Improved invite UX

lib/views/invitation_selection.dart

@@ -1,3 +1,5 @@
+import 'dart:async';
+
 import 'package:famedlysdk/famedlysdk.dart';
 import 'package:fluffychat/components/adaptive_page_layout.dart';
 import 'package:fluffychat/components/avatar.dart';
@@ -8,13 +10,24 @@ import 'package:toast/toast.dart';
 
 import 'chat_list.dart';
 
-class InvitationSelection extends StatelessWidget {
+class InvitationSelection extends StatefulWidget {
   final Room room;
   const InvitationSelection(this.room, {Key key}) : super(key: key);
 
+  @override
+  _InvitationSelectionState createState() => _InvitationSelectionState();
+}
+
+class _InvitationSelectionState extends State<InvitationSelection> {
+  TextEditingController controller = TextEditingController();
+  String currentSearchTerm;
+  bool loading = false;
+  List<Map<String, dynamic>> foundProfiles = [];
+  Timer coolDown;
+
   Future<List<User>> getContacts(BuildContext context) async {
     final Client client = Matrix.of(context).client;
-    List<User> participants = await room.requestParticipants();
+    List<User> participants = await widget.room.requestParticipants();
     List<User> contacts = [];
     Map<String, bool> userMap = {};
     for (int i = 0; i < client.rooms.length; i++) {
@@ -36,7 +49,7 @@ class InvitationSelection extends StatelessWidget {
 
   void inviteAction(BuildContext context, String id) async {
     final success = await Matrix.of(context).tryRequestWithLoadingDialog(
-      room.invite(id),
+      widget.room.invite(id),
     );
     if (success != false) {
       Toast.show(
@@ -47,18 +60,117 @@ class InvitationSelection extends StatelessWidget {
     }
   }
 
+  void searchUserWithCoolDown(BuildContext context, String text) async {
+    coolDown?.cancel();
+    coolDown = Timer(
+      Duration(seconds: 1),
+      () => searchUser(context, text),
+    );
+  }
+
+  void searchUser(BuildContext context, String text) async {
+    coolDown?.cancel();
+    if (text.isEmpty) {
+      setState(() {
+        foundProfiles = [];
+      });
+    }
+    currentSearchTerm = text;
+    if (currentSearchTerm.isEmpty) return;
+    if (loading) return;
+    setState(() => loading = true);
+    final MatrixState matrix = Matrix.of(context);
+    final response = await matrix.tryRequestWithErrorToast(
+      matrix.client.jsonRequest(
+          type: HTTPType.POST,
+          action: "/client/r0/user_directory/search",
+          data: {
+            "search_term": text,
+            "limit": 10,
+          }),
+    );
+    setState(() => loading = false);
+    if (response == false ||
+        !(response is Map) ||
+        (response["results"] == null)) return;
+    setState(() {
+      foundProfiles = List<Map<String, dynamic>>.from(response["results"]);
+      if ("@$text".isValidMatrixId &&
+          foundProfiles
+                  .indexWhere((profile) => "@$text" == profile["user_id"]) ==
+              -1) {
+        setState(() => foundProfiles = [
+              {"user_id": "@$text"}
+            ]);
+      }
+      foundProfiles.removeWhere((profile) =>
+          widget.room
+              .getParticipants()
+              .indexWhere((u) => u.id == profile["user_id"]) !=
+          -1);
+    });
+  }
+
   @override
   Widget build(BuildContext context) {
-    final String groupName =
-        room.name?.isEmpty ?? false ? I18n.of(context).group : room.name;
+    final String groupName = widget.room.name?.isEmpty ?? false
+        ? I18n.of(context).group
+        : widget.room.name;
     return AdaptivePageLayout(
       primaryPage: FocusPage.SECOND,
-      firstScaffold: ChatList(activeChat: room.id),
+      firstScaffold: ChatList(activeChat: widget.room.id),
       secondScaffold: Scaffold(
           appBar: AppBar(
-            title: Text(I18n.of(context).inviteContactToGroup(groupName)),
+            title: Text(I18n.of(context).inviteContact),
+            bottom: PreferredSize(
+              preferredSize: Size.fromHeight(68),
+              child: Padding(
+                padding: const EdgeInsets.all(16.0),
+                child: TextField(
+                  controller: controller,
+                  autofocus: true,
+                  autocorrect: false,
+                  textInputAction: TextInputAction.search,
+                  onChanged: (String text) =>
+                      searchUserWithCoolDown(context, text),
+                  onSubmitted: (String text) => searchUser(context, text),
+                  decoration: InputDecoration(
+                    border: OutlineInputBorder(),
+                    prefixText: "@",
+                    hintText: I18n.of(context).username,
+                    labelText: I18n.of(context).inviteContactToGroup(groupName),
+                    suffixIcon: loading
+                        ? Container(
+                            padding: const EdgeInsets.all(8.0),
+                            width: 12,
+                            height: 12,
+                            child: CircularProgressIndicator(),
+                          )
+                        : Icon(Icons.search),
                   ),
-          body: FutureBuilder<List<User>>(
+                ),
+              ),
+            ),
+          ),
+          body: foundProfiles.isNotEmpty
+              ? ListView.builder(
+                  itemCount: foundProfiles.length,
+                  itemBuilder: (BuildContext context, int i) => ListTile(
+                    leading: Avatar(
+                      MxContent(foundProfiles[i]["avatar_url"] ?? ""),
+                      foundProfiles[i]["display_name"] ??
+                          foundProfiles[i]["user_id"],
+                    ),
+                    title: Text(
+                      foundProfiles[i]["display_name"] ??
+                          (foundProfiles[i]["user_id"] as String).localpart,
+                    ),
+                    subtitle: Text(foundProfiles[i]["user_id"]),
+                    onTap: () =>
+                        inviteAction(context, foundProfiles[i]["user_id"]),
+                  ),
+                )
+              : FutureBuilder<List<User>>(
                   future: getContacts(context),
                   builder: (BuildContext context, snapshot) {
                     if (!snapshot.hasData) {