feat(ui): implement client-side [PAYWALL_TRIGGER] token parser, styling and tests

src/NexusReader.UI.Shared/Components/Molecules/AiResponseRenderer.razor

@@ -8,7 +8,7 @@
 @inject NavigationManager NavigationManager
 
 <div class="message-row @(Message.Sender == "User" ? "user-row" : "ai-row")">
-    <div class="message-avatar">
+    <div class="message-avatar" aria-hidden="true">
         @if (Message.Sender == "User")
         {
             <i class="bi bi-person-fill"></i>
@@ -32,10 +32,10 @@
             }
             else
             {
-                @if (Message.IsPaywalled && !_isUnlocked)
+                @if (_hasPaywall)
                 {
-                    <div class="clear-teaser">
+                    <div class="paywall-teaser" aria-hidden="true">
-                        @foreach (var segment in ParseSegments(Message.ClearText))
+                        @foreach (var segment in ParseSegments(_displayTeaserText))
                         {
                             @if (segment.IsCitation)
                             {
@@ -48,47 +48,31 @@
                         }
                     </div>
                     
-                    <div class="teaser-blur">
+                    <div class="upsell-card" role="alert" aria-live="polite">
-                        @foreach (var segment in ParseSegments(Message.BlurredTeaserText))
-                        {
-                            @if (segment.IsCitation)
-                            {
-                                <NexusCitationMarker SourceId="@segment.CitationId" Citations="@Message.Citations" />
-                            }
-                            else
-                            {
-                                @RenderMarkdown(segment.Text)
-                            }
-                        }
-                    </div>
-                    
-                    <div class="upsell-card">
                         <div class="upsell-header">
-                            <span class="upsell-icon">🔒</span>
+                            <span class="upsell-icon" aria-hidden="true">🔒</span>
-                            <h4>Zablokowano pełną odpowiedź (Paywall)</h4>
+                            <h4>Dostęp Premium Zablokowany</h4>
                         </div>
                         
                         <p class="upsell-text">
-                            Powyższy fragment wiedzy pochodzi z materiału: 
+                            Twoje zasoby odpowiadają na to pytanie w <strong>@_localScore%</strong>. W materiale <strong>'@_lockedBookTitle'</strong> znaleźliśmy odpowiedź dopasowaną w <strong>@_globalScore%</strong>.
-                            <strong>'@(string.IsNullOrEmpty(Message.SourceBookTitle) ? "Architektura .NET 10 i Ekosystem Blazor" : Message.SourceBookTitle)'</strong>. 
-                            Ta pozycja nie znajduje się w Twojej bibliotece (/my-books). Aby uzyskać dostęp do pełnych instrukcji technicznych oraz gotowych kodów C#, odblokuj ten materiał w katalogu.
                         </p>
                         
                         <div class="upsell-actions">
                             @if (_isSimulatingPayment)
                             {
-                                <button class="btn-upsell btn-primary loading" disabled>
+                                <button class="btn-upsell btn-primary loading" disabled aria-busy="true">
-                                    <div class="payment-spinner"></div>
+                                    <div class="payment-spinner" aria-hidden="true"></div>
                                     PRZETWARZANIE PŁATNOŚCI...
                                 </button>
                             }
                             else
                             {
                                 <button class="btn-upsell btn-primary" @onclick="HandlePurchase">
-                                    KUP PUBLIKACJĘ (29 PLN)
+                                    ODBLOKUJ PEŁNĄ TREŚĆ (29 PLN)
                                 </button>
                             }
-                            <a href="/catalog" target="_blank" class="btn-upsell btn-secondary">
+                            <a href="/catalog?bookId=@_lockedBookId" class="btn-upsell btn-secondary">
                                 Zobacz szczegóły w Katalogu
                             </a>
                         </div>
@@ -97,7 +81,7 @@
                 else
                 {
                     <div class="full-response">
-                        @foreach (var segment in Message.Segments)
+                        @foreach (var segment in ParseSegments(GetCleanText()))
                         {
                             @if (segment.IsCitation)
                             {
@@ -112,8 +96,8 @@
                     
