AKModel/migrations/0066_akpreference_slot_alter_akpreference_unique_together_and_more.py

+# Generated by Django 4.2.13 on 2025-02-10 22:31
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("AKModel", "0065_eventparticipant_akpreference_and_more"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="akpreference",
+            name="slot",
+            field=models.ForeignKey(
+                default=None,
+                help_text="AKSlot this preference belongs to",
+                on_delete=django.db.models.deletion.CASCADE,
+                to="AKModel.akslot",
+                verbose_name="AKSlot",
+            ),
+            preserve_default=False,
+        ),
+        migrations.AlterUniqueTogether(
+            name="akpreference",
+            unique_together={("event", "participant", "slot")},
+        ),
+        migrations.RemoveField(
+            model_name="akpreference",
+            name="ak",
+        ),
+    ]

AKModel/migrations/0067_eventparticipant_requirements_and_more.py

+# Generated by Django 4.2.13 on 2025-02-11 00:23
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        (
+            "AKModel",
+            "0066_akpreference_slot_alter_akpreference_unique_together_and_more",
+        ),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="eventparticipant",
+            name="requirements",
+            field=models.ManyToManyField(
+                blank=True,
+                help_text="Participant's Requirements",
+                to="AKModel.akrequirement",
+                verbose_name="Requirements",
+            ),
+        ),
+        migrations.AlterField(
+            model_name="akpreference",
+            name="slot",
+            field=models.ForeignKey(
+                help_text="AK Slot this preference belongs to",
+                on_delete=django.db.models.deletion.CASCADE,
+                to="AKModel.akslot",
+                verbose_name="AK Slot",
+            ),
+        ),
+    ]

AKModel/migrations/0068_aktype_slug.py

+# Generated by Django 5.1.6 on 2025-05-11 15:21
+
+from django.db import migrations, models
+
+
+def create_slugs(apps, schema_editor):
+    """
+    Automatically generate slugs from existing type names
+    """
+    AKType = apps.get_model("AKModel", "AKType")
+    for ak_type in AKType.objects.all():
+        slug = ak_type.name.lower().split(" ")[0]
+        ak_type.slug = slug[:30] if len(slug) > 30 else slug
+        ak_type.save()
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('AKModel', '0067_eventparticipant_requirements_and_more'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='aktype',
+            name='slug',
+            field=models.SlugField(max_length=30, null=True, verbose_name='Slug'),
+        ),
+        migrations.RunPython(create_slugs, migrations.RunPython.noop),
+        migrations.AlterUniqueTogether(
+            name='aktype',
+            unique_together={('event', 'name')},
+        ),
+        migrations.AlterField(
+            model_name='aktype',
+            name='slug',
+            field=models.SlugField(max_length=30, verbose_name='Slug'),
+        ),
+        migrations.AlterUniqueTogether(
+            name='aktype',
+            unique_together={('event', 'name'), ('event', 'slug')},
+        ),
+    ]

AKModel/migrations/0068_event_export_delete_preferences_participants.py

+# Generated by Django 5.2.1 on 2025-06-17 15:57
+
+import django.db.models.deletion
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('AKModel', '0067_eventparticipant_requirements_and_more'),
+        ('AKPreference', '0001_initial'),
+    ]
+
+    operations = [
+        migrations.RemoveField(
+            model_name='eventparticipant',
+            name='event',
+        ),
+        migrations.RemoveField(
+            model_name='eventparticipant',
+            name='requirements',
+        ),
+        migrations.RemoveField(
+            model_name='availability',
+            name='participant',
+        ),
+        migrations.AddField(
+            model_name='event',
+            name='poll_hidden',
+            field=models.BooleanField(default=True, help_text='Hides preference poll for non-staff users', verbose_name='Poll Hidden'),
+        ),
+        migrations.AddField(
+            model_name='event',
+            name='poll_published_at',
+            field=models.DateTimeField(blank=True, help_text='Timestamp at which the preference poll was published', null=True, verbose_name='Poll published at'),
+        ),
+        migrations.DeleteModel(
+            name='AKPreference',
+        ),
+        migrations.DeleteModel(
+            name='EventParticipant',
+        ),
+        migrations.AddField(
+            model_name='availability',
+            name='participant',
+            field=models.ForeignKey(blank=True, help_text='Participant whose availability this is', null=True,
+                                    on_delete=django.db.models.deletion.CASCADE, related_name='availabilities',
+                                    to='AKPreference.eventparticipant', verbose_name='Participant'),
+        ),
+    ]

AKModel/migrations/0069_merge_20250617_1844.py

+# Generated by Django 5.2.1 on 2025-06-17 18:44
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('AKModel', '0068_aktype_slug'),
+        ('AKModel', '0068_event_export_delete_preferences_participants'),
+    ]
+
+    operations = [
+    ]

AKModel/models.py

 import itertools
-from datetime import timedelta
-
-from django.db import models
+import json
+import math
+from dataclasses import dataclass
+from datetime import datetime, timedelta
+from typing import Any, Generator, Iterable
+
+from django.apps import apps
+from django.conf import settings
+from django.core.validators import RegexValidator
+from django.db import models, transaction
 from django.db.models import Count
 from django.urls import reverse_lazy
 from django.utils import timezone
-from django.utils.datetime_safe import datetime
 from django.utils.text import slugify
 from django.utils.translation import gettext_lazy as _
 from simple_history.models import HistoricalRecords
 from timezone_field import TimeZoneField
 
+# Custom validators to be used for some of the fields
+# Prevent inclusion of the quotation marks ' " ´ `
+# This may be necessary to prevent javascript issues
+no_quotation_marks_validator = RegexValidator(regex=r"['\"´`]+", inverse_match=True,
+                                              message=_('May not contain quotation marks'))
+# Enforce that the field contains of at least one letter or digit (and not just special characters
+# This prevents issues when autogenerating slugs from that field
+slugable_validator = RegexValidator(regex=r"[\w\s]+", message=_('Must contain at least one letter or digit'))
+
+
+@dataclass
+class OptimizerTimeslot:
+    """Class describing a discrete timeslot. Used to interface with an optimizer."""
+
+    avail: "Availability"
+    """The availability object corresponding to this timeslot."""
+
+    idx: int
+    """The unique index of this optimizer timeslot."""
+
+    constraints: set[str]
+    """The set of time constraints fulfilled by this object."""
+
+    def merge(self, other: "OptimizerTimeslot") -> "OptimizerTimeslot":
+        """Merge with other OptimizerTimeslot.
+
+        Creates a new OptimizerTimeslot object.
+        Its availability is constructed by merging the availabilities of self and other,
+        its constraints by taking the union of both constraint sets.
+        As an index, the index of self is used.
+        """
+        avail = self.avail.merge_with(other.avail)
+        constraints = self.constraints.union(other.constraints)
+        return OptimizerTimeslot(
+            avail=avail, idx=self.idx, constraints=constraints
+        )
+
+    def __repr__(self) -> str:
+        return f"({self.avail.simplified}, {self.idx}, {self.constraints})"
+
+TimeslotBlock = list[OptimizerTimeslot]
+
+
+def merge_blocks(
+    blocks: Iterable[TimeslotBlock]
+) -> Iterable[TimeslotBlock]:
+    """Merge iterable of blocks together.
+
+    The timeslots of all blocks are grouped into maximal blocks.
+    Timeslots with the same start and end are identified with each other
+    and merged (cf `OptimizerTimeslot.merge`).
+    Throws a ValueError if any timeslots are overlapping but do not
+    share the same start and end, i.e. partial overlap is not allowed.
+
+    :param blocks: iterable of blocks to merge.
+    :return: iterable of merged blocks.
+    :rtype: iterable over lists of OptimizerTimeslot objects
+    """
+    if not blocks:
+        return []
+
+    # flatten timeslot iterables to single chain
+    timeslot_chain = itertools.chain.from_iterable(blocks)
+
+    # sort timeslots according to start
+    timeslots = sorted(
+        timeslot_chain,
+        key=lambda slot: slot.avail.start
+    )
+
+    if not timeslots:
+        return []
+
+    all_blocks = []
+    current_block = [timeslots[0]]
+    timeslots = timeslots[1:]
+
+    for slot in timeslots:
+        if current_block and slot.avail.overlaps(current_block[-1].avail, strict=True):
+            if (
+                slot.avail.start == current_block[-1].avail.start
+                and slot.avail.end == current_block[-1].avail.end
+            ):
+                # the same timeslot -> merge
+                current_block[-1] = current_block[-1].merge(slot)
+            else:
+                # partial overlap of interiors -> not supported
+                raise ValueError(
+                    "Partially overlapping timeslots are not supported!"
+                    f" ({current_block[-1].avail.simplified}, {slot.avail.simplified})"
+                )
+        elif not current_block or slot.avail.overlaps(current_block[-1].avail, strict=False):
+            # only endpoints in intersection -> same block
+            current_block.append(slot)
+        else:
+            # no overlap at all -> new block
+            all_blocks.append(current_block)
+            current_block = [slot]
+
+    if current_block:
+        all_blocks.append(current_block)
+
+    return all_blocks
+
 
 class Event(models.Model):
-    """ An event supplies the frame for all Aks.
+    """
+    An event supplies the frame for all Aks.
     """
     name = models.CharField(max_length=64, unique=True, verbose_name=_('Name'),
                             help_text=_('Name or iteration of the event'))
@@ -22,7 +133,7 @@ class Event(models.Model):
 
     place = models.CharField(max_length=128, blank=True, verbose_name=_('Place'),
                              help_text=_('City etc. the event takes place in'))
-    timezone = TimeZoneField(default='Europe/Berlin', display_GMT_offset=True, blank=False,
+    timezone = TimeZoneField(default='Europe/Berlin', blank=False, choices_display="WITH_GMT_OFFSET",
                              verbose_name=_('Time Zone'), help_text=_('Time Zone where this event takes place in'))
     start = models.DateTimeField(verbose_name=_('Start'), help_text=_('Time the event begins'))
     end = models.DateTimeField(verbose_name=_('End'), help_text=_('Time the event ends'))
@@ -30,7 +141,10 @@ class Event(models.Model):
                                          help_text=_('When should AKs with intention to submit a resolution be done?'))
 
     interest_start = models.DateTimeField(verbose_name=_('Interest Window Start'), blank=True, null=True,
-                                          help_text=_('Opening time for expression of interest.'))
+                                          help_text=
+                                          _('Opening time for expression of interest. When left blank, no interest '
+                                            'indication will be possible.'))
+
     interest_end = models.DateTimeField(verbose_name=_('Interest Window End'), blank=True, null=True,
                                         help_text=_('Closing time for expression of interest.'))
 
