps.AkmodelConfig',
+    'AKDashboard.apps.AkdashboardConfig',
+    'AKSubmission.apps.AksubmissionConfig',
+    'AKScheduling.apps.AkschedulingConfig',
+    'AKPlan.apps.AkplanConfig',
+    'AKOnline.apps.AkonlineConfig',
+    'AKModel.apps.AKAdminConfig',
+    'django.contrib.auth',
+    'django.contrib.contenttypes',
+    'django.contrib.sessions',
+    'django.contrib.messages',
+    'django.contrib.staticfiles',
+    'debug_toolbar',
+    'django_bootstrap5',
+    'fontawesomefree',
+    'fontawesome_6',
+    'timezone_field',
+    'rest_framework',
+    'simple_history',
+    'registration',
+    'django_tex',
+    'compressor',
+    'docs',
+]
+
+MIDDLEWARE = [
+    'django.middleware.gzip.GZipMiddleware',
+    'debug_toolbar.middleware.DebugToolbarMiddleware',
+    'django.middleware.security.SecurityMiddleware',
+    'django.contrib.sessions.middleware.SessionMiddleware',
+    'django.middleware.locale.LocaleMiddleware',
+    'django.middleware.common.CommonMiddleware',
+    'django.middleware.csrf.CsrfViewMiddleware',
+    'django.contrib.auth.middleware.AuthenticationMiddleware',
+    'django.contrib.messages.middleware.MessageMiddleware',
+    'csp.middleware.CSPMiddleware',
+    'django.middleware.clickjacking.XFrameOptionsMiddleware',
+    'simple_history.middleware.HistoryRequestMiddleware',
+]
+
+ROOT_URLCONF = 'AKPlanning.urls'
+
+TEMPLATES = [
+    {
+        'BACKEND': 'django.template.backends.django.DjangoTemplates',
+        'DIRS': [
+            os.path.join(BASE_DIR, 'templates'),
+        ],
+        'APP_DIRS': True,
+        'OPTIONS': {
+            'context_processors': [
+                'django.template.context_processors.debug',
+                'django.template.context_processors.request',
+                'django.contrib.auth.context_processors.auth',
+                'django.contrib.messages.context_processors.messages',
+            ],
+        },
+    },
+    {
+        'NAME': 'tex',
+        'BACKEND': 'django_tex.engine.TeXEngine',
+        'APP_DIRS': True,
+        'OPTIONS': {
+            'environment': 'AKModel.environment.improved_tex_environment',
+        },
+    },
+]
+
+WSGI_APPLICATION = 'AKPlanning.wsgi.application'
+
+DEFAULT_AUTO_FIELD = 'django.db.models.AutoField'
+
+# Database
+# https://docs.djangoproject.com/en/2.2/ref/settings/#databases
+
+DATABASES = {
+    'default': {
+        'ENGINE': 'django.db.backends.sqlite3',
+        'NAME': os.path.join(BASE_DIR, 'db.sqlite3'),
+    }
+}
+
+# Password validation
+# https://docs.djangoproject.com/en/2.2/ref/settings/#auth-password-validators
+
+AUTH_PASSWORD_VALIDATORS = [
+    {
+        'NAME': 'django.contrib.auth.password_validation.UserAttributeSimilarityValidator',
+    },
+    {
+        'NAME': 'django.contrib.auth.password_validation.MinimumLengthValidator',
+    },
+    {
+        'NAME': 'django.contrib.auth.password_validation.CommonPasswordValidator',
+    },
+    {
+        'NAME': 'django.contrib.auth.password_validation.NumericPasswordValidator',
+    },
+]
+
+# Internationalization
+# https://docs.djangoproject.com/en/2.2/topics/i18n/
+
+LANGUAGE_CODE = 'en-US'
+
+TIME_ZONE = 'UTC'
+
+USE_I18N = True
+
+USE_TZ = True
+
+LANGUAGES = [
+    ('de', _('German')),
+    ('en', _('English')),
+]
+
+INTERNAL_IPS = ['127.0.0.1', '::1']
+
+LATEX_INTERPRETER = 'lualatex'
+LATEX_RUN_COUNT = 2
+
+# Static files (CSS, JavaScript, Images)
+# https://docs.djangoproject.com/en/2.2/howto/static-files/
+
+STATIC_URL = '/static/'
+STATIC_ROOT = os.path.join(BASE_DIR, 'static')
+STATICFILES_DIRS = (
+    'static_common',
+)
+
+STATICFILES_FINDERS = (
+    'django.contrib.staticfiles.finders.FileSystemFinder',
+    'django.contrib.staticfiles.finders.AppDirectoriesFinder',
+    'compressor.finders.CompressorFinder',
+)
+
+# Settings for Bootstrap
+BOOTSTRAP5 = {
+    "javascript_url": {
+        "url": STATIC_URL + "common/vendor/bootstrap/bootstrap-5.0.2.bundle.min.js",
+    },
+}
+
+# Settings for FontAwesome
+FONTAWESOME_6_CSS_URL = STATIC_URL + "fontawesomefree/css/all.min.css"
+FONTAWESOME_6_PREFIX = "fa"
+
+# Compressor and minifier config
+COMPRESS_ENABLED = True
+COMPRESS_CSS_HASHING_METHOD = 'content'
+COMPRESS_PRECOMPILERS = (
+    ('text/x-scss', 'django_libsass.SassCompiler'),
+)
+COMPRESS_FILTERS = {
+    'css': [
+        'compressor.filters.css_default.CssAbsoluteFilter',
+        'compressor.filters.cssmin.rCSSMinFilter',
+    ],
+    'js': [
+        'compressor.filters.jsmin.JSMinFilter',
+    ]
+}
+
+# Treat wishes as seperate category in submission views?
+WISHES_AS_CATEGORY = True
+
+FOOTER_INFO = {
+    "repo_url": "https://gitlab.fachschaften.org/kif/akplanning",
+    "impress_text": "",
+    "impress_url": ""
+}
+
+# How many AKs should be visible as next AKs
+PLAN_MAX_NEXT_AKS = 10
+# Specify range of plan for screen/projector view
+PLAN_WALL_HOURS_RETROSPECT = 3
+# Should the plan use a hierarchy of buildings and rooms?
+PLAN_SHOW_HIERARCHY = True
+# For which time (in seconds) should changes of akslots be highlighted in plan?
+PLAN_MAX_HIGHLIGHT_UPDATE_SECONDS = 2 * 60 * 60
+
+# Show feed of recent changes in dashboard
+DASHBOARD_SHOW_RECENT = True
+# How many entries max?
+DASHBOARD_RECENT_MAX = 25
+# How many events should be featured in the dashboard
+# (active events will always be featured, even if their number is higher than this threshold)
+DASHBOARD_MAX_FEATURED_EVENTS = 3
+
+# Registration/login behavior
+SIMPLE_BACKEND_REDIRECT_URL = "/user/"
+LOGIN_REDIRECT_URL = SIMPLE_BACKEND_REDIRECT_URL
+
+# Content Security Policy
+CSP_DEFAULT_SRC = ("'self'",)
+CSP_SCRIPT_SRC = ("'self'", "'unsafe-inline'", "'unsafe-eval'")
+CSP_STYLE_SRC = ("'self'", "'unsafe-inline'", "fonts.googleapis.com")
+CSP_IMG_SRC = ("'self'", "data:")
+CSP_FRAME_SRC = ("'self'", )
+CSP_FONT_SRC = ("'self'", "data:", "fonts.gstatic.com")
+
+# Emails
+SEND_MAILS = True
+EMAIL_BACKEND = 'django.core.mail.backends.console.EmailBackend'
+
+# Documentation
+
+DOCS_ROOT = os.path.join(BASE_DIR, 'docs/_build/html')
+DOCS_ACCESS = 'public'
+
+include(optional("settings/*.py"))

