Add Shorts look preview and visual crop editor

Show opening/closing 9:16 stills from the same filtergraph, and let
users drag a keep-region on a source frame to fill the crop insets.

AmiReel.Tests/Models/SourceCropSelectionTests.cs

@@ -0,0 +1,100 @@
+using AmiReel.Models;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+namespace AmiReel.Tests.Models;
+
+[TestClass]
+public class SourceCropSelectionTests
+{
+    [TestMethod]
+    public void FitUniform_WiderContainer_LetterboxesHorizontally()
+    {
+        // Act
+        (double offsetX, double offsetY, double width, double height) =
+            SourceCropSelection.FitUniform(400, 200, 100, 100);
+
+        // Assert
+        Assert.AreEqual(100, offsetX);
+        Assert.AreEqual(0, offsetY);
+        Assert.AreEqual(200, width);
+        Assert.AreEqual(200, height);
+    }
+
+    [TestMethod]
+    public void FitUniform_TallerContainer_LetterboxesVertically()
+    {
+        // Act
+        (double offsetX, double offsetY, double width, double height) =
+            SourceCropSelection.FitUniform(200, 400, 100, 100);
+
+        // Assert
+        Assert.AreEqual(0, offsetX);
+        Assert.AreEqual(100, offsetY);
+        Assert.AreEqual(200, width);
+        Assert.AreEqual(200, height);
+    }
+
+    [TestMethod]
+    public void ToInsets_FullFrameSelection_ReturnsEmptyInsets()
+    {
+        // Act
+        PixelInsets insets = SourceCropSelection.ToInsets(640, 512, 640, 512, 0, 0, 640, 512);
+
+        // Assert
+        Assert.IsTrue(insets.IsEmpty);
+    }
+
+    [TestMethod]
+    public void ToInsets_CenteredSelection_ComputesAllFourEdges()
+    {
+        // Act
+        PixelInsets insets = SourceCropSelection.ToInsets(100, 100, 100, 100, 10, 20, 70, 50);
+
+        // Assert
+        Assert.AreEqual(10, insets.Left);
+        Assert.AreEqual(20, insets.Right);
+        Assert.AreEqual(20, insets.Top);
+        Assert.AreEqual(30, insets.Bottom);
+    }
+
+    [TestMethod]
+    public void ToInsets_DraggedUpAndLeft_NormalizesTheRectangle()
+    {
+        // Act
+        PixelInsets insets = SourceCropSelection.ToInsets(100, 100, 100, 100, 80, 70, -70, -50);
+
+        // Assert
+        Assert.AreEqual(10, insets.Left);
+        Assert.AreEqual(20, insets.Right);
+        Assert.AreEqual(20, insets.Top);
+        Assert.AreEqual(30, insets.Bottom);
+    }
+
+    [TestMethod]
+    public void ToDisplayRect_RoundTripsKnownInsets()
+    {
+        // Arrange
+        PixelInsets insets = new(20, 20, 10, 10);
+
+        // Act
+        (double x, double y, double width, double height) =
+            SourceCropSelection.ToDisplayRect(100, 100, 200, 200, insets);
+
+        // Assert
+        Assert.AreEqual(40, x);
+        Assert.AreEqual(20, y);
+        Assert.AreEqual(120, width);
+        Assert.AreEqual(160, height);
+    }
+
+    [TestMethod]
+    public void ClampToDisplay_OutsideBounds_ClampsToEdges()
+    {
+        // Act
+        (double x, double y) = SourceCropSelection.ClampToDisplay(-8, 90, 80, 60);
+
+        // Assert
+        Assert.AreEqual(0, x);
+        Assert.AreEqual(60, y);
+    }
+}