@@ -41,16 +155,28 @@ class Event(models.Model):
     plan_hidden = models.BooleanField(verbose_name=_('Plan Hidden'), help_text=_('Hides plan for non-staff users'),
                                       default=True)
     plan_published_at = models.DateTimeField(verbose_name=_('Plan published at'), blank=True, null=True,
-                                         help_text=_('Timestamp at which the plan was published'))
+                                             help_text=_('Timestamp at which the plan was published'))
+
+    poll_hidden = models.BooleanField(verbose_name=_('Poll Hidden'),
+                                      help_text=_('Hides preference poll for non-staff users'),
+                                      default=True)
+    poll_published_at = models.DateTimeField(verbose_name=_('Poll published at'), blank=True, null=True,
+                                             help_text=_('Timestamp at which the preference poll was published'))
 
     base_url = models.URLField(verbose_name=_("Base URL"), help_text=_("Prefix for wiki link construction"), blank=True)
     wiki_export_template_name = models.CharField(verbose_name=_("Wiki Export Template Name"), blank=True, max_length=50)
     default_slot = models.DecimalField(max_digits=4, decimal_places=2, default=2, verbose_name=_('Default Slot Length'),
                                        help_text=_('Default length in hours that is assumed for AKs in this event.'))
+    export_slot = models.DecimalField(max_digits=4, decimal_places=2, default=1, verbose_name=_('Export Slot Length'),
+                                        help_text=_(
+                                            'Slot duration in hours that is used in the timeslot discretization, '
+                                            'when this event is exported for the solver.'
+                                        ))
+
 
     contact_email = models.EmailField(verbose_name=_("Contact email address"), blank=True,
-                                      help_text=_(
-                                          "An email address that is displayed on every page and can be used for all kinds of questions"))
+                                      help_text=_("An email address that is displayed on every page "
+                                                  "and can be used for all kinds of questions"))
 
     class Meta:
         verbose_name = _('Event')
@@ -62,65 +188,374 @@ class Event(models.Model):
 
     @staticmethod
     def get_by_slug(slug):
+        """
+        Get event by its slug
+
+        :param slug: slug of the event
+        :return: event identified by the slug
+        :rtype: Event
+        """
         return Event.objects.get(slug=slug)
 
     @staticmethod
     def get_next_active():
-        # Get first active event taking place
+        """
+        Get first active event taking place
+        :return: matching event (if any) or None
+        :rtype: Event
+        """
         event = Event.objects.filter(active=True).order_by('start').first()
         # No active event? Return the next event taking place
         if event is None:
-            event = Event.objects.order_by('start').filter(start__gt=datetime.now()).first()
+            event = Event.objects.order_by('start').filter(start__gt=datetime.now().astimezone()).first()
         return event
 
-    def get_categories_with_aks(self, wishes_seperately=False, filter=lambda ak: True, hide_empty_categories=False):
+    def get_categories_with_aks(self, wishes_seperately=False,
+                                filter_func=lambda ak: True, hide_empty_categories=False, types=None):
         """
         Get AKCategories as well as a list of AKs belonging to the category for this event
 
         :param wishes_seperately: Return wishes as individual list.
         :type wishes_seperately: bool
-        :param filter: Optional filter predicate, only include AK in list if filter returns True
-        :type filter: (AK)->bool
+        :param filter_func: Optional filter predicate, only include AK in list if filter returns True
+        :type filter_func: (AK)->bool
+        :param hide_empty_categories: If True, categories with no AKs will not be included in the result
+        :type hide_empty_categories: bool
+        :param types: Optional list of AK types to filter by, if None, all types are included
+        :type types: list[AKType] | None
         :return: list of category-AK-list-tuples, optionally the additional list of AK wishes
         :rtype: list[(AKCategory, list[AK])] [, list[AK]]
         """
-        categories = self.akcategory_set.all()
+        categories = self.akcategory_set.select_related('event').all()
         categories_with_aks = []
         ak_wishes = []
 
+        # Fill lists by iterating
+        # A different behavior is needed depending on whether wishes should show up inside their categories
+        # or as a separate category
+
+        def _get_category_aks(category, types):
+            """
+            Get all AKs belonging to a category
+            Use joining and prefetching to reduce the number of necessary SQL queries
+
+            :param category: category the AKs should belong to
+            :return: QuerySet over AKs
+            :return: QuerySet[AK]
+            """
+            s = category.ak_set
+            if types is not None:
+                s = s.filter(types__in=types).distinct()
+            return s.select_related('event').prefetch_related('owners', 'akslot_set', 'types').all()
+
         if wishes_seperately:
             for category in categories:
                 ak_list = []
-                for ak in category.ak_set.all():
-                    if ak.wish:
-                        ak_wishes.append(ak)
-                    else:
-                        if filter(ak):
+                for ak in _get_category_aks(category, types):
+                    if filter_func(ak):
+                        if ak.wish:
+                            ak_wishes.append(ak)
+                        else:
                             ak_list.append(ak)
                 if not hide_empty_categories or len(ak_list) > 0:
                     categories_with_aks.append((category, ak_list))
             return categories_with_aks, ak_wishes
-        else:
-            for category in categories:
-                ak_list = []
-                for ak in category.ak_set.all():
-                    if filter(ak):
-                        ak_list.append(ak)
-                if not hide_empty_categories or len(ak_list) > 0:
-                    categories_with_aks.append((category, ak_list))
-            return categories_with_aks
+
+        for category in categories:
+            ak_list = []
+            for ak in _get_category_aks(category, types):
+                if filter_func(ak):
+                    ak_list.append(ak)
+            if not hide_empty_categories or len(ak_list) > 0:
+                categories_with_aks.append((category, ak_list))
+        return categories_with_aks
 
     def get_unscheduled_wish_slots(self):
+        """
+        Get all slots of wishes that are currently not scheduled
+        :return: queryset of theses slots
+        :rtype: QuerySet[AKSlot]
+        """
         return self.akslot_set.filter(start__isnull=True).annotate(Count('ak__owners')).filter(ak__owners__count=0)
 
