Organizer-level plugins (#5305)

* Add version notes to the docs

* Adapt signal handling

* Add UI

* Add API

* API and tests

* Fix registry

* Update doc/development/api/plugins.rst

Co-authored-by: Felix Rindt <felix@rindt.me>

* Fix failing tests

* Apply suggestions from code review

Co-authored-by: Richard Schreiber <schreiber@rami.io>

* Update src/pretix/control/templates/pretixcontrol/organizers/plugin_events.html

Co-authored-by: luelista <weller@rami.io>

* Update src/pretix/control/templates/pretixcontrol/organizers/plugins.html

Co-authored-by: luelista <weller@rami.io>

* Update src/pretix/control/templates/pretixcontrol/organizers/plugins.html

Co-authored-by: luelista <weller@rami.io>

* Update src/pretix/control/navigation.py

Co-authored-by: luelista <weller@rami.io>

* Update src/pretix/control/urls.py

Co-authored-by: luelista <weller@rami.io>

* Apply suggestion from @wiffbi

* REbase migration

* Fix review note

* Fix test cases

* Remove plugin from all events if disabled on org level

* Update doc/development/api/plugins.rst

* Unify registries

* Rebase migration

---------

Co-authored-by: Felix Rindt <felix@rindt.me>
Co-authored-by: Richard Schreiber <schreiber@rami.io>
Co-authored-by: luelista <weller@rami.io>

src/pretix/base/models/organizer.py

@@ -68,6 +68,8 @@ class Organizer(LoggedModel):
     :param slug: A globally unique, short name for this organizer, to be used
                  in URLs and similar places.
     :type slug: str
+    :param plugins: A comma-separated list of plugin names that are active for this organizer.
+    :type plugins: str
     """
 
     settings_namespace = 'organizer'
@@ -91,6 +93,10 @@ class Organizer(LoggedModel):
         verbose_name=_("Short form"),
         unique=True
     )
+    plugins = models.TextField(
+        verbose_name=_("Plugins"),
+        null=False, blank=True, default="",
+    )
 
     class Meta:
         verbose_name = _("Organizer")
@@ -119,6 +125,11 @@ class Organizer(LoggedModel):
         """
         self.settings.cookie_consent = True
 
+        plugins = [p for p in settings.PRETIX_PLUGINS_ORGANIZER_DEFAULT.split(",") if p]
+        if plugins:
+            self.set_active_plugins(plugins, allow_restricted=plugins)
+            self.save()
+
     def get_cache(self):
         """
         Returns an :py:class:`ObjectRelatedCache` object. This behaves equivalent to
@@ -143,6 +154,61 @@ class Organizer(LoggedModel):
 
         return ObjectRelatedCache(self)
 
+    def get_plugins(self):
+        """
+        Returns the names of the plugins activated for this organizer as a list.
+        """
+        if not self.plugins:
+            return []
+        return self.plugins.split(",")
+
+    def get_available_plugins(self):
+        from pretix.base.plugins import get_all_plugins
+
+        return {
+            p.module: p for p in get_all_plugins(organizer=self)
+            if not p.name.startswith('.') and getattr(p, 'visible', True)
+        }
+
+    def set_active_plugins(self, modules, allow_restricted=frozenset()):
+        plugins_active = self.get_plugins()
+        plugins_available = self.get_available_plugins()
+
+        enable = [m for m in modules if m not in plugins_active and m in plugins_available]
+
+        for module in enable:
+            if getattr(plugins_available[module].app, 'restricted', False) and module not in allow_restricted:
+                modules.remove(module)
+            elif hasattr(plugins_available[module].app, 'installed'):
+                getattr(plugins_available[module].app, 'installed')(self)
+
+        self.plugins = ",".join(modules)
+
+    def enable_plugin(self, module, allow_restricted=frozenset()):
+        """
+        Adds a plugin to the list of plugins, calling its ``installed`` hook (if available).
+        It is the caller's responsibility to save the organizer object.
+        """
+        plugins_active = self.get_plugins()
+        if module not in plugins_active:
+            plugins_active.append(module)
+            self.set_active_plugins(plugins_active, allow_restricted=allow_restricted)
+
+    def disable_plugin(self, module):
+        """
+        Removes a plugin from the list of plugins, calling its ``uninstalled`` hook (if available).
+        It is the caller's responsibility to save the organizer object and, in case of a hybrid organizer-event plugin,
+        to remove it from all events.
+        """
+        plugins_active = self.get_plugins()
+        if module in plugins_active:
+            plugins_active.remove(module)
+            self.set_active_plugins(plugins_active)
+
+            plugins_available = self.get_available_plugins()
+            if module in plugins_available and hasattr(plugins_available[module].app, 'uninstalled'):
+                getattr(plugins_available[module].app, 'uninstalled')(self)
+
     @property
     def timezone(self):
         return pytz_deprecation_shim.timezone(self.settings.timezone)