Add power level management

lib/src/Room.dart

@@ -232,6 +232,20 @@ class Room {
     return res;
   }
 
+  /// Call the Matrix API to unban a banned user from this room.
+  Future<dynamic> setPower(String userID, int power) async {
+    Map<String,int> powerMap = await client.store.getPowerLevels(id);
+    powerMap[userID] = power;
+
+    dynamic res = await client.connection.jsonRequest(
+        type: "PUT",
+        action:
+        "/client/r0/rooms/$id/state/m.room.power_levels/",
+        data: {"users": powerMap});
+    if (res is ErrorResponse) client.connection.onError.add(res);
+    return res;
+  }
+
   /// Call the Matrix API to invite a user to this room.
   Future<dynamic> invite(String userID) async {
     dynamic res = await client.connection.jsonRequest(

lib/src/Store.dart

@@ -531,6 +531,27 @@ class Store {
     return res[0]["id"];
   }
 
+  /// Returns the power level of the user for the given [roomID]. Returns null if
+  /// the room or the own user wasn't found.
+  Future<int> getPowerLevel(String roomID) async {
+    List<Map<String, dynamic>> res = await db.rawQuery(
+        "SELECT power_level FROM Users WHERE matrix_id=? AND chat_id=?",
+        [roomID, client.userID]);
+    if (res.length != 1) return null;
+    return res[0]["power_level"];
+  }
+
+  /// Returns the power levels from all users for the given [roomID].
+  Future<Map<String, int>> getPowerLevels(String roomID) async {
+    List<Map<String, dynamic>> res = await db.rawQuery(
+        "SELECT matrix_id, power_level FROM Users WHERE chat_id=?",
+        [roomID, client.userID]);
+    Map<String, int> powerMap = {};
+    for (int i = 0; i < res.length; i++)
+      powerMap[res[i]["matrix_id"]] = res[i]["power_level"];
+    return powerMap;
+  }
+
   /// The database sheme for the Client class.
   static final String ClientsScheme = 'CREATE TABLE IF NOT EXISTS Clients(' +
       'client TEXT PRIMARY KEY, ' +

lib/src/User.dart

@@ -87,6 +87,18 @@ class User {
         room: room);
   }
 
+  /// Checks if the client's user has the permission to kick this user.
+  Future<bool> get canKick async {
+    final int ownPowerLevel = await room.client.store.getPowerLevel(room.id);
+    return ownPowerLevel > powerLevel && ownPowerLevel >= room.powerLevels["power_kick"];
+  }
+
+  /// Checks if the client's user has the permission to ban or unban this user.
+  Future<bool> get canBan async {
+    final int ownPowerLevel = await room.client.store.getPowerLevel(room.id);
+    return ownPowerLevel > powerLevel && ownPowerLevel >= room.powerLevels["power_ban"];
+  }
+
   /// Call the Matrix API to kick this user from this room.
   Future<dynamic> kick() async {
     dynamic res = await room.kick(id);
@@ -105,6 +117,12 @@ class User {
     return res;
   }
 
+  /// Call the Matrix API to change the power level of this user.
+  Future<dynamic> setPower(int power) async {
+    dynamic res = await room.setPower(id, power);
+    return res;
+  }
+
   /// Returns an existing direct chat with this user or creates a new one.
   Future<String> startDirectChat() async {
     // Try to find an existing direct chat