                     @if (_showSuccessBanner)
                     {
-                        <div class="success-unlock-banner">
+                        <div class="success-unlock-banner" role="status">
-                            <span class="success-icon">✓</span>
+                            <span class="success-icon" aria-hidden="true">✓</span>
                             <span>Odblokowano pełną odpowiedź! Książka została dodana do Twojej biblioteki.</span>
                         </div>
                     }
@@ -126,17 +110,61 @@
 @code {
     [Parameter] public ChatMessage Message { get; set; } = default!;
     [Parameter] public List<LastReadBookDto>? OwnedBooks { get; set; }
+    [Parameter] public EventCallback<Guid> OnUnlockRequested { get; set; }
 
-    private string GetBubbleClass()
+    private bool _hasPaywall;
-    {
+    private string _displayTeaserText = string.Empty;
-        if (Message.Sender == "User") return "user-bubble";
+    private Guid _lockedBookId;
-        return Message.IsPaywalled && !_isUnlocked ? "ai-bubble paywalled-bubble" : "ai-bubble";
+    private string _lockedBookTitle = string.Empty;
-    }
+    private int _localScore;
+    private int _globalScore;
 
     private bool _isUnlocked = false;
     private bool _isSimulatingPayment = false;
     private bool _showSuccessBanner = false;
 
+    protected override void OnParametersSet()
+    {
+        base.OnParametersSet();
+        
+        if (Message != null && Message.Sender != "User" && !_isUnlocked)
+        {
+            _hasPaywall = PaywallParser.TryParsePaywallTrigger(Message.Text, out _displayTeaserText, out _lockedBookId, out _lockedBookTitle, out _localScore, out _globalScore);
+            
+            // Additional check: if user already owns the book, don't show the paywall
+            if (_hasPaywall && OwnedBooks != null)
+            {
+                var isOwned = OwnedBooks.Any(b => 
+                    b.Id == _lockedBookId || 
+                    (!string.IsNullOrEmpty(b.Title) && b.Title.Equals(_lockedBookTitle, StringComparison.OrdinalIgnoreCase)));
+                if (isOwned)
+                {
+                    _hasPaywall = false;
+                }
+            }
+        }
+        else
+        {
+            _hasPaywall = false;
+        }
+    }
+
+    private string GetCleanText()
+    {
+        if (Message == null) return string.Empty;
+        if (PaywallParser.TryParsePaywallTrigger(Message.Text, out var cleanText, out _, out _, out _, out _))
+        {
+            return cleanText;
+        }
+        return Message.Text;
+    }
+
+    private string GetBubbleClass()
+    {
+        if (Message.Sender == "User") return "user-bubble";
+        return _hasPaywall ? "ai-bubble paywalled-bubble" : "ai-bubble";
+    }
+
     private async Task HandlePurchase()
     {
         if (_isSimulatingPayment) return;
@@ -149,21 +177,26 @@
 
         try
         {
-            var bookTitle = string.IsNullOrEmpty(Message.SourceBookTitle) 
+            var bookTitle = string.IsNullOrEmpty(_lockedBookTitle) 
                 ? "Architektura .NET 10 i Ekosystem Blazor" 
-                : Message.SourceBookTitle;
+                : _lockedBookTitle;
 
             // Call POST endpoint to persist the purchase
             var response = await Http.PostAsJsonAsync("api/library/purchase", new { Title = bookTitle });
             if (response.IsSuccessStatusCode)
             {
                 _isUnlocked = true;
-                Message.IsPaywalled = false;
+                _hasPaywall = false;
                 _showSuccessBanner = true;
                 
