Add citation handling and styling in Ask.razor

Updated Ask.razor to include regex for citation extraction and display.
Introduced a new method to extract citations and updated the Message
class to store them. Added a Citation class for individual citation
representation. Enhanced app.css with styles for citation display.

SqlDatabaseVectorSearch/Components/Pages/Ask.razor

@@ -1,4 +1,5 @@
 @page "/ask"
+@using System.Text.RegularExpressions
 
 @inject IServiceProvider ServiceProvider
 @inject IJSRuntime JSRuntime
@@ -72,6 +73,23 @@
                                                 </Tooltip>
                                             </div>
                                         </div>
+                                        @if (message.Citations is not null && message.Citations.Count() > 0)
+                                        {
+                                            <div class="mt-3 d-flex flex-wrap">
+                                                @foreach (var citation in message.Citations)
+                                                {
+                                                    <div class="border rounded p-2 me-2 mb-2 citation-box small">
+                                                        <div>
+                                                            <strong>@citation.FileName</strong> @if (!string.IsNullOrEmpty(citation.PageNumber))
+                                                            {
+                                                                <span class="ms-2">pag. @citation.PageNumber</span>
+                                                            }
+                                                        </div>
+                                                        <div class="text-secondary small mt-1">@citation.Quote</div>
+                                                    </div>
+                                                }
+                                            </div>
+                                        }
                                     }
                                 </div>
                             }
@@ -178,10 +196,17 @@
                 }
                 else if (delta.StreamState == StreamState.Append)
                 {
+                    // Adds tokens to the assistant message as they are received
                     assistantMessage.Text += delta.Answer;
                 }
                 else if (delta.StreamState == StreamState.End)
                 {
+                    // Extracts citations, if any.
+                    var (cleanText, citations) = ExtractCitations(assistantMessage.Text);
+
+                    assistantMessage.Text = cleanText;
+                    assistantMessage.Citations = citations;
+
                     assistantMessage.IsCompleted = true;
                     assistantMessage.TokenUsage += FormatTokenUsage(delta.TokenUsage);
                 }
@@ -269,6 +294,36 @@
         await JSRuntime.InvokeVoidAsync("scrollTo", chat);
     }
 
+    private static (string, IEnumerable<Citation>) ExtractCitations(string? text)
+    {
+        var citations = new List<Citation>();
+
+        if (string.IsNullOrEmpty(text))
+        {
+            return (text ?? string.Empty, citations);
+        }
+
+        var pattern = "<citation\\s+filename='([^']*)'\\s+page_number='([^']*)'>(.*?)<\\/citation>";
+
+        var matches = Regex.Matches(text, pattern, RegexOptions.Singleline);
+        foreach (Match match in matches)
+        {
+            if (match.Success && match.Groups.Count == 4)
+            {
+                citations.Add(new Citation
+                {
+                    FileName = match.Groups[1].Value,
+                    PageNumber = match.Groups[2].Value,
+                    Quote = match.Groups[3].Value
+                });
+            }
+        }
+
+        // Remove all <citation> tags from the text
+        var cleanText = Regex.Replace(text, pattern, string.Empty, RegexOptions.Singleline).TrimEnd();
+        return (cleanText, citations);
+    }
+
     public class Message
     {
         public string? Text { get; set; }
@@ -278,5 +333,17 @@
         public bool IsCompleted { get; set; }
 
         public string? TokenUsage { get; set; }
+
+        // List of citations extracted from the answer
+        public IEnumerable<Citation>? Citations { get; set; }
+    }
+
+    public class Citation
+    {
+        public string FileName { get; set; } = null!;
+
+        public string Quote { get; set; } = null!;
+
+        public string PageNumber { get; set; } = null!;
     }
 }

SqlDatabaseVectorSearch/wwwroot/css/app.css

@@ -62,3 +62,9 @@ h1:focus {
     .blazor-error-boundary::after {
         content: "An error has occurred."
     }
+
+.citation-box {
+    width: fit-content;
+    max-width: 100%;
+    background-color: #f8f9fa;
+}