Feature/hint agent

JustBigO(Fun).Tests/Controllers/HomeControllerTests.cs

@@ -25,7 +25,7 @@ public HomeControllerTests()
         }
 
         [Fact]
-        public async Task Index_ReturnsViewWithProblems()
+        public async Task Problems_ReturnsViewWithProblems()
         {
             // Arrange
             using var db = new ApplicationDbContext(_options);
@@ -44,7 +44,7 @@ public async Task Index_ReturnsViewWithProblems()
             };
 
             // Act
-            var result = await controller.Index(null, null);
+            var result = await controller.Problems(null, null);
 
             // Assert
             var viewResult = Assert.IsType<ViewResult>(result);
@@ -53,7 +53,7 @@ public async Task Index_ReturnsViewWithProblems()
         }
 
         [Fact]
-        public async Task Index_FiltersByDifficulty()
+        public async Task Problems_FiltersByDifficulty()
         {
             // Arrange
             using var db = new ApplicationDbContext(_options);
@@ -72,7 +72,7 @@ public async Task Index_FiltersByDifficulty()
             };
 
             // Act
-            var result = await controller.Index(null, "Easy");
+            var result = await controller.Problems(null, "Easy");
 
             // Assert
             var viewResult = Assert.IsType<ViewResult>(result);

JustBigO(Fun).Tests/Services/GeminiHintGeneratorTests.cs

@@ -1,6 +1,9 @@
 using Microsoft.Extensions.Configuration;
 using Moq;
+using Moq.Protected;
+using System.Net;
 using System.Net.Http;
+using System.Threading;
 using System.Threading.Tasks;
 using Xunit;
 using JustBigO_Fun_.Services;
@@ -25,5 +28,54 @@ public async Task GenerateHintAsync_ReturnsMissingKeyMessage_WhenApiKeyIsMissing
             // Assert
             Assert.Contains("GeminiApiKey is missing", result);
         }
+
+        [Fact]
+        public async Task GenerateHintAsync_StripsCodeAndLimitsToTwoSentences()
+        {
+            // Arrange
+            var apiResponse = """
+                {
+                  "candidates": [
+                    {
+                      "content": {
+                        "parts": [
+                          {
+                            "text": "Try tracking the needed counts with a hash map. ```python\nfor x in nums:\n    pass\n``` Then move two pointers only when the window is valid. Extra explanation that should be removed."
+                          }
+                        ]
+                      }
+                    }
+                  ]
+                }
+                """;
+
+            var mockHandler = new Mock<HttpMessageHandler>(MockBehavior.Strict);
+            mockHandler
+                .Protected()
+                .Setup<Task<HttpResponseMessage>>(
+                    "SendAsync",
+                    ItExpr.IsAny<HttpRequestMessage>(),
+                    ItExpr.IsAny<CancellationToken>())
+                .ReturnsAsync(new HttpResponseMessage
+                {
+                    StatusCode = HttpStatusCode.OK,
+                    Content = new StringContent(apiResponse)
+                });
+
+            var httpClient = new HttpClient(mockHandler.Object);
+            var mockConfig = new Mock<IConfiguration>();
+            mockConfig.Setup(c => c["GeminiApiKey"]).Returns("fake-key");
+            var service = new GeminiHintGenerator(httpClient, mockConfig.Object);
+
+            // Act
+            var result = await service.GenerateHintAsync("Two Sum", "desc", "code", "python");
+
+            // Assert
+            Assert.DoesNotContain("```", result);
+            Assert.DoesNotContain("pass", result);
+            Assert.DoesNotContain("Extra explanation", result);
+            Assert.Equal("Try tracking the needed counts with a hash map. Then move two pointers only when the window is valid.", result);
+        }
     }
 }
+

JustBigO(Fun)/Controllers/HomeController.cs

@@ -24,9 +24,18 @@ public HomeController(ILogger<HomeController> logger, ApplicationDbContext db, I
             _markdown = markdown;
         }
 
-        // --- INCEPUT MODIFICARE ---
-        // Am adăugat parametrul `difficultyFilter` și am implementat logica de filtrare `.Where(...)`
-        public async Task<IActionResult> Index(string sortOrder, string difficultyFilter)
+        public IActionResult Index()
+        {
+            return View();
+        }
+
+        public async Task<IActionResult> Problems(string sortOrder, string difficultyFilter)
+        {
+            var problemItems = await BuildProblemListAsync(sortOrder, difficultyFilter);
+            return View(problemItems);
+        }
+
+        private async Task<List<ProblemListItem>> BuildProblemListAsync(string sortOrder, string difficultyFilter)
         {
             // Salvăm parametrii în ViewData pentru a menține starea în butoanele de pe UI
             ViewData["DifficultySortParm"] = sortOrder == "diff_asc" ? "diff_desc" : "diff_asc";
@@ -76,7 +85,7 @@ public async Task<IActionResult> Index(string sortOrder, string difficultyFilter
                 _ => problemItems.OrderBy(p => problems.First(x => x.Id == p.Id).OrderIndex)
             };
 