     def get_aks_without_availabilities(self):
-        return self.ak_set.annotate(Count('availabilities', distinct=True)).annotate(Count('owners', distinct=True)).filter(availabilities__count=0, owners__count__gt=0)
+        """
+        Gt all AKs that don't have any availability at all
+
+        :return: generator over these AKs
+        :rtype: Generator[AK]
+        """
+        return (self.ak_set
+                .annotate(Count('availabilities', distinct=True))
+                .annotate(Count('owners', distinct=True))
+                .filter(availabilities__count=0, owners__count__gt=0)
+                )
+
+    def _generate_slots_from_block(
+        self,
+        start: datetime,
+        end: datetime,
+        slot_duration: timedelta,
+        *,
+        slot_index: int = 0,
+        constraints: set[str] | None = None,
+    ) -> Generator[TimeslotBlock, None, int]:
+        """Discretize a time range into timeslots.
+
+        Uses a uniform discretization into discrete slots of length `slot_duration`,
+        starting at `start`. No incomplete timeslots are generated, i.e.
+        if (`end` - `start`) is not a whole number multiple of `slot_duration`
+        then the last incomplete timeslot is dropped.
+
+        :param start: Start of the time range.
+        :param end: Start of the time range.
+        :param slot_duration: Duration of a single timeslot in the discretization.
+        :param slot_index: index of the first timeslot. Defaults to 0.
+
+        :yield: Block of optimizer timeslots as the discretization result.
+        :ytype: list of OptimizerTimeslot
+
+        :return: The first slot index after the yielded blocks, i.e.
+            `slot_index` + total # generated timeslots
+        :rtype: int
+        """
+        # local import to prevent cyclic import
+        # pylint: disable=import-outside-toplevel
+        from AKModel.availability.models import Availability
+
+        current_slot_start = start
+        previous_slot_start: datetime | None = None
+
+        if constraints is None:
+            constraints = set()
+
+        current_block = []
+
+        room_availabilities = list({
+            availability
+            for room in Room.objects.filter(event=self)
+            for availability in room.availabilities.all()
+        })
+
+        while current_slot_start + slot_duration <= end:
+            slot = Availability(
+                event=self,
+                start=current_slot_start,
+                end=current_slot_start + slot_duration,
+            )
+
+            if any((availability.contains(slot) for availability in room_availabilities)):
+                # no gap in a block
+                if (
+                    previous_slot_start is not None
+                    and previous_slot_start + slot_duration < current_slot_start
+                ):
+                    yield current_block
+                    current_block = []
+
+                current_block.append(
+                    OptimizerTimeslot(avail=slot, idx=slot_index, constraints=constraints)
+                )
+                previous_slot_start = current_slot_start
+
+            slot_index += 1
+            current_slot_start += slot_duration
+
+        if current_block:
+            yield current_block
+
+        return slot_index
+
+    def uniform_time_slots(self, *, slots_in_an_hour: float) -> Iterable[TimeslotBlock]:
+        """Uniformly discretize the entire event into blocks of timeslots.
+
+        Discretizes entire event uniformly. May not necessarily result in a single block
+        as slots with no room availability are dropped.
+
+        :param slots_in_an_hour: The percentage of an hour covered by a single slot.
+            Determines the discretization granularity.
+        :yield: Block of optimizer timeslots as the discretization result.
+        :ytype: list of OptimizerTimeslot
+        """
+        all_category_constraints = AKCategory.create_category_optimizer_constraints(
+            AKCategory.objects.filter(event=self).all()
+        )
+
+        yield from self._generate_slots_from_block(
+            start=self.start,
+            end=self.end,
+            slot_duration=timedelta(hours=1.0 / slots_in_an_hour),
+            constraints=all_category_constraints,
+        )
+
+    def default_time_slots(self, *, slots_in_an_hour: float) -> Iterable[TimeslotBlock]:
+        """Discretize all default slots into blocks of timeslots.
+
+        In the discretization each default slot corresponds to one block.
+
+        :param slots_in_an_hour: The percentage of an hour covered by a single slot.
+            Determines the discretization granularity.
+        :yield: Block of optimizer timeslots as the discretization result.
+        :ytype: list of TimeslotBlock
+        """
+        slot_duration = timedelta(hours=1.0 / slots_in_an_hour)
+        slot_index = 0
+
+        for block_slot in DefaultSlot.objects.filter(event=self).order_by("start", "end"):
+            category_constraints = AKCategory.create_category_optimizer_constraints(
+                block_slot.primary_categories.all()
+            )
+
+            slot_index = yield from self._generate_slots_from_block(
+                start=block_slot.start,
+                end=block_slot.end,
+                slot_duration=slot_duration,
+                slot_index=slot_index,
+                constraints=category_constraints,
+            )
+
+    def discretize_timeslots(self, *, slots_in_an_hour: float | None = None) -> Iterable[TimeslotBlock]:
+        """"Choose discretization scheme.
+
+        Uses default_time_slots if the event has any DefaultSlot, otherwise uniform_time_slots.
+
+        :param slots_in_an_hour: The percentage of an hour covered by a single slot.
+            Determines the discretization granularity.
+        :yield: Block of optimizer timeslots as the discretization result.
+        :ytype: list of TimeslotBlock
+        """
+
+        if slots_in_an_hour is None:
+            slots_in_an_hour = 1.0 / float(self.export_slot)
+
+        if DefaultSlot.objects.filter(event=self).exists():
+            # discretize default slots if they exists
+            yield from merge_blocks(self.default_time_slots(slots_in_an_hour=slots_in_an_hour))
+        else:
+            yield from self.uniform_time_slots(slots_in_an_hour=slots_in_an_hour)
+
+    @transaction.atomic
+    def schedule_from_json(
+        self, schedule: str | dict[str, Any], *, check_for_data_inconsistency: bool = True
+    ) -> int:
+        """Load AK schedule from a json string.
+
+        :param schedule: A string that can be decoded to json, describing
+            the AK schedule. The json data is assumed to be constructed
+            following the output specification of the KoMa conference optimizer, cf.
+            https://github.com/Die-KoMa/ak-plan-optimierung/wiki/Input-&-output-format
+        """
+        if isinstance(schedule, str):
+            schedule = json.loads(schedule)
+
+        if "input" not in schedule or "scheduled_aks" not in schedule:
+            raise ValueError(_("Cannot parse malformed JSON input."))
+
+        if apps.is_installed("AKSolverInterface") and check_for_data_inconsistency:
+            from AKSolverInterface.serializers import ExportEventSerializer   # pylint: disable=import-outside-toplevel
+            export_dict = ExportEventSerializer(self).data
+
+            if schedule["input"] != export_dict:
+                raise ValueError(_("Data has changed since the export. Reexport and run the solver again."))
+
+        slots_in_an_hour = schedule["input"]["timeslots"]["info"]["duration"]
+
+        timeslot_dict = {
+            timeslot.idx: timeslot
+            for block in self.discretize_timeslots(slots_in_an_hour=slots_in_an_hour)
+            for timeslot in block
+        }
+
+        slots_updated = 0
+        for scheduled_slot in schedule["scheduled_aks"]:
+            scheduled_slot["timeslot_ids"] = list(map(int, scheduled_slot["timeslot_ids"]))
+            slot = AKSlot.objects.get(id=int(scheduled_slot["ak_id"]))
+
+            if not scheduled_slot["timeslot_ids"]:
+                raise ValueError(
+                    _("AK {ak_name} is not assigned any timeslot by the solver").format(ak_name=slot.ak.name)
+                )
+
+            start_timeslot = timeslot_dict[min(scheduled_slot["timeslot_ids"])].avail
+            end_timeslot = timeslot_dict[max(scheduled_slot["timeslot_ids"])].avail
+            solver_duration = (end_timeslot.end - start_timeslot.start).total_seconds() / 3600.0
+
+            if solver_duration + 2e-4 < slot.duration:
+                raise ValueError(
+                    _(
+                        "Duration of AK {ak_name} assigned by solver ({solver_duration} hours) "
+                        "is less than the duration required by the slot ({slot_duration} hours)"
+                    ).format(
+                        ak_name=slot.ak.name,
+                        solver_duration=solver_duration,
+                        slot_duration=slot.duration,
+                    )
+                )
+
+            if slot.fixed:
+                solver_room = Room.objects.get(id=int(scheduled_slot["room_id"]))
+                if slot.room != solver_room:
+                    raise ValueError(
+                        _(
+                            "Fixed AK {ak_name} assigned by solver to room {solver_room} "
+                            "is fixed to room {slot_room}"
+                        ).format(
+                            ak_name=slot.ak.name,
+                            solver_room=solver_room.name,
+                            slot_room=slot.room.name,
+                        )
+                    )
+                if slot.start != start_timeslot.start:
+                    raise ValueError(
+                        _(
+                            "Fixed AK {ak_name} assigned by solver to start at {solver_start} "
+                            "is fixed to start at {slot_start}"
+                        ).format(
+                            ak_name=slot.ak.name,
+                            solver_start=start_timeslot.start,
+                            slot_start=slot.start,
+                        )
+                    )
+            else:
+                slot.room = Room.objects.get(id=int(scheduled_slot["room_id"]))
+                slot.start = start_timeslot.start
+                slot.save()
+                slots_updated += 1
+
+        return slots_updated
+
+    @property
+    def rooms(self):
+        """Ordered queryset of all rooms associated to this event."""
+        return Room.objects.filter(event=self).order_by()
+
+    @property
+    def slots(self):
+        """Ordered queryset of all AKSlots associated to this event."""
+        return AKSlot.objects.filter(event=self).order_by()
+
+    @property
+    def participants(self):
+        """Ordered queryset of all participants associated to this event."""
+        if apps.is_installed("AKPreference"):
+            # local import to prevent cyclic import
+            # pylint: disable=import-outside-toplevel
+            from AKPreference.models import EventParticipant
+            return EventParticipant.objects.filter(event=self).order_by()
+        return []
+
+    @property
+    def owners(self):
+        """Ordered queryset of all AK owners associated to this event."""
+        return AKOwner.objects.filter(event=self).order_by()
 
 
 class AKOwner(models.Model):
     """ An AKOwner describes the person organizing/holding an AK.
     """
-    name = models.CharField(max_length=64, verbose_name=_('Nickname'), help_text=_('Name to identify an AK owner by'))
+    name = models.CharField(max_length=64, verbose_name=_('Nickname'),
+                            validators=[no_quotation_marks_validator, slugable_validator],
+                            help_text=_('Name to identify an AK owner by'))
     slug = models.SlugField(max_length=64, blank=True, verbose_name=_('Slug'), help_text=_('Slug for URL generation'))
     institution = models.CharField(max_length=128, blank=True, verbose_name=_('Institution'), help_text=_('Uni etc.'))
     link = models.URLField(blank=True, verbose_name=_('Web Link'), help_text=_('Link to Homepage'))
@@ -140,21 +575,34 @@ class AKOwner(models.Model):
         return self.name
 
     def _generate_slug(self):
+        """
+        Auto-generate a slug for an owner
+        This will start with a very simple slug (the name truncated to a maximum length) and then gradually produce
+        more complicated slugs when the previous candidates are already used
+
+        :return: the slug
+        :rtype: str
+        """
         max_length = self._meta.get_field('slug').max_length
 
