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

namespace XCEngine {
namespace Rendering {

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;
}

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;
    return plan;
}

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

void CameraFramePlan::ConfigureGraphManagedMainSceneSurface() {
    graphManagedMainSceneSurface =
        BuildGraphManagedIntermediateSurfaceTemplate(request.surface);
}

bool CameraFramePlan::UsesGraphManagedMainSceneColor() const {
    return colorChain.usesGraphManagedMainSceneColor;
}

bool CameraFramePlan::UsesGraphManagedOutputColor(CameraFrameStage stage) const {
    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::IsPostProcessStageValid() const {
    if (!postProcess.IsRequested()) {
        return true;
    }

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

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

bool CameraFramePlan::IsFinalOutputStageValid() const {
    if (!finalOutput.IsRequested()) {
        return true;
    }

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

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

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

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

        return GetPassSequence(stage) != nullptr;
    }

    switch (GetCameraFrameStageRequestKind(stage)) {
    case CameraFrameStageRequestKind::ShadowCaster:
        return shadowCaster.IsRequested() || directionalShadow.IsValid();
    case CameraFrameStageRequestKind::DepthOnly:
        return request.depthOnly.IsRequested();
    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::GetMainSceneSurface() const {
    if (UsesGraphManagedMainSceneColor() &&
        graphManagedMainSceneSurface.GetWidth() > 0u &&
        graphManagedMainSceneSurface.GetHeight() > 0u) {
        return graphManagedMainSceneSurface;
    }

    if (postProcess.IsRequested() &&
        HasValidColorTarget(postProcess.sourceSurface)) {
        return postProcess.sourceSurface;
    }

    if (finalOutput.IsRequested() &&
        HasValidColorTarget(finalOutput.sourceSurface)) {
        return finalOutput.sourceSurface;
    }

    return request.surface;
}

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

    if (postProcess.IsRequested() &&
        HasValidColorTarget(postProcess.destinationSurface)) {
        return postProcess.destinationSurface;
    }

    return request.surface;
}

bool CameraFramePlan::RequiresIntermediateSceneColor() const {
    return postProcess.IsRequested() || finalOutput.IsRequested();
}

} // namespace Rendering
} // namespace XCEngine