#include <XCEngine/Rendering/Execution/CameraFramePlan.h>

namespace XCEngine {
namespace Rendering {

namespace {

CameraFrameFullscreenStagePlan* GetMutableFullscreenStagePlan(
    CameraFramePlan& plan,
    CameraFrameStage stage) {
    switch (stage) {
    case CameraFrameStage::PostProcess:
        return &plan.colorChain.postProcess;
    case CameraFrameStage::FinalOutput:
        return &plan.colorChain.finalOutput;
    default:
        return nullptr;
    }
}

FullscreenPassRenderRequest* GetMutableFullscreenPassRequest(
    CameraFramePlan& plan,
    CameraFrameStage stage) {
    switch (stage) {
    case CameraFrameStage::PostProcess:
        return &plan.postProcess;
    case CameraFrameStage::FinalOutput:
        return &plan.finalOutput;
    default:
        return nullptr;
    }
}

bool DoesStageNeedGraphManagedSceneColor(
    const CameraFrameFullscreenStagePlan& stagePlan) {
    return stagePlan.requested &&
           stagePlan.source == CameraFrameColorSource::MainSceneColor;
}

} // namespace

RenderSurface CameraFramePlan::BuildGraphManagedIntermediateSurfaceTemplate(
    const RenderSurface& surface) {
    RenderSurface graphManagedSurface = surface;
    graphManagedSurface.SetColorAttachments({});
    graphManagedSurface.SetAutoTransitionEnabled(false);
    graphManagedSurface.SetColorStateBefore(RHI::ResourceStates::Common);
    graphManagedSurface.SetColorStateAfter(RHI::ResourceStates::Common);
    return graphManagedSurface;
}

RenderSurface CameraFramePlan::BuildCameraDepthOnlySurfaceTemplate(
    const RenderSurface& surface) {
    RenderSurface depthOnlySurface = surface;
    depthOnlySurface.SetColorAttachments({});
    depthOnlySurface.ClearClearColorOverride();
    return depthOnlySurface;
}

CameraFramePlan CameraFramePlan::FromRequest(const CameraRenderRequest& request) {
    CameraFramePlan plan = {};
    plan.request = request;
    plan.shadowCaster = request.shadowCaster;
    plan.directionalShadow = request.directionalShadow;
    plan.postProcess = request.postProcess;
    plan.finalOutput = request.finalOutput;
    plan.finalColorPolicy = request.finalColorPolicy;
    plan.preScenePasses = request.preScenePasses;
    plan.postScenePasses = request.postScenePasses;
    plan.overlayPasses = request.overlayPasses;
    plan.shadowCasterStage.requested =
        request.shadowCaster.IsRequested() ||
        request.directionalShadow.IsValid();
    plan.depthOnlyStage.requested =
        request.depthOnly.IsRequested();
    plan.colorChain.postProcess.requested = request.postProcess.IsRequested();
    plan.colorChain.finalOutput.requested = request.finalOutput.IsRequested();
    return plan;
}

bool CameraFramePlan::IsValid() const {
    return request.IsValid();
}

void CameraFramePlan::ConfigureGraphManagedSceneSurface() {
    graphManagedSceneSurface =
        BuildGraphManagedIntermediateSurfaceTemplate(request.surface);
}

void CameraFramePlan::ClearOwnedPostProcessSequence() {
    if (postProcess.passes == m_ownedPostProcessSequence.get()) {
        postProcess.passes = nullptr;
    }

    m_ownedPostProcessSequence.reset();
}

void CameraFramePlan::SetOwnedPostProcessSequence(
    std::shared_ptr<RenderPassSequence> sequence) {
    ClearOwnedPostProcessSequence();
    m_ownedPostProcessSequence = std::move(sequence);
    if (m_ownedPostProcessSequence != nullptr) {
        postProcess.passes = m_ownedPostProcessSequence.get();
    }
}

void CameraFramePlan::ClearOwnedFinalOutputSequence() {
    if (finalOutput.passes == m_ownedFinalOutputSequence.get()) {
        finalOutput.passes = nullptr;
    }

    m_ownedFinalOutputSequence.reset();
}

void CameraFramePlan::SetOwnedFinalOutputSequence(
    std::shared_ptr<RenderPassSequence> sequence) {
    ClearOwnedFinalOutputSequence();
    m_ownedFinalOutputSequence = std::move(sequence);
    if (m_ownedFinalOutputSequence != nullptr) {
        finalOutput.passes = m_ownedFinalOutputSequence.get();
    }
}