+        # Try name alone (truncated if necessary)
         slug_candidate = slugify(self.name)[:max_length]
         if not AKOwner.objects.filter(event=self.event, slug=slug_candidate).exists():
             self.slug = slug_candidate
             return
+
+        # Try name and institution separated by '_' (truncated if necessary)
         slug_candidate = slugify(slug_candidate + '_' + self.institution)[:max_length]
         if not AKOwner.objects.filter(event=self.event, slug=slug_candidate).exists():
             self.slug = slug_candidate
             return
+
+        # Try name + institution + an incrementing digit
         for i in itertools.count(1):
             if not AKOwner.objects.filter(event=self.event, slug=slug_candidate).exists():
                 break
             digits = len(str(i))
-            slug_candidate = '{}-{}'.format(slug_candidate[:-(digits + 1)], i)
+            slug_candidate = f'{slug_candidate[:-(digits + 1)]}-{i}'
 
         self.slug = slug_candidate
 
@@ -166,6 +614,15 @@ class AKOwner(models.Model):
 
     @staticmethod
     def get_by_slug(event, slug):
+        """
+        Get owner by slug
+        Will be identified by the combination of event slug and owner slug which is unique
+
+        :param event: event
+        :param slug: slug of the owner
+        :return: owner identified by slugs
+        :rtype: AKOwner
+        """
         return AKOwner.objects.get(event=event, slug=slug)
 
 
@@ -177,8 +634,8 @@ class AKCategory(models.Model):
     description = models.TextField(blank=True, verbose_name=_("Description"),
                                    help_text=_("Short description of this AK Category"))
     present_by_default = models.BooleanField(blank=True, default=True, verbose_name=_("Present by default"),
-                                             help_text=_(
-                                                 "Present AKs of this category by default if AK owner did not specify whether this AK should be presented?"))
+                                             help_text=_("Present AKs of this category by default if AK owner did not "
+                                                         "specify whether this AK should be presented?"))
 
     event = models.ForeignKey(to=Event, on_delete=models.CASCADE, verbose_name=_('Event'),
                               help_text=_('Associated event'))
@@ -192,6 +649,20 @@ class AKCategory(models.Model):
     def __str__(self):
         return self.name
 
+    @staticmethod
+    def create_category_optimizer_constraints(categories: Iterable["AKCategory"]) -> set[str]:
+        """Create a set of constraint strings from an AKCategory iterable.
+
+        :param categories: The iterable of categories to derive the constraint strings from.
+        :return: A set of category constraint strings, i.e. strings of the form
+            'availability-cat-<cat.name>'.
+        :rtype: set of strings.
+        """
+        return {
+            f"availability-cat-{cat.name}"
+            for cat in categories
+        }
+
 
 class AKTrack(models.Model):
     """ An AKTrack describes a set of semantically related AKs.
@@ -211,34 +682,47 @@ class AKTrack(models.Model):
     def __str__(self):
         return self.name
 
+    def aks_with_category(self):
+        """
+        Get all AKs that belong to this track with category already joined to prevent additional SQL queries
+        :return: queryset over the AKs
+        :rtype: QuerySet[AK]
+        """
+        return self.ak_set.select_related('category').all()
+
 
-class AKTag(models.Model):
-    """ An AKTag is a keyword given to an AK by (one of) its owner(s).
+class AKRequirement(models.Model):
+    """ An AKRequirement describes something needed to hold an AK, e.g. infrastructure.
     """
-    name = models.CharField(max_length=64, unique=True, verbose_name=_('Name'), help_text=_('Name of the AK Tag'))
+    name = models.CharField(max_length=128, verbose_name=_('Name'), help_text=_('Name of the Requirement'))
+
+    event = models.ForeignKey(to=Event, on_delete=models.CASCADE, verbose_name=_('Event'),
+                              help_text=_('Associated event'))
 
     class Meta:
-        verbose_name = _('AK Tag')
-        verbose_name_plural = _('AK Tags')
+        verbose_name = _('AK Requirement')
+        verbose_name_plural = _('AK Requirements')
         ordering = ['name']
+        unique_together = ['event', 'name']
 
     def __str__(self):
         return self.name
 
 
-class AKRequirement(models.Model):
-    """ An AKRequirement describes something needed to hold an AK, e.g. infrastructure.
+class AKType(models.Model):
+    """ An AKType allows to associate one or multiple types with an AK, e.g., to better describe the format of that AK
+    or to which group of people it is addressed. Types are specified per event and are an optional feature.
     """
-    name = models.CharField(max_length=128, verbose_name=_('Name'), help_text=_('Name of the Requirement'))
-
+    name = models.CharField(max_length=128, verbose_name=_('Name'), help_text=_('Name describing the type'))
+    slug = models.SlugField(max_length=30, blank=False, verbose_name=_('Slug'),)
     event = models.ForeignKey(to=Event, on_delete=models.CASCADE, verbose_name=_('Event'),
                               help_text=_('Associated event'))
 
     class Meta:
-        verbose_name = _('AK Requirement')
-        verbose_name_plural = _('AK Requirements')
+        verbose_name = _('AK Type')
+        verbose_name_plural = _('AK Types')
         ordering = ['name']
-        unique_together = ['event', 'name']
+        unique_together = [['event', 'name'], ['event', 'slug']]
 
     def __str__(self):
         return self.name
@@ -247,21 +731,24 @@ class AKRequirement(models.Model):
 class AK(models.Model):
     """ An AK is a slot-based activity to be scheduled during an event.
     """
-    name = models.CharField(max_length=256, verbose_name=_('Name'), help_text=_('Name of the AK'))
+    name = models.CharField(max_length=256, verbose_name=_('Name'), help_text=_('Name of the AK'),
+                            validators=[no_quotation_marks_validator, slugable_validator])
     short_name = models.CharField(max_length=64, blank=True, verbose_name=_('Short Name'),
+                                  validators=[no_quotation_marks_validator],
                                   help_text=_('Name displayed in the schedule'))
     description = models.TextField(blank=True, verbose_name=_('Description'), help_text=_('Description of the AK'))
 
     owners = models.ManyToManyField(to=AKOwner, blank=True, verbose_name=_('Owners'),
                                     help_text=_('Those organizing the AK'))
 
-    # TODO generate automatically
+    # Will be automatically generated in save method if not set
     link = models.URLField(blank=True, verbose_name=_('Web Link'), help_text=_('Link to wiki page'))
     protocol_link = models.URLField(blank=True, verbose_name=_('Protocol Link'), help_text=_('Link to protocol'))
 
     category = models.ForeignKey(to=AKCategory, on_delete=models.PROTECT, verbose_name=_('Category'),
                                  help_text=_('Category of the AK'))
-    tags = models.ManyToManyField(to=AKTag, blank=True, verbose_name=_('Tags'), help_text=_('Tags provided by owners'))
+    types = models.ManyToManyField(to=AKType, blank=True, verbose_name=_('Types'),
+                                   help_text=_("This AK is"))
     track = models.ForeignKey(to=AKTrack, blank=True, on_delete=models.SET_NULL, null=True, verbose_name=_('Track'),
                               help_text=_('Track the AK belongs to'))
 
@@ -279,7 +766,8 @@ class AK(models.Model):
                                            help_text=_('AKs that should precede this AK in the schedule'))
 
     notes = models.TextField(blank=True, verbose_name=_('Organizational Notes'), help_text=_(
-        'Notes to organizers. These are public. For private notes, please use the button for private messages on the detail page of this AK (after creation/editing).'))
+            'Notes to organizers. These are public. For private notes, please use the button for private messages '
+            'on the detail page of this AK (after creation/editing).'))
 
     interest = models.IntegerField(default=-1, verbose_name=_('Interest'), help_text=_('Expected number of people'))
     interest_counter = models.IntegerField(default=0, verbose_name=_('Interest Counter'),
@@ -288,12 +776,16 @@ class AK(models.Model):
     event = models.ForeignKey(to=Event, on_delete=models.CASCADE, verbose_name=_('Event'),
                               help_text=_('Associated event'))
 
-    history = HistoricalRecords(excluded_fields=['interest_counter'])
+    include_in_export = models.BooleanField(default=True, verbose_name=_('Export?'),
+                                            help_text=_("Include AK in wiki export?"))
+
+    history = HistoricalRecords(excluded_fields=['interest', 'interest_counter', 'include_in_export'])
 
     class Meta:
         verbose_name = _('AK')
         verbose_name_plural = _('AKs')
         unique_together = [['event', 'name'], ['event', 'short_name']]
+        ordering = ['pk']
 
     def __str__(self):
         if self.short_name:
@@ -302,43 +794,142 @@ class AK(models.Model):
 
     @property
     def details(self):
+        """
+        Generate a detailed string representation, e.g., for usage in scheduling
+        :return: string representation of that AK with all details
+        :rtype: str
+        """
+        # local import to prevent cyclic import
+        # pylint: disable=import-outside-toplevel
         from AKModel.availability.models import Availability
-        availabilities = ', \n'.join(f'{a.simplified}' for a in Availability.objects.filter(ak=self))
-        return f"""{self.name}{" (R)" if self.reso else ""}:
-        
+        availabilities = ', \n'.join(f'{a.simplified}' for a in Availability.objects.select_related('event')
+                                     .filter(ak=self))
+        detail_string = f"""{self.name}{" (R)" if self.reso else ""}:
+
         {self.owners_list}
 
