Terminal.Gui/Tests/UnitTestsParallelizable/View/Layout/ViewportTests.cs

using Xunit.Abstractions;

namespace Terminal.Gui.ViewTests;

/// <summary>
/// Test the <see cref="View.Viewport"/>.
/// DOES NOT TEST Adornment.Viewport methods. Those are in ./Adornment/ViewportTests.cs
/// </summary>
/// <param name="output"></param>
public class ViewportTests (ITestOutputHelper output)
{
    private readonly ITestOutputHelper _output = output;

    [Theory]
    [CombinatorialData]
    public void Get_Viewport_NoSuperView_WithoutAdornments ([CombinatorialRange (-11, 11)] int x)
    {
        // We test with only X because Y is equivalent. Height/Width are irrelevant.
        // Arrange
        var frame = new Rectangle (x, 0, 10, 10);

        var view = new View ();
        view.Frame = frame;
        view.BeginInit ();
        view.EndInit ();

        // Act
        var bounds = view.Viewport;

        // Assert
        Assert.Equal (10, bounds.Width);
    }

    [Theory]
    [InlineData (0, 0, 10)]
    [InlineData (1, 0, 9)]
    [InlineData (-1, 0, 11)]
    [InlineData (10, 0, 0)]
    [InlineData (11, 0, 0)]

    [InlineData (0, 1, 6)]
    [InlineData (1, 1, 5)]
    [InlineData (-1, 1, 7)]
    [InlineData (10, 1, 0)]
    [InlineData (11, 1, 0)]

    public void Get_Viewport_NestedSuperView_WithAdornments (int frameX, int borderThickness, int expectedW)
    {
        // We test with only X because Y is equivalent. Height/Width are irrelevant.
        // Arrange
        var superSuperView = new View ()
        {
            X = 0,
            Y = 0,
            Height = 10,
            Width = 10,
        };
        superSuperView.Border.Thickness = new Thickness (borderThickness);

        var superView = new View ()
        {
            X = 0,
            Y = 0,
            Height = Dim.Fill (),
            Width = Dim.Fill ()
        };
        superView.Border.Thickness = new Thickness (borderThickness);

        superSuperView.Add (superView);

        var view = new View ()
        {
            X = frameX,
            Y = 0,
            Height = Dim.Fill (),
            Width = Dim.Fill ()
        };

        superView.Add (view);
        superSuperView.BeginInit ();
        superSuperView.EndInit ();
        superSuperView.LayoutSubViews ();

        // Act
        var bounds = view.Viewport;

        // Assert
        Assert.Equal (expectedW, bounds.Width);
    }



    [Theory]
    [InlineData (0, 0, 10)]
    [InlineData (1, 0, 9)]
    [InlineData (-1, 0, 11)]
    [InlineData (10, 0, 0)]
    [InlineData (11, 0, 0)]

    [InlineData (0, 1, 4)]
    [InlineData (1, 1, 3)]
    [InlineData (-1, 1, 5)]
    [InlineData (10, 1, 0)]
    [InlineData (11, 1, 0)]
    public void Get_Viewport_NestedSuperView_WithAdornments_WithBorder (int frameX, int borderThickness, int expectedW)
    {
        // We test with only X because Y is equivalent. Height/Width are irrelevant.
        // Arrange
        var superSuperView = new View ()
        {
            X = 0,
            Y = 0,
            Height = 10,
            Width = 10,
        };
        superSuperView.Border.Thickness = new Thickness (borderThickness);

        var superView = new View ()
        {
            X = 0,
            Y = 0,
            Height = Dim.Fill (),
            Width = Dim.Fill ()
        };
        superView.Border.Thickness = new Thickness (borderThickness);

        superSuperView.Add (superView);

        var view = new View ()
        {
            X = frameX,
            Y = 0,
            Height = Dim.Fill (),
            Width = Dim.Fill ()
        };
        view.Border.Thickness = new Thickness (borderThickness);

        superView.Add (view);
        superSuperView.BeginInit ();
        superSuperView.EndInit ();
        superSuperView.LayoutSubViews ();

