Updated scanner to infer when it has reached the end of results.

JSMR.Infrastructure/Scanning/VoiceWorksScanner.cs

@@ -8,6 +8,7 @@ using JSMR.Infrastructure.Http;
 using JSMR.Infrastructure.Scanning.Extensions;
 using JSMR.Infrastructure.Scanning.Models;
 using System.Globalization;
+using System.Net;
 using System.Text.RegularExpressions;
 
 namespace JSMR.Infrastructure.Scanning;
@@ -20,24 +21,46 @@ public abstract class VoiceWorksScanner(IHtmlLoader htmlLoader) : IVoiceWorksSca
     protected abstract DateOnly? GetEstimatedReleaseDate(string expectedDate);
     protected abstract DateOnly? GetSalesDate(string salesDate);
 
-    public async Task<IReadOnlyList<DLSiteWork>> ScanPageAsync(VoiceWorkScanOptions options, CancellationToken cancellationToken = default)
+    public async Task<VoiceWorkScanResult> ScanPageAsync(VoiceWorkScanOptions options, CancellationToken cancellationToken = default)
     {
-        DLSiteHtmlDocument document = await GetDLSiteHtmlCollectionAsync(options, cancellationToken);
+        string url = GetUrl(options);
+        HtmlLoadResult result = await htmlLoader.GetHtmlDocumentAsync(url, cancellationToken);
+
+        // Expected boundary: past the last search page
+        if (result.StatusCode == HttpStatusCode.NotFound)
+        {
+            return new VoiceWorkScanResult(
+                Works: [],
+                EndOfResults: true
+            );
+        }
+
+        // Unexpected non-success response
+        if (!result.IsSuccessStatusCode || result.Document is null)
+        {
+            throw new HttpRequestException(
+                $"Unexpected response status code {(int)result.StatusCode} ({result.StatusCode}) while scanning {url}");
+        }
+
+        DLSiteHtmlDocument document = new(result.Document);
         DLSiteHtmlNode[] nodes = document.GetDLSiteNodes();
 
+        // Defensive fallback in case DLsite changes from 404 to 200 with empty page
+        if (nodes.Length == 0)
+        {
+            return new VoiceWorkScanResult(
+                Works: [],
+                EndOfResults: true
+            );
+        }
+
         DLSiteWork[] works = GetDLSiteWorks(nodes, options);
         works.InferAndUpdateExpectedDates();
 
-        return works;
-    }
-
-    private async Task<DLSiteHtmlDocument> GetDLSiteHtmlCollectionAsync(VoiceWorkScanOptions options, CancellationToken cancellationToken)
-    {
-        string url = GetUrl(options);
-
-        HtmlDocument document = await htmlLoader.GetHtmlDocumentAsync(url, cancellationToken);
-
-        return new DLSiteHtmlDocument(document);
+        return new VoiceWorkScanResult(
+            Works: works,
+            EndOfResults: false
+        );
     }
 
     protected string GetUrl(VoiceWorkScanOptions options)