-        {_("Requirements")}: {", ".join(str(r) for r in self.requirements.all())}  
-        {_("Conflicts")}: {", ".join(str(c) for c in self.conflicts.all())}  
-        {_("Prerequisites")}: {", ".join(str(p) for p in self.prerequisites.all())}
-        {_("Availabilities")}: \n{availabilities}"""
+        {_('Interest')}: {self.interest}"""
+        if self.requirements.count() > 0:
+            detail_string += f"\n{_('Requirements')}: {', '.join(str(r) for r in self.requirements.all())}"
+        if self.types.count() > 0:
+            detail_string += f"\n{_('Types')}: {', '.join(str(r) for r in self.types.all())}"
+
+        # Find conflicts
+        # (both directions, those specified for this AK and those were this AK was specified as conflict)
+        # Deduplicate and order list alphabetically
+        conflicts = set()
+        if self.conflicts.count() > 0:
+            for c in self.conflicts.all():
+                conflicts.add(str(c))
+        if self.conflict.count() > 0:
+            for c in self.conflict.all():
+                conflicts.add(str(c))
+        if len(conflicts) > 0:
+            conflicts = list(conflicts)
+            conflicts.sort()
+            detail_string += f"\n{_('Conflicts')}: {', '.join(conflicts)}"
+
+        if self.prerequisites.count() > 0:
+            detail_string += f"\n{_('Prerequisites')}: {', '.join(str(p) for p in self.prerequisites.all())}"
+        detail_string += f"\n{_('Availabilities')}: \n{availabilities}"
+        return detail_string
 
     @property
     def owners_list(self):
+        """
+        Get a stringified list of stringified representations of all owners
+
+        :return: stringified list of owners
+        :rtype: str
+        """
         return ", ".join(str(owner) for owner in self.owners.all())
 
     @property
     def durations_list(self):
-        return ", ".join(str(slot.duration_simplified) for slot in self.akslot_set.all())
+        """
+        Get a stringified list of stringified representations of all durations of associated slots
+
+        :return: stringified list of durations
+        :rtype: str
+        """
+        return ", ".join(str(slot.duration_simplified) for slot in self.akslot_set.select_related('event').all())
 
     @property
-    def tags_list(self):
-        return ", ".join(str(tag) for tag in self.tags.all())
+    def types_list(self):
+        """
+        Get a stringified list of all types of this AK
+
+        :return: stringified list of types
+        :rtype: str
+        """
+        return ", ".join(str(t) for t in self.types.all())
 
     @property
     def wish(self):
+        """
+        Is the AK a wish?
+        :return: true if wish, false if not
+        :rtype: bool
+        """
         return self.owners.count() == 0
 
     def increment_interest(self):
+        """
+        Increment the interest counter for this AK by one
+        without tracking that change to prevent an unreadable and large history
+        """
         self.interest_counter += 1
-        self.skip_history_when_saving = True
+        self.skip_history_when_saving = True  # pylint: disable=attribute-defined-outside-init
         self.save()
         del self.skip_history_when_saving
 
     @property
     def availabilities(self):
+        """
+        Get all availabilities associated to this AK
+        :return: availabilities
+        :rtype: QuerySet[Availability]
+        """
         return "Availability".objects.filter(ak=self)
 
+    @property
+    def edit_url(self):
+        """
+        Get edit URL for this AK
+        Will link to frontend if AKSubmission is active, otherwise to the edit view for this object in admin interface
+
+        :return: URL
+        :rtype: str
+        """
+        if apps.is_installed("AKSubmission"):
+            return reverse_lazy('submit:ak_edit', kwargs={'event_slug': self.event.slug, 'pk': self.id})
+        return reverse_lazy('admin:AKModel_ak_change', kwargs={'object_id': self.id})
+
+    @property
+    def detail_url(self):
+        """
+        Get detail URL for this AK
+        Will link to frontend if AKSubmission is active, otherwise to the edit view for this object in admin interface
+
+        :return: URL
+        :rtype: str
+        """
+        if apps.is_installed("AKSubmission"):
+            return reverse_lazy('submit:ak_detail', kwargs={'event_slug': self.event.slug, 'pk': self.id})
+        return self.edit_url
+
+    def save(self, *args, force_insert=False, force_update=False, using=None, update_fields=None):
+        # Auto-Generate Link if not set yet
+        if self.link == "":
+            link = self.event.base_url + self.name.replace(" ", "_")
+            # Truncate links longer than 200 characters (default length of URL fields in django)
+            self.link = link[:200]
+            # Tell Django that we have updated the link field
+            if update_fields is not None:
+                update_fields = {"link"}.union(update_fields)
+        super().save(*args,
+                     force_insert=force_insert, force_update=force_update, using=using, update_fields=update_fields)
+
 
 class Room(models.Model):
     """ A room describes where an AK can be held.
@@ -362,6 +953,12 @@ class Room(models.Model):
 
     @property
     def title(self):
+        """
+        Get title of a room, which consists of location and name if location is set, otherwise only the name
+
+        :return: title
+        :rtype: str
+        """
         if self.location:
             return f"{self.location} {self.name}"
         return self.name
@@ -369,6 +966,32 @@ class Room(models.Model):
     def __str__(self):
         return self.title
 
+    def get_time_constraints(self) -> list[str]:
+        """Construct list of required time constraint labels."""
+        # local import to prevent cyclic import
+        # pylint: disable=import-outside-toplevel
+        from AKModel.availability.models import Availability
+
+        # check if room is available for the whole event
+        # -> no time constraint needs to be introduced
+        if Availability.is_event_covered(self.event, self.availabilities.all()):
+            time_constraints = []
+        else:
+            time_constraints = [f"availability-room-{self.pk}"]
+
+        return time_constraints
+
+    def get_fulfilled_room_constraints(self) -> list[str]:
+        """Construct list of fulfilled room constraint labels."""
+        fulfilled_room_constraints = list(self.properties.values_list("name", flat=True))
+        fulfilled_room_constraints.append(f"fixed-room-{self.pk}")
+
+        if not any(constr.startswith("proxy") for constr in fulfilled_room_constraints):
+            fulfilled_room_constraints.append("no-proxy")
+
+        fulfilled_room_constraints.sort()
+        return fulfilled_room_constraints
+
 
 class AKSlot(models.Model):
     """ An AK Mapping matches an AK to a room during a certain time.
@@ -427,7 +1050,8 @@ class AKSlot(models.Model):
         start = self.start.astimezone(self.event.timezone)
         end = self.end.astimezone(self.event.timezone)
 
-        return f"{start.strftime('%a %H:%M')} - {end.strftime('%H:%M') if start.day == end.day else end.strftime('%a %H:%M')}"
+        return (f"{start.strftime('%a %H:%M')} - "
+                f"{end.strftime('%H:%M') if start.day == end.day else end.strftime('%a %H:%M')}")
 
     @property
     def end(self):
@@ -446,10 +1070,103 @@ class AKSlot(models.Model):
         return (timezone.now() - self.updated).total_seconds()
 
     def overlaps(self, other: "AKSlot"):
+        """
+        Check whether two slots overlap
+
+        :param other: second slot to compare with
+        :return: true if they overlap, false if not:
+        :rtype: bool
+        """
         return self.start < other.end <= self.end or self.start <= other.start < self.end
 
+    def save(self, *args, force_insert=False, force_update=False, using=None, update_fields=None):
+        # Make sure duration is not longer than the event
+        if update_fields is None or 'duration' in update_fields:
+            event_duration = self.event.end - self.event.start
+            event_duration_hours = event_duration.days * 24 + event_duration.seconds // 3600
+            self.duration = min(self.duration, event_duration_hours)
+        super().save(*args,
+                     force_insert=force_insert, force_update=force_update, using=using, update_fields=update_fields)
+
+    def get_room_constraints(self) -> list[str]:
+        """Construct list of required room constraint labels."""
+        room_constraints = list(self.ak.requirements.values_list("name", flat=True).order_by())
+        if self.fixed and self.room is not None:
+            room_constraints.append(f"fixed-room-{self.room.pk}")
+
+        if not any(constr.startswith("proxy") for constr in room_constraints):
+            room_constraints.append("no-proxy")
+
+        room_constraints.sort()
+        return room_constraints
+
+    def get_time_constraints(self) -> list[str]:
+        """Construct list of required time constraint labels."""
+        # local import to prevent cyclic import
+        # pylint: disable=import-outside-toplevel
+        from AKModel.availability.models import Availability
+
+        def _owner_time_constraints(owner: AKOwner):
+            owner_avails = owner.availabilities.all()
+            if not owner_avails or Availability.is_event_covered(self.event, owner_avails):
+                return []
+            return [f"availability-person-{owner.pk}"]
+
+        # check if ak resp. owner is available for the whole event
+        # -> no time constraint needs to be introduced
+        if self.fixed and self.start is not None:
+            time_constraints = [f"fixed-akslot-{self.id}"]
+        elif not Availability.is_event_covered(self.event, self.ak.availabilities.all()):
+            time_constraints = [f"availability-ak-{self.ak.pk}"]
+        else:
+            time_constraints = []
+
+        if self.ak.reso:
+            time_constraints.append("resolution")
+        for owner in self.ak.owners.all():
+            time_constraints.extend(_owner_time_constraints(owner))
+
+        if self.ak.category:
+            category_constraints = AKCategory.create_category_optimizer_constraints([self.ak.category])
+            time_constraints.extend(category_constraints)
+
+        time_constraints.sort()
+        return time_constraints
+
+    @property
+    def export_duration(self) -> int:
+        """Number of discrete export timeslots covered by this AKSlot."""
+        export_duration = self.duration / self.event.export_slot
+        # We need to return an int, so we round up.
+        # If the exact result for `export_duration` is an integer `k`,
+        # FLOP inaccuracies could yield `k + eps`. Then, rounding up
+        # would return `k + 1` instead of `k`. To avoid this, we subtract
+        # a small epsilon before rounding.
+        return math.ceil(export_duration - settings.EXPORT_CEIL_OFFSET_EPS)
+
+    @property
+    def type_names(self):
+        """Ordered queryset of the names of all types of this slot's AK."""
+        return self.ak.types.values_list("name", flat=True).order_by()
+
+    @property
+    def conflict_pks(self) -> list[int]:
+        """Ordered queryset of the PKs of all AKSlots that in conflict to this slot."""
+        conflict_slots = AKSlot.objects.filter(ak__in=self.ak.conflicts.all())
+        other_ak_slots = AKSlot.objects.filter(ak=self.ak).exclude(pk=self.pk)
+        return list((conflict_slots | other_ak_slots).values_list("pk", flat=True).order_by())
+
+    @property
+    def depencency_pks(self) -> list[int]:
+        """Ordered queryset of the PKs of all AKSlots that this slot depends on."""
+        dependency_slots = AKSlot.objects.filter(ak__in=self.ak.prerequisites.all())
+        return list(dependency_slots.values_list("pk", flat=True).order_by())
+
 