                 // Fetch updated library list and update state manager
                 var updatedBooks = await Http.GetFromJsonAsync<List<LastReadBookDto>>("api/library/books");
                 LibraryStateService.OwnedBooks = updatedBooks;
+
+                if (OnUnlockRequested.HasDelegate)
+                {
+                    await OnUnlockRequested.InvokeAsync(_lockedBookId);
+                }
             }
             else
             {

src/NexusReader.UI.Shared/Components/Molecules/AiResponseRenderer.razor.css

@@ -106,27 +106,25 @@
 }
 
 /* Paywall Blur Styles */
-.teaser-blur {
+.paywall-teaser {
     position: relative;
-    filter: blur(5px);
+    margin-bottom: 1.5rem;
+    -webkit-mask-image: linear-gradient(to bottom, black 30%, transparent 100%);
+    mask-image: linear-gradient(to bottom, black 30%, transparent 100%);
+    filter: blur(2px);
     pointer-events: none;
     -webkit-user-select: none;
     user-select: none;
-    opacity: 0.35;
-    margin-top: 1rem;
-    margin-bottom: 1.5rem;
-    -webkit-mask-image: linear-gradient(to bottom, rgba(0,0,0,1) 40%, rgba(0,0,0,0) 100%);
-    mask-image: linear-gradient(to bottom, rgba(0,0,0,1) 40%, rgba(0,0,0,0) 100%);
 }
 
 /* Upsell Card */
 .upsell-card {
     background: #1a1a1e;
     border-radius: 12px;
-    border: 1px solid rgba(16, 185, 129, 0.2);
+    border: 1px solid rgba(16, 185, 129, 0.25);
     padding: 1.5rem;
     margin-top: 1rem;
-    box-shadow: 0 8px 30px rgba(0, 0, 0, 0.3);
+    box-shadow: 0 8px 32px rgba(16, 185, 129, 0.08), 0 4px 12px rgba(0, 0, 0, 0.4);
     animation: card-slide-in 0.4s cubic-bezier(0.16, 1, 0.3, 1) forwards;
 }
 

src/NexusReader.UI.Shared/Services/PaywallParser.cs

@@ -0,0 +1,72 @@
+using System;
+
+namespace NexusReader.UI.Shared.Services;
+
+/// <summary>
+/// AOT-safe string parsing utility to isolate paywall teaser details without regex overhead.
+/// </summary>
+public static class PaywallParser
+{
+    public static bool TryParsePaywallTrigger(
+        string rawText,
+        out string displayTeaserText,
+        out Guid lockedBookId,
+        out string lockedBookTitle,
+        out int localScore,
+        out int globalScore)
+    {
+        displayTeaserText = rawText;
+        lockedBookId = Guid.Empty;
+        lockedBookTitle = string.Empty;
+        localScore = 0;
+        globalScore = 0;
+
+        if (string.IsNullOrEmpty(rawText))
+            return false;
+
+        ReadOnlySpan<char> span = rawText.AsSpan();
+        int tokenStartIndex = span.IndexOf("[PAYWALL_TRIGGER:");
+        if (tokenStartIndex == -1)
+            return false;
+
+        displayTeaserText = span.Slice(0, tokenStartIndex).Trim().ToString();
+
+        ReadOnlySpan<char> tokenContent = span.Slice(tokenStartIndex + "[PAYWALL_TRIGGER:".Length);
+        int tokenEndIndex = tokenContent.IndexOf(']');
+        if (tokenEndIndex == -1)
+            return false;
+
+        tokenContent = tokenContent.Slice(0, tokenEndIndex);
+
+        int firstColonIdx = tokenContent.IndexOf(':');
+        if (firstColonIdx == -1)
+            return false;
+
+        ReadOnlySpan<char> guidSpan = tokenContent.Slice(0, firstColonIdx);
+        if (!Guid.TryParse(guidSpan, out lockedBookId))
+            return false;
+
+        ReadOnlySpan<char> remaining = tokenContent.Slice(firstColonIdx + 1);
+
+        int lastColonIdx = remaining.LastIndexOf(':');
+        if (lastColonIdx == -1)
+            return false;
+
+        ReadOnlySpan<char> globalScoreSpan = remaining.Slice(lastColonIdx + 1);
+        if (!int.TryParse(globalScoreSpan, out globalScore))
+            return false;
+
+        remaining = remaining.Slice(0, lastColonIdx);
+
+        int secondLastColonIdx = remaining.LastIndexOf(':');
+        if (secondLastColonIdx == -1)
+            return false;
+
+        ReadOnlySpan<char> localScoreSpan = remaining.Slice(secondLastColonIdx + 1);
+        if (!int.TryParse(localScoreSpan, out localScore))
+            return false;
+
+        lockedBookTitle = remaining.Slice(0, secondLastColonIdx).ToString();
+        return true;
+    }
+}

