feat(tutorial): add /tutorial/gift_receive — grant + receipt + idempotent re-claim

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

SVSim.UnitTests/Controllers/GiftControllerTests.cs

@@ -47,4 +47,87 @@ public class GiftControllerTests
         Assert.That(root.GetProperty("present_history_list").GetArrayLength(), Is.EqualTo(0));
         Assert.That(root.GetProperty("limit_over_present_list").GetArrayLength(), Is.EqualTo(0));
     }
+
+    [Test]
+    public async Task GiftReceive_grants_currency_and_items_then_history_is_populated()
+    {
+        using var factory = new SVSimTestFactory();
+        await factory.SeedGlobalsAsync();
+        long viewerId = await factory.SeedViewerAsync(tutorialState: 31);
+        using var client = factory.CreateAuthenticatedClient(viewerId);
+
+        var pre = await factory.GetViewerCurrencyAsync(viewerId);
+
+        var requestJson = $$"""
+        {"present_id_array":["71478626","71478627","71478628","71478629","71478630"],"state":1,{{BaseAuthBlock}}}
+        """;
+        var response = await client.PostAsync("/tutorial/gift_receive",
+            new StringContent(requestJson, Encoding.UTF8, "application/json"));
+
+        Assert.That(response.StatusCode, Is.EqualTo(HttpStatusCode.OK));
+        using var doc = JsonDocument.Parse(await response.Content.ReadAsStringAsync());
+        var root = doc.RootElement;
+
+        // Five received ids echoed.
+        var ids = root.GetProperty("received_ids").EnumerateArray()
+            .Select(e => e.GetString()).ToHashSet();
+        Assert.That(ids, Is.EquivalentTo(new[] { "71478626", "71478627", "71478628", "71478629", "71478630" }));
+
+        // present_list emptied, history populated.
+        Assert.That(root.GetProperty("present_list").GetArrayLength(), Is.EqualTo(0));
+        Assert.That(root.GetProperty("present_history_list").GetArrayLength(), Is.EqualTo(5));
+
+        // Currency credited: +400 crystals, +100 rupees.
+        var post = await factory.GetViewerCurrencyAsync(viewerId);
+        Assert.That(post.Crystals - pre.Crystals, Is.EqualTo(400UL));
+        Assert.That(post.Rupees - pre.Rupees, Is.EqualTo(100UL));
+    }
+
+    [Test]
+    public async Task GiftReceive_advances_tutorial_state_from_31_to_41()
+    {
+        using var factory = new SVSimTestFactory();
+        await factory.SeedGlobalsAsync();
+        long viewerId = await factory.SeedViewerAsync(tutorialState: 31);
+        using var client = factory.CreateAuthenticatedClient(viewerId);
+
+        var json = $$"""{"present_id_array":["71478626"],"state":1,{{BaseAuthBlock}}}""";
+        var response = await client.PostAsync("/tutorial/gift_receive",
+            new StringContent(json, Encoding.UTF8, "application/json"));
+
+        Assert.That(response.StatusCode, Is.EqualTo(HttpStatusCode.OK));
+        using var doc = JsonDocument.Parse(await response.Content.ReadAsStringAsync());
+        var root = doc.RootElement;
+
+        // Response carries the new step inline.
+        Assert.That(root.GetProperty("tutorial_step").GetInt32(), Is.EqualTo(41));
+        Assert.That(root.GetProperty("is_unreceived_present").GetBoolean(), Is.False);
+        Assert.That(root.GetProperty("reward_list").GetArrayLength(), Is.EqualTo(1));
+
+        // Side effect: viewer state advanced to 41.
+        Assert.That(await factory.GetViewerTutorialStateAsync(viewerId), Is.EqualTo(41));
+    }
+
+    [Test]
+    public async Task GiftReceive_second_call_with_same_ids_does_not_double_grant()
+    {
+        using var factory = new SVSimTestFactory();
+        await factory.SeedGlobalsAsync();
+        long viewerId = await factory.SeedViewerAsync(tutorialState: 31);
+        using var client = factory.CreateAuthenticatedClient(viewerId);
+
+        var preFirst = await factory.GetViewerCurrencyAsync(viewerId);
+        var json = $$"""{"present_id_array":["71478626","71478627"],"state":1,{{BaseAuthBlock}}}""";
+
+        await client.PostAsync("/tutorial/gift_receive", new StringContent(json, Encoding.UTF8, "application/json"));
+        var midPost = await factory.GetViewerCurrencyAsync(viewerId);
+        Assert.That(midPost.Crystals - preFirst.Crystals, Is.EqualTo(400UL));
+        Assert.That(midPost.Rupees - preFirst.Rupees, Is.EqualTo(100UL));
+
+        var second = await client.PostAsync("/tutorial/gift_receive", new StringContent(json, Encoding.UTF8, "application/json"));
+        Assert.That(second.StatusCode, Is.EqualTo(HttpStatusCode.OK));
+        var finalPost = await factory.GetViewerCurrencyAsync(viewerId);
+        Assert.That(finalPost.Crystals, Is.EqualTo(midPost.Crystals), "Second claim of same present_ids must not re-grant.");
+        Assert.That(finalPost.Rupees, Is.EqualTo(midPost.Rupees));
+    }
 }