 class AKOrgaMessage(models.Model):
+    """
+    Model representing confidential messages to the organizers/scheduling people, belonging to a certain AK
+    """
     ak = models.ForeignKey(to=AK, on_delete=models.CASCADE, verbose_name=_('AK'),
                            help_text=_('AK this message belongs to'))
     text = models.TextField(verbose_name=_("Message text"),
@@ -457,6 +1174,8 @@ class AKOrgaMessage(models.Model):
     timestamp = models.DateTimeField(auto_now_add=True)
     event = models.ForeignKey(to=Event, on_delete=models.CASCADE, verbose_name=_('Event'),
                               help_text=_('Associated event'))
+    resolved = models.BooleanField(verbose_name=_('Resolved'), default=False,
+                                   help_text=_('This message has been resolved (no further action needed)'))
 
     class Meta:
         verbose_name = _('AK Orga Message')
@@ -468,12 +1187,24 @@ class AKOrgaMessage(models.Model):
 
 
 class ConstraintViolation(models.Model):
+    """
+    Model to represent any kind of constraint violation
+
+    Can have two different severities: violation and warning
+    The list of possible types is defined in :class:`ViolationType`
+    Depending on the type, different fields (references to other models) will be filled. Each violation should always
+    be related to an event and at least on other instance of a causing entity
+    """
+
     class Meta:
         verbose_name = _('Constraint Violation')
         verbose_name_plural = _('Constraint Violations')
         ordering = ['-timestamp']
 
     class ViolationType(models.TextChoices):
+        """
+        Possible types of violations with their text representation
+        """
         OWNER_TWO_SLOTS = 'ots', _('Owner has two parallel slots')
         SLOT_OUTSIDE_AVAIL = 'soa', _('AK Slot was scheduled outside the AK\'s availabilities')
         ROOM_TWO_SLOTS = 'rts', _('Room has two AK slots scheduled at the same time')
@@ -481,13 +1212,16 @@ class ConstraintViolation(models.Model):
         AK_CONFLICT_COLLISION = 'acc', _('AK Slot is scheduled at the same time as an AK listed as a conflict')
         AK_BEFORE_PREREQUISITE = 'abp', _('AK Slot is scheduled before an AK listed as a prerequisite')
         AK_AFTER_RESODEADLINE = 'aar', _(
-            'AK Slot for AK with intention to submit a resolution is scheduled after resolution deadline')
+                'AK Slot for AK with intention to submit a resolution is scheduled after resolution deadline')
         AK_CATEGORY_MISMATCH = 'acm', _('AK Slot in a category is outside that categories availabilities')
         AK_SLOT_COLLISION = 'asc', _('Two AK Slots for the same AK scheduled at the same time')
         ROOM_CAPACITY_EXCEEDED = 'rce', _('Room does not have enough space for interest in scheduled AK Slot')
         SLOT_OUTSIDE_EVENT = 'soe', _('AK Slot is scheduled outside the event\'s availabilities')
 
     class ViolationLevel(models.IntegerChoices):
+        """
+        Possible severities/levels of a CV
+        """
         WARNING = 1, _('Warning')
         VIOLATION = 10, _('Violation')
 
@@ -499,6 +1233,7 @@ class ConstraintViolation(models.Model):
     event = models.ForeignKey(to=Event, on_delete=models.CASCADE, verbose_name=_('Event'),
                               help_text=_('Associated event'))
 
+    # Possible "causes":
     aks = models.ManyToManyField(to=AK, blank=True, verbose_name=_('AKs'),
                                  help_text=_('AK(s) belonging to this constraint'))
     ak_slots = models.ManyToManyField(to=AKSlot, blank=True, verbose_name=_('AK Slots'),
@@ -549,22 +1284,37 @@ class ConstraintViolation(models.Model):
 
     @property
     def details(self):
+        """
+        Property: Details
+        """
         return self.get_details()
 
     @property
-    def edit_url(self):
+    def edit_url(self) -> str:
+        """
+        Property: Edit URL for this CV
+        """
         return reverse_lazy('admin:AKModel_constraintviolation_change', kwargs={'object_id': self.pk})
 
     @property
-    def level_display(self):
+    def level_display(self) -> str:
+        """
+        Property: Severity as string
+        """
         return self.get_level_display()
 
     @property
-    def type_display(self):
+    def type_display(self) -> str:
+        """
+        Property: Type as string
+        """
         return self.get_type_display()
 
     @property
-    def timestamp_display(self):
+    def timestamp_display(self) -> str:
+        """
+        Property: Creation timestamp as string
+        """
         return self.timestamp.astimezone(self.event.timezone).strftime('%d.%m.%y %H:%M')
 
     @property
@@ -583,7 +1333,10 @@ class ConstraintViolation(models.Model):
         return self.aks_tmp
 
     @property
-    def _aks_str(self):
+    def _aks_str(self) -> str:
+        """
+        Property: AKs as string
+        """
         if self.pk and self.pk > 0:
             return ', '.join(str(a) for a in self.aks.all())
         return ', '.join(str(a) for a in self.aks_tmp)
@@ -604,9 +1357,12 @@ class ConstraintViolation(models.Model):
         return self.ak_slots_tmp
 
     @property
-    def _ak_slots_str(self):
+    def _ak_slots_str(self) -> str:
+        """
+        Property: Slots as string
+        """
         if self.pk and self.pk > 0:
-            return ', '.join(str(a) for a in self.ak_slots.all())
+            return ', '.join(str(a) for a in self.ak_slots.select_related('event').all())
         return ', '.join(str(a) for a in self.ak_slots_tmp)
 
     def save(self, *args, **kwargs):
@@ -653,6 +1409,11 @@ class ConstraintViolation(models.Model):
 
 
 class DefaultSlot(models.Model):
+    """
+    Model representing a default slot,
+    i.e., a prefered slot to use for typical AKs in the schedule to guarantee enough breaks etc.
+    """
+
     class Meta:
         verbose_name = _('Default Slot')
         verbose_name_plural = _('Default Slots')
@@ -665,15 +1426,36 @@ class DefaultSlot(models.Model):
                               help_text=_('Associated event'))
 
     primary_categories = models.ManyToManyField(to=AKCategory, verbose_name=_('Primary categories'), blank=True,
-                                            help_text=_('Categories that should be assigned to this slot primarily'))
+                                                help_text=_(
+                                                        'Categories that should be assigned to this slot primarily'))
 
     @property
-    def start_simplified(self):
+    def start_simplified(self) -> str:
+        """
+        Property: Simplified version of the start timetstamp (weekday, hour, minute) as string
+        """
         return self.start.astimezone(self.event.timezone).strftime('%a %H:%M')
 
     @property
-    def end_simplified(self):
+    def start_iso(self) -> str:
+        """
+        Property: Start timestamp as ISO timestamp for usage in calendar views
+        """
+        return timezone.localtime(self.start, self.event.timezone).strftime("%Y-%m-%dT%H:%M:%S")
+
+    @property
+    def end_simplified(self) -> str:
+        """
+        Property: Simplified version of the end timetstamp (weekday, hour, minute) as string
+        """
         return self.end.astimezone(self.event.timezone).strftime('%a %H:%M')
 
+    @property
+    def end_iso(self) -> str:
+        """
+        Property: End timestamp as ISO timestamp for usage in calendar views
+        """
+        return timezone.localtime(self.end, self.event.timezone).strftime("%Y-%m-%dT%H:%M:%S")
+
     def __str__(self):
         return f"{self.event}: {self.start_simplified} - {self.end_simplified}"

