// Copyright (C) 2026 SharpEmu Emulator Project
// SPDX-License-Identifier: GPL-2.0-or-later

using SharpEmu.Libs.Gpu;
using SharpEmu.Libs.VideoOut;
using Xunit;

namespace SharpEmu.Libs.Tests.VideoOut;

public sealed class VulkanStorageFeedbackTargetResolverTests
{
    private const ulong TargetAddress = 0x1044_500000;

    [Fact]
    public void ZeroWriteSingleTargetAliasUsesCompatibilityAttachment()
    {
        var target = Target();
        var supported = VulkanStorageFeedbackTargetResolver.TryResolve(
            [target], [Texture(TargetAddress, true)], [Blend(0)],
            out var resolved, out var usedCompatibilityAttachment, out var unsupportedAddress);

        Assert.True(supported);
        Assert.True(usedCompatibilityAttachment);
        Assert.Equal(0UL, unsupportedAddress);
        Assert.Equal(0UL, resolved[0].Address);
        Assert.Equal(target.Width, resolved[0].Width);
        Assert.Equal(target.Height, resolved[0].Height);
        Assert.Equal(target.Format, resolved[0].Format);
        Assert.Equal(target.NumberType, resolved[0].NumberType);
    }

    [Fact]
    public void WritableColorAliasRemainsUnsupported()
    {
        var supported = VulkanStorageFeedbackTargetResolver.TryResolve(
            [Target()], [Texture(TargetAddress, true)], [Blend(0xF)],
            out var resolved, out var usedCompatibilityAttachment, out var unsupportedAddress);

        Assert.False(supported);
        Assert.False(usedCompatibilityAttachment);
        Assert.Equal(TargetAddress, unsupportedAddress);
        Assert.Equal(TargetAddress, resolved[0].Address);
    }

    [Fact]
    public void NonStorageAliasDoesNotNeedCompatibilityAttachment()
    {
        var supported = VulkanStorageFeedbackTargetResolver.TryResolve(
            [Target()], [Texture(TargetAddress, false)], [Blend(0xF)],
            out var resolved, out var usedCompatibilityAttachment, out var unsupportedAddress);

        Assert.True(supported);
        Assert.False(usedCompatibilityAttachment);
        Assert.Equal(0UL, unsupportedAddress);
        Assert.Equal(TargetAddress, resolved[0].Address);
    }

    [Fact]
    public void AliasedMrtRemainsUnsupported()
    {
        const ulong otherAddress = 0x1042_F00000;
        var supported = VulkanStorageFeedbackTargetResolver.TryResolve(
            [Target(), Target(otherAddress)],
            [Texture(TargetAddress, true)], [Blend(0), Blend(0)],
            out _, out var usedCompatibilityAttachment, out var unsupportedAddress);

        Assert.False(supported);
        Assert.False(usedCompatibilityAttachment);
        Assert.Equal(TargetAddress, unsupportedAddress);
    }

    private static GuestRenderTarget Target(ulong address = TargetAddress) =>
        new(address, 2048, 2048, Format: 10, NumberType: 6);

    private static GuestDrawTexture Texture(ulong address, bool isStorage) =>
        new(address, 2048, 2048, Format: 10, NumberType: 0, RgbaPixels: [],
            IsFallback: false, IsStorage: isStorage);

    private static GuestBlendState Blend(uint writeMask) =>
        GuestBlendState.Default with { WriteMask = writeMask };
}