using Ghost.Core;
using Ghost.Engine.Components;
using Ghost.Engine.Systems;
using Ghost.Engine.Utilities;
using Ghost.Entities;
using Ghost.Graphics.Core;
using Ghost.Graphics.RHI;
using Ghost.Graphics.Utilities;
using Microsoft.UI.Xaml;
using Microsoft.UI.Xaml.Controls;
using Microsoft.UI.Xaml.Media;
using Misaki.HighPerformance.LowLevel.Buffer;
using Misaki.HighPerformance.Mathematics;

namespace Ghost.Graphics.Test.Windows;

public sealed partial class GraphicsTestWindow : Window
{
    private RenderSystem? _renderSystem;
    private ISwapChain? _swapChain;
    //private JobScheduler _jobScheduler;
    private World? _world;

    private Handle<Mesh> _meshHandle;

    private bool _isFirstActivationHandled;

    public GraphicsTestWindow()
    {
        InitializeComponent();

        Activated += GraphicsTestWindow_Activated;
        Closed += GraphicsTestWindow_Closed;

        Panel.SizeChanged += SwapChainPanel_SizeChanged;
        Panel.CompositionScaleChanged += SwapChainPanel_CompositionScaleChanged;

        var opts = new AllocationManagerInitOpts
        {
            ArenaCapacity = 1024 * 1024 * 1024, // 1GB
            StackCapacity = 1024 * 1024 * 32, // 32MB
            FreeListConcurrencyLevel = Environment.ProcessorCount,
        };

        AllocationManager.Initialize(opts);

        //_jobScheduler = new JobScheduler(Environment.ProcessorCount - 1);
    }

    private void GraphicsTestWindow_Activated(object sender, WindowActivatedEventArgs e)
    {
        if (_isFirstActivationHandled)
        {
            return;
        }

        e.Handled = true;
        _isFirstActivationHandled = true;

        _renderSystem = new RenderSystem(new RenderSystemDesc()
        {
            FrameBufferCount = 2,
            GraphicsAPI = GraphicsAPI.Direct3D12,
            InitialRenderPipelineSettings = new RenderPasses.TestRenderPipelineSettings()
        });

        _swapChain = _renderSystem.SwapChainManager.EnsureSwapChain(0, new SwapChainDesc
        {
            Width = (uint)AppWindow.Size.Width,
            Height = (uint)AppWindow.Size.Height,
            ScaleX = Panel.CompositionScaleX,
            ScaleY = Panel.CompositionScaleY,
            Format = TextureFormat.B8G8R8A8_UNorm,
            Target = SwapChainTarget.FromCompositionSurface(Panel)
        });

        _renderSystem.Start();

        // ECS Setup
        _world = World.Create();
        _world.AddService(_renderSystem);

        // Add Systems
        var group = _world.SystemManager.GetSystem<DefaultSystemGroup>();
        group.AddSystem<RenderExtractionSystem>();
        group.SortSystems();

        _world.SystemManager.InitializeAll(default);

        // Create Camera Entity

        using var scope = AllocationManager.CreateStackScope();
        var camSet = new ComponentSet(scope.AllocationHandle, ComponentTypeID<Camera>.Value, ComponentTypeID<LocalToWorld>.Value);
        var cameraEntity = _world.EntityManager.CreateEntity(camSet);

        _world.EntityManager.SetComponent(cameraEntity, new Camera
        {
            swapChainIndex = 0,
            depthTarget = Handle<GPUTexture>.Invalid,
            nearClipPlane = 0.1f,
            farClipPlane = 1000.0f,
            focalLength = 50.0f,
            sensorSize = new float2(36.0f, 24.0f),
            gateFit = GateFit.Vertical,
            renderingLayerMask = RenderingLayerMask.All,
        });

        _world.EntityManager.SetComponent(cameraEntity, new LocalToWorld
        {
            matrix = float4x4.TRS(new float3(0.0f, 1.0f, 5.0f), quaternion.EulerXYZ(new float3(0, math.radians(180.0f), 0)), float3.one)
        });