        // Act
        var bounds = view.Viewport;

        // Assert
        Assert.Equal (expectedW, bounds.Width);
    }

    [Theory]
    [InlineData (0, 0)]
    [InlineData (1, 0)]
    [InlineData (0, 1)]
    [InlineData (-1, -1)]
    public void Set_Viewport_Location_Preserves_Size_And_Frame (int xOffset, int yOffset)
    {
        View view = new ()
        {
            Width = 10,
            Height = 10,
            ViewportSettings = ViewportSettings.AllowNegativeLocation
        };
        view.Layout ();

        Assert.Equal (new Rectangle (0, 0, 10, 10), view.Frame);

        Rectangle testRect = new Rectangle (0, 0, 1, 1);
        Assert.Equal (new Point (0, 0), view.ViewportToScreen (testRect).Location);
        view.Viewport = view.Viewport with { Location = new Point (xOffset, yOffset) };
        Assert.Equal (new Rectangle (xOffset, yOffset, 10, 10), view.Viewport);

        Assert.Equal (new Rectangle (0, 0, 10, 10), view.Frame);
    }

    [Fact]
    public void Set_Viewport_Changes_Frame ()
    {
        var frame = new Rectangle (1, 2, 3, 4);
        var newViewport = new Rectangle (0, 0, 30, 40);

        var v = new View { Frame = frame };

        v.Viewport = newViewport;
        Assert.Equal (newViewport, v.Viewport);
        Assert.Equal (new Rectangle (1, 2, newViewport.Width, newViewport.Height), v.Frame);
        Assert.Equal (new Rectangle (0, 0, newViewport.Width, newViewport.Height), v.Viewport);
        Assert.Equal (Pos.Absolute (1), v.X);
        Assert.Equal (Pos.Absolute (2), v.Y);
        Assert.Equal (Dim.Absolute (30), v.Width);
        Assert.Equal (Dim.Absolute (40), v.Height);

        newViewport = new Rectangle (0, 0, 3, 4);
        v.Viewport = newViewport;
        Assert.Equal (newViewport, v.Viewport);
        Assert.Equal (new Rectangle (1, 2, newViewport.Width, newViewport.Height), v.Frame);
        Assert.Equal (new Rectangle (0, 0, newViewport.Width, newViewport.Height), v.Viewport);
        Assert.Equal (Pos.Absolute (1), v.X);
        Assert.Equal (Pos.Absolute (2), v.Y);
        Assert.Equal (Dim.Absolute (3), v.Width);
        Assert.Equal (Dim.Absolute (4), v.Height);

        v.BorderStyle = LineStyle.Single;

        // Viewport should shrink
        Assert.Equal (new Rectangle (0, 0, 1, 2), v.Viewport);

        // Frame should not change
        Assert.Equal (new Rectangle (1, 2, 3, 4), v.Frame);
        Assert.Equal (Pos.Absolute (1), v.X);
        Assert.Equal (Pos.Absolute (2), v.Y);
        Assert.Equal (Dim.Absolute (3), v.Width);
        Assert.Equal (Dim.Absolute (4), v.Height);

        // Now set bounds bigger as before
        newViewport = new Rectangle (0, 0, 3, 4);
        v.Viewport = newViewport;
        Assert.Equal (newViewport, v.Viewport);

        // Frame grows because there's now a border
        Assert.Equal (new Rectangle (1, 2, 5, 6), v.Frame);
        Assert.Equal (new Rectangle (0, 0, newViewport.Width, newViewport.Height), v.Viewport);
        Assert.Equal (Pos.Absolute (1), v.X);
        Assert.Equal (Pos.Absolute (2), v.Y);
        Assert.Equal (Dim.Absolute (5), v.Width);
        Assert.Equal (Dim.Absolute (6), v.Height);
    }