AKPlanning/settings_ci.py

+# noinspection PyUnresolvedReferences
+from AKPlanning.settings import *
+
+DEBUG = False
+SECRET_KEY = '+7#&=$grg7^x62m#3cuv)k$)tqx!xkj_o&y9sm)@@sgj7_7-!+'
+
+SESSION_COOKIE_SECURE = True
+CSRF_COOKIE_SECURE = True
+
+DATABASES = {
+    'default': {
+        'ENGINE': 'django.db.backends.mysql',
+        'HOST': 'mysql',
+        'NAME': 'test',
+        'USER': 'django',
+        'PASSWORD': 'mysql',
+        'OPTIONS': {
+            'init_command': "SET sql_mode='STRICT_TRANS_TABLES'",
+        },
+        'TEST': {
+            'NAME': 'tests',
+            'CHARSET': "utf8mb4",
+            'COLLATION': 'utf8mb4_unicode_ci',
+        },
+    }
+}
+
+TEST_RUNNER = 'xmlrunner.extra.djangotestrunner.XMLTestRunner'
+TEST_OUTPUT_FILE_NAME = 'unit.xml'

AKPlanning/settings_production.py

+"""
+This is the settings file used in production.
+First, it imports all default settings, then overrides respective ones.
+Secrets are stored in and imported from an additional file, not set under version control.
+"""
+
+import AKPlanning.settings_secrets as secrets
+
+# noinspection PyUnresolvedReferences
+from AKPlanning.settings import *
+
+### SECURITY ###
+
+DEBUG = False
+
+ALLOWED_HOSTS = secrets.HOSTS
+
+SECRET_KEY = secrets.SECRET_KEY
+
+SESSION_COOKIE_SECURE = True
+CSRF_COOKIE_SECURE = True
+
+### DATABASE ###
+
+DATABASES = {
+    'default': {
+        'ENGINE': 'django.db.backends.mysql',
+        'HOST': getattr(secrets, "DB_HOST", "localhost"),
+        'NAME': secrets.DB_NAME,
+        'USER': secrets.DB_USER,
+        'PASSWORD': secrets.DB_PASSWORD,
+        'OPTIONS': {
+            'init_command': "SET sql_mode='STRICT_TRANS_TABLES'"
+        }
+    }
+}
+
+### EMAILS ###
+SEND_MAILS = True
+EMAIL_BACKEND = 'django.core.mail.backends.smtp.EmailBackend'
+
+# TODO: caching

AKPlanning/settings_secrets.py.sample

+SECRET_KEY = ''
+
+HOSTS = []
+
+DB_NAME = ''
+
+DB_USER = ''
+
+DB_PASSWORD = ''
+
+# Optional, if not set, localhost is assumed
+# DB_HOST = ''

AKPlanning/urls.py

+"""
+AKPlanning URL Configuration
+
+The `urlpatterns` list routes URLs to views. For more information please see:
+    https://docs.djangoproject.com/en/2.2/topics/http/urls/
+Examples:
+Function views
+    1. Add an import:  from my_app import views
+    2. Add a URL to urlpatterns:  path('', views.home, name='home')
+Class-based views
+    1. Add an import:  from other_app.views import Home
+    2. Add a URL to urlpatterns:  path('', Home.as_view(), name='home')
+Including another URLconf
+    1. Import the include() function: from django.urls import include, path
+    2. Add a URL to urlpatterns:  path('blog/', include('blog.urls'))
+"""
+
+import debug_toolbar
+from django.apps import apps
+from django.contrib import admin
+from django.urls import path, include, re_path
+
+urlpatterns = [
+    path('admin/', admin.site.urls),
+    re_path(r'^docs/', include('docs.urls')),
+    path('accounts/', include('django.contrib.auth.urls')),
+    path('accounts/', include('registration.backends.simple.urls')),
+    path('', include('AKModel.urls', namespace='model')),
+    path('i18n/', include('django.conf.urls.i18n')),
+    path('__debug__/', include(debug_toolbar.urls)),
+]
+
+# Load URLs dynamically (only if components are active)
+if apps.is_installed("AKSubmission"):
+    urlpatterns.append(path('', include('AKSubmission.urls', namespace='submit')))
+if apps.is_installed("AKDashboard"):
+    urlpatterns.append(path('', include('AKDashboard.urls', namespace='dashboard')))
+if apps.is_installed("AKPlan"):
+    urlpatterns.append(path('', include('AKPlan.urls', namespace='plan')))

AKPlanning/wsgi.py

+"""
+WSGI config for AKPlanning project.
+
+It exposes the WSGI callable as a module-level variable named ``application``.
+
+For more information on this file, see
+https://docs.djangoproject.com/en/2.2/howto/deployment/wsgi/
+"""
+
+import os
+
+from django.core.wsgi import get_wsgi_application
+
+os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'AKPlanning.settings')
+
+application = get_wsgi_application()