AKModel/serializers.py

 from rest_framework import serializers
 
-from AKModel.models import AK, Room, AKSlot, AKTrack, AKCategory, AKOwner
+from AKModel.models import AK, AKCategory, AKOwner, AKSlot, AKTrack, Room
+
+
+class StringListField(serializers.ListField):
+    """List field containing strings."""
+
+    child = serializers.CharField()
+
+
+class IntListField(serializers.ListField):
+    """List field containing integers."""
+
+    child = serializers.IntegerField()
 
 
 class AKOwnerSerializer(serializers.ModelSerializer):
+    """
+    REST Framework Serializer for AKOwner
+    """
     class Meta:
         model = AKOwner
         fields = '__all__'
 
 
 class AKCategorySerializer(serializers.ModelSerializer):
+    """
+    REST Framework Serializer for AKCategory
+    """
     class Meta:
         model = AKCategory
         fields = '__all__'
 
 
 class AKTrackSerializer(serializers.ModelSerializer):
+    """
+    REST Framework Serializer for AKTrack
+    """
     class Meta:
         model = AKTrack
         fields = '__all__'
 
 
 class AKSerializer(serializers.ModelSerializer):
+    """
+    REST Framework Serializer for AK
+    """
     class Meta:
         model = AK
         fields = '__all__'
 
 
 class RoomSerializer(serializers.ModelSerializer):
+    """
+    REST Framework Serializer for Room
+    """
     class Meta:
         model = Room
         fields = '__all__'
 
 
 class AKSlotSerializer(serializers.ModelSerializer):
+    """
+    REST Framework Serializer for AKSlot
+    """
     class Meta:
         model = AKSlot
         fields = '__all__'
+
+    treat_as_local = serializers.BooleanField(required=False, default=False, write_only=True)
+
+    def create(self, validated_data:dict):
+        # Handle timezone adaption based upon the control field "treat_as_local":
+        # If it is set, ignore timezone submitted from the browser (will always be UTC)
+        # and treat it as input in the events timezone instead
+        if validated_data['treat_as_local']:
+            validated_data['start'] = validated_data['start'].replace(tzinfo=None).astimezone(
+                validated_data['event'].timezone)
+        del validated_data['treat_as_local']
+        return super().create(validated_data)

AKModel/site.py

 from django.contrib.admin import AdminSite
 from django.utils.translation import gettext_lazy as _
+# from django.urls import path
 
 from AKModel.models import Event
 
 
 class AKAdminSite(AdminSite):
+    """
+    Custom admin interface definition (extend the admin functionality of Django)
+    """
     index_template = "admin/ak_index.html"
     site_header = f"AKPlanning - {_('Administration')}"
     index_title = _('Administration')
 
     def get_urls(self):
-        from django.urls import path
-
+        """
+        Get URLs -- add further views that are not related to a certain model here if needed
+        """
         urls = super().get_urls()
         urls += [
             # path('...', self.admin_view(...)),
@@ -19,6 +24,8 @@ class AKAdminSite(AdminSite):
         return urls
 
     def index(self, request, extra_context=None):
+        # Override index page rendering to provide extra context (the list of active events)
+        # to be used in the adapted template
         if extra_context is None:
             extra_context = {}
         extra_context["active_events"] = Event.objects.filter(active=True)

AKModel/templates/AKModel/load_fullcalendar.html

+{% load compress %}
+{% load static %}
+{% load i18n %}
+{% get_current_language as LANGUAGE_CODE %}
+
+{% compress js %}
+    <script src='{% static 'common/vendor/fullcalendar-scheduler/fullcalendar-6.0.2.js' %}'></script>
+    <script src='{% static 'common/vendor/fullcalendar-scheduler/fullcalendar.bootstrap5-5.0.2.min.js' %}'></script>
+
+    {% with 'common/vendor/fullcalendar-scheduler/locales/'|add:LANGUAGE_CODE|add:'.js' as locale_file %}
+        {% if LANGUAGE_CODE != "en" %}
+            {# Locale 'en' is included in main.js and does not exist separately #}
+            <script src="{% static locale_file %}"></script>
+        {% endif %}
+    {% endwith %}
+{% endcompress %}
+
+

AKModel/templates/AKModel/load_fullcalendar_availabilities.html

+{% load compress %}
+{% load static %}
+{% load i18n %}
+{% get_current_language as LANGUAGE_CODE %}
+
+{% compress js %}
+    <script src='{% static 'common/vendor/fullcalendar-scheduler/fullcalendar-6.0.2.js' %}'></script>
+    <script src='{% static 'common/vendor/fullcalendar-scheduler/fullcalendar.bootstrap5-5.0.2.min.js' %}'></script>
+    <script src="{% static "common/vendor/moment/moment-with-locales.js" %}"></script>
+    <script src="{% static "common/js/availabilities.js" %}"></script>
+
+    {% with 'common/vendor/fullcalendar-scheduler/locales/'|add:LANGUAGE_CODE|add:'.js' as locale_file %}
+        {% if LANGUAGE_CODE != "en" %}
+            {# Locale 'en' is included in main.js and does not exist separately #}
+            <script src="{% static locale_file %}"></script>
+        {% endif %}
+    {% endwith %}
+{% endcompress %}

AKModel/templates/AKModel/user.html

 {% extends 'base.html' %}
 
-{% load fontawesome_5 %}
+{% load fontawesome_6 %}
 {% load i18n %}
 {% load static %}
 
 {% load tags_AKModel %}
 
-{% block imports %}
-
-    {{ block.super }}
-
-    <link rel="stylesheet" href="{% static 'AKDashboard/style.css' %}">
-
-{% endblock %}
-
 {% block breadcrumbs %}
     <li class="breadcrumb-item">
         {% if 'AKDashboard'|check_app_installed %}

AKModel/templates/admin/AKModel/action_intermediate.html

@@ -2,8 +2,8 @@
 {% load tags_AKModel %}
 
 {% load i18n %}
-{% load bootstrap4 %}
-{% load fontawesome_5 %}
+{% load django_bootstrap5 %}
+{% load fontawesome_6 %}
 
 
 {% block title %}{{event}}: {{ title }}{% endblock %}
@@ -18,13 +18,13 @@
     <form method="post">{% csrf_token %}
         {% bootstrap_form form %}
 
-        <div class="float-right">
+        <div class="float-end">
             <button type="submit" class="save btn btn-success" value="Submit">
-                {% fa5_icon "check" 'fas' %} {% trans "Confirm" %}
+                {% fa6_icon "check" 'fas' %} {% trans "Confirm" %}
             </button>
         </div>
         <a href="javascript:history.back()" class="btn btn-info">
-            {% fa5_icon "times" 'fas' %} {% trans "Cancel" %}
+            {% fa6_icon "times" 'fas' %} {% trans "Cancel" %}
         </a>
     </form>
 {% endblock %}

AKModel/templates/admin/AKModel/ak_csv_export.html

@@ -4,8 +4,8 @@
 
 {% block content %}
 <pre>
-title;duration;who;requirements;prerequisites;conflicts;availabilities;category;track;reso;notes;
-{% for slot in slots %}{{ slot.ak.short_name }};{{ slot.duration }};{{ slot.ak.owners.all|join:", " }};{{ slot.ak.requirements.all|join:", " }};{{ slot.ak.prerequisites.all|join:", " }};{{ slot.ak.conflicts.all|join:", " }};{% for a in slot.ak.availabilities.all %}{{ a.start | timezone:event.timezone | date:"l H:i"  }} - {{ a.end | timezone:event.timezone | date:"l H:i" }}, {% endfor %};{{ slot.ak.category }};{{ slot.ak.track }};{{ slot.ak.reso }};{{ slot.ak.notes }};
+title;duration;who;requirements;prerequisites;conflicts;availabilities;category;types;track;reso;notes;
+{% for slot in slots %}{{ slot.ak.short_name }};{{ slot.duration }};{{ slot.ak.owners.all|join:", " }};{{ slot.ak.requirements.all|join:", " }};{{ slot.ak.prerequisites.all|join:", " }};{{ slot.ak.conflicts.all|join:", " }};{% for a in slot.ak.availabilities.all %}{{ a.start | timezone:event.timezone | date:"l H:i"  }} - {{ a.end | timezone:event.timezone | date:"l H:i" }}, {% endfor %};{{ slot.ak.category }};{{ slot.ak.types.all|join:", " }};{{ slot.ak.track }};{{ slot.ak.reso }};{{ slot.ak.notes }};
 {% endfor %}
 </pre>
 {% endblock %}

AKModel/templates/admin/AKModel/aks_by_user.html

+{% extends "admin/base_site.html" %}
+{% load tags_AKModel %}
+
+{% load i18n %}
+{% load tz %}
+{% load fontawesome_6 %}
+
+{% block title %}{% trans "AKs by Owner" %}: {{owner}}{% endblock %}
+
+{% block content %}
+    {% timezone event.timezone %}
+        <h2>[{{event}}] <a href="{% url 'admin:AKModel_akowner_change' owner.pk %}">{{owner}}</a> - {% trans "AKs" %}</h2>
+
+        <div class="row mt-4">
+            <table class="table table-striped">
+                {% for ak in owner.ak_set.all %}
+                    <tr>
+                        <td>{{ ak }}</td>
+                        {% if "AKSubmission"|check_app_installed %}
+                            <td class="text-end">
+                                <a href="{{ ak.detail_url }}" data-bs-toggle="tooltip"
+                                   title="{% trans 'Details' %}"
+                                   class="btn btn-primary">{% fa6_icon 'info' 'fas' %}</a>
+                                {% if event.active %}
+                                    <a href="{{ ak.edit_url }}" data-bs-toggle="tooltip"
+                                       title="{% trans 'Edit' %}"
+                                       class="btn btn-success">{% fa6_icon 'pencil-alt' 'fas' %}</a>
+                                {% endif %}
+                            {% endif %}
+                        </td>
+                    </tr>
+                {% empty %}
+                    <tr><td>{% trans "This user does not have any AKs currently" %}</td></tr>
+                {% endfor %}
+            </table>
+        </div>
+    {% endtimezone %}
+{% endblock %}

