feat: Improve CSV output handling in AiExtractionService, including legacy quoting and empty result skipping

MaddoShared.Tests/Test1.cs

@@ -1,6 +1,7 @@
 using ImageCatalog_2.Services;
 using ImageCatalog_2.Models;
 using Shouldly;
+using System.Text;
 
 namespace MaddoShared.Tests;
 
@@ -8,7 +9,7 @@ namespace MaddoShared.Tests;
 public sealed class AiExtractionServiceCsvTests
 {
     [TestMethod]
-    public void WriteCsvOutput_UsesLegacyCompatibleHeaderAndFilenameColumn()
+    public void WriteCsvOutput_UsesLegacyCompatibleQuotingAndSkipsEmptyResults()
     {
         using var tempDir = new TempDirectory();
         var csvPath = Path.Combine(tempDir.Path, "ocr.csv");
@@ -16,15 +17,35 @@ public sealed class AiExtractionServiceCsvTests
         AiExtractionService.WriteCsvOutput(
             csvPath,
             [
-                new AiResultItem { Path = @"C:\images\IMG_7146.JPG", Text = "43,84,61" },
+                new AiResultItem { Path = @"C:\images\IMG_7146.JPG", Text = "43" },
-                new AiResultItem { Path = @"C:\images\IMG_7207.JPG", Text = "a\"b" }
+                new AiResultItem { Path = @"C:\images\IMG_7207.JPG", Text = "43,84,61" },
+                new AiResultItem { Path = @"C:\images\IMG_7208.JPG", Text = string.Empty },
+                new AiResultItem { Path = @"C:\images\IMG_7209.JPG", Text = "   " },
+                new AiResultItem { Path = @"C:\images\IMG_7210.JPG", Text = "a\"b,c" }
             ]);
 
-        var lines = File.ReadAllLines(csvPath);
+        var csv = File.ReadAllText(csvPath, Encoding.UTF8);
 
-        lines[0].ShouldBe("filename,text");
+        csv.ShouldBe("filename,text\r"
-        lines[1].ShouldBe("\"IMG_7146.JPG\",\"43,84,61\"");
+            + "IMG_7146.JPG,43\r"
-        lines[2].ShouldBe("\"IMG_7207.JPG\",\"a\"\"b\"");
+            + "IMG_7207.JPG,\"43,84,61\"\r"
+            + "IMG_7210.JPG,\"a\"\"b,c\"\r");
+    }
+
+    [TestMethod]
+    public void WriteCsvOutput_WritesUtf8WithoutBom()
+    {
+        using var tempDir = new TempDirectory();
+        var csvPath = Path.Combine(tempDir.Path, "ocr.csv");
+
+        AiExtractionService.WriteCsvOutput(
+            csvPath,
+            [new AiResultItem { Path = @"C:\images\IMG_7146.JPG", Text = "43" }]);
+
+        var bytes = File.ReadAllBytes(csvPath);
+
+        bytes[.."filename,text\r".Length].ShouldBe(Encoding.ASCII.GetBytes("filename,text\r"));
+        bytes[..3].ShouldNotBe(new byte[] { 0xEF, 0xBB, 0xBF });
     }
 
     private sealed class TempDirectory : IDisposable

imagecatalog/Services/AiExtractionService.cs

@@ -217,16 +217,31 @@ public class AiExtractionService : IAiExtractionService
             Directory.CreateDirectory(dir);
         }
 
-        using var sw = new StreamWriter(csvOutputPath, false, Encoding.UTF8);
+        using var sw = new StreamWriter(csvOutputPath, false, new UTF8Encoding(encoderShouldEmitUTF8Identifier: false));
+        sw.NewLine = "\r";
         sw.WriteLine("filename,text");
         foreach (var result in extractedResults)
         {
+            var text = result.Text ?? string.Empty;
+            if (string.IsNullOrWhiteSpace(text))
+            {
+                continue;
+            }
+
             var csvFileName = Path.GetFileName(result.Path ?? string.Empty);
-            var safeText = (result.Text ?? string.Empty).Replace("\"", "\"\"");
+            sw.Write(csvFileName);
-            sw.WriteLine($"\"{csvFileName}\",\"{safeText}\"");
+            sw.Write(',');
+            sw.WriteLine(FormatLegacyTextField(text));
         }
     }
 
+    private static string FormatLegacyTextField(string text)
+    {
+        return text.Contains(',', StringComparison.Ordinal)
+            ? $"\"{text.Replace("\"", "\"\"")}\""
+            : text;
+    }
+
     private static double CalculateAverageImagesPerSecond(int processed, TimeSpan elapsed)
     {
         return elapsed.TotalSeconds > 0 ? processed / elapsed.TotalSeconds : 0;