bool CameraFramePlan::UsesGraphManagedSceneColor() const {
    return colorChain.usesGraphManagedSceneColor;
}

bool CameraFramePlan::UsesGraphManagedOutputColor(CameraFrameStage stage) const {
    if (SupportsCameraFramePipelineGraphRecording(stage)) {
        return UsesGraphManagedSceneColor();
    }

    if (const CameraFrameFullscreenStagePlan* fullscreenStagePlan =
            GetFullscreenStagePlan(stage);
        fullscreenStagePlan != nullptr) {
        return fullscreenStagePlan->usesGraphManagedOutputColor;
    }

    return false;
}

CameraFrameColorSource CameraFramePlan::ResolveStageColorSource(CameraFrameStage stage) const {
    if (const CameraFrameFullscreenStagePlan* fullscreenStagePlan =
            GetFullscreenStagePlan(stage);
        fullscreenStagePlan != nullptr) {
        return fullscreenStagePlan->source;
    }

    return CameraFrameColorSource::ExplicitSurface;
}

bool CameraFramePlan::IsFullscreenStageRequested(CameraFrameStage stage) const {
    if (const CameraFrameFullscreenStagePlan* fullscreenStagePlan =
            GetFullscreenStagePlan(stage);
        fullscreenStagePlan != nullptr) {
        return fullscreenStagePlan->requested;
    }

    return false;
}

bool CameraFramePlan::RequestFullscreenStage(
    CameraFrameStage stage,
    CameraFrameColorSource source,
    bool usesGraphManagedOutputColor,
    bool explicitlyConfigured) {
    CameraFrameFullscreenStagePlan* const fullscreenStagePlan =
        GetMutableFullscreenStagePlan(*this, stage);
    FullscreenPassRenderRequest* const fullscreenRequest =
        GetMutableFullscreenPassRequest(*this, stage);
    if (fullscreenStagePlan == nullptr || fullscreenRequest == nullptr) {
        return false;
    }

    fullscreenStagePlan->requested = true;
    fullscreenStagePlan->source = source;
    fullscreenStagePlan->usesGraphManagedOutputColor =
        stage == CameraFrameStage::PostProcess
            ? usesGraphManagedOutputColor
            : false;
    fullscreenStagePlan->explicitlyConfigured =
        fullscreenStagePlan->explicitlyConfigured ||
        explicitlyConfigured;

    if (source != CameraFrameColorSource::ExplicitSurface) {
        fullscreenRequest->sourceSurface = {};
        fullscreenRequest->sourceColorView = nullptr;
        fullscreenRequest->sourceColorState = RHI::ResourceStates::Common;
    }

    if (stage == CameraFrameStage::PostProcess) {
        fullscreenRequest->destinationSurface =
            fullscreenStagePlan->usesGraphManagedOutputColor
                ? RenderSurface{}
                : request.surface;
    } else {
        fullscreenRequest->destinationSurface = request.surface;
    }

    RefreshGraphManagedSceneSurfaceState();
    return true;
}

void CameraFramePlan::ClearFullscreenStage(
    CameraFrameStage stage,
    bool explicitlyConfigured) {
    if (stage == CameraFrameStage::PostProcess) {
        ClearOwnedPostProcessSequence();
        postProcess = {};
        colorChain.postProcess = {};
        colorChain.postProcess.explicitlyConfigured =
            explicitlyConfigured;
    } else if (stage == CameraFrameStage::FinalOutput) {
        ClearOwnedFinalOutputSequence();
        finalOutput = {};
        colorChain.finalOutput = {};
        colorChain.finalOutput.explicitlyConfigured =
            explicitlyConfigured;
    } else {
        return;
    }

    RefreshGraphManagedSceneSurfaceState();
}

bool CameraFramePlan::RequestShadowCasterStage(
    bool explicitlyConfigured) {
    shadowCasterStage.requested =
        shadowCaster.IsRequested() ||
        directionalShadow.IsValid();
    shadowCasterStage.explicitlyConfigured =
        shadowCasterStage.explicitlyConfigured ||
        explicitlyConfigured;
    return shadowCasterStage.requested;
}

void CameraFramePlan::ClearShadowCasterStage(
    bool explicitlyConfigured) {
    shadowCasterStage.requested = false;
    shadowCasterStage.explicitlyConfigured =
        shadowCasterStage.explicitlyConfigured ||
        explicitlyConfigured;
}

