Can block the creation of new responses on a survey

lib/helpers/survey_helper.dart

@@ -34,6 +34,12 @@ class SurveyHelper {
         .isOK;
   }
 
+  /// Prevent new choices from being created on a survey
+  static Future<void> blockNewChoicesCreation(int postID) async =>
+      await APIRequest.withLogin("surveys/block_new_choices_creation")
+          .addInt("postID", postID)
+          .execWithThrow();
+
   /// Turn an API entry into a [Survey] object
   static Survey apiToSurvey(Map<String, dynamic> map) {
     // Parse survey responses
@@ -50,6 +56,7 @@ class SurveyHelper {
       question: map["question"],
       userChoice: map["user_choice"],
       choices: choices,
+      allowNewChoicesCreation: map["allowNewChoices"],
     );
   }
 }

lib/models/survey.dart

@@ -1,4 +1,5 @@
 import 'package:comunic/models/survey_choice.dart';
+import 'package:comunic/utils/account_utils.dart' as account;
 import 'package:meta/meta.dart';
 
 /// Survey information
@@ -13,6 +14,7 @@ class Survey {
   final String question;
   int userChoice;
   final Set<SurveyChoice> choices;
+  bool allowNewChoicesCreation;
 
   Survey({
     @required this.id,
@@ -22,6 +24,7 @@ class Survey {
     @required this.question,
     @required this.userChoice,
     @required this.choices,
+    @required this.allowNewChoicesCreation,
   })  : assert(id != null),
         assert(userID != null),
         assert(postID != null),
@@ -29,13 +32,17 @@ class Survey {
         assert(question != null),
         assert(userChoice != null),
         assert(choices != null),
-        assert(choices.length > 0);
+        assert(choices.length > 0),
+        assert(allowNewChoicesCreation != null);
 
   bool get hasResponded => this.userChoice != null && this.userChoice > 0;
 
   bool get hasResponses =>
       this.choices.where((f) => f.responses > 0).length > 0;
 
+  bool get canBlockNewChoicesCreation =>
+      allowNewChoicesCreation && account.userID() == this.userID;
+
   SurveyChoice get userResponse {
     if (!hasResponded) return null;
 

lib/ui/widgets/survey_widget.dart

@@ -1,6 +1,7 @@
 import 'package:comunic/helpers/survey_helper.dart';
 import 'package:comunic/models/survey.dart';
 import 'package:comunic/models/survey_choice.dart';
+import 'package:comunic/ui/widgets/safe_state.dart';
 import 'package:comunic/utils/intl_utils.dart';
 import 'package:comunic/utils/ui_utils.dart';
 import 'package:flutter/material.dart';
@@ -21,7 +22,7 @@ class SurveyWidget extends StatefulWidget {
   _SurveyWidgetState createState() => _SurveyWidgetState();
 }
 
-class _SurveyWidgetState extends State<SurveyWidget> {
+class _SurveyWidgetState extends SafeState<SurveyWidget> {
   final SurveyHelper _helper = SurveyHelper();
 
   Survey get survey => widget.survey;
@@ -42,6 +43,12 @@ class _SurveyWidgetState extends State<SurveyWidget> {
           style: TextStyle(fontWeight: FontWeight.bold),
         ),
         _buildUserResponse(),
+
+        // Offer to block the creation of new responses, if possible
+        survey.allowNewChoicesCreation
+            ? _buildBlockNewResponsesLink()
+            : Container(),
+
         survey.hasResponses ? _buildChart() : _buildNoResponseNotice(),
       ],
     );
@@ -109,6 +116,11 @@ class _SurveyWidgetState extends State<SurveyWidget> {
     );
   }
 
+  Widget _buildBlockNewResponsesLink() => InkWell(
+        onTap: _blockNewChoices,
+        child: Text(tr("Block the creation of new responses")),
+      );
+
   Widget _buildChart() {
     return PieChart(
       dataMap: _buildDataMap(),
@@ -133,4 +145,21 @@ class _SurveyWidgetState extends State<SurveyWidget> {
       survey.setUserResponse(choice);
     });
   }
+
+  /// Block the creation of new choices on this survey
+  void _blockNewChoices() async {
+    try {
+      if (!await showConfirmDialog(
+          context: context,
+          message: tr("Do you really want to block new responses ?"))) return;
+
+      await SurveyHelper.blockNewChoicesCreation(survey.postID);
+
+      setState(() => survey.allowNewChoicesCreation = false);
+    } catch (e, s) {
+      print("Could not block the creation of new choices! $e\n$s");
+      showSimpleSnack(
+          context, tr("Could not block the creation of new choices!"));
+    }
+  }
 }