        // Create Mesh Entity
        //MeshBuilder.CreateCube(0.75f, default, Allocator.Persistent, out var vertices, out var indices);
        Utilities.MeshUtility.LoadMesh("F:/c/SimpleRayTracer/native/assets/bunny.obj", Allocator.Persistent, out var vertices, out var indices).ThrowIfFailed();

        // TODO: Put this to the beginning of the frame without createing another command buffer?
        using var directCmd = _renderSystem.GraphicsEngine.CreateCommandBuffer(CommandBufferType.Graphics);
        var ctx = new RenderingContext(_renderSystem.GraphicsEngine, _renderSystem.ResourceManager, directCmd);

        using var cmdAllocator = _renderSystem.GraphicsEngine.CreateCommandAllocator(CommandBufferType.Graphics);
        directCmd.Begin(cmdAllocator);

        _meshHandle = ctx.CreateMesh(vertices, indices, true);
        ctx.UpdateObjectData(_meshHandle);

        directCmd.End().ThrowIfFailed();
        _renderSystem.GraphicsEngine.Device.GraphicsQueue.Submit(directCmd);
        _renderSystem.GraphicsEngine.Device.GraphicsQueue.WaitIdle();

        var meshSet = new ComponentSet(scope.AllocationHandle, ComponentTypeID<MeshInstance>.Value, ComponentTypeID<LocalToWorld>.Value);
        var meshEntity = _world.EntityManager.CreateEntity(meshSet);
        _world.EntityManager.SetComponent(meshEntity, new MeshInstance
        {
            mesh = _meshHandle,
            renderingLayerMask = RenderingLayerMask.All,
            shadowCastingMode = Engine.ShadowCastingMode.On
        });

        _world.EntityManager.SetComponent(meshEntity, new LocalToWorld
        {
            matrix = float4x4.TRS(float3.zero, quaternion.EulerXYZ(new float3(0, 0, 0)), float3.one)
        });

        CompositionTarget.Rendering += OnRendering;
    }

    private void GraphicsTestWindow_Closed(object sender, WindowEventArgs e)
    {
        try
        {
            CompositionTarget.Rendering -= OnRendering;
            _renderSystem?.Stop();

            if (_world != null)
            {
                World.Destroy(_world.ID);
            }

            _renderSystem?.ResourceManager.ReleaseMesh(_meshHandle);

            _swapChain?.Dispose();
            //_jobScheduler.Dispose();
            _renderSystem?.Dispose();

            AllocationManager.Dispose();
        }
        catch (Exception ex)
        {
            Environment.FailFast("Failed to close the window properly.", ex);
        }
        finally
        {
        }
    }

    private void SwapChainPanel_SizeChanged(object sender, SizeChangedEventArgs e)
    {
        if (_renderSystem == null || _swapChain == null)
        {
            return;
        }

        var newWidth = (uint)(Panel.ActualWidth * Panel.CompositionScaleX);
        var newHeight = (uint)(Panel.ActualHeight * Panel.CompositionScaleY);

        if (newWidth < 8 || newHeight < 8)
        {
            return;
        }

        _renderSystem.RequestSwapChainResize(_swapChain, new uint2(newWidth, newHeight));
    }

    private void SwapChainPanel_CompositionScaleChanged(SwapChainPanel sender, object args)
    {
        _swapChain?.SetScale(sender.CompositionScaleX, sender.CompositionScaleY);
    }

    private void OnRendering(object? sender, object e)
    {
        if (_renderSystem == null || _world == null || _swapChain == null)
        {
            return;
        }

        if (_renderSystem.CPUFenceValue < _renderSystem.GPUFenceValue + _renderSystem.MaxFrameLatency)
        {
            _world.SystemManager.UpdateAll(default);
            _renderSystem.SignalCPUReady();
        }
    }
}