AKScheduling/api.py

+from django.contrib.auth.mixins import LoginRequiredMixin
+from django.http import JsonResponse
+from django.shortcuts import get_object_or_404
+from django.urls import reverse
+from django.utils import timezone
+from django.views.generic import ListView
+from rest_framework import viewsets, mixins, serializers, permissions
+
+from AKModel.availability.models import Availability
+from AKModel.models import Room, AKSlot, ConstraintViolation, DefaultSlot
+from AKModel.metaviews.admin import EventSlugMixin
+
+
+class ResourceSerializer(serializers.ModelSerializer):
+    """
+    REST Framework Serializer for Rooms to produce format required for fullcalendar resources
+    """
+    class Meta:
+        model = Room
+        fields = ['id', 'title']
+
+    title = serializers.SerializerMethodField('transform_title')
+
+    @staticmethod
+    def transform_title(obj):
+        """
+        Adapt title, add capacity information if room has a restriction (capacity is not -1)
+        """
+        if obj.capacity > 0:
+            return f"{obj.title} [{obj.capacity}]"
+        return obj.title
+
+
+class ResourcesViewSet(EventSlugMixin, mixins.ListModelMixin, viewsets.GenericViewSet):
+    """
+    API View: Rooms (resources to schedule for in fullcalendar)
+
+    Read-only, adaption to fullcalendar format through :class:`ResourceSerializer`
+    """
+    permission_classes = (permissions.DjangoModelPermissions,)
+    serializer_class = ResourceSerializer
+
+    def get_queryset(self):
+        return Room.objects.filter(event=self.event).order_by('location', 'name')
+
+
+class EventsView(LoginRequiredMixin, EventSlugMixin, ListView):
+    """
+    API View: Slots (events to schedule in fullcalendar)
+
+    Read-only, JSON formatted response is created manually since it requires a bunch of "custom" fields that have
+    different names compared to the normal model or are not present at all and need to be computed to create the
+    required format for fullcalendar.
+    """
+    model = AKSlot
+
+    def get_queryset(self):
+        return super().get_queryset().select_related('ak').filter(event=self.event, room__isnull=False)
+
+    def render_to_response(self, context, **response_kwargs):
+        return JsonResponse(
+            [{
+                "slotID": slot.pk,
+                "title": f'{slot.ak.short_name}:\n{slot.ak.owners_list}',
+                "description": slot.ak.details,
+                "resourceId": slot.room.id,
+                "start": timezone.localtime(slot.start, self.event.timezone).strftime("%Y-%m-%d %H:%M:%S"),
+                "end": timezone.localtime(slot.end, self.event.timezone).strftime("%Y-%m-%d %H:%M:%S"),
+                "backgroundColor": slot.ak.category.color,
+                "borderColor":
+                    "#2c3e50" if slot.fixed
+                    else '#e74c3c' if slot.constraintviolation_set.count() > 0
+                    else slot.ak.category.color,
+                "constraint": 'roomAvailable',
+                "editable": not slot.fixed,
+                'url': str(reverse('admin:AKModel_akslot_change', args=[slot.pk])),
+            } for slot in context["object_list"]],
+            safe=False,
+            **response_kwargs
+        )
+
+
+class RoomAvailabilitiesView(LoginRequiredMixin, EventSlugMixin, ListView):
+    """
+    API view: Availabilities of rooms
+
+    Read-only, JSON formatted response is created manually since it requires a bunch of "custom" fields that have
+    different names compared to the normal model or are not present at all and need to be computed to create the
+    required format for fullcalendar.
+    """
+    model = Availability
+    context_object_name = "availabilities"
+
+    def get_queryset(self):
+        return super().get_queryset().filter(event=self.event, room__isnull=False)
+
+    def render_to_response(self, context, **response_kwargs):
+        return JsonResponse(
+            [{
+                "title": "",
+                "resourceId": a.room.id,
+                "start": timezone.localtime(a.start, self.event.timezone).strftime("%Y-%m-%d %H:%M:%S"),
+                "end": timezone.localtime(a.end, self.event.timezone).strftime("%Y-%m-%d %H:%M:%S"),
+                "display": 'background',
+                "groupId": 'roomAvailable',
+            } for a in context["availabilities"]],
+            safe=False,
+            **response_kwargs
+        )
+
+
+class DefaultSlotsView(LoginRequiredMixin, EventSlugMixin, ListView):
+    """
+    API view: default slots
+
+    Read-only, JSON formatted response is created manually since it requires a bunch of "custom" fields that have
+    different names compared to the normal model or are not present at all and need to be computed to create the
+    required format for fullcalendar.
+    """
+    model = DefaultSlot
+    context_object_name = "default_slots"
+
+    def get_queryset(self):
+        return super().get_queryset().filter(event=self.event)
+
+    def render_to_response(self, context, **response_kwargs):
+        all_room_ids = [r.pk for r in self.event.room_set.all()]
+        return JsonResponse(
+            [{
+                "title": "",
+                "resourceIds": all_room_ids,
+                "start": timezone.localtime(a.start, self.event.timezone).strftime("%Y-%m-%d %H:%M:%S"),
+                "end": timezone.localtime(a.end, self.event.timezone).strftime("%Y-%m-%d %H:%M:%S"),
+                "display": 'background',
+                "groupId": 'defaultSlot',
+                "backgroundColor": '#69b6d4'
+            } for a in context["default_slots"]],
+            safe=False,
+            **response_kwargs
+        )
+
+
+class EventSerializer(serializers.ModelSerializer):
+    """
+    REST framework serializer to adapt between AKSlot model and the event format of fullcalendar
+    """
+    class Meta:
+        model = AKSlot
+        fields = ['id', 'start', 'end', 'roomId']
+
+    start = serializers.DateTimeField()
+    end = serializers.DateTimeField()
+    roomId = serializers.IntegerField(source='room.pk')
+
+    def update(self, instance, validated_data):
+        # Ignore timezone of input (treat it as timezone-less) and set the event timezone
+        # By working like this, the client does not need to know about timezones, since every timestamp it deals with
+        # has the timezone offsets already applied
+        start = timezone.make_aware(timezone.make_naive(validated_data.get('start')), instance.event.timezone)
+        end = timezone.make_aware(timezone.make_naive(validated_data.get('end')), instance.event.timezone)
+        instance.start = start
+        # Also, adapt from start & end format of fullcalendar to our start & duration model
+        diff = end - start
+        instance.duration = round(diff.days * 24 + (diff.seconds / 3600), 2)
+
+        # Updated room if needed (pk changed -- otherwise, no need for an additional database lookup)
+        new_room_id = validated_data.get('room')["pk"]
+        if instance.room is None or instance.room.pk != new_room_id:
+            instance.room = get_object_or_404(Room, pk=new_room_id)
+
+        instance.save()
+        return instance
+
+
+class EventsViewSet(EventSlugMixin, mixins.UpdateModelMixin, viewsets.GenericViewSet):
+    """
+    API view: Update scheduling of a slot (event in fullcalendar format)
+
+    Write-only (will however reply with written values to PUT request)
+    """
+    permission_classes = (permissions.DjangoModelPermissions,)
+    serializer_class = EventSerializer
+
+    def get_object(self):
+        return get_object_or_404(AKSlot, pk=self.kwargs["pk"])
+
+    def get_queryset(self):
+        return AKSlot.objects.filter(event=self.event)
+
+
+class ConstraintViolationSerializer(serializers.ModelSerializer):
+    """
+    REST Framework Serializer for constraint violations
+    """
+    class Meta:
+        model = ConstraintViolation
+        fields = ['pk', 'type_display', 'aks', 'ak_slots', 'ak_owner', 'room', 'requirement', 'category', 'comment',
+                  'timestamp_display', 'manually_resolved', 'level_display', 'details', 'edit_url']
+
+
+class ConstraintViolationsViewSet(EventSlugMixin, mixins.ListModelMixin, viewsets.GenericViewSet):
+    """
+    API View: Constraint Violations of an event
+
+    Read-only, fields and model selected in :class:`ConstraintViolationSerializer`
+    """
+    permission_classes = (permissions.DjangoModelPermissions,)
+    serializer_class = ConstraintViolationSerializer
+
+    def get_queryset(self):
+        # Optimize query to reduce database load
+        return (ConstraintViolation.objects.select_related('event', 'room')
+                .prefetch_related('aks', 'ak_slots', 'ak_owner', 'requirement', 'category')
+                .filter(event=self.event).order_by('manually_resolved', '-type', '-timestamp'))

AKScheduling/apps.py

+from django.apps import AppConfig
+
+
+class AkschedulingConfig(AppConfig):
+    """
+    App configuration (default, only specifies name of the app)
+    """
+    name = 'AKScheduling'

AKScheduling/forms.py

+from django import forms
+from django.utils.translation import gettext_lazy as _
+
+from AKModel.models import AK
+
+
+class AKInterestForm(forms.ModelForm):
+    """
+    Form for quickly changing the interest count and notes of an AK
+    """
+    required_css_class = 'required'
+
+    class Meta:
+        model = AK
+        fields = ['interest',
+                  'notes',
+                  ]
+
+
+class AKAddSlotForm(forms.Form):
+    """
+    Form to create a new slot for an existing AK directly from scheduling view
+    """
+    start = forms.CharField(label=_("Start"), disabled=True)
+    end = forms.CharField(label=_("End"), disabled=True)
+    duration = forms.CharField(label=_("Duration"), disabled=True)
+    room = forms.IntegerField(label=_("Room"), disabled=True, widget=forms.HiddenInput())
+    room_name = forms.CharField(label=_("Room"), disabled=True)
+
+    def __init__(self, event):
+        super().__init__()
+        self.fields['ak'] = forms.ModelChoiceField(event.ak_set.all(), label=_("AK"))

