[Room] Add powerlevels getter

lib/src/Event.dart

@@ -138,4 +138,7 @@ class Event extends RoomState {
     final String eventID = await room.sendTextEvent(text, txid: txid);
     return eventID;
   }
+
+  /// Whether the client is allowed to redact this event.
+  bool get canRedact => senderId == room.client.userID || room.canRedact;
 }

lib/src/Room.dart

@@ -465,7 +465,7 @@ class Room {
   /// Set the power level of the user with the [userID] to the value [power].
   Future<dynamic> setPower(String userID, int power) async {
     if (states["m.room.power_levels"] == null) return null;
-    Map<String, int> powerMap = states["m.room.power_levels"].content["users"];
+    Map powerMap = states["m.room.power_levels"].content["users"];
     powerMap[userID] = power;
 
     dynamic res = await client.connection.jsonRequest(
@@ -819,4 +819,41 @@ class Room {
     if (setAvatarResp is ErrorResponse) return setAvatarResp;
     return setAvatarResp["event_id"];
   }
+
+  bool _hasPermissionFor(String action) {
+    if (getState("m.room.power_levels") == null ||
+        getState("m.room.power_levels").content[action] == null) return false;
+    return ownPowerLevel >= getState("m.room.power_levels").content[action];
+  }
+
+  /// The level required to ban a user.
+  bool get canBan => _hasPermissionFor("ban");
+
+  /// The default level required to send message events. Can be overridden by the events key.
+  bool get canSendDefaultMessages => _hasPermissionFor("events_default");
+
+  /// The level required to invite a user.
+  bool get canInvite => _hasPermissionFor("invite");
+
+  /// The level required to kick a user.
+  bool get canKick => _hasPermissionFor("kick");
+
+  /// The level required to redact an event.
+  bool get canRedact => _hasPermissionFor("redact");
+
+  ///  	The default level required to send state events. Can be overridden by the events key.
+  bool get canSendDefaultStates => _hasPermissionFor("state_default");
+
+  bool get canChangePowerLevel => canSendEvent("m.room.power_levels");
+
+  bool canSendEvent(String eventType) {
+    if (getState("m.room.power_levels") == null ||
+        getState("m.room.power_levels").content["events"] == null) return false;
+    if (getState("m.room.power_levels").content["events"][eventType] == null)
+      return eventType == "m.room.message"
+          ? canSendDefaultMessages
+          : canSendDefaultStates;
+    return ownPowerLevel >=
+        getState("m.room.power_levels").content["events"][eventType];
+  }
 }

lib/src/User.dart

@@ -165,4 +165,15 @@ class User extends RoomState {
 
     return newRoomID;
   }
+
+  /// Whether the client is allowed to ban/unban this user.
+  bool get canBan => room.canBan && powerLevel < room.ownPowerLevel;
+
+  /// Whether the client is allowed to kick this user.
+  bool get canKick => room.canKick && powerLevel < room.ownPowerLevel;
+
+  /// Whether the client is allowed to change the power level of this user.
+  /// Please be aware that you can only set the power level to at least your own!
+  bool get canChangePowerLevel =>
+      room.canChangePowerLevel && powerLevel < room.ownPowerLevel;
 }

test/Room_test.dart

@@ -214,8 +214,51 @@ void main() {
       expect(room.ownPowerLevel, 100);
       expect(room.getPowerLevelByUserId(matrix.userID), room.ownPowerLevel);
       expect(room.getPowerLevelByUserId("@nouser:example.com"), 10);
+      expect(room.ownPowerLevel, 100);
+      expect(room.canBan, true);
+      expect(room.canInvite, true);
+      expect(room.canKick, true);
+      expect(room.canRedact, true);
+      expect(room.canSendDefaultMessages, true);
+      expect(room.canSendDefaultStates, true);
+      expect(room.canChangePowerLevel, true);
+      expect(room.canSendEvent("m.room.name"), true);
+      expect(room.canSendEvent("m.room.power_levels"), true);
+      expect(room.canSendEvent("m.room.member"), true);
       expect(room.powerLevels,
           room.states["m.room.power_levels"].content["users"]);
+
+      room.states["m.room.power_levels"] = RoomState(
+          senderId: "@test:example.com",
+          typeKey: "m.room.power_levels",
+          roomId: room.id,
+          room: room,
+          eventId: "123abc",
+          content: {
+            "ban": 50,
+            "events": {"m.room.name": 0, "m.room.power_levels": 100},
+            "events_default": 0,
+            "invite": 50,
+            "kick": 50,
+            "notifications": {"room": 20},
+            "redact": 50,
+            "state_default": 50,
+            "users": {},
+            "users_default": 0
+          },
+          stateKey: "");
+      expect(room.ownPowerLevel, 0);
+      expect(room.canBan, false);
+      expect(room.canInvite, false);
+      expect(room.canKick, false);
+      expect(room.canRedact, false);
+      expect(room.canSendDefaultMessages, true);
+      expect(room.canSendDefaultStates, false);
+      expect(room.canChangePowerLevel, false);
+      expect(room.canSendEvent("m.room.name"), true);
+      expect(room.canSendEvent("m.room.power_levels"), false);
+      expect(room.canSendEvent("m.room.member"), false);
+      expect(room.canSendEvent("m.room.message"), true);
       final dynamic resp =
           await room.setPower("@test:fakeServer.notExisting", 90);
       expect(resp["event_id"], "42");