add diffing for a lot of events

lib/models/power_level_permission.dart

@@ -0,0 +1,115 @@
+import "package:fast_immutable_collections/fast_immutable_collections.dart";
+import "package:material_ui/material_ui.dart";
+import "package:nexus/models/content/content.dart";
+import "package:nexus/models/content/power_levels.dart";
+
+enum PowerLevelPermission(
+  final String title,
+  final String description,
+  final IconData icon,
+) {
+  usersDefault(
+    "Default Power Level",
+    "The power level of users who aren't given one.",
+    Icons.person,
+  ),
+  eventsDefault(
+    "Default for Events",
+    "The power level needed to send events without their own.",
+    Icons.more_horiz,
+  ),
+  stateDefault(
+    "Default for State Events",
+    "The power level needed to send state events without their own.",
+    Icons.tune,
+  ),
+  invite(
+    "Invite Users",
+    "The power level needed to invite users.",
+    Icons.person_add,
+  ),
+  kick(
+    "Kick Users",
+    "The power level needed to kick users.",
+    Icons.sports_martial_arts,
+  ),
+  ban(
+    "Ban Users",
+    "The power level needed to ban and unban users.",
+    Icons.gavel,
+  ),
+  redact(
+    "Delete Others' Messages",
+    "The power level needed to remove others' messages.",
+    Icons.delete,
+  ),
+  notifyRoom(
+    "Notify Everyone",
+    "The power level needed to notify everyone in the room with @room.",
+    Icons.campaign,
+  );
+
+  int levelIn(PowerLevelsContent content) => switch (this) {
+    .usersDefault => content.usersDefault,
+    .eventsDefault => content.eventsDefault,
+    .stateDefault => content.stateDefault,
+    .invite => content.invite,
+    .kick => content.kick,
+    .ban => content.ban,
+    .redact => content.redact,
+    .notifyRoom => content.notifications?.room ?? 50,
+  };
+
+  PowerLevelsContent withLevel(PowerLevelsContent content, int level) =>
+      switch (this) {
+        .usersDefault => content.copyWith(usersDefault: level),
+        .eventsDefault => content.copyWith(eventsDefault: level),
+        .stateDefault => content.copyWith(stateDefault: level),
+        .invite => content.copyWith(invite: level),
+        .kick => content.copyWith(kick: level),
+        .ban => content.copyWith(ban: level),
+        .redact => content.copyWith(redact: level),
+        .notifyRoom => content.copyWith(
+          notifications: (content.notifications ?? const Notifications())
+              .copyWith(room: level),
+        ),
+      };
+}
+
+enum PowerLevelEvent(
+  final String title,
+  final String description,
+  final IconData icon,
+) {
+  message(
+    "Send Messages",
+    "The power level needed to send messages.",
+    Icons.message,
+  ),
+  sticker(
+    "Send Stickers",
+    "The power level needed to send stickers.",
+    Icons.sticky_note_2,
+  ),
+  reaction(
+    "Send Reactions",
+    "The power level needed to react to messages.",
+    Icons.add_reaction,
+  ),
+  pinnedEvents(
+    "Pin Messages",
+    "The power level needed to pin messages.",
+    Icons.push_pin,
+  );
+
+  IList<EventType> get types => .new(switch (this) {
+    .message => [.message, .encrypted],
+    .sticker => [.sticker],
+    .reaction => [.reaction],
+    .pinnedEvents => [.pinnedEvents],
+  });
+
+  static PowerLevelEvent? of(String type) => values
+      .where((event) => event.types.any((eventType) => eventType.type == type))
+      .firstOrNull;
+}