AmiReel.Tests/Services/ShortsPipelineTests.cs

@@ -389,4 +389,128 @@ public class ShortsPipelineTests
         // Assert
         Assert.AreEqual(1000, width);
     }
+
+    [TestMethod]
+    public void ValidatePreview_WithMissingTitleAndOutput_DoesNotThrow()
+    {
+        // Arrange
+        string directory = CreateTempDirectory();
+        string input = Path.Combine(directory, "clip.mp4");
+        File.WriteAllText(input, "data");
+        ShortSettings settings = ValidSettings(input, Path.Combine(directory, "missing-font.ttf")) with
+        {
+            Title = "",
+            OutputPath = "",
+        };
+
+        // Act & Assert (no exception)
+        ShortsPipeline.ValidatePreview(settings);
+    }
+
+    [TestMethod]
+    public void ValidatePreview_WithMissingInput_ThrowsFileNotFoundException()
+    {
+        // Arrange
+        string directory = CreateTempDirectory();
+        ShortSettings settings = ValidSettings(Path.Combine(directory, "missing.mp4"), "font.ttf");
+
+        // Act & Assert
+        Assert.ThrowsExactly<FileNotFoundException>(() => ShortsPipeline.ValidatePreview(settings));
+    }
+
+    [TestMethod]
+    public void PreviewOverlayWindows_Opening_HidesTitleCard()
+    {
+        // Act
+        (double hookEnd, double infoStart, double ctaStart) = ShortsPipeline.PreviewOverlayWindows(ShortPreviewShot.Opening, 30);
+
+        // Assert
+        Assert.AreEqual(30, hookEnd);
+        Assert.AreEqual(31, infoStart);
+        Assert.AreEqual(31, ctaStart);
+    }
+
+    [TestMethod]
+    public void PreviewOverlayWindows_Closing_ShowsTitlesImmediately()
+    {
+        // Act
+        (double hookEnd, double infoStart, double ctaStart) = ShortsPipeline.PreviewOverlayWindows(ShortPreviewShot.Closing, 30);
+
+        // Assert
+        Assert.AreEqual(-1, hookEnd);
+        Assert.AreEqual(0, infoStart);
+        Assert.AreEqual(0, ctaStart);
+    }
+
+    [TestMethod]
+    public void PreviewSeekSeconds_OpeningAndClosing_StayInsideDuration()
+    {
+        // Act
+        double opening = ShortsPipeline.PreviewSeekSeconds(ShortPreviewShot.Opening, 30);
+        double closing = ShortsPipeline.PreviewSeekSeconds(ShortPreviewShot.Closing, 30);
+
+        // Assert
+        Assert.AreEqual(1.2, opening);
+        Assert.AreEqual(29.6, closing);
+    }
+
+    [TestMethod]
+    public void AddTimestampOffset_AddsFractionalSeconds()
+    {
+        // Act
+        string result = ShortsPipeline.AddTimestampOffset("00:01:10", 1.2);
+
+        // Assert
+        Assert.AreEqual("00:01:11.200", result);
+    }
+
+    [TestMethod]
+    public void BuildInputArguments_VideoStyle_IncludesLoopedBackgroundVideo()
+    {
+        // Arrange
+        ShortSettings settings = ValidSettings("in.mp4", "font.ttf", ShortStyle.Video) with
+        {
+            BackgroundVideo = @"D:\bg.mp4",
+        };
+
+        // Act
+        List<string> args = ShortsPipeline.BuildInputArguments(settings, 0.12, "00:00:01.200");
+
+        // Assert
+        CollectionAssert.Contains(args, "00:00:01.200");
+        CollectionAssert.Contains(args, "-stream_loop");
+        CollectionAssert.Contains(args, @"D:\bg.mp4");
+        CollectionAssert.Contains(args, "in.mp4");
+    }
+
+    [TestMethod]
+    public void BuildExtractFrameArguments_SeeksToStartAndWritesOnePng()
+    {
+        // Act
+        List<string> args = ShortsPipeline.BuildExtractFrameArguments(@"D:\clip.mp4", "00:00:05", @"C:\tmp\frame.png");
+
+        // Assert
+        CollectionAssert.Contains(args, "00:00:05");
+        CollectionAssert.Contains(args, @"D:\clip.mp4");
+        CollectionAssert.Contains(args, "-frames:v");
+        CollectionAssert.Contains(args, "1");
+        CollectionAssert.Contains(args, @"C:\tmp\frame.png");
+    }
+
+    [TestMethod]
+    public void BuildFilterComplex_WithoutTextOverlays_SkipsDrawtext()
+    {
+        // Act
+        string result = ShortsPipeline.BuildFilterComplex(
+            "[0:v]copy[base]",
+            fontEsc: "", hookEsc: "", titleEsc: "", metaEsc: "", websiteEsc: "",
+            hookEnd: 2.7, infoStart: 23, ctaStart: 26.5,
+            includeTextOverlays: false);
+
+        // Assert
+        StringAssert.Contains(result, "[0:v]copy[base]");
+        StringAssert.Contains(result, "[vout]");
+        Assert.IsFalse(result.Contains("drawtext", StringComparison.Ordinal));
+        Assert.IsFalse(result.Contains("drawbox", StringComparison.Ordinal));
+    }
 }