AKScheduling/locale/de_DE/LC_MESSAGES/django.po

+# SOME DESCRIPTIVE TITLE.
+# Copyright (C) YEAR THE PACKAGE'S COPYRIGHT HOLDER
+# This file is distributed under the same license as the PACKAGE package.
+# FIRST AUTHOR <EMAIL@ADDRESS>, YEAR.
+#
+#, fuzzy
+msgid ""
+msgstr ""
+"Project-Id-Version: PACKAGE VERSION\n"
+"Report-Msgid-Bugs-To: \n"
+"POT-Creation-Date: 2024-04-25 00:24+0200\n"
+"PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
+"Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
+"Language-Team: LANGUAGE <LL@li.org>\n"
+"Language: \n"
+"MIME-Version: 1.0\n"
+"Content-Type: text/plain; charset=UTF-8\n"
+"Content-Transfer-Encoding: 8bit\n"
+
+#: AKScheduling/forms.py:24
+msgid "Start"
+msgstr "Start"
+
+#: AKScheduling/forms.py:25
+msgid "End"
+msgstr "Ende"
+
+#: AKScheduling/forms.py:26
+msgid "Duration"
+msgstr ""
+
+#: AKScheduling/forms.py:27
+#: AKScheduling/templates/admin/AKScheduling/scheduling.html:171
+msgid "Room"
+msgstr "Raum"
+
+#: AKScheduling/forms.py:31
+msgid "AK"
+msgstr "AK"
+
+#: AKScheduling/models.py:92
+#, python-format
+msgid ""
+"Not enough space for AK interest (Interest: %(interest)d, Capacity: "
+"%(capacity)d)"
+msgstr ""
+"Nicht genug Platz für AK-Interesse (Interesse: %(interest)d, Kapazität: "
+"%(capacity)d)"
+
+#: AKScheduling/models.py:106
+#, python-format
+msgid ""
+"Space is too close to AK interest (Interest: %(interest)d, Capacity: "
+"%(capacity)d)"
+msgstr ""
+"Verfügbarer Platz zu dicht an Interesse (Interesse: %(interest)d, Kapazität: "
+"%(capacity)d)"
+
+#: AKScheduling/templates/admin/AKScheduling/constraint_violations.html:11
+msgid "Constraint Violations for"
+msgstr ""
+
+#: AKScheduling/templates/admin/AKScheduling/constraint_violations.html:44
+#: AKScheduling/templates/admin/AKScheduling/constraint_violations.html:105
+#: AKScheduling/templates/admin/AKScheduling/scheduling.html:240
+#: AKScheduling/templates/admin/AKScheduling/scheduling.html:375
+msgid "No violations"
+msgstr "Keine Verletzungen"
+
+#: AKScheduling/templates/admin/AKScheduling/constraint_violations.html:82
+#: AKScheduling/templates/admin/AKScheduling/scheduling.html:346
+msgid "Violation(s)"
+msgstr "Verletzung(en)"
+
+#: AKScheduling/templates/admin/AKScheduling/constraint_violations.html:85
+msgid "Auto reload?"
+msgstr "Automatisch neu laden?"
+
+#: AKScheduling/templates/admin/AKScheduling/constraint_violations.html:89
+msgid "Reload now"
+msgstr "Jetzt neu laden"
+
+#: AKScheduling/templates/admin/AKScheduling/constraint_violations.html:95
+#: AKScheduling/templates/admin/AKScheduling/scheduling.html:228
+msgid "Violation"
+msgstr "Verletzung"
+
+#: AKScheduling/templates/admin/AKScheduling/constraint_violations.html:96
+#: AKScheduling/templates/admin/AKScheduling/scheduling.html:369
+msgid "Problem"
+msgstr "Problem"
+
+#: AKScheduling/templates/admin/AKScheduling/constraint_violations.html:97
+msgid "Details"
+msgstr "Details"
+
+#: AKScheduling/templates/admin/AKScheduling/constraint_violations.html:98
+msgid "Since"
+msgstr "Seit"
+
+#: AKScheduling/templates/admin/AKScheduling/constraint_violations.html:111
+#: AKScheduling/templates/admin/AKScheduling/manage_tracks.html:256
+#: AKScheduling/templates/admin/AKScheduling/scheduling.html:332
+#: AKScheduling/templates/admin/AKScheduling/special_attention.html:48
+#: AKScheduling/templates/admin/AKScheduling/unscheduled.html:34
+msgid "Event Status"
+msgstr "Event-Status"
+
+#: AKScheduling/templates/admin/AKScheduling/constraint_violations.html:113
+msgid "Scheduling"
+msgstr "Scheduling"
+
+#: AKScheduling/templates/admin/AKScheduling/interest.html:32
+msgid "Submit"
+msgstr "Abschicken"
+
+#: AKScheduling/templates/admin/AKScheduling/manage_tracks.html:11
+#: AKScheduling/templates/admin/AKScheduling/scheduling.html:21
+#: AKScheduling/templates/admin/AKScheduling/scheduling.html:329
+msgid "Scheduling for"
+msgstr "Scheduling für"
+
+#: AKScheduling/templates/admin/AKScheduling/manage_tracks.html:135
+msgid "Name of new ak track"
+msgstr "Name des neuen AK-Tracks"
+
+#: AKScheduling/templates/admin/AKScheduling/manage_tracks.html:151
+msgid "Could not create ak track"
+msgstr "Konnte neuen AK-Track nicht anlegen"
+
+#: AKScheduling/templates/admin/AKScheduling/manage_tracks.html:177
+msgid "Could not update ak track name"
+msgstr "Konnte Namen des AK-Tracks nicht ändern"
+
+#: AKScheduling/templates/admin/AKScheduling/manage_tracks.html:183
+msgid "Do you really want to delete this ak track?"
+msgstr "Soll dieser AK-Track wirklich gelöscht werden?"
+
+#: AKScheduling/templates/admin/AKScheduling/manage_tracks.html:197
+msgid "Could not delete ak track"
+msgstr "AK-Track konnte nicht gelöscht werden"
+
+#: AKScheduling/templates/admin/AKScheduling/manage_tracks.html:216
+msgid "Manage AK Tracks"
+msgstr "AK-Tracks verwalten"
