using Silk.NET.Vulkan;

namespace AcDream.App.Rendering.Gpu.Vk;

/// <summary>
/// The half of <see cref="VulkanGpuDevice"/> that owns sampled resources,
/// pipelines and passes.
///
/// <para>Split into its own file because the three V6 commits divide along
/// exactly this line: V6a lands memory, buffers, rings and the frame timeline —
/// everything in <c>VulkanGpuDevice.cs</c> — while textures, the descriptor
/// table and render targets arrive at V6b and pipelines, passes and readback at
/// V6c. Until each lands, the corresponding contract member throws with the
/// slice named, rather than returning something that would fail later and
/// further away.</para>
/// </summary>
internal sealed unsafe partial class VulkanGpuDevice
{
    private void InitialiseResources(string? shaderSpirvDirectory, string? pipelineCacheDirectory)
    {
        _ = shaderSpirvDirectory;
        _ = pipelineCacheDirectory;
    }

    private void BeginFrameResources(int slotIndex) => _ = slotIndex;

    private void EndFrameResources(int slotIndex, CommandBuffer commands)
    {
        _ = slotIndex;
        _ = commands;
    }

    private void DisposeResources()
    {
    }

    public IGpuTimerPool Timers => throw NotYet("GPU timer scopes", "V6c");

    public GpuTextureSlot DefaultTextureSlot => throw NotYet("the default 1x1 white table slot", "V6b");

    public IGpuTexture CreateTexture(in GpuTextureDescription description) =>
        throw NotYet($"texture creation ('{description.Name}')", "V6b");

    public IGpuSampler CreateSampler(in GpuSamplerDescription description) =>
        throw NotYet("sampler creation", "V6b");

    public IGpuRenderTarget CreateRenderTarget(in GpuRenderTargetDescription description) =>
        throw NotYet($"render targets ('{description.Name}')", "V6b");

    public GpuTextureSlot RegisterTexture(IGpuTexture texture, IGpuSampler sampler) =>
        throw NotYet("the global texture table", "V6b");

    public void ReleaseTextureSlot(GpuTextureSlot slot) =>
        throw NotYet("the global texture table", "V6b");

    public IGpuPipeline CreatePipeline(GpuPipelineDescription description) =>
        throw NotYet($"pipelines ('{description?.Name}')", "V6c");

    internal IGpuPassEncoder BeginPass(VulkanGpuFrame frame, GpuPassDescription description) =>
        throw NotYet($"render passes ('{description.Name}')", "V6c");

    public byte[] CaptureBackbuffer(int width, int height) =>
        throw NotYet("backbuffer capture", "V6c");

    private static NotSupportedException NotYet(string what, string slice) =>
        new($"The Vulkan backend does not implement {what} yet; it lands at Campaign V slice {slice}.");
}