Add wrong answer follow-up prompts

api/QuestionsApi/Controllers/QuestionsController.cs

@@ -220,6 +220,9 @@ public class QuestionsController : ControllerBase
             return "explanation required";
         if (req.ChoiceSelectionPercentages.Any(entry => entry.Value is < 0 or > 100))
             return "choiceSelectionPercentages values must be between 0 and 100";
+        var followupValidation = ValidateWrongAnswerFollowups(req);
+        if (followupValidation is not null)
+            return followupValidation;
         if (string.IsNullOrWhiteSpace(req.System))
             return "system required";
         if (string.IsNullOrWhiteSpace(req.Discipline))
@@ -230,6 +233,28 @@ public class QuestionsController : ControllerBase
         return null;
     }
 
+    private static string? ValidateWrongAnswerFollowups(UpsertQuestionRequest req)
+    {
+        var choiceIds = req.Choices.Select(c => c.Id).Where(id => !string.IsNullOrWhiteSpace(id)).ToHashSet();
+        foreach (var entry in req.WrongAnswerFollowups)
+        {
+            if (!choiceIds.Contains(entry.Key))
+                return "wrongAnswerFollowups keys must match a choice id";
+            if (entry.Key == req.CorrectChoiceId)
+                return "wrongAnswerFollowups should only target incorrect choices";
+            if (string.IsNullOrWhiteSpace(entry.Value.Prompt))
+                return "wrongAnswerFollowups prompt required";
+            if (string.IsNullOrWhiteSpace(entry.Value.TeachingPoint))
+                return "wrongAnswerFollowups teachingPoint required";
+            if (entry.Value.Choices.Count == 0)
+                return "wrongAnswerFollowups choices required";
+            if (!entry.Value.Choices.Any(c => c.Id == entry.Value.CorrectChoiceId))
+                return "wrongAnswerFollowups correctChoiceId must match a follow-up choice id";
+        }
+
+        return null;
+    }
+
     private string CurrentUserId() =>
         User.FindFirstValue(ClaimTypes.NameIdentifier)
         ?? User.FindFirstValue(ClaimTypes.Name)

api/QuestionsApi/Models/Question.cs

@@ -16,6 +16,7 @@ public class Question
     public string CorrectChoiceId { get; set; } = "";
     public string Explanation { get; set; } = "";
     public Dictionary<string, string> ChoiceExplanations { get; set; } = [];
+    public Dictionary<string, WrongAnswerFollowup> WrongAnswerFollowups { get; set; } = [];
     public Dictionary<string, int> ChoiceSelectionPercentages { get; set; } = [];
     public string Discipline { get; set; } = "";
     public string System { get; set; } = "";
@@ -42,3 +43,11 @@ public class QuestionLab
     public string Unit { get; set; } = "";
     public string Reference { get; set; } = "";
 }
+
+public class WrongAnswerFollowup
+{
+    public string Prompt { get; set; } = "";
+    public List<QuestionChoice> Choices { get; set; } = [];
+    public string CorrectChoiceId { get; set; } = "";
+    public string TeachingPoint { get; set; } = "";
+}

api/QuestionsApi/Models/QuestionRequests.cs

@@ -19,6 +19,7 @@ public class UpsertQuestionRequest
     public string CorrectChoiceId { get; set; } = "";
     public string Explanation { get; set; } = "";
     public Dictionary<string, string> ChoiceExplanations { get; set; } = [];
+    public Dictionary<string, WrongAnswerFollowup> WrongAnswerFollowups { get; set; } = [];
     public Dictionary<string, int> ChoiceSelectionPercentages { get; set; } = [];
     public string Discipline { get; set; } = "";
     public string System { get; set; } = "";

api/QuestionsApi/Models/QuestionResponse.cs

@@ -10,6 +10,7 @@ public class QuestionResponse
     public string CorrectChoiceId { get; set; } = "";
     public string Explanation { get; set; } = "";
     public Dictionary<string, string> ChoiceExplanations { get; set; } = [];
+    public Dictionary<string, WrongAnswerFollowup> WrongAnswerFollowups { get; set; } = [];
     public Dictionary<string, int> ChoiceSelectionPercentages { get; set; } = [];
     public string Discipline { get; set; } = "";
     public string System { get; set; } = "";
@@ -33,6 +34,7 @@ public class QuestionResponse
         CorrectChoiceId = question.CorrectChoiceId,
         Explanation = question.Explanation,
         ChoiceExplanations = question.ChoiceExplanations,
+        WrongAnswerFollowups = question.WrongAnswerFollowups,
         ChoiceSelectionPercentages = BuildChoiceSelectionPercentages(question, liveChoiceSelectionPercentages),
         Discipline = question.Discipline,
         System = question.System,

api/QuestionsApi/Services/QuestionStore.cs

@@ -136,6 +136,7 @@ public class QuestionStore
         CorrectChoiceId = req.CorrectChoiceId.Trim(),
         Explanation = req.Explanation.Trim(),
         ChoiceExplanations = req.ChoiceExplanations,
+        WrongAnswerFollowups = req.WrongAnswerFollowups,
         ChoiceSelectionPercentages = req.ChoiceSelectionPercentages,
         Discipline = req.Discipline.Trim(),
         System = req.System.Trim(),