Add data-driven dynamic question mode

2026-07-23 12:33:23 -05:00
parent 50f07a77a5
commit fcbc288a49
22 changed files with 1247 additions and 21 deletions
@@ -0,0 +1,107 @@
+using QuestionsApi.Models;
+using System.Security.Cryptography;
+
+namespace QuestionsApi.Services;
+
+public sealed class DynamicQuestionService
+{
+    private readonly DynamicQuestionStore _store;
+    private readonly DynamicQuestionGenerator _generator;
+    private readonly DynamicQuestionTokenService _tokens;
+
+    public DynamicQuestionService(
+        DynamicQuestionStore store,
+        DynamicQuestionGenerator generator,
+        DynamicQuestionTokenService tokens)
+    {
+        _store = store;
+        _generator = generator;
+        _tokens = tokens;
+    }
+
+    public Task<DynamicQuestionStatusResponse> StatusAsync(string userId) => _store.StatusAsync(userId);
+
+    public async Task<DynamicQuestionEnvelope> NextAsync(string userId, string runToken)
+    {
+        var blueprints = await _store.PublishedAsync();
+        if (blueprints.Count == 0)
+            throw new InvalidOperationException("No dynamic question blueprints are published.");
+
+        var run = string.IsNullOrWhiteSpace(runToken)
+            ? NewRun(userId)
+            : _tokens.ReadRun(runToken, userId);
+        var byObjective = blueprints.GroupBy(value => value.ObjectiveId).ToList();
+        var objectiveIds = byObjective.Select(value => value.Key).ToHashSet(StringComparer.Ordinal);
+        run.SeenObjectiveIds = run.SeenObjectiveIds.Where(objectiveIds.Contains).Distinct(StringComparer.Ordinal).ToList();
+
+        var unseen = byObjective.Where(group => !run.SeenObjectiveIds.Contains(group.Key, StringComparer.Ordinal)).ToList();
+        if (unseen.Count == 0)
+        {
+            run.Cycle++;
+            run.SeenObjectiveIds.Clear();
+            unseen = byObjective;
+        }
+
+        var mastery = await _store.MasteryAsync(userId);
+        var candidates = unseen
+            .Where(group => group.Key != run.PreviousObjectiveId || unseen.Count == 1)
+            .OrderBy(group => mastery.TryGetValue(group.Key, out var value) ? value.Elo : 1000)
+            .ThenBy(_ => RandomNumberGenerator.GetInt32(int.MaxValue))
+            .ToList();
+        var weakestBand = candidates.Take(Math.Min(4, candidates.Count)).ToList();
+        var selectedObjective = weakestBand[RandomNumberGenerator.GetInt32(weakestBand.Count)];
+        var blueprint = selectedObjective
+            .OrderByDescending(value => value.Version)
+            .First();
+
+        var claims = new DynamicGenerationClaims
+        {
+            UserId = userId,
+            BlueprintExternalId = blueprint.ExternalId,
+            BlueprintVersion = blueprint.Version,
+            ObjectiveId = blueprint.ObjectiveId,
+            Seed = Convert.ToHexString(RandomNumberGenerator.GetBytes(16)).ToLowerInvariant(),
+            Nonce = Guid.NewGuid().ToString("N"),
+            GeneratorVersion = DynamicQuestionGenerator.CurrentVersion,
+            ExpiresUtc = DateTime.UtcNow.AddDays(7)
+        };
+        var generated = _generator.Generate(blueprint, claims.Seed, claims.Nonce);
+        run.SeenObjectiveIds.Add(blueprint.ObjectiveId);
+        run.PreviousObjectiveId = blueprint.ObjectiveId;
+        run.ExpiresUtc = DateTime.UtcNow.AddDays(7);
+        return new DynamicQuestionEnvelope
+        {
+            Question = QuestionResponse.FromModel(generated.Question),
+            ObjectiveId = blueprint.ObjectiveId,
+            ObjectiveTitle = blueprint.Title,
+            GenerationToken = _tokens.SignGeneration(claims),
+            RunToken = _tokens.SignRun(run),
+            CycleSeen = run.SeenObjectiveIds.Count,
+            TotalObjectives = byObjective.Count
+        };
+    }
+
+    public async Task<DynamicAttemptResponse> AttemptAsync(string userId, DynamicAttemptRequest request)
+    {
+        var (claims, generated) = await RegenerateAsync(userId, request.GenerationToken);
+        return await _store.RecordAsync(claims, generated, request);
+    }
+
+    public async Task<(DynamicGenerationClaims Claims, DynamicGeneratedQuestion Generated)> RegenerateAsync(
+        string userId,
+        string generationToken)
+    {
+        var claims = _tokens.ReadGeneration(generationToken, userId);
+        if (claims.GeneratorVersion != DynamicQuestionGenerator.CurrentVersion)
+            throw new InvalidOperationException("This generated question version is no longer supported.");
+        var blueprint = await _store.GetAsync(claims.BlueprintExternalId, claims.BlueprintVersion)
+            ?? throw new KeyNotFoundException("The question blueprint is no longer available.");
+        return (claims, _generator.Generate(blueprint, claims.Seed, claims.Nonce));
+    }
+
+    private static DynamicRunClaims NewRun(string userId) => new()
+    {
+        UserId = userId,
+        ExpiresUtc = DateTime.UtcNow.AddDays(7)
+    };
+}