#include "nmVTKMeshLayer.h"

#include <QCoreApplication>
#include <QThread>
#include <QtGlobal>

#include <vtkActor.h>
#include <vtkCellData.h>
#include <vtkDataArray.h>
#include <vtkDataSet.h>
#include <vtkDataSetMapper.h>
#include <vtkLookupTable.h>
#include <vtkMath.h>
#include <vtkPointData.h>
#include <vtkProperty.h>

namespace {

// Mapper、Actor 和输入数据都属于 VTK 状态，只允许 GUI 线程修改。
bool isMeshLayerGuiThread()
{
    QCoreApplication* pApplication = QCoreApplication::instance();
    return pApplication == NULL ||
            pApplication->thread() == QThread::currentThread();
}

}

nmVTKMeshLayer::nmVTKMeshLayer(const QString& sLayerId)
    : nmVTKRenderLayer(sLayerId),
      m_pDataSet(NULL),
      m_pMapper(vtkSmartPointer<vtkDataSetMapper>::New()),
      m_pActor(vtkSmartPointer<vtkActor>::New()),
      m_pLookupTable(vtkSmartPointer<vtkLookupTable>::New()),
      m_eDisplayMode(DisplayMode_Surface),
      m_eScalarAssociation(ScalarAssociation_CellData),
      m_bUsingExplicitScalarRange(false)
{
    Q_ASSERT(isMeshLayerGuiThread());

    // 图层独占 Mapper、Actor 和 LookupTable；数据集通过智能指针共享。
    m_pLookupTable->SetNumberOfTableValues(256);
    m_pLookupTable->SetHueRange(0.67, 0.0);
    m_pLookupTable->Build();

    m_pMapper->SetLookupTable(m_pLookupTable);
    m_pMapper->ScalarVisibilityOff();
    m_pActor->SetMapper(m_pMapper);
    m_pActor->GetProperty()->SetRepresentationToSurface();
    m_pActor->GetProperty()->EdgeVisibilityOff();
    setRenderProp(m_pActor);
}

nmVTKMeshLayer::~nmVTKMeshLayer()
{
    Q_ASSERT(isMeshLayerGuiThread());
    // 派生成员释放前先解除 Renderer，基类析构中的 detach 仍保持幂等。
    detach();
    m_pDataSet = NULL;
}

bool nmVTKMeshLayer::setDataSet(vtkDataSet* pDataSet)
{
    Q_ASSERT(isMeshLayerGuiThread());
    if(!isMeshLayerGuiThread()) {
        return false;
    }

    // vtkSmartPointer 仅增加引用计数，不复制点、单元或属性数组。
    m_pDataSet = pDataSet;
    m_pMapper->SetInputData(pDataSet);

    if(pDataSet == NULL) {
        clearInvalidScalarState();
        return false;
    }

    // 更换数据集时保留调用方此前的数组选择；若同名数组存在则恢复其映射方式。
    if(!m_aScalarArrayName.isEmpty()) {
        if(getSelectedScalarArray() == NULL) {
            clearInvalidScalarState();
            return false;
        }
        if(m_eScalarAssociation == ScalarAssociation_CellData) {
            m_pMapper->SetScalarModeToUseCellFieldData();
        } else {
            m_pMapper->SetScalarModeToUsePointFieldData();
        }
        m_pMapper->SelectColorArray(m_aScalarArrayName.constData());
        if(!m_bUsingExplicitScalarRange) {
            if(!applyDataScalarRange()) {
                clearInvalidScalarState();
                return false;
            }
        }
    }
    return true;
}

vtkDataSet* nmVTKMeshLayer::getDataSet() const
{
    return m_pDataSet;
}

void nmVTKMeshLayer::setDisplayMode(DisplayMode eMode)
{
    Q_ASSERT(isMeshLayerGuiThread());
    if(!isMeshLayerGuiThread() || m_pActor == NULL) {
        return;
    }

    // 未识别枚举值按纯表面处理，避免把无效值带入 VTK Property。
    m_eDisplayMode = eMode == DisplayMode_SurfaceWithEdges
            ? DisplayMode_SurfaceWithEdges : DisplayMode_Surface;
    vtkProperty* pProperty = m_pActor->GetProperty();
    pProperty->SetRepresentationToSurface();
    pProperty->SetEdgeVisibility(
                m_eDisplayMode == DisplayMode_SurfaceWithEdges ? 1 : 0);
}

nmVTKMeshLayer::DisplayMode nmVTKMeshLayer::getDisplayMode() const
{
    return m_eDisplayMode;
}

bool nmVTKMeshLayer::setOpacity(double dOpacity)
{
    Q_ASSERT(isMeshLayerGuiThread());
    if(!isMeshLayerGuiThread() || !vtkMath::IsFinite(dOpacity) ||
       m_pActor == NULL) {
        return false;
    }
    m_pActor->GetProperty()->SetOpacity(qBound(0.0, dOpacity, 1.0));
    return true;
}

double nmVTKMeshLayer::getOpacity() const
{
    return m_pActor != NULL ? m_pActor->GetProperty()->GetOpacity() : 0.0;
}

void nmVTKMeshLayer::setScalarVisibility(bool bVisible)
{
    Q_ASSERT(isMeshLayerGuiThread());
    if(!isMeshLayerGuiThread() || m_pMapper == NULL) {
        return;
    }
    m_pMapper->SetScalarVisibility(bVisible ? 1 : 0);
}

bool nmVTKMeshLayer::isScalarVisible() const
{
    return m_pMapper != NULL && m_pMapper->GetScalarVisibility() != 0;
}