    [Theory]
    [InlineData (0, 0, 10, 10, 0, 0)]
    [InlineData (10, 0, 10, 10, 9, 0)] // 9 because without AllowGreaterThanContentWidth, the location is clamped to size - 1
    [InlineData (0, 10, 10, 10, 0, 9)]
    [InlineData (10, 10, 10, 10, 9, 9)]
    public void Set_Viewport_ValidValue_UpdatesViewport (int viewWidth, int viewHeight, int viewportX, int viewportY, int expectedX, int expectedY)
    {
        // Arrange
        var view = new View ()
        {
            Width = viewWidth,
            Height = viewHeight,
        };
        view.Layout ();
        var newViewport = new Rectangle (viewportX, viewportY, viewWidth, viewHeight);

        // Act
        view.Viewport = newViewport;

        // Assert
        Assert.Equal (new Rectangle (expectedX, expectedY, viewWidth, viewHeight), view.Viewport);
    }

    [Theory]
    [CombinatorialData]
    public void Set_Viewport_ValidValue_UpdatesViewport_AllowLocationGreaterThanContentSize ([CombinatorialRange (0, 5)] int viewWidth, [CombinatorialRange (0, 5)] int viewHeight)
    {
        // Arrange
        var view = new View ()
        {
            Width = viewWidth,
            Height = viewHeight,
            ViewportSettings = ViewportSettings.AllowLocationGreaterThanContentSize
        };
        var newViewport = new Rectangle (10, 10, viewWidth, viewHeight);

        // Act
        view.Viewport = newViewport;

        // Assert
        Assert.Equal (new Rectangle (10, 10, viewWidth, viewHeight), view.Viewport);
    }

    [Fact]
    public void Set_Viewport_ValueGreaterThanContentSize_UpdatesViewportToContentSize ()
    {
        // Arrange
        var view = new View ();
        view.SetContentSize (new (100, 100));
        var newViewport = new Rectangle (0, 0, 200, 200);
        view.ViewportSettings = ViewportSettings.AllowLocationGreaterThanContentSize;

        // Act
        view.Viewport = newViewport;

        // Assert
        Assert.Equal (newViewport, view.Viewport);
    }

    [Fact]
    public void Set_Viewport_NegativeValue_AllowedBySettings ()
    {
        // Arrange
        var view = new View ();
        var newViewport = new Rectangle (-10, -10, 100, 100);
        view.ViewportSettings = ViewportSettings.AllowNegativeLocation;

        // Act
        view.Viewport = newViewport;

        // Assert
        Assert.Equal (newViewport, view.Viewport);
    }

    [Fact]
    public void Set_Viewport_NegativeValue_NotAllowedBySettings ()
    {
        // Arrange
        var view = new View ();
        var newViewport = new Rectangle (-10, -10, 100, 100);
        view.ViewportSettings = ViewportSettings.None;

        // Act
        view.Viewport = newViewport;

        // Assert
        Assert.Equal (new Rectangle (0, 0, 100, 100), view.Viewport);
    }

    [Theory]
    [InlineData (0, 0)]
    [InlineData (1, 1)]
    public void GetViewportOffset_Returns_Offset_From_Frame (int adornmentThickness, int expectedOffset)
    {
        View view = new ()
        {
            X = 1,
            Y = 1,
            Width = 10,
            Height = 10
        };
        view.BeginInit ();
        view.EndInit ();
        view.Margin.Thickness = new (adornmentThickness);

        Assert.Equal (expectedOffset, view.GetViewportOffsetFromFrame ().X);
    }

    [Fact]
    public void ContentSize_Tracks_ViewportSize_If_Not_Set ()
    {
        View view = new ()
        {
            Width = 1,
            Height = 1
        };
        Assert.True (view.ContentSizeTracksViewport);
        Assert.Equal (view.Viewport.Size, view.GetContentSize ());
    }

