Can cancel a group membership invitation

lib/helpers/groups_helper.dart

@@ -268,6 +268,15 @@ class GroupsHelper {
             .map((f) => _apiToGroupMembership(f))
             .toList());
 
+  /// Cancel a group membership invitation
+  ///
+  /// Throws an exception in case of failure
+  static Future<void> cancelInvitation(int groupID, int userID) async =>
+      await APIRequest.withLogin("groups/cancel_invitation")
+          .addInt("groupID", groupID)
+          .addInt("userID", userID)
+          .execWithThrow();
+
   /// Turn an API entry into a group object
   Group _getGroupFromAPI(Map<String, dynamic> map) {
     return Group(

lib/models/api_request.dart

@@ -36,6 +36,12 @@ class APIRequest {
     if (this.args == null) this.args = Map();
   }
 
+  APIRequest.withLogin(this.uri, {this.args})
+      : needLogin = true,
+        assert(uri != null) {
+    if (args == null) this.args = Map();
+  }
+
   APIRequest addString(String name, String value) {
     args[name] = value;
     return this;

lib/ui/screens/group_members_screen.dart

@@ -4,11 +4,13 @@ import 'package:comunic/lists/group_members_list.dart';
 import 'package:comunic/lists/users_list.dart';
 import 'package:comunic/models/group.dart';
 import 'package:comunic/models/group_membership.dart';
+import 'package:comunic/models/user.dart';
 import 'package:comunic/ui/dialogs/multi_choices_dialog.dart';
 import 'package:comunic/ui/widgets/account_image_widget.dart';
 import 'package:comunic/ui/widgets/async_screen_widget.dart';
 import 'package:comunic/ui/widgets/comunic_back_button_widget.dart';
 import 'package:comunic/utils/intl_utils.dart';
+import 'package:comunic/utils/ui_utils.dart';
 import 'package:flutter/material.dart';
 
 /// Group members screen
@@ -27,6 +29,7 @@ class GroupMembersScreen extends StatefulWidget {
 }
 
 class _GroupMembersScreenState extends State<GroupMembersScreen> {
+  final _key = GlobalKey<AsyncScreenWidgetState>();
   GroupMembersList _members;
   UsersList _users;
 
@@ -50,6 +53,7 @@ class _GroupMembersScreenState extends State<GroupMembersScreen> {
   }
 
   Widget _buildBody() => AsyncScreenWidget(
+        key: _key,
         onReload: _refresh,
         onBuild: _buildBodyContent,
         errorMessage: tr("Could not load the list of members of this group!"),
@@ -62,6 +66,17 @@ class _GroupMembersScreenState extends State<GroupMembersScreen> {
     );
   }
 
+  Widget _buildGroupMemberTile(GroupMembership membership) {
+    final user = _users.getUser(membership.userID);
+
+    return _GroupMembershipTile(
+      membership: membership,
+      user: user,
+      onUpdated: () => _key.currentState.refresh(),
+    );
+  }
+}
+
 List<MultiChoiceEntry<GroupMembershipLevel>> get _membershipLevels => [
       MultiChoiceEntry(
           id: GroupMembershipLevel.ADMINISTRATOR,
@@ -79,22 +94,92 @@ class _GroupMembersScreenState extends State<GroupMembersScreen> {
           subtitle: tr("Can access to all group posts")),
       MultiChoiceEntry(
           id: GroupMembershipLevel.PENDING, title: tr("Requested")),
-        MultiChoiceEntry(
-            id: GroupMembershipLevel.INVITED, title: tr("Invited")),
-        MultiChoiceEntry(
-            id: GroupMembershipLevel.VISITOR, title: tr("Visitor")),
+      MultiChoiceEntry(id: GroupMembershipLevel.INVITED, title: tr("Invited")),
+      MultiChoiceEntry(id: GroupMembershipLevel.VISITOR, title: tr("Visitor")),
     ];
 
-  ListTile _buildGroupMemberTile(GroupMembership membership) {
-    final user = _users.getUser(membership.userID);
+class _GroupMembershipTile extends StatefulWidget {
+  final GroupMembership membership;
+  final User user;
+  final void Function() onUpdated;
 
+  const _GroupMembershipTile({
+    Key key,
+    @required this.membership,
+    @required this.user,
+    @required this.onUpdated,
+  })  : assert(membership != null),
+        assert(user != null),
+        assert(onUpdated != null),
+        super(key: key);
+
+  @override
+  __GroupMembershipTileState createState() => __GroupMembershipTileState();
+}
+
+class __GroupMembershipTileState extends State<_GroupMembershipTile> {
+  int get groupID => widget.membership.groupID;
+
+  int get userID => widget.membership.userID;
+
+  @override
+  Widget build(BuildContext context) {
     return ListTile(
       leading: AccountImageWidget(
-        user: user,
+        user: widget.user,
       ),
-      title: Text(user.displayName),
-      subtitle: Text(
-          _membershipLevels.firstWhere((f) => f.id == membership.level).title),
+      title: Text(widget.user.displayName),
+      subtitle: Text(_membershipLevels
+          .firstWhere((f) => f.id == widget.membership.level)
+          .title),
+      trailing: _buildTrailing(),
     );
   }
+
+  Widget _buildTrailing() {
+    switch (widget.membership.level) {
+      case GroupMembershipLevel.ADMINISTRATOR:
+        // TODO: Handle this case.
+        break;
+      case GroupMembershipLevel.MODERATOR:
+        // TODO: Handle this case.
+        break;
+      case GroupMembershipLevel.MEMBER:
+        // TODO: Handle this case.
+        break;
+
+      case GroupMembershipLevel.INVITED:
+        return _buildInvitedCase();
+        break;
+
+      case GroupMembershipLevel.PENDING:
+        // TODO: Handle this case.
+        break;
+
+      case GroupMembershipLevel.VISITOR:
+        // This case should never happen
+        break;
+    }
+
+    return null;
+  }
+
+  Widget _buildInvitedCase() {
+    return MaterialButton(
+      onPressed: _cancelMembership,
+      child: Text(tr("Cancel").toUpperCase()),
+      textColor: Colors.red,
+    );
+  }
+
+  void _cancelMembership() async {
+    try {
+      await GroupsHelper.cancelInvitation(groupID, userID);
+    } catch (e, s) {
+      print("Could not cancel invitation! $e\n$s");
+      showSimpleSnack(context, tr("Could not cancel invitation!"));
+    }
+
+    widget.onUpdated();
+  }
 }