bool CameraFramePlan::RequestDepthOnlyStage(
    bool explicitlyConfigured) {
    depthOnlyStage.requested =
        request.depthOnly.IsRequested();
    depthOnlyStage.explicitlyConfigured =
        depthOnlyStage.explicitlyConfigured ||
        explicitlyConfigured;
    return depthOnlyStage.requested;
}

void CameraFramePlan::ClearDepthOnlyStage(
    bool explicitlyConfigured) {
    depthOnlyStage.requested = false;
    depthOnlyStage.explicitlyConfigured =
        depthOnlyStage.explicitlyConfigured ||
        explicitlyConfigured;
}

bool CameraFramePlan::HasExplicitFullscreenStageConfiguration(
    CameraFrameStage stage) const {
    if (const CameraFrameFullscreenStagePlan* fullscreenStagePlan =
            GetFullscreenStagePlan(stage);
        fullscreenStagePlan != nullptr) {
        return fullscreenStagePlan->explicitlyConfigured;
    }

    return false;
}

bool CameraFramePlan::HasExplicitShadowCasterStageConfiguration() const {
    return shadowCasterStage.explicitlyConfigured;
}

bool CameraFramePlan::HasExplicitDepthOnlyStageConfiguration() const {
    return depthOnlyStage.explicitlyConfigured;
}

bool CameraFramePlan::IsShadowCasterStageRequested() const {
    return shadowCasterStage.requested;
}

bool CameraFramePlan::IsDepthOnlyStageRequested() const {
    return depthOnlyStage.requested;
}

bool CameraFramePlan::IsPostProcessStageValid() const {
    if (!IsFullscreenStageRequested(CameraFrameStage::PostProcess)) {
        return true;
    }

    const CameraFrameColorSource postProcessSource =
        ResolveStageColorSource(CameraFrameStage::PostProcess);
    if (postProcessSource == CameraFrameColorSource::ExplicitSurface) {
        return postProcess.IsValid();
    }

    if (postProcessSource != CameraFrameColorSource::MainSceneColor) {
        return false;
    }

    const bool hasUsableDestination =
        UsesGraphManagedOutputColor(CameraFrameStage::PostProcess) ||
        (HasValidColorTarget(postProcess.destinationSurface) &&
         HasValidSurfaceSampleDescription(postProcess.destinationSurface));
    return UsesGraphManagedOutputColor(CameraFrameStage::MainScene) &&
           HasValidSingleSampleColorSource(request.surface) &&
           hasUsableDestination;
}

bool CameraFramePlan::IsFinalOutputStageValid() const {
    if (!IsFullscreenStageRequested(CameraFrameStage::FinalOutput)) {
        return true;
    }

    const CameraFrameColorSource finalOutputSource =
        ResolveStageColorSource(CameraFrameStage::FinalOutput);
    if (finalOutputSource == CameraFrameColorSource::ExplicitSurface) {
        return finalOutput.IsValid();
    }

    const bool hasUsableSource =
        finalOutputSource == CameraFrameColorSource::MainSceneColor
            ? UsesGraphManagedOutputColor(CameraFrameStage::MainScene)
            : UsesGraphManagedOutputColor(CameraFrameStage::PostProcess);
    return hasUsableSource &&
           HasValidColorTarget(finalOutput.destinationSurface) &&
           HasValidSurfaceSampleDescription(finalOutput.destinationSurface);
}

bool CameraFramePlan::HasFrameStage(CameraFrameStage stage) const {
    if (SupportsCameraFramePipelineGraphRecording(stage)) {
        return true;
    }

    if (IsCameraFrameSequenceStage(stage)) {
        if (IsCameraFrameFullscreenSequenceStage(stage)) {
            return IsFullscreenStageRequested(stage);
        }

        if (const FullscreenPassRenderRequest* fullscreenRequest =
                GetFullscreenPassRequest(stage);
            fullscreenRequest != nullptr) {
            return fullscreenRequest->IsRequested();
        }

        return GetPassSequence(stage) != nullptr;
    }

    switch (GetCameraFrameStageRequestKind(stage)) {
    case CameraFrameStageRequestKind::ShadowCaster:
        return IsShadowCasterStageRequested();
    case CameraFrameStageRequestKind::DepthOnly:
        return IsDepthOnlyStageRequested();
    case CameraFrameStageRequestKind::ObjectId:
        return request.objectId.IsRequested();
    default:
        return false;
    }
}