+
+#: AKScheduling/templates/admin/AKScheduling/manage_tracks.html:217
+msgid "Add ak track"
+msgstr "AK-Track hinzufügen"
+
+#: AKScheduling/templates/admin/AKScheduling/manage_tracks.html:222
+msgid "AKs without track"
+msgstr "AKs ohne Track"
+
+#: AKScheduling/templates/admin/AKScheduling/scheduling.html:106
+msgid "Day (Horizontal)"
+msgstr "Tag (horizontal)"
+
+#: AKScheduling/templates/admin/AKScheduling/scheduling.html:113
+msgid "Day (Vertical)"
+msgstr "Tag (vertikal)"
+
+#: AKScheduling/templates/admin/AKScheduling/scheduling.html:124
+msgid "Event (Horizontal)"
+msgstr "Event (horizontal)"
+
+#: AKScheduling/templates/admin/AKScheduling/scheduling.html:133
+msgid "Event (Vertical)"
+msgstr "Event (vertikal)"
+
+#: AKScheduling/templates/admin/AKScheduling/scheduling.html:271
+msgid "Please choose AK"
+msgstr "Bitte AK auswählen"
+
+#: AKScheduling/templates/admin/AKScheduling/scheduling.html:291
+msgid "Could not create slot"
+msgstr "Konnte Slot nicht anlegen"
+
+#: AKScheduling/templates/admin/AKScheduling/scheduling.html:307
+msgid "Add slot"
+msgstr "Slot hinzufügen"
+
+#: AKScheduling/templates/admin/AKScheduling/scheduling.html:315
+msgid "Add"
+msgstr "Hinzufügen"
+
+#: AKScheduling/templates/admin/AKScheduling/scheduling.html:316
+msgid "Cancel"
+msgstr "Abbrechen"
+
+#: AKScheduling/templates/admin/AKScheduling/scheduling.html:343
+msgid "Unscheduled"
+msgstr "Nicht gescheduled"
+
+#: AKScheduling/templates/admin/AKScheduling/scheduling.html:368
+msgid "Level"
+msgstr "Level"
+
+#: AKScheduling/templates/admin/AKScheduling/special_attention.html:14
+msgid "AKs with public notes"
+msgstr "AKs mit öffentlichen Kommentaren"
+
+#: AKScheduling/templates/admin/AKScheduling/special_attention.html:21
+msgid "AKs without availabilities"
+msgstr "AKs ohne Verfügbarkeiten"
+
+#: AKScheduling/templates/admin/AKScheduling/special_attention.html:28
+msgid "Create default availabilities"
+msgstr "Standardverfügbarkeiten anlegen"
+
+#: AKScheduling/templates/admin/AKScheduling/special_attention.html:31
+msgid "AK wishes with slots"
+msgstr "AK-Wünsche mit Slots"
+
+#: AKScheduling/templates/admin/AKScheduling/special_attention.html:38
+msgid "Delete slots for wishes"
+msgstr ""
+
+#: AKScheduling/templates/admin/AKScheduling/special_attention.html:40
+msgid "AKs without slots"
+msgstr "AKs ohne Slots"
+
+#: AKScheduling/templates/admin/AKScheduling/status/cvs.html:6
+msgid ""
+"\n"
+"            <h3>Constraint Violation</h3>\n"
+"            "
+msgid_plural ""
+"\n"
+"            <h3>Constraint Violations</h3>\n"
+"        "
+msgstr[0] ""
+"\n"
+"            <h3>Constraintverletzung</h3>\n"
+"            "
+msgstr[1] ""
+"\n"
+"            <h3>Constraintverletzungen</h3>\n"
+"        "
+
+#: AKScheduling/templates/admin/AKScheduling/unscheduled.html:7
+msgid "Unscheduled AK Slots"
+msgstr "Noch nicht geschedulte AK-Slots"
+
+#: AKScheduling/templates/admin/AKScheduling/unscheduled.html:11
+msgid "Count"
+msgstr "Anzahl"
+
+#: AKScheduling/views.py:150
+msgid "Interest updated"
+msgstr "Interesse aktualisiert"
+
+#: AKScheduling/views.py:201
+msgid "Wishes"
+msgstr "Wünsche"
+
+#: AKScheduling/views.py:219
+msgid "Cleanup: Delete unscheduled slots for wishes"
+msgstr "Aufräumen: Noch nicht geplante Slots für Wünsche löschen"
+
+#: AKScheduling/views.py:226
+#, python-brace-format
+msgid ""
+"The following {count} unscheduled slots of wishes will be deleted:\n"
+"\n"
+" {slots}"
+msgstr ""
+"Die folgenden {count} noch nicht geplanten Slots von Wünschen werden "
+"gelöscht:\n"
+"\n"
+" {slots}"
+
+#: AKScheduling/views.py:233
+msgid "Unscheduled slots for wishes successfully deleted"
+msgstr "Noch nicht geplante Slots für Wünsche erfolgreich gelöscht"
+
+#: AKScheduling/views.py:247
+msgid "Create default availabilities for AKs"
+msgstr "Standardverfügbarkeiten für AKs anlegen"
+
+#: AKScheduling/views.py:254
+#, python-brace-format
+msgid ""
+"The following {count} AKs don't have any availability information. Create "
+"default availability for them:\n"
+"\n"
+" {aks}"
+msgstr ""
+"Die folgenden {count} AKs haben keine Verfügbarkeitsinformationen. "
+"Standardverfügbarkeiten für sie anlegen:\n"
+"\n"
+" {aks}"
+
+#: AKScheduling/views.py:274
+#, python-brace-format
+msgid "Could not create default availabilities for AK: {ak}"
+msgstr "Konnte keine Verfügbarkeit anlegen für AK: {ak}"
+
+#: AKScheduling/views.py:279
+#, python-brace-format
+msgid "Created default availabilities for {count} AKs"
+msgstr "Standardverfügbarkeiten für {count} AKs angelegt"
+
+#: AKScheduling/views.py:290
+msgid "Constraint Violations"
+msgstr "Constraintverletzungen"
+
+#~ msgid "Bitte AK auswählen"
+#~ msgstr "Please sel"
+
+#~ msgid "Cannot load current violations from server"
+#~ msgstr "Kann die aktuellen Verletzungen nicht vom Server laden"

