add power level groups

lib/models/content/content.dart

@@ -58,6 +58,7 @@ enum EventType(
   avatar("m.room.avatar", AvatarContent.fromJson),
   topic("m.room.topic", TopicContent.fromJson),
   name("m.room.name", NameContent.fromJson),
+  tombstone("m.room.tombstone", Content.fromJson),
   reaction("m.reaction", ReactionContent.fromJson),
   pinnedEvents("m.room.pinned_events", PinnedEventsContent.fromJson),
   message("m.room.message", MessageContent.fromJson),

lib/models/power_level_permission.dart

@@ -1,3 +1,5 @@
+import "dart:math";
+
 import "package:fast_immutable_collections/fast_immutable_collections.dart";
 import "package:material_ui/material_ui.dart";
 import "package:nexus/models/content/content.dart";
@@ -113,14 +115,133 @@ enum PowerLevelEvent(
     "Pin Messages",
     "The power level needed to pin messages.",
     Icons.push_pin,
+  ),
+  name(
+    .name,
+    "Change Name",
+    "The power level needed to change the room's name.",
+    Icons.title,
+  ),
+  topic(
+    .topic,
+    "Change Topic",
+    "The power level needed to change the room's topic.",
+    Icons.description,
+  ),
+  avatar(
+    .avatar,
+    "Change Avatar",
+    "The power level needed to change the room's avatar.",
+    Icons.image,
+  ),
+  canonicalAlias(
+    .canonicalAlias,
+    "Change Aliases",
+    "The power level needed to change the room's canonical alias and published aliases.",
+    Icons.numbers,
+  ),
+  powerLevels(
+    .powerLevels,
+    "Change Power Levels",
+    "The power level needed to change power levels, including these.",
+    Icons.admin_panel_settings,
+  ),
+  joinRules(
+    .joinRules,
+    "Change Join Rule",
+    "The power level needed to change who can join the room.",
+    Icons.login,
+  ),
+  historyVisibility(
+    .historyVisibility,
+    "Change History Visibility",
+    "The power level needed to change who can read the room's history.",
+    Icons.history,
+  ),
+  serverACL(
+    .serverACL,
+    "Change Server ACL",
+    "The power level needed to change which servers can take part in the room.",
+    Icons.dns,
+  ),
+  encryption(
+    .encryption,
+    "Enable Encryption",
+    "The power level needed to enable encryption, which can't be turned off.",
+    Icons.lock,
+  ),
+  tombstone(
+    .tombstone,
+    "Upgrade Room",
+    "The power level needed to replace the room with an upgraded one.",
+    Icons.upgrade,
   );
 
   static IList<PowerLevelEvent> shownIn({required bool encrypted}) => .new([
     if (encrypted) .encrypted else ...[.message, .sticker],
     .reaction,
-    .pinnedEvents,
   ]);
 
   static PowerLevelEvent? of(String type) =>
       values.where((event) => event.type.type == type).firstOrNull;
 }
+
+/// Power levels set together, like everything moderators need, to save
+/// setting each one. Each can still be set on its own, by expanding it.
+enum PowerLevelGroup(final String title, final IconData icon) {
+  moderation("Moderation", Icons.shield),
+  roomDetails("Room Details", Icons.edit),
+  administration("Administration", Icons.admin_panel_settings);
+
+  IList<PowerLevelPermission> get permissions => .new(switch (this) {
+    .moderation => [.kick, .ban, .redact, .notifyRoom],
+    .roomDetails || .administration => [],
+  });
+
+  IList<PowerLevelEvent> get events => .new(switch (this) {
+    .moderation => [],
+    .roomDetails => [.name, .topic, .avatar, .canonicalAlias, .pinnedEvents],
+    .administration => [
+      .powerLevels,
+      .joinRules,
+      .historyVisibility,
+      .serverACL,
+      .encryption,
+      .tombstone,
+    ],
+  });
+
+  String get description => [
+    ...permissions.map((permission) => permission.title),
+    ...events.map((event) => event.title),
+  ].join(", ");
+
+  int? levelIn(PowerLevelsContent content) {
+    final levels = {
+      ...permissions.map((permission) => permission.levelIn(content)),
+      ...events.map(
+        (event) => content.events[event.type.type] ?? content.stateDefault,
+      ),
+    };
+    return levels.length == 1 ? levels.single : null;
+  }
+
+  int highestIn(PowerLevelsContent content) => [
+    ...permissions.map((permission) => permission.levelIn(content)),
+    ...events.map(
+      (event) => content.events[event.type.type] ?? content.stateDefault,
+    ),
+  ].reduce(max);
+
+  PowerLevelsContent withLevel(PowerLevelsContent content, int level) =>
+      permissions
+          .fold(
+            content,
+            (content, permission) => permission.withLevel(content, level),
+          )
+          .copyWith(
+            events: content.events.addEntries(
+              events.map((event) => MapEntry(event.type.type, level)),
+            ),
+          );
+}