RenderPassSequence* CameraFramePlan::GetPassSequence(CameraFrameStage stage) const {
    if (!IsCameraFrameSequenceStage(stage)) {
        return nullptr;
    }

    switch (stage) {
    case CameraFrameStage::PreScenePasses:
        return preScenePasses;
    case CameraFrameStage::PostProcess:
        return postProcess.passes;
    case CameraFrameStage::FinalOutput:
        return finalOutput.passes;
    case CameraFrameStage::PostScenePasses:
        return postScenePasses;
    case CameraFrameStage::OverlayPasses:
        return overlayPasses;
    default:
        return nullptr;
    }
}

const FullscreenPassRenderRequest* CameraFramePlan::GetFullscreenPassRequest(
    CameraFrameStage stage) const {
    switch (stage) {
    case CameraFrameStage::PostProcess:
        return &postProcess;
    case CameraFrameStage::FinalOutput:
        return &finalOutput;
    default:
        return nullptr;
    }
}

const CameraFrameFullscreenStagePlan* CameraFramePlan::GetFullscreenStagePlan(
    CameraFrameStage stage) const {
    switch (stage) {
    case CameraFrameStage::PostProcess:
        return &colorChain.postProcess;
    case CameraFrameStage::FinalOutput:
        return &colorChain.finalOutput;
    default:
        return nullptr;
    }
}

const ScenePassRenderRequest* CameraFramePlan::GetScenePassRequest(CameraFrameStage stage) const {
    switch (GetCameraFrameStageRequestKind(stage)) {
    case CameraFrameStageRequestKind::ShadowCaster:
        return &shadowCaster;
    case CameraFrameStageRequestKind::DepthOnly:
        return &request.depthOnly;
    default:
        return nullptr;
    }
}

const ObjectIdRenderRequest* CameraFramePlan::GetObjectIdRequest(CameraFrameStage stage) const {
    return GetCameraFrameStageRequestKind(stage) ==
               CameraFrameStageRequestKind::ObjectId
        ? &request.objectId
        : nullptr;
}

const RenderSurface* CameraFramePlan::GetSharedStageOutputSurface(
    CameraFrameStage stage) const {
    switch (GetCameraFrameStageSharedOutputSurfaceRole(stage)) {
    case CameraFrameStageSharedSurfaceRole::MainScene:
        return &GetMainSceneSurface();
    case CameraFrameStageSharedSurfaceRole::FinalComposited:
        return &GetFinalCompositedSurface();
    default:
        return nullptr;
    }
}

const RenderSurface& CameraFramePlan::GetMainSceneSurface() const {
    if (UsesGraphManagedOutputColor(CameraFrameStage::MainScene) &&
        graphManagedSceneSurface.GetWidth() > 0u &&
        graphManagedSceneSurface.GetHeight() > 0u) {
        return graphManagedSceneSurface;
    }

    if (IsFullscreenStageRequested(CameraFrameStage::PostProcess) &&
        HasValidColorTarget(postProcess.sourceSurface)) {
        return postProcess.sourceSurface;
    }

    if (IsFullscreenStageRequested(CameraFrameStage::FinalOutput) &&
        HasValidColorTarget(finalOutput.sourceSurface)) {
        return finalOutput.sourceSurface;
    }

    return request.surface;
}

const RenderSurface& CameraFramePlan::GetFinalCompositedSurface() const {
    if (IsFullscreenStageRequested(CameraFrameStage::FinalOutput) &&
        HasValidColorTarget(finalOutput.destinationSurface)) {
        return finalOutput.destinationSurface;
    }

    if (IsFullscreenStageRequested(CameraFrameStage::PostProcess) &&
        HasValidColorTarget(postProcess.destinationSurface)) {
        return postProcess.destinationSurface;
    }

    return request.surface;
}

bool CameraFramePlan::RequiresIntermediateSceneColor() const {
    return IsFullscreenStageRequested(CameraFrameStage::PostProcess) ||
           IsFullscreenStageRequested(CameraFrameStage::FinalOutput);
}

void CameraFramePlan::RefreshGraphManagedSceneSurfaceState() {
    colorChain.usesGraphManagedSceneColor =
        DoesStageNeedGraphManagedSceneColor(colorChain.postProcess) ||
        DoesStageNeedGraphManagedSceneColor(colorChain.finalOutput);

    if (colorChain.usesGraphManagedSceneColor) {
        ConfigureGraphManagedSceneSurface();
    } else {
        graphManagedSceneSurface = {};
    }
}

} // namespace Rendering
} // namespace XCEngine