AKScheduling/models.py

+# This file mainly contains signal receivers, which follow a very strong interface, having e.g., a sender attribute
+# that is hardly used by us. Nevertheless, to follow the django receiver coding style and since changes might
+# cause issues when loading fixtures or model dumps, it is not wise to replace that attribute with "_".
+# Therefore, the check that finds unused arguments is disabled for this whole file:
+# pylint: disable=unused-argument
+
+from django.db.models.signals import post_save, m2m_changed, pre_delete
+from django.dispatch import receiver
+from django.utils.translation import gettext_lazy as _
+
+from AKModel.availability.models import Availability
+from AKModel.models import AK, AKSlot, Room, Event, ConstraintViolation
+
+
+def update_constraint_violations(new_violations, existing_violations_to_check):
+    """
+    Update existing constraint violations (subset for which new violations were computed) based on these new violations.
+    This will add all new violations without a match, preserve the matching ones
+    and delete the obsolete ones (those without a match from the newly calculated violations).
+
+    :param new_violations: list of new (not yet saved) violations that exist after the last change
+    :type new_violations: list[ConstraintViolation]
+    :param existing_violations_to_check: list of related violations currently in the db
+    :type existing_violations_to_check: list[ConstraintViolation]
+    """
+    for new_violation in new_violations:
+        found_match = False
+        for existing_violation in existing_violations_to_check:
+            if existing_violation.matches(new_violation):
+                # Remove from existing violations set since it should stay in db
+                existing_violations_to_check.remove(existing_violation)
+                found_match = True
+                break
+
+        # Only save new violation if no match was found
+        if not found_match:
+            new_violation.save()
+
+    # Cleanup obsolete violations (ones without matches computed under current conditions)
+    for outdated_violation in existing_violations_to_check:
+        outdated_violation.delete()
+
+
+def update_cv_reso_deadline_for_slot(slot):
+    """
+    Update constraint violation AK_AFTER_RESODEADLINE for given slot
+
+    :param slot: slot to check/update
+    :type slot: AKSlot
+    """
+    event = slot.event
+
+    # Update only if reso_deadline exists
+    # if event was changed and reso_deadline is removed, CVs will be deleted by event changed handler
+    # Update only has to be done for already scheduled slots with reso intention
+    if slot.ak.reso and slot.event.reso_deadline and slot.start:
+        violation_type = ConstraintViolation.ViolationType.AK_AFTER_RESODEADLINE
+        new_violations = []
+
+        # Violation?
+        if slot.end > event.reso_deadline:
+            c = ConstraintViolation(
+                type=violation_type,
+                level=ConstraintViolation.ViolationLevel.VIOLATION,
+                event=event,
+            )
+            c.aks_tmp.add(slot.ak)
+            c.ak_slots_tmp.add(slot)
+            new_violations.append(c)
+        update_constraint_violations(new_violations, list(slot.constraintviolation_set.filter(type=violation_type)))
+
+
+def check_capacity_for_slot(slot: AKSlot):
+    """
+    Check whether this slot violates the capacity requirement
+
+    :param slot: slot to check
+    :type slot: AKSlot
+    :return: Violation (if any) or None
+    :rtype: ConstraintViolation or None
+    """
+
+    # If slot is scheduled in a room and interest was specified
+    if slot.room and slot.room.capacity >= 0 and slot.ak.interest >= 0:
+        # Create a violation if interest exceeds room capacity
+        if slot.room.capacity < slot.ak.interest:
+            c = ConstraintViolation(
+                type=ConstraintViolation.ViolationType.ROOM_CAPACITY_EXCEEDED,
+                level=ConstraintViolation.ViolationLevel.VIOLATION,
+                event=slot.event,
+                room=slot.room,
+                comment=_("Not enough space for AK interest (Interest: %(interest)d, Capacity: %(capacity)d)")
+                        % {'interest': slot.ak.interest, 'capacity': slot.room.capacity},
+            )
+            c.ak_slots_tmp.add(slot)
+            c.aks_tmp.add(slot.ak)
+            return c
+
+        # Create a warning if interest is close to room capacity
+        if slot.room.capacity < slot.ak.interest + 5 or slot.room.capacity < slot.ak.interest * 1.25:
+            c = ConstraintViolation(
+                type=ConstraintViolation.ViolationType.ROOM_CAPACITY_EXCEEDED,
+                level=ConstraintViolation.ViolationLevel.WARNING,
+                event=slot.event,
+                room=slot.room,
+                comment=_("Space is too close to AK interest (Interest: %(interest)d, Capacity: %(capacity)d)")
+                        % {'interest': slot.ak.interest, 'capacity': slot.room.capacity}
+            )
+            c.ak_slots_tmp.add(slot)
+            c.aks_tmp.add(slot.ak)
+            return c
+
+    return None
+
+
+@receiver(post_save, sender=AK)
+def ak_changed_handler(sender, instance: AK, **kwargs):
+    """
+    Signal receiver: Check for violations after AK changed
+
+    Changes might affect: Reso intention, Category, Interest
+    """
+    # TODO Reso intention changes
+
+    # Check room capacities
+    violation_type = ConstraintViolation.ViolationType.ROOM_CAPACITY_EXCEEDED
+    new_violations = []
+    for slot in instance.akslot_set.all():
+        cv = check_capacity_for_slot(slot)
+        if cv is not None:
+            new_violations.append(cv)
+
+    existing_violations_to_check = list(instance.constraintviolation_set.filter(type=violation_type))
+    update_constraint_violations(new_violations, existing_violations_to_check)
+
+
+@receiver(m2m_changed, sender=AK.owners.through)
+def ak_owners_changed_handler(sender, instance: AK, action: str, **kwargs):
+    """
+    Signal receiver: Owners of AK changed
+    """
+    # Only signal after change (post_add, post_delete, post_clear) are relevant
+    if not action.startswith("post"):
+        return
+
+    event = instance.event
+
+    # Owner(s) changed: Might affect multiple AKs by the same owner(s) at the same time
+    violation_type = ConstraintViolation.ViolationType.OWNER_TWO_SLOTS
+    new_violations = []
+
+    slots_of_this_ak: [AKSlot] = instance.akslot_set.filter(start__isnull=False)
+
+    # For all owners (after recent change)...
+    for owner in instance.owners.all():
+        # ...find other slots that might be overlapping...
+
+        for ak in owner.ak_set.all():
+            # ...find overlapping slots...
+            if ak != instance:
+                for slot in slots_of_this_ak:
+                    for other_slot in ak.akslot_set.filter(start__isnull=False):
+                        if slot.overlaps(other_slot):
+                            # ...and create a temporary violation if necessary...
+                            c = ConstraintViolation(
+                                type=violation_type,
+                                level=ConstraintViolation.ViolationLevel.VIOLATION,
+                                event=event,
+                                ak_owner=owner
+                            )
+                            c.aks_tmp.add(instance)
+                            c.aks_tmp.add(other_slot.ak)
+                            c.ak_slots_tmp.add(slot)
+                            c.ak_slots_tmp.add(other_slot)
+                            new_violations.append(c)
+
+    # ... and compare to/update list of existing violations of this type
+    # belonging to the AK that was recently changed (important!)
+    existing_violations_to_check = list(instance.constraintviolation_set.filter(type=violation_type))
+    # print(existing_violations_to_check)
+    update_constraint_violations(new_violations, existing_violations_to_check)
+
+
+@receiver(m2m_changed, sender=AK.conflicts.through)
+def ak_conflicts_changed_handler(sender, instance: AK, action: str, **kwargs):
+    """
+    Signal receiver: Conflicts of AK changed
+    """
+    # Only signal after change (post_add, post_delete, post_clear) are relevant
+    if not action.startswith("post"):
+        return
+
+    event = instance.event
+
+    # Conflict(s) changed: Might affect multiple AKs that are conflicts of each other
+    violation_type = ConstraintViolation.ViolationType.AK_CONFLICT_COLLISION
+    new_violations = []
+
+    slots_of_this_ak: [AKSlot] = instance.akslot_set.filter(start__isnull=False)
+    conflicts_of_this_ak: [AK] = instance.conflicts.all()
+
+    # Loop over all existing conflicts
+    for ak in conflicts_of_this_ak:
+        if ak != instance:
+            for other_slot in ak.akslot_set.filter(start__isnull=False):
+                for slot in slots_of_this_ak:
+                    # ...find overlapping slots...
+                    if slot.overlaps(other_slot):
+                        # ...and create a temporary violation if necessary...
+                        c = ConstraintViolation(
+                            type=violation_type,
+                            level=ConstraintViolation.ViolationLevel.VIOLATION,
+                            event=event,
+                        )
+                        c.aks_tmp.add(instance)
+                        c.ak_slots_tmp.add(slot)
+                        c.ak_slots_tmp.add(other_slot)
+                        new_violations.append(c)
+