    [Fact]
    public void ContentSize_Ignores_ViewportSize_If_Set ()
    {
        View view = new ()
        {
            Width = 1,
            Height = 1,
        };
        view.SetContentSize (new Size (5, 5));
        Assert.False (view.ContentSizeTracksViewport);
        Assert.NotEqual (view.Viewport.Size, view.GetContentSize ());
    }

    [Fact]
    public void ContentSize_Tracks_ViewportSize_If_ContentSizeTracksViewport_Is_True ()
    {
        View view = new ()
        {
            Width = 1,
            Height = 1,
        };
        view.SetContentSize (new Size (5, 5));
        view.Viewport = new (0, 0, 10, 10);
        view.ContentSizeTracksViewport = true;
        Assert.Equal (view.Viewport.Size, view.GetContentSize ());
    }


    [Fact]
    public void ContentSize_Ignores_ViewportSize_If_ContentSizeTracksViewport_Is_False ()
    {
        View view = new ()
        {
            Width = 1,
            Height = 1,
        };
        view.SetContentSize (new Size (5, 5));
        view.Viewport = new (0, 0, 10, 10);
        view.ContentSizeTracksViewport = false;
        Assert.NotEqual (view.Viewport.Size, view.GetContentSize ());
    }

    private class TestViewportEventsView : View
    {
        public int OnViewportChangedCallCount { get; private set; }
        public int ViewportChangedEventCallCount { get; private set; }

        public TestViewportEventsView ()
        {
            ViewportChanged += (sender, args) => ViewportChangedEventCallCount++;
        }

        protected override void OnViewportChanged (DrawEventArgs e)
        {
            OnViewportChangedCallCount++;
            base.OnViewportChanged (e);
        }
    }

    [Fact]
    public void OnViewportChanged_Called_When_Viewport_Changes ()
    {
        // Arrange
        var view = new TestViewportEventsView ();
        var initialViewport = new Rectangle (0, 0, 10, 10);
        var newViewport = new Rectangle (0, 0, 20, 20);
        Assert.Equal (0, view.OnViewportChangedCallCount);
        view.Viewport = initialViewport;
        Assert.Equal (1, view.OnViewportChangedCallCount);

        // Act
        view.Viewport = newViewport;

        // Assert
        Assert.Equal (2, view.OnViewportChangedCallCount);
    }

    [Fact]
    public void ViewportChanged_Event_Raised_When_Viewport_Changes ()
    {
        // Arrange
        var view = new TestViewportEventsView ();
        var initialViewport = new Rectangle (0, 0, 10, 10);
        var newViewport = new Rectangle (0, 0, 20, 20);
        view.Viewport = initialViewport;
        Assert.Equal (1, view.ViewportChangedEventCallCount);

        // Act
        view.Viewport = newViewport;

        // Assert
        Assert.Equal (2, view.ViewportChangedEventCallCount);
    }

    [Fact]
    public void OnViewportChanged_Called_When_Frame_Changes ()
    {
        // Arrange
        var view = new TestViewportEventsView ();
        var initialFrame = new Rectangle (0, 0, 10, 10);
        var newFrame = new Rectangle (0, 0, 20, 20);
        Assert.Equal (0, view.OnViewportChangedCallCount);
        view.Frame = initialFrame;
        Assert.Equal (1, view.OnViewportChangedCallCount);

        // Act
        view.Frame = newFrame;

        // Assert
        Assert.Equal (2, view.OnViewportChangedCallCount);
    }

    [Fact]
    public void ViewportChanged_Event_Raised_When_Frame_Changes ()
    {
        // Arrange
        var view = new TestViewportEventsView ();
        var initialFrame = new Rectangle (0, 0, 10, 10);
        var newFrame = new Rectangle (0, 0, 20, 20);
        view.Frame = initialFrame;
        Assert.Equal (1, view.ViewportChangedEventCallCount);

        // Act
        view.Frame = newFrame;

        // Assert
        Assert.Equal (2, view.ViewportChangedEventCallCount);
    }

}