bool nmVTKMeshLayer::setScalarArray(
        const QString& sArrayName,
        ScalarAssociation eAssociation)
{
    Q_ASSERT(isMeshLayerGuiThread());
    if(!isMeshLayerGuiThread() || sArrayName.isEmpty() ||
       m_pDataSet == NULL || m_pMapper == NULL ||
       (eAssociation != ScalarAssociation_CellData &&
        eAssociation != ScalarAssociation_PointData)) {
        return false;
    }

    const QByteArray aArrayName = sArrayName.toUtf8();
    vtkDataArray* pArray = eAssociation == ScalarAssociation_CellData
            ? m_pDataSet->GetCellData()->GetArray(aArrayName.constData())
            : m_pDataSet->GetPointData()->GetArray(aArrayName.constData());
    if(pArray == NULL) {
        // 失败时保留原数组选择和原 Mapper 状态。
        return false;
    }

    double dRange[2] = { 0.0, 0.0 };
    if(!m_bUsingExplicitScalarRange) {
        pArray->GetRange(dRange);
        if(!vtkMath::IsFinite(dRange[0]) ||
           !vtkMath::IsFinite(dRange[1]) || dRange[0] > dRange[1]) {
            // 自动范围无效时不提交新数组选择，避免形成半更新状态。
            return false;
        }
    }

    m_aScalarArrayName = aArrayName;
    m_eScalarAssociation = eAssociation;
    if(eAssociation == ScalarAssociation_CellData) {
        m_pMapper->SetScalarModeToUseCellFieldData();
    } else {
        m_pMapper->SetScalarModeToUsePointFieldData();
    }
    m_pMapper->SelectColorArray(m_aScalarArrayName.constData());

    // 已设置显式范围时不覆盖，否则同步提交已经验证的数据范围。
    if(!m_bUsingExplicitScalarRange) {
        m_pMapper->SetScalarRange(dRange);
        m_pLookupTable->SetRange(dRange);
        m_pLookupTable->Build();
    }
    return true;
}

QString nmVTKMeshLayer::getScalarArrayName() const
{
    return QString::fromUtf8(m_aScalarArrayName.constData());
}

nmVTKMeshLayer::ScalarAssociation
nmVTKMeshLayer::getScalarAssociation() const
{
    return m_eScalarAssociation;
}

bool nmVTKMeshLayer::setScalarRange(double dMinimum, double dMaximum)
{
    Q_ASSERT(isMeshLayerGuiThread());
    if(!isMeshLayerGuiThread() || !vtkMath::IsFinite(dMinimum) ||
       !vtkMath::IsFinite(dMaximum) || dMinimum > dMaximum ||
       m_pMapper == NULL || m_pLookupTable == NULL) {
        return false;
    }

    // Mapper 与 LookupTable 使用同一范围，保证几何着色和外接色标一致。
    m_pMapper->SetScalarRange(dMinimum, dMaximum);
    m_pLookupTable->SetRange(dMinimum, dMaximum);
    m_pLookupTable->Build();
    m_bUsingExplicitScalarRange = true;
    return true;
}

bool nmVTKMeshLayer::restoreDataScalarRange()
{
    Q_ASSERT(isMeshLayerGuiThread());
    if(!isMeshLayerGuiThread() || !applyDataScalarRange()) {
        return false;
    }
    // 只有成功应用数据范围后才退出显式范围模式。
    m_bUsingExplicitScalarRange = false;
    return true;
}

bool nmVTKMeshLayer::isUsingExplicitScalarRange() const
{
    return m_bUsingExplicitScalarRange;
}

vtkDataSetMapper* nmVTKMeshLayer::getMapper() const
{
    return m_pMapper;
}

vtkActor* nmVTKMeshLayer::getActor() const
{
    return m_pActor;
}

vtkLookupTable* nmVTKMeshLayer::getLookupTable() const
{
    return m_pLookupTable;
}

vtkDataArray* nmVTKMeshLayer::getSelectedScalarArray() const
{
    if(m_pDataSet == NULL || m_aScalarArrayName.isEmpty()) {
        return NULL;
    }
    return m_eScalarAssociation == ScalarAssociation_CellData
            ? m_pDataSet->GetCellData()->GetArray(
                m_aScalarArrayName.constData())
            : m_pDataSet->GetPointData()->GetArray(
                m_aScalarArrayName.constData());
}

bool nmVTKMeshLayer::applyDataScalarRange()
{
    vtkDataArray* pArray = getSelectedScalarArray();
    if(pArray == NULL || m_pMapper == NULL || m_pLookupTable == NULL) {
        return false;
    }

    // GetRange 只扫描当前选中的数组；无效或非有限范围不会污染现有颜色表。
    double dRange[2] = { 0.0, 0.0 };
    pArray->GetRange(dRange);
    if(!vtkMath::IsFinite(dRange[0]) || !vtkMath::IsFinite(dRange[1]) ||
       dRange[0] > dRange[1]) {
        return false;
    }

    m_pMapper->SetScalarRange(dRange);
    m_pLookupTable->SetRange(dRange);
    m_pLookupTable->Build();
    return true;
}

void nmVTKMeshLayer::clearInvalidScalarState()
{
    // 失效选择不能继续驱动几何着色，也不能让外接色标沿用上一数据集范围。
    m_aScalarArrayName.clear();
    m_eScalarAssociation = ScalarAssociation_CellData;
    m_bUsingExplicitScalarRange = false;
    m_pMapper->ScalarVisibilityOff();
    m_pMapper->SetScalarModeToDefault();
    m_pMapper->SetScalarRange(0.0, 1.0);
    m_pLookupTable->SetRange(0.0, 1.0);
    m_pLookupTable->Build();
}