+    # ... and compare to/update list of existing violations of this type
+    # belonging to the AK that was recently changed (important!)
+    existing_violations_to_check = list(instance.constraintviolation_set.filter(type=violation_type))
+    # print(existing_violations_to_check)
+    update_constraint_violations(new_violations, existing_violations_to_check)
+
+
+@receiver(m2m_changed, sender=AK.prerequisites.through)
+def ak_prerequisites_changed_handler(sender, instance: AK, action: str, **kwargs):
+    """
+    Signal receiver: Prerequisites of AK changed
+    """
+    # Only signal after change (post_add, post_delete, post_clear) are relevant
+    if not action.startswith("post"):
+        return
+
+    event = instance.event
+
+    # Prerequisite(s) changed: Might affect multiple AKs that should have a certain order
+    violation_type = ConstraintViolation.ViolationType.AK_BEFORE_PREREQUISITE
+    new_violations = []
+
+    slots_of_this_ak: [AKSlot] = instance.akslot_set.filter(start__isnull=False)
+    prerequisites_of_this_ak: [AK] = instance.prerequisites.all()
+
+    # Loop over all prerequisites
+    for ak in prerequisites_of_this_ak:
+        if ak != instance:
+            for other_slot in ak.akslot_set.filter(start__isnull=False):
+                for slot in slots_of_this_ak:
+                    # ...find overlapping slots...
+                    if other_slot.end > slot.start:
+                        # ...and create a temporary violation if necessary...
+                        c = ConstraintViolation(
+                            type=violation_type,
+                            level=ConstraintViolation.ViolationLevel.VIOLATION,
+                            event=event,
+                        )
+                        c.aks_tmp.add(instance)
+                        c.ak_slots_tmp.add(slot)
+                        c.ak_slots_tmp.add(other_slot)
+                        new_violations.append(c)
+
+    # ... and compare to/update list of existing violations of this type
+    # belonging to the AK that was recently changed (important!)
+    existing_violations_to_check = list(instance.constraintviolation_set.filter(type=violation_type))
+    # print(existing_violations_to_check)
+    update_constraint_violations(new_violations, existing_violations_to_check)
+
+
+@receiver(m2m_changed, sender=AK.requirements.through)
+def ak_requirements_changed_handler(sender, instance: AK, action: str, **kwargs):
+    """
+    Signal receiver: Requirements of AK changed
+    """
+    # Only signal after change (post_add, post_delete, post_clear) are relevant
+    if not action.startswith("post"):
+        return
+
+    event = instance.event
+
+    # Requirement(s) changed: Might affect slots and rooms
+    violation_type = ConstraintViolation.ViolationType.REQUIRE_NOT_GIVEN
+    new_violations = []
+
+    slots_of_this_ak: [AKSlot] = instance.akslot_set.filter(start__isnull=False)
+
+    # For all requirements (after recent change)...
+    for slot in slots_of_this_ak:
+
+        room = slot.room
+        room_requirements = room.properties.all()
+
+        for requirement in instance.requirements.all():
+
+            if not requirement in room_requirements:
+                # ...and create a temporary violation if necessary...
+                c = ConstraintViolation(
+                    type=violation_type,
+                    level=ConstraintViolation.ViolationLevel.VIOLATION,
+                    event=event,
+                    requirement=requirement,
+                    room=room,
+                )
+                c.aks_tmp.add(instance)
+                c.ak_slots_tmp.add(slot)
+                new_violations.append(c)
+
+    # ... and compare to/update list of existing violations of this type
+    # belonging to the AK that was recently changed (important!)
+    existing_violations_to_check = list(instance.constraintviolation_set.filter(type=violation_type))
+    # print(existing_violations_to_check)
+    update_constraint_violations(new_violations, existing_violations_to_check)
+
+
+@receiver(post_save, sender=AKSlot)
+def akslot_changed_handler(sender, instance: AKSlot, **kwargs):
+    """
+    Signal receiver: AKSlot changed
+
+    Changes might affect: Duplicate parallel, Two in room, Resodeadline
+    """
+    # TODO Consider rewriting this very long and complex method to resolve several (style) issues:
+    # pylint: disable=too-many-nested-blocks,too-many-locals,too-many-branches,too-many-statements
+    event = instance.event
+
+    # == Check for two parallel slots by one of the owners ==
+
+    violation_type = ConstraintViolation.ViolationType.OWNER_TWO_SLOTS
+    new_violations = []
+
+    if instance.start:
+        # For all owners (after recent change)...
+        for owner in instance.ak.owners.all():
+            # ...find other slots that might be overlapping...
+
+            for ak in owner.ak_set.all():
+                # ...find overlapping slots...
+                if ak != instance.ak:
+                    for other_slot in ak.akslot_set.filter(start__isnull=False):
+                        if instance.overlaps(other_slot):
+                            # ...and create a temporary violation if necessary...
+                            c = ConstraintViolation(
+                                type=violation_type,
+                                level=ConstraintViolation.ViolationLevel.VIOLATION,
+                                event=event,
+                                ak_owner=owner
+                            )
+                            c.aks_tmp.add(instance.ak)
+                            c.aks_tmp.add(other_slot.ak)
+                            c.ak_slots_tmp.add(instance)
+                            c.ak_slots_tmp.add(other_slot)
+                            new_violations.append(c)
+
+    # ... and compare to/update list of existing violations of this type
+    # belonging to the AK that was recently changed (important!)
+    existing_violations_to_check = list(instance.constraintviolation_set.filter(type=violation_type))
+    # print(existing_violations_to_check)
+    update_constraint_violations(new_violations, existing_violations_to_check)
+
+    # == Check for two aks in the same room at the same time ==
+
+    violation_type = ConstraintViolation.ViolationType.ROOM_TWO_SLOTS
+    new_violations = []
+
+    # For all slots in this room...
+    if instance.room:
+        for other_slot in instance.room.akslot_set.all():
+            if other_slot != instance:
+                # ... find overlapping slots...
+                if instance.overlaps(other_slot):
+                    # ...and create a temporary violation if necessary...
+                    c = ConstraintViolation(
+                        type=violation_type,
+                        level=ConstraintViolation.ViolationLevel.WARNING,
+                        event=event,
+                        room=instance.room
+                    )
+                    c.aks_tmp.add(instance.ak)
+                    c.aks_tmp.add(other_slot.ak)
+                    c.ak_slots_tmp.add(instance)
+                    c.ak_slots_tmp.add(other_slot)
+                    new_violations.append(c)
+
+    # ... and compare to/update list of existing violations of this type
+    # belonging to the slot that was recently changed (important!)
+    existing_violations_to_check = list(instance.constraintviolation_set.filter(type=violation_type))
+    # print(existing_violations_to_check)
+    update_constraint_violations(new_violations, existing_violations_to_check)
+
+    # == Check for reso ak after reso deadline ==
+
+    update_cv_reso_deadline_for_slot(instance)
+
+    # == Check for two slots of the same AK at the same time (warning) ==
+
+    violation_type = ConstraintViolation.ViolationType.AK_SLOT_COLLISION
+    new_violations = []
+
+    if instance.start:
+        # For all other slots of this ak...
+        for other_slot in instance.ak.akslot_set.filter(start__isnull=False):
+            if other_slot != instance:
+                # ... find overlapping slots...
+                if instance.overlaps(other_slot):
+                    # ...and create a temporary violation if necessary...
+                    c = ConstraintViolation(
+                        type=violation_type,
+                        level=ConstraintViolation.ViolationLevel.WARNING,
+                        event=event,
+                    )
+                    c.aks_tmp.add(instance.ak)
+                    c.ak_slots_tmp.add(instance)
+                    c.ak_slots_tmp.add(other_slot)
+                    new_violations.append(c)
+
+    # ... and compare to/update list of existing violations of this type
+    # belonging to the slot that was recently changed (important!)
+    existing_violations_to_check = list(instance.constraintviolation_set.filter(type=violation_type))
+    update_constraint_violations(new_violations, existing_violations_to_check)
+
+    # == Check for slot outside availability ==
+
+    # An AK's availability changed: Might affect AK slots scheduled outside the permitted time
+    violation_type = ConstraintViolation.ViolationType.SLOT_OUTSIDE_AVAIL
+    new_violations = []
+
+    if instance.start:
+        availabilities_of_this_ak: [Availability] = instance.ak.availabilities.all()
+
+        covered = False
+
+        for availability in availabilities_of_this_ak:
+            covered = availability.start <= instance.start and availability.end >= instance.end
+            if covered:
+                break
+        if not covered:
