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

@using NexusReader.UI.Shared.Models
@using NexusReader.UI.Shared.Services
@using NexusReader.Application.DTOs.AI
@using NexusReader.Application.DTOs.User
@using Microsoft.Extensions.Logging
@using System.Net.Http.Json
@inject HttpClient Http
@inject ILibraryStateService LibraryStateService
@inject NavigationManager NavigationManager
@inject ILogger<AiResponseRenderer> Logger

<div class="message-row @(Message.Sender == "User" ? "user-row" : "ai-row")">
    <div class="message-avatar" aria-hidden="true">
        @if (Message.Sender == "User")
        {
            <i class="bi bi-person-fill"></i>
        }
        else
        {
            <i class="bi bi-robot"></i>
        }
    </div>
    
    <div class="message-bubble @GetBubbleClass()">
        <div class="message-header">
            <span class="sender-name">@Message.Sender</span>
            <span class="message-time">@Message.Timestamp.ToString("HH:mm")</span>
        </div>
        
        <div class="message-content">
            @if (Message.Sender == "User")
            {
                <p>@Message.Text</p>
            }
            else
            {
                @if (_hasPaywall)
                {
                    <div class="paywall-teaser" aria-hidden="true">
                        @foreach (var segment in ParseSegments(_displayTeaserText))
                        {
                            @if (segment.IsCitation)
                            {
                                <NexusCitationMarker SourceId="@segment.CitationId" Citations="@Message.Citations" />
                            }
                            else
                            {
                                @RenderMarkdown(segment.Text)
                            }
                        }
                    </div>
                    
                    <div class="upsell-card" role="alert" aria-live="polite">
                        <div class="upsell-header">
                            <span class="upsell-icon" aria-hidden="true">🔒</span>
                            <h4>Dostęp Premium Zablokowany</h4>
                        </div>
                        
                        <p class="upsell-text">
                            Twoje zasoby odpowiadają na to pytanie w <strong>@_localScore%</strong>. W materiale <strong>'@_lockedBookTitle'</strong> znaleźliśmy odpowiedź dopasowaną w <strong>@_globalScore%</strong>.
                        </p>
                        
                        <div class="upsell-actions">
                            @if (_isSimulatingPayment)
                            {
                                <button class="btn-upsell btn-primary loading" disabled aria-busy="true">
                                    <div class="payment-spinner" aria-hidden="true"></div>
                                    PRZETWARZANIE PŁATNOŚCI...
                                </button>
                            }
                            else
                            {
                                <button class="btn-upsell btn-primary" @onclick="HandlePurchase">
                                    ODBLOKUJ PEŁNĄ TREŚĆ (29 PLN)
                                </button>
                            }
                            <a href="/catalog?bookId=@_lockedBookId" class="btn-upsell btn-secondary">
                                Zobacz szczegóły w Katalogu
                            </a>
                        </div>
                    </div>
                }
                else
                {
                    <div class="full-response">
                        @foreach (var segment in ParseSegments(GetCleanText()))
                        {
                            @if (segment.IsCitation)
                            {
                                <NexusCitationMarker SourceId="@segment.CitationId" Citations="@Message.Citations" />
                            }
                            else
                            {
                                @RenderMarkdown(segment.Text)
                            }
                        }
                    </div>
                    
                    @if (_showSuccessBanner)
                    {
                        <div class="success-unlock-banner" role="status">
                            <span class="success-icon" aria-hidden="true">✓</span>
                            <span>Odblokowano pełną odpowiedź! Książka została dodana do Twojej biblioteki.</span>
                        </div>
                    }
                }
            }
        </div>
    </div>
</div>

@code {
    [Parameter] public ChatMessage Message { get; set; } = default!;
    [Parameter] public List<LastReadBookDto>? OwnedBooks { get; set; }
    [Parameter] public EventCallback<Guid> OnUnlockRequested { get; set; }

    private bool _hasPaywall;
    private string _displayTeaserText = string.Empty;
    private Guid _lockedBookId;
    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;
        
        _isSimulatingPayment = true;
        StateHasChanged();

        // Simulate payment gateway delay (1.5 seconds)
        await Task.Delay(1500);

        try
        {
            var bookTitle = string.IsNullOrEmpty(_lockedBookTitle) 
                ? "Architektura .NET 10 i Ekosystem Blazor" 
                : _lockedBookTitle;

            // Call POST endpoint to persist the purchase
            var response = await Http.PostAsJsonAsync("api/library/purchase", new { Title = bookTitle });
            if (response.IsSuccessStatusCode)
            {
                _isUnlocked = true;
                _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
            {
                Logger.LogWarning("[AiResponseRenderer] Purchase failed on server for book {BookId}.", _lockedBookId);
            }
        }
        catch (Exception ex)
        {
            Logger.LogError(ex, "[AiResponseRenderer] Error processing purchase for book {BookId}.", _lockedBookId);
        }
        finally
        {
            _isSimulatingPayment = false;
            StateHasChanged();
        }
    }

    private List<ResponseSegment> ParseSegments(string text)
    {
        var segments = new List<ResponseSegment>();
        if (string.IsNullOrEmpty(text)) return segments;

        var regex = new System.Text.RegularExpressions.Regex(
            @"\[Source ID:\s*([^\]]+)\]|\[([a-fA-F0-9]{8}-[a-fA-F0-9]{4}-[a-fA-F0-9]{4}-[a-fA-F0-9]{4}-[a-fA-F0-9]{12})\]", 
            System.Text.RegularExpressions.RegexOptions.IgnoreCase);
        var matches = regex.Matches(text);

        int lastIndex = 0;
        foreach (System.Text.RegularExpressions.Match match in matches)
        {
            if (match.Index > lastIndex)
            {
                segments.Add(new ResponseSegment
                {
                    Text = text.Substring(lastIndex, match.Index - lastIndex),
                    IsCitation = false
                });
            }

            var citationId = match.Groups[1].Success 
                ? match.Groups[1].Value.Trim() 
                : match.Groups[2].Value.Trim();

            segments.Add(new ResponseSegment
            {
                IsCitation = true,
                CitationId = citationId
            });

            lastIndex = match.Index + match.Length;
        }

        if (lastIndex < text.Length)
        {
            segments.Add(new ResponseSegment
            {
                Text = text.Substring(lastIndex),
                IsCitation = false
            });
        }

        return segments;
    }

    private MarkupString RenderMarkdown(string text)
    {
        if (string.IsNullOrEmpty(text)) return new MarkupString(string.Empty);

        var html = System.Net.WebUtility.HtmlEncode(text);
        html = System.Text.RegularExpressions.Regex.Replace(html, @"\*\*(.*?)\*\*", "<strong>$1</strong>");
        html = System.Text.RegularExpressions.Regex.Replace(html, @"\*(.*?)\*", "<em>$1</em>");
        html = System.Text.RegularExpressions.Regex.Replace(html, @"```(?:[a-zA-Z0-9+#]+)?\s*([\s\S]*?)\s*```", "<pre class=\"nexus-code-block\"><code>$1</code></pre>");
        html = System.Text.RegularExpressions.Regex.Replace(html, @"`(.*?)`", "<code class=\"nexus-inline-code\">$1</code>");
        html = html.Replace("\n", "<br />");

        return new MarkupString(html);
    }
}