using AcDream.App.Composition;
using AcDream.App.Input;
using AcDream.App.Rendering;

namespace AcDream.App.Tests.Composition;

/// <summary>
/// #387: the V11 null viewport target assumed the driver's OUT_OF_DATE/
/// SUBOPTIMAL results would drive swapchain recreation on window resize; on
/// Windows AMD the driver instead presents the stale-extent swapchain scaled
/// to the new window (the "resolution pick just stretches" 2026-08-13 user
/// gate report). These pin the replacement target's contract: every resize
/// event reaching the seam arms the context's frame-boundary recreation.
/// </summary>
public sealed class SwapchainRecreateViewportTargetTests
{
    [Fact]
    public void ResizeViewport_ArmsRecreation_OncePerEvent()
    {
        int armed = 0;
        IFramebufferViewportTarget target =
            new VulkanHostInputCameraCompositionFactory.SwapchainRecreateViewportTarget(
                () => armed++);

        target.ResizeViewport(1024, 768);
        Assert.Equal(1, armed);

        // A second resize arms again — the context collapses bursts itself at
        // the frame boundary (it re-reads the live FramebufferSize), so the
        // target must never de-duplicate or latch.
        target.ResizeViewport(800, 600);
        Assert.Equal(2, armed);
    }

    [Fact]
    public void ResizeViewport_IgnoresTheEventSize_ContextReadsLiveFramebuffer()
    {
        // The width/height are deliberately unused (doc on the target): the
        // context reads the CURRENT framebuffer size at the frame boundary,
        // so a stale event cannot install a stale extent. Pin that the arm
        // fires regardless of the reported size values.
        int armed = 0;
        IFramebufferViewportTarget target =
            new VulkanHostInputCameraCompositionFactory.SwapchainRecreateViewportTarget(
                () => armed++);

        target.ResizeViewport(int.MaxValue, 1);
        Assert.Equal(1, armed);
    }

    [Fact]
    public void Constructor_RejectsNullRecreateHook()
    {
        Assert.Throws<ArgumentNullException>(() =>
            new VulkanHostInputCameraCompositionFactory.SwapchainRecreateViewportTarget(null!));
    }

    [Fact]
    public void ResizeController_DeliversResizeEventsToTheBoundTarget()
    {
        // The end-to-end seam FramebufferResizeController.Resize →
        // ResizeViewport → arm: the same event flow GameWindow's
        // OnFramebufferResize drives in production. Zero-area (minimised)
        // events are gated by the controller and must NOT arm.
        int armed = 0;
        var controller = new FramebufferResizeController(new ViewportAspectState());
        controller.BindViewport(
            new VulkanHostInputCameraCompositionFactory.SwapchainRecreateViewportTarget(
                () => armed++));

        controller.Resize(1280, 720);
        Assert.Equal(1, armed);

        controller.Resize(0, 0);       // minimised — gated, no arm
        Assert.Equal(1, armed);

        controller.Resize(1024, 768);
        Assert.Equal(2, armed);
    }
}