-            return View(problemItems.ToList());
+            return problemItems.ToList();
         }
 
         private static int GetDifficultyWeight(string difficulty)
@@ -89,8 +98,6 @@ private static int GetDifficultyWeight(string difficulty)
                 _ => 0
             };
         }
-        // --- SFARSIT MODIFICARE ---
-
         public async Task<IActionResult> Solve(int? id)
         {
             Problem? problem;

JustBigO(Fun)/JustBigO(Fun).csproj

@@ -25,6 +25,7 @@
 
   <ItemGroup>
     <PackageReference Include="HtmlSanitizer" Version="9.0.892" />
+    <PackageReference Include="HtmlSanitizer.NetCore3.1" Version="1.0.0" />
     <PackageReference Include="Markdig" Version="1.2.0" />
     <PackageReference Include="Microsoft.AspNetCore.Diagnostics.EntityFrameworkCore" Version="9.0.11" />
     <PackageReference Include="Microsoft.AspNetCore.Identity.EntityFrameworkCore" Version="9.0.11" />

JustBigO(Fun)/Services/GeminiHintGenerator.cs

@@ -1,6 +1,7 @@
 using Microsoft.Extensions.Configuration;
 using System.Text;
 using System.Text.Json;
+using System.Text.RegularExpressions;
 
 namespace JustBigO_Fun_.Services;
 
@@ -28,9 +29,13 @@ public async Task<string> GenerateHintAsync(string problemTitle, string problemD
 
         var prompt = $"""
             You are a programming mentor for an algorithms platform.
-            Return exactly one concise hint in English, max 2 short paragraphs.
-            Do NOT provide full solution code.
-            Keep the hint actionable and contextual.
+            Return exactly ONE subtle hint in English, maximum 1-2 short sentences.
+            STRICT RULES:
+            - Do NOT provide code, pseudocode, or step-by-step algorithm.
+            - Do NOT reveal the full strategy or optimal full solution.
+            - Prefer a nudge: mention one data structure, one invariant, or one leading question.
+            - If the user is already close, only point to the next tiny step.
+            - Keep it spoiler-free and concise.
             Note: The platform uses a Standard IO model (Competitive Programming style). The user must READ from stdin and PRINT to stdout.
 
             Problem title: {problemTitle}
@@ -86,11 +91,46 @@ Problem statement (HTML possible):
                 return "No valid hint was returned. Please try again.";
             }
 
-            return hintText.Trim();
+            return SanitizeHint(hintText);
         }
         catch
         {
             return "An error occurred while generating the hint. Please try again.";
         }
     }
+
+    private static string SanitizeHint(string hintText)
+    {
+        if (string.IsNullOrWhiteSpace(hintText))
+            return "Try focusing on one small invariant that must stay true at each step.";
+
+        // Remove fenced code blocks or inline code to avoid accidental full solutions.
+        var sanitized = Regex.Replace(hintText, "```[\\s\\S]*?```", string.Empty);
+        sanitized = Regex.Replace(sanitized, "`[^`]*`", string.Empty).Trim();
+
+        // Keep only first 1-2 sentences to force a subtle nudge.
+        var sentenceMatches = Regex.Matches(sanitized, @"[^.!?]+[.!?]?");
+        if (sentenceMatches.Count > 0)
+        {
+            var sentenceCount = Math.Min(2, sentenceMatches.Count);
+            var parts = new List<string>(sentenceCount);
+            for (var i = 0; i < sentenceCount; i++)
+            {
+                var s = sentenceMatches[i].Value.Trim();
+                if (!string.IsNullOrWhiteSpace(s))
+                    parts.Add(s);
+            }
+
+            sanitized = string.Join(" ", parts).Trim();
+        }
+
+        if (string.IsNullOrWhiteSpace(sanitized))
+            return "Try focusing on one small invariant that must stay true at each step.";
+
+        // Gentle length cap to reduce chance of spoiler-ish detail.
+        if (sanitized.Length > 260)
+            sanitized = sanitized[..260].TrimEnd() + "...";
+
+        return sanitized;
+    }
 }

JustBigO(Fun)/Services/HtmlSanitizerService.cs

@@ -1,3 +1,8 @@
+// To fix CS0246, you must add a reference to the Ganss.Xss NuGet package.
+// In Visual Studio, right-click your project > Manage NuGet Packages > Browse > search for "Ganss.Xss" > Install.
+// Or, run the following command in the Package Manager Console:
+// Install-Package Ganss.Xss
+
 using Ganss.Xss;
 
 namespace JustBigO_Fun_.Services;

JustBigO(Fun)/Views/Home/Index.cshtml

@@ -1,7 +1,5 @@
-@model IEnumerable<JustBigO_Fun_.Models.ProblemListItem>
 @{
-    ViewData["Title"] = "Dashboard";
-    string GetDifficultyClass(string d) => d?.ToLowerInvariant() switch { "medium" => "medium", "hard" => "hard", _ => "easy" };
+    ViewData["Title"] = "Home";
 }
 