+            c = ConstraintViolation(
+                type=violation_type,
+                level=ConstraintViolation.ViolationLevel.VIOLATION,
+                event=event
+            )
+            c.aks_tmp.add(instance.ak)
+            c.ak_slots_tmp.add(instance)
+            new_violations.append(c)
+
+    # ... and compare to/update list of existing violations of this type
+    # belonging to the AK that was recently changed (important!)
+    existing_violations_to_check = list(instance.constraintviolation_set.filter(type=violation_type))
+    # print(existing_violations_to_check)
+    update_constraint_violations(new_violations, existing_violations_to_check)
+
+    # == Check for requirement not fulfilled by room ==
+
+    # Room(s) changed: Might affect slots and rooms
+    violation_type = ConstraintViolation.ViolationType.REQUIRE_NOT_GIVEN
+    new_violations = []
+
+    if instance.room:
+
+        room_requirements = instance.room.properties.all()
+
+        for requirement in instance.ak.requirements.all():
+
+            if requirement not in room_requirements:
+                # ...and create a temporary violation if necessary...
+                c = ConstraintViolation(
+                    type=violation_type,
+                    level=ConstraintViolation.ViolationLevel.VIOLATION,
+                    event=event,
+                    requirement=requirement,
+                    room=instance.room,
+                )
+                c.aks_tmp.add(instance.ak)
+                c.ak_slots_tmp.add(instance)
+                new_violations.append(c)
+
+    # ... and compare to/update list of existing violations of this type
+    # belonging to the AK that was recently changed (important!)
+    existing_violations_to_check = list(instance.constraintviolation_set.filter(type=violation_type))
+    # print(existing_violations_to_check)
+    update_constraint_violations(new_violations, existing_violations_to_check)
+
+    # == check for simultaneous slots of conflicting AKs ==
+
+    violation_type = ConstraintViolation.ViolationType.AK_CONFLICT_COLLISION
+    new_violations = []
+
+    if instance.start:
+        conflicts_of_this_ak: [AK] = instance.ak.conflicts.all()
+
+        for ak in conflicts_of_this_ak:
+            if ak != instance.ak:
+                for other_slot in ak.akslot_set.filter(start__isnull=False):
+                    # ...find overlapping slots...
+                    if instance.overlaps(other_slot):
+                        # ...and create a temporary violation if necessary...
+                        c = ConstraintViolation(
+                            type=violation_type,
+                            level=ConstraintViolation.ViolationLevel.VIOLATION,
+                            event=event,
+                        )
+                        c.aks_tmp.add(instance.ak)
+                        c.ak_slots_tmp.add(instance)
+                        c.ak_slots_tmp.add(other_slot)
+                        new_violations.append(c)
+
+    # ... and compare to/update list of existing violations of this type
+    # belonging to the AK that was recently changed (important!)
+    existing_violations_to_check = list(instance.ak.constraintviolation_set.filter(type=violation_type))
+    # print(existing_violations_to_check)
+    update_constraint_violations(new_violations, existing_violations_to_check)
+
+    # == check for missing prerequisites ==
+
+    violation_type = ConstraintViolation.ViolationType.AK_BEFORE_PREREQUISITE
+    new_violations = []
+
+    if instance.start:
+        prerequisites_of_this_ak: [AK] = instance.ak.prerequisites.all()
+
+        for ak in prerequisites_of_this_ak:
+            if ak != instance.ak:
+                for other_slot in ak.akslot_set.filter(start__isnull=False):
+                    # ...find slots in the wrong order...
+                    if other_slot.end > instance.start:
+                        # ...and create a temporary violation if necessary...
+                        c = ConstraintViolation(
+                            type=violation_type,
+                            level=ConstraintViolation.ViolationLevel.VIOLATION,
+                            event=event,
+                        )
+                        c.aks_tmp.add(instance.ak)
+                        c.ak_slots_tmp.add(instance)
+                        c.ak_slots_tmp.add(other_slot)
+                        new_violations.append(c)
+
+    # ... and compare to/update list of existing violations of this type
+    # belonging to the AK that was recently changed (important!)
+    existing_violations_to_check = list(instance.ak.constraintviolation_set.filter(type=violation_type))
+    # print(existing_violations_to_check)
+    update_constraint_violations(new_violations, existing_violations_to_check)
+
+    # == Check for room capacity ==
+    cv = check_capacity_for_slot(instance)
+    new_violations = [cv] if cv is not None else []
+
+    # Compare to/update list of existing violations of this type for this slot
+    existing_violations_to_check = list(
+        instance.constraintviolation_set.filter(type=ConstraintViolation.ViolationType.ROOM_CAPACITY_EXCEEDED)
+    )
+    update_constraint_violations(new_violations, existing_violations_to_check)
+
+
+@receiver(pre_delete, sender=AKSlot)
+def akslot_deleted_handler(sender, instance: AKSlot, **kwargs):
+    """
+    Signal receiver: AKSlot deleted
+
+    Manually clean up or remove constraint violations that belong to this slot since there is no cascade deletion
+    for many2many relationships. Explicitly listening for AK deletion signals is not necessary since they will
+    transitively trigger this signal and we always set both AK and AKSlot references in a constraint violation
+    """
+    # print(f"{instance} deleted")
+
+    for cv in instance.constraintviolation_set.all():
+        # Make sure not delete CVs that e.g., show three parallel slots in a single room
+        if cv.ak_slots.count() <= 2:
+            cv.delete()
+
+
+@receiver(post_save, sender=Room)
+def room_changed_handler(sender, instance: Room, **kwargs):
+    """
+    Signal receiver: Room changed
+
+    Changes might affect: Room size
+    """
+    # Check room capacities
+    violation_type = ConstraintViolation.ViolationType.ROOM_CAPACITY_EXCEEDED
+    new_violations = []
+    for slot in instance.akslot_set.all():
+        cv = check_capacity_for_slot(slot)
+        if cv is not None:
+            new_violations.append(cv)
+
+    existing_violations_to_check = list(instance.constraintviolation_set.filter(type=violation_type))
+    update_constraint_violations(new_violations, existing_violations_to_check)
+
+
+@receiver(m2m_changed, sender=Room.properties.through)
+def room_requirements_changed_handler(sender, instance: Room, action: str, **kwargs):
+    """
+    Signal Receiver: Requirements of room changed
+    """
+    # Only signal after change (post_add, post_delete, post_clear) are relevant
+    if not action.startswith("post"):
+        return
+
+    # event = instance.event
+    # TODO React to changes
+
+
+@receiver(post_save, sender=Availability)
+def availability_changed_handler(sender, instance: Availability, **kwargs):
+    """
+    Signal receiver: Availalability changed
+
+    Changes might affect: category availability, AK availability, Room availability
+    """
+    event = instance.event
+
+    # An AK's availability changed: Might affect AK slots scheduled outside the permitted time
+    if instance.ak:
+        violation_type = ConstraintViolation.ViolationType.SLOT_OUTSIDE_AVAIL
+        new_violations = []
+
+        availabilities_of_this_ak: [Availability] = instance.ak.availabilities.all()
+        slots_of_this_ak: [AKSlot] = instance.ak.akslot_set.filter(start__isnull=False)
+
+        for slot in slots_of_this_ak:
+            covered = False
+            for availability in availabilities_of_this_ak:
+                covered = availability.start <= slot.start and availability.end >= slot.end
+                if covered:
+                    break
+            if not covered:
+                c = ConstraintViolation(
+                    type=violation_type,
+                    level=ConstraintViolation.ViolationLevel.VIOLATION,
+                    event=event
+                )
+                c.aks_tmp.add(instance.ak)
+                c.ak_slots_tmp.add(slot)
+                new_violations.append(c)
+
+        # ... and compare to/update list of existing violations of this type
+        # belonging to the AK that was recently changed (important!)
+        existing_violations_to_check = list(instance.ak.constraintviolation_set.filter(type=violation_type))
+        # print(existing_violations_to_check)
+        update_constraint_violations(new_violations, existing_violations_to_check)
+
+
+@receiver(post_save, sender=Event)
+def event_changed_handler(sender, instance: Event, **kwargs):
+    """
+    Signal receiver: Event changed
+
+    Changes might affect: Reso deadline
+    """
+    # Check for reso ak after reso deadline (which might have changed)
+    if instance.reso_deadline:
+        for slot in instance.akslot_set.filter(start__isnull=False, ak__reso=True):
+            update_cv_reso_deadline_for_slot(slot)
+    else:
+        # No reso deadline, delete all violations
+        violation_type = ConstraintViolation.ViolationType.AK_AFTER_RESODEADLINE
+        existing_violations_to_check = list(instance.constraintviolation_set.filter(type=violation_type))
+        update_constraint_violations([], existing_violations_to_check)