tests/NexusReader.Application.Tests/Services/PaywallParserTests.cs

@@ -0,0 +1,81 @@
+using System;
+using FluentAssertions;
+using NexusReader.UI.Shared.Services;
+using Xunit;
+
+namespace NexusReader.Application.Tests.Services;
+
+public class PaywallParserTests
+{
+    [Fact]
+    public void TryParsePaywallTrigger_WithValidSimpleToken_ReturnsTrueAndCorrectValues()
+    {
+        // Arrange
+        var guid = Guid.NewGuid();
+        var rawText = $"Teaser sentence. [PAYWALL_TRIGGER:{guid}:Clean Book Title:45:82]";
+
+        // Act
+        var result = PaywallParser.TryParsePaywallTrigger(
+            rawText,
+            out var teaser,
+            out var bookId,
+            out var title,
+            out var localScore,
+            out var globalScore);
+
+        // Assert
+        result.Should().BeTrue();
+        teaser.Should().Be("Teaser sentence.");
+        bookId.Should().Be(guid);
+        title.Should().Be("Clean Book Title");
+        localScore.Should().Be(45);
+        globalScore.Should().Be(82);
+    }
+
+    [Fact]
+    public void TryParsePaywallTrigger_WithColonsInBookTitle_ReturnsTrueAndCorrectValues()
+    {
+        // Arrange
+        var guid = Guid.NewGuid();
+        var rawText = $"Teaser text. [PAYWALL_TRIGGER:{guid}:Architektura: .NET 10 i C# 14:15:99]";
+
+        // Act
+        var result = PaywallParser.TryParsePaywallTrigger(
+            rawText,
+            out var teaser,
+            out var bookId,
+            out var title,
+            out var localScore,
+            out var globalScore);
+
+        // Assert
+        result.Should().BeTrue();
+        teaser.Should().Be("Teaser text.");
+        bookId.Should().Be(guid);
+        title.Should().Be("Architektura: .NET 10 i C# 14");
+        localScore.Should().Be(15);
+        globalScore.Should().Be(99);
+    }
+
+    [Theory]
+    [InlineData("")]
+    [InlineData("Just plain text with no trigger token.")]
+    [InlineData("Plain text [PAYWALL_TRIGGER:invalid-guid:Title:50:80]")]
+    [InlineData("Plain text [PAYWALL_TRIGGER:00000000-0000-0000-0000-000000000000:Title:50:invalid]")]
+    [InlineData("Plain text [PAYWALL_TRIGGER:00000000-0000-0000-0000-000000000000:Title:invalid:80]")]
+    [InlineData("Plain text [PAYWALL_TRIGGER:00000000-0000-0000-0000-000000000000:Title]")]
+    public void TryParsePaywallTrigger_WithInvalidInputs_ReturnsFalse(string rawText)
+    {
+        // Act
+        var result = PaywallParser.TryParsePaywallTrigger(
+            rawText,
+            out var teaser,
+            out var bookId,
+            out var title,
+            out var localScore,
+            out var globalScore);
+
+        // Assert
+        result.Should().BeFalse();
+    }
+}