 <section class="jbo-hero">
@@ -25,7 +23,7 @@
             and get instant feedback from smart agents on complexity, transpilations, and hints.
         </p>
         <div class="jbo-hero-cta">
-            <a asp-area="" asp-controller="Home" asp-action="Index" asp-fragment="problemset" class="btn jbo-btn-primary">
+            <a asp-area="" asp-controller="Home" asp-action="Problems" class="btn jbo-btn-primary">
                 Start solving problems
             </a>
             <a asp-area="Identity" asp-page="/Account/Login" class="btn jbo-btn-ghost">
@@ -104,96 +102,8 @@
     </div>
 </section>
 
-<div class="jbo-grid-row" id="problemset">
+<div class="jbo-grid-row" id="agents">
     <section class="jbo-section-card">
-        <header class="jbo-section-header">
-            <div>
-                <h2 class="jbo-section-title">
-                    Problemset &amp;
-                    progress
-                </h2>
-                <p class="jbo-section-subtitle">
-                    Browse problems by difficulty and track the status of your submissions.
-                </p>
-            </div>
-            <div class="jbo-chip-row">
-                <a asp-action="Index"
-                       asp-route-sortOrder="@Context.Request.Query["sortOrder"]"
-                       asp-route-difficultyFilter=""
-                       asp-fragment="problemset"
-                       class="jbo-chip"
-                       style="text-decoration: none; color: inherit; @(string.IsNullOrEmpty(ViewData["CurrentFilter"]?.ToString()) ? "outline: 2px solid currentColor; outline-offset: 2px;" : "opacity: 0.6;")">
-                    All
-                </a>
-                <a asp-action="Index"
-                       asp-route-sortOrder="@Context.Request.Query["sortOrder"]"
-                       asp-route-difficultyFilter="Easy"
-                       asp-fragment="problemset"
-                       class="jbo-chip jbo-chip--easy"
-                       style="text-decoration: none; @(ViewData["CurrentFilter"]?.ToString() == "Easy" ? "outline: 2px solid currentColor; outline-offset: 2px;" : "opacity: 0.6;")">
-                    Easy
-                </a>
-                <a asp-action="Index"
-                       asp-route-sortOrder="@Context.Request.Query["sortOrder"]"
-                       asp-route-difficultyFilter="Medium"
-                       asp-fragment="problemset"
-                       class="jbo-chip jbo-chip--medium"
-                       style="text-decoration: none; @(ViewData["CurrentFilter"]?.ToString() == "Medium" ? "outline: 2px solid currentColor; outline-offset: 2px;" : "opacity: 0.6;")">
-                    Medium
-                </a>
-                <a asp-action="Index"
-                       asp-route-sortOrder="@Context.Request.Query["sortOrder"]"
-                       asp-route-difficultyFilter="Hard"
-                       asp-fragment="problemset"
-                       class="jbo-chip jbo-chip--hard"
-                       style="text-decoration: none; @(ViewData["CurrentFilter"]?.ToString() == "Hard" ? "outline: 2px solid currentColor; outline-offset: 2px;" : "opacity: 0.6;")">
-                    Hard
-                </a>
-            </div>
-        </header>
-
-        <table class="jbo-mini-table">
-            <thead>
-                <tr>
-                    <th>Problem</th>
-                    <th>Tags</th>
-                    <th>
-                        <a asp-action="Index"
-                               asp-route-sortOrder="@ViewData["DifficultySortParm"]"
-                               asp-route-difficultyFilter="@ViewData["CurrentFilter"]"
-                               asp-fragment="problemset"
-                               style="color: inherit; text-decoration: underline; cursor: pointer;">
-                            Difficulty ↕
-                        </a>
-                    </th>
-                    <th>Best status</th>
-                </tr>
-            </thead>
-            <tbody>
-                @foreach (var p in Model ?? Enumerable.Empty<JustBigO_Fun_.Models.ProblemListItem>())
-                {
-
-                    <tr>
-                        <td><a asp-action="Solve" asp-route-id="@p.Id" class="jbo-problem-link">@p.Title</a></td>
-                        <td>@p.Tags</td>
-                        <td><span class="jbo-chip jbo-chip--@GetDifficultyClass(p.Difficulty)">@p.Difficulty</span></td>
-
-                        <td>
-                            @{
-                                string statusClass = "";
-                                if (p.BestStatus == "Accepted") statusClass = "jbo-status-chip--accepted";
-                                else if (p.BestStatus == "TimeLimitExceeded") statusClass = "jbo-status-chip--tle";
-                                else if (p.BestStatus != "—") statusClass = "jbo-status-chip--wa";
-                            }
-                            <span class="jbo-status-chip @statusClass">@p.BestStatus</span>
-                        </td>
-                    </tr>
-                }
-            </tbody>
-        </table>
-    </section>
-
-    <section class="jbo-section-card" id="agents">
         <header class="jbo-section-header">
 
             <div>