AKModel/templates/admin/AKModel/default_slot_editor.html

+{% extends "admin/AKModel/action_intermediate.html" %}
+{% load tags_AKModel %}
+{% load i18n admin_urls %}
+{% load static %}
+{% load django_bootstrap5 %}
+{% load tz %}
+
+{% block extrahead %}
+    {{ block.super }}
+    {% bootstrap_javascript %}
+    <script src="{% static 'common/vendor/jquery/jquery-3.6.3.min.js' %}"></script>
+    {% include "AKModel/load_fullcalendar_availabilities.html" %}
+
+    <script>
+        {% get_current_language as LANGUAGE_CODE %}
+
+        document.addEventListener('DOMContentLoaded', function () {
+            createAvailabilityEditors(
+                '{{ event.timezone }}',
+                '{{ LANGUAGE_CODE }}',
+                '{{ event.start | timezone:event.timezone | date:"Y-m-d H:i:s" }}',
+                '{{ event.end | timezone:event.timezone | date:"Y-m-d H:i:s" }}',
+                '00:15:00'
+            );
+        });
+    </script>
+{% endblock %}
+
+{% block action_preview %}
+    <h3>{{ event.name }}</h3>
+{% endblock %}
+

AKModel/templates/admin/AKModel/event_wizard/activate.html

@@ -2,34 +2,37 @@
 {% load tags_AKModel %}
 
 {% load i18n %}
-{% load bootstrap4 %}
-{% load fontawesome_5 %}
+{% load django_bootstrap5 %}
+{% load fontawesome_6 %}
 {% load tz %}
 
 {% block title %}{% trans "New event wizard" %}: {{ wizard_step_text }}{% endblock %}
 
+{% block extrahead %}
+    {{ block.super }}
+    {{ form.media }}
+{% endblock %}
+
 {% block content %}
     {% include "admin/AKModel/event_wizard/wizard_steps.html" %}
 
     <div class="text-center btn-success disabled mt-3 mb-3" style="font-size: 8em;">
-        {% fa5_icon "copy" "fas" %}
+        {% fa6_icon "copy" "fas" %}
     </div>
 
     <h5 class="mb-3">{% trans "Successfully imported.<br><br>Do you want to activate your event now?" %}</h5>
 
-    {{ form.media }}
-
     <form method="post">{% csrf_token %}
         {% bootstrap_form form %}
 
-        <div class="float-right">
+        <div class="float-end">
             <button type="submit" class="save btn btn-success" value="Submit">
-            {% fa5_icon "check" 'fas' %} {% trans "Finish" %}
+            {% fa6_icon "check" 'fas' %} {% trans "Finish" %}
         </button>
         </div>
 
         <a href="{% url 'admin:event_status' event.slug %}" class="btn btn-info">
-            {% fa5_icon "info" 'fas' %} {% trans "Status" %}
+            {% fa6_icon "info" 'fas' %} {% trans "Status" %}
         </a>
     </form>
 

AKModel/templates/admin/AKModel/event_wizard/created_prepare_import.html

@@ -2,12 +2,17 @@
 {% load tags_AKModel %}
 
 {% load i18n %}
-{% load bootstrap4 %}
-{% load fontawesome_5 %}
+{% load django_bootstrap5 %}
+{% load fontawesome_6 %}
 {% load tz %}
 
 {% block title %}{% trans "New event wizard" %}: {{ wizard_step_text }}{% endblock %}
 
+{% block extrahead %}
+    {{ block.super }}
+    {{ form.media }}
+{% endblock %}
+
 {% block content %}
     {% include "admin/AKModel/event_wizard/wizard_steps.html" %}
 
@@ -22,30 +27,28 @@
     {% endtimezone %}
 
     <div class="text-center btn-success disabled mb-3" style="font-size: 8em;">
-        {% fa5_icon "calendar-plus" "fas" %}
+        {% fa6_icon "calendar-plus" "fas" %}
     </div>
 
 
 
     <h5 class="mb-3">{% trans "Your event was created and can now be further configured." %}</h5>
 
-    {{ form.media }}
-
     <form method="post">{% csrf_token %}
         {% bootstrap_form form %}
 
-        <div class="float-right">
+        <div class="float-end">
             <a href="{% url 'admin:new_event_wizard_activate' event.slug %}" class="btn btn-info">
-                {% fa5_icon "forward" 'fas' %} {% trans "Skip Import" %}
+                {% fa6_icon "forward" 'fas' %} {% trans "Skip Import" %}
             </a>
 
             <button type="submit" class="save btn btn-success" value="Submit">
-            {% fa5_icon "check" 'fas' %} {% trans "Continue" %}
+            {% fa6_icon "check" 'fas' %} {% trans "Continue" %}
         </button>
         </div>
 
         <a href="{% url 'admin:event_status' event.slug %}" class="btn btn-info">
-            {% fa5_icon "info" 'fas' %} {% trans "Status" %}
+            {% fa6_icon "info" 'fas' %} {% trans "Status" %}
         </a>
     </form>
 

AKModel/templates/admin/AKModel/event_wizard/finish.html

@@ -2,8 +2,8 @@
 {% load tags_AKModel %}
 
 {% load i18n %}
-{% load bootstrap4 %}
-{% load fontawesome_5 %}
+{% load django_bootstrap5 %}
+{% load fontawesome_6 %}
 {% load tz %}
 
 {% block title %}{% trans "New event wizard" %}: {{ wizard_step_text }}{% endblock %}
@@ -12,13 +12,13 @@
     {% include "admin/AKModel/event_wizard/wizard_steps.html" %}
 
     <div class="text-center btn-success disabled mt-3 mb-3" style="font-size: 8em;">
-        {% fa5_icon "check-circle" "fas" %}
+        {% fa6_icon "check-circle" "fas" %}
     </div>
 
     <h5>{% trans "Congratulations. Everything is set up!" %}</h5>
 
-    <a href="{% url 'admin:event_status' event.slug %}" class="btn btn-info float-right">
-            {% fa5_icon "info" 'fas' %}&nbsp;{% trans "Status" %}
+    <a href="{% url 'admin:event_status' event.slug %}" class="btn btn-info float-end">
+            {% fa6_icon "info" 'fas' %}&nbsp;{% trans "Status" %}
     </a>
 
 {% endblock %}

AKModel/templates/admin/AKModel/event_wizard/import.html

@@ -2,26 +2,29 @@
 {% load tags_AKModel %}
 
 {% load i18n %}
-{% load bootstrap4 %}
-{% load fontawesome_5 %}
+{% load django_bootstrap5 %}
+{% load fontawesome_6 %}
 {% load tz %}
 
 {% block title %}{% trans "New event wizard" %}: {{ wizard_step_text }}{% endblock %}
 
+{% block extrahead %}
+    {{ block.super }}
+    {{ form.media }}
+{% endblock %}
+
 {% block content %}
     {% include "admin/AKModel/event_wizard/wizard_steps.html" %}
 
-    {{ form.media }}
-
     <form method="post">{% csrf_token %}
         {% bootstrap_form form %}
 
-        <button type="submit" class="save btn btn-success float-right" value="Submit">
-            {% fa5_icon "check" 'fas' %} {% trans "Continue" %}
+        <button type="submit" class="save btn btn-success float-end" value="Submit">
+            {% fa6_icon "check" 'fas' %} {% trans "Continue" %}
         </button>
 
         <a href="{% url 'admin:index' %}" class="btn btn-info">
-            {% fa5_icon "times" 'fas' %} {% trans "Cancel" %}
+            {% fa6_icon "times" 'fas' %} {% trans "Cancel" %}
         </a>
     </form>
 

AKModel/templates/admin/AKModel/event_wizard/settings.html

@@ -2,31 +2,34 @@
 {% load tags_AKModel %}
 
 {% load i18n %}
-{% load bootstrap4 %}
-{% load fontawesome_5 %}
+{% load django_bootstrap5 %}
+{% load fontawesome_6 %}
 {% load tz %}
 
 {% block title %}{% trans "New event wizard" %}: {{ wizard_step_text }}{% endblock %}
 
+{% block extrahead %}
+    {{ block.super }}
+    {{ form.media }}
+{% endblock %}
+
 {% block content %}
     {% include "admin/AKModel/event_wizard/wizard_steps.html" %}
 
-    {{ form.media }}
-
     {% timezone timezone %}
 
     <form method="post">{% csrf_token %}
         {% bootstrap_form form %}
 
-        <button type="submit" class="save btn btn-success float-right" value="Submit">
-            {% fa5_icon "check" 'fas' %} {% trans "Continue" %}
+        <button type="submit" class="save btn btn-success float-end" value="Submit">
+            {% fa6_icon "check" 'fas' %} {% trans "Continue" %}
         </button>
 
         <a href="{% url 'admin:new_event_wizard_start' %}" class="btn btn-info">
-            {% fa5_icon "chevron-left" 'fas' %} {% trans "Back" %}
+            {% fa6_icon "chevron-left" 'fas' %} {% trans "Back" %}
         </a>
         <a href="{% url 'admin:index' %}" class="btn btn-warning">
-            {% fa5_icon "times" 'fas' %} {% trans "Cancel" %}
+            {% fa6_icon "times" 'fas' %} {% trans "Cancel" %}
         </a>
     </form>