#include "ViewportRenderTargets.h"

namespace XCEngine::UI::Editor::App {

namespace {

bool CreateViewportColorResources(
    ::XCEngine::RHI::RHIDevice& device,
    ViewportRenderTargets& targets) {
    const auto colorDesc =
        BuildViewportTextureDesc(targets.width, targets.height, ::XCEngine::RHI::Format::R8G8B8A8_UNorm);
    targets.colorTexture = device.CreateTexture(colorDesc);
    if (targets.colorTexture == nullptr) {
        return false;
    }

    const auto colorViewDesc =
        BuildViewportTextureViewDesc(::XCEngine::RHI::Format::R8G8B8A8_UNorm);
    targets.colorView = device.CreateRenderTargetView(targets.colorTexture, colorViewDesc);
    return targets.colorView != nullptr;
}

bool CreateViewportDepthResources(
    ::XCEngine::RHI::RHIDevice& device,
    ViewportRenderTargets& targets) {
    const auto depthDesc =
        BuildViewportTextureDesc(targets.width, targets.height, ::XCEngine::RHI::Format::D24_UNorm_S8_UInt);
    targets.depthTexture = device.CreateTexture(depthDesc);
    if (targets.depthTexture == nullptr) {
        return false;
    }

    const auto depthViewDesc =
        BuildViewportTextureViewDesc(::XCEngine::RHI::Format::D24_UNorm_S8_UInt);
    targets.depthView = device.CreateDepthStencilView(targets.depthTexture, depthViewDesc);
    if (targets.depthView == nullptr) {
        return false;
    }

    ::XCEngine::RHI::ResourceViewDesc depthShaderViewDesc = {};
    depthShaderViewDesc.dimension = ::XCEngine::RHI::ResourceViewDimension::Texture2D;
    depthShaderViewDesc.mipLevel = 0;
    targets.depthShaderView = device.CreateShaderResourceView(
        targets.depthTexture,
        depthShaderViewDesc);
    return targets.depthShaderView != nullptr;
}

bool CreateViewportObjectIdResources(
    ::XCEngine::RHI::RHIDevice& device,
    ViewportRenderTargets& targets) {
    const auto objectIdDesc =
        BuildViewportTextureDesc(targets.width, targets.height, ::XCEngine::RHI::Format::R8G8B8A8_UNorm);
    targets.objectIdTexture = device.CreateTexture(objectIdDesc);
    if (targets.objectIdTexture == nullptr) {
        return false;
    }

    const auto objectIdViewDesc =
        BuildViewportTextureViewDesc(::XCEngine::RHI::Format::R8G8B8A8_UNorm);
    targets.objectIdView = device.CreateRenderTargetView(targets.objectIdTexture, objectIdViewDesc);
    if (targets.objectIdView == nullptr) {
        return false;
    }

    targets.objectIdShaderView = device.CreateShaderResourceView(
        targets.objectIdTexture,
        objectIdViewDesc);
    if (targets.objectIdShaderView == nullptr) {
        return false;
    }

    const auto objectIdDepthDesc =
        BuildViewportTextureDesc(targets.width, targets.height, ::XCEngine::RHI::Format::D24_UNorm_S8_UInt);
    targets.objectIdDepthTexture = device.CreateTexture(objectIdDepthDesc);
    if (targets.objectIdDepthTexture == nullptr) {
        return false;
    }

    const auto objectIdDepthViewDesc =
        BuildViewportTextureViewDesc(::XCEngine::RHI::Format::D24_UNorm_S8_UInt);
    targets.objectIdDepthView = device.CreateDepthStencilView(
        targets.objectIdDepthTexture,
        objectIdDepthViewDesc);
    return targets.objectIdDepthView != nullptr;
}

bool CreateViewportSelectionMaskResources(
    ::XCEngine::RHI::RHIDevice& device,
    ViewportRenderTargets& targets) {
    const auto selectionMaskDesc =
        BuildViewportTextureDesc(targets.width, targets.height, ::XCEngine::RHI::Format::R8G8B8A8_UNorm);
    targets.selectionMaskTexture = device.CreateTexture(selectionMaskDesc);
    if (targets.selectionMaskTexture == nullptr) {
        return false;
    }

    const auto selectionMaskViewDesc =
        BuildViewportTextureViewDesc(::XCEngine::RHI::Format::R8G8B8A8_UNorm);
    targets.selectionMaskView = device.CreateRenderTargetView(
        targets.selectionMaskTexture,
        selectionMaskViewDesc);
    if (targets.selectionMaskView == nullptr) {
        return false;
    }

    targets.selectionMaskShaderView = device.CreateShaderResourceView(
        targets.selectionMaskTexture,
        selectionMaskViewDesc);
    return targets.selectionMaskShaderView != nullptr;
}

bool CreateViewportTextureDescriptor(
    Host::D3D12ShaderResourceDescriptorAllocator& textureDescriptorAllocator,
    ViewportRenderTargets& targets) {
    if (!textureDescriptorAllocator.CreateTextureDescriptor(
            targets.colorTexture,
            &targets.srvCpuHandle,
            &targets.srvGpuHandle)) {
        return false;
    }

    targets.textureHandle.nativeHandle = static_cast<std::uintptr_t>(targets.srvGpuHandle.ptr);
    targets.textureHandle.width = targets.width;
    targets.textureHandle.height = targets.height;
    targets.textureHandle.kind = ::XCEngine::UI::UITextureHandleKind::ShaderResourceView;
    targets.textureHandle.resourceHandle =
        reinterpret_cast<std::uintptr_t>(targets.colorTexture);
    return true;
}

} // namespace

bool ViewportRenderTargetManager::EnsureTargets(
    ViewportKind kind,
    std::uint32_t width,
    std::uint32_t height,
    ::XCEngine::RHI::RHIDevice& device,
    Host::D3D12ShaderResourceDescriptorAllocator& textureDescriptorAllocator,
    ViewportRenderTargets& targets) const {
    if (width == 0u || height == 0u) {
        return false;
    }

    DestroyTargets(&textureDescriptorAllocator, targets);
    targets.width = width;
    targets.height = height;

    if (!CreateViewportColorResources(device, targets) ||
        !CreateViewportDepthResources(device, targets) ||
        (ViewportRequiresObjectIdResources(kind) &&
         (!CreateViewportObjectIdResources(device, targets) ||
          !CreateViewportSelectionMaskResources(device, targets))) ||
        !CreateViewportTextureDescriptor(textureDescriptorAllocator, targets)) {
        DestroyTargets(&textureDescriptorAllocator, targets);
        return false;
    }

    targets.colorState = ::XCEngine::RHI::ResourceStates::Common;
    targets.objectIdState = ::XCEngine::RHI::ResourceStates::Common;
    targets.selectionMaskState = ::XCEngine::RHI::ResourceStates::Common;
    targets.hasValidObjectIdFrame = false;
    return true;
}

} // namespace XCEngine::UI::Editor::App