// -*- c++ -*-
/*=========================================================================

  Program:   Visualization Toolkit
  Module:    vtkNetCDFReader.h

  Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
  All rights reserved.
  See Copyright.txt or http://www.kitware.com/Copyright.htm for details.

     This software is distributed WITHOUT ANY WARRANTY; without even
     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
     PURPOSE.  See the above copyright notice for more information.

=========================================================================*/

/*-------------------------------------------------------------------------
  Copyright 2008 Sandia Corporation.
  Under the terms of Contract DE-AC04-94AL85000 with Sandia Corporation,
  the U.S. Government retains certain rights in this software.
-------------------------------------------------------------------------*/

/**
 * @class   vtkNetCDFReader
 *
 *
 *
 * A superclass for reading netCDF files.  Subclass add conventions to the
 * reader.  This class just outputs data into a multi block data set with a
 * vtkImageData at each block.  A block is created for each variable except that
 * variables with matching dimensions will be placed in the same block.
 */

#ifndef vtkNetCDFReader_h
#define vtkNetCDFReader_h

#include "vtkDataObjectAlgorithm.h"
#include "vtkIONetCDFModule.h" // For export macro

#include "vtkSmartPointer.h" // For ivars
#include <string>            //For std::string

class vtkDataArraySelection;
class vtkDataSet;
class vtkDoubleArray;
class vtkIntArray;
class vtkStdString;
class vtkStringArray;
class vtkNetCDFReaderPrivate;

class VTKIONETCDF_EXPORT vtkNetCDFReader : public vtkDataObjectAlgorithm
{
public:
  vtkTypeMacro(vtkNetCDFReader, vtkDataObjectAlgorithm);
  static vtkNetCDFReader* New();
  void PrintSelf(ostream& os, vtkIndent indent) override;

  virtual void SetFileName(const char* filename);
  vtkGetStringMacro(FileName);

  /**
   * Update the meta data from the current file.  Automatically called
   * during the RequestInformation pipeline update stage.
   */
  int UpdateMetaData();

  //   // Description:
  //   // Get the data array selection tables used to configure which variables to
  //   // load.
  //   vtkGetObjectMacro(VariableArraySelection, vtkDataArraySelection);

  //@{
  /**
   * Variable array selection.
   */
  virtual int GetNumberOfVariableArrays();
  virtual const char* GetVariableArrayName(int idx);
  virtual int GetVariableArrayStatus(const char* name);
  virtual void SetVariableArrayStatus(const char* name, int status);
  //@}

  /**
   * Convenience method to get a list of variable arrays.  The length of the
   * returned list is the same as GetNumberOfVariableArrays, and the string
   * at each index i is the same as returned from GetVariableArrayname(i).
   */
  virtual vtkStringArray* GetAllVariableArrayNames();

  //@{
  /**
   * Returns an array with string encodings for the dimensions used in each of
   * the variables.  The indices in the returned array correspond to those used
   * in the GetVariableArrayName method.  Two arrays with the same dimensions
   * will have the same encoded string returned by this method.
   */
  vtkGetObjectMacro(VariableDimensions, vtkStringArray);
  //@}

  /**
   * Loads the grid with the given dimensions.  The dimensions are encoded in a
   * string that conforms to the same format as returned by
   * GetVariableDimensions and GetAllDimensions.  This method is really a
   * convenience method for SetVariableArrayStatus.  It turns on all variables
   * that have the given dimensions and turns off all other variables.
   */
  virtual void SetDimensions(const char* dimensions);

  /**
   * Enables arrays in VariableArraySelection depending on Dimensions.
   * Returns true if one variable matching Dimensions was found.
   */
  bool ComputeArraySelection();

  //@{
  /**
   * Returns an array with string encodings for the dimension combinations used
   * in the variables.  The result is the same as GetVariableDimensions except
   * that each entry in the array is unique (a set of dimensions is only given
   * once even if it occurs for multiple variables) and the order is
   * meaningless.
   */
  vtkGetObjectMacro(AllDimensions, vtkStringArray);
  //@}

  //@{
  /**
   * If on, any float or double variable read that has a _FillValue attribute
   * will have that fill value replaced with a not-a-number (NaN) value.  The
   * advantage of setting these to NaN values is that, if implemented properly
   * by the system and careful math operations are used, they can implicitly be
   * ignored by calculations like finding the range of the values.  That said,
   * this option should be used with caution as VTK does not fully support NaN
   * values and therefore odd calculations may occur.  By default this is off.
   */
  vtkGetMacro(ReplaceFillValueWithNan, vtkTypeBool);
  vtkSetMacro(ReplaceFillValueWithNan, vtkTypeBool);
  vtkBooleanMacro(ReplaceFillValueWithNan, vtkTypeBool);
  //@}

  //@{
  /**
   * Access to the time dimensions units.
   * Can be used by the udunits library to convert raw numerical time values
   * into meaningful representations.
   */
  vtkGetStringMacro(TimeUnits);
  vtkGetStringMacro(Calendar);
  //@}

  /**
   * Get units attached to a particular array in the netcdf file.
   */
  std::string QueryArrayUnits(const char* ArrayName);

protected:
  vtkNetCDFReader();
  ~vtkNetCDFReader() override;

  char* FileName;
  vtkTimeStamp FileNameMTime;
  vtkTimeStamp MetaDataMTime;

  /**
   * The dimension ids of the arrays being loaded into the data.
   */
  vtkSmartPointer<vtkIntArray> LoadingDimensions;

  vtkSmartPointer<vtkDataArraySelection> VariableArraySelection;

  vtkSmartPointer<vtkStringArray> AllVariableArrayNames;

  /**
   * Placeholder for structure returned from GetVariableDimensions().
   */
  vtkStringArray* VariableDimensions;

  std::string CurrentDimensions;

  /**
   * Placeholder for structure returned from GetAllDimensions().
   */
  vtkStringArray* AllDimensions;

  vtkTypeBool ReplaceFillValueWithNan;

  int WholeExtent[6];

  int RequestDataObject(vtkInformation* request, vtkInformationVector** inputVector,
    vtkInformationVector* outputVector) override;

  int RequestInformation(vtkInformation* request, vtkInformationVector** inputVector,
    vtkInformationVector* outputVector) override;

  int RequestData(vtkInformation* request, vtkInformationVector** inputVector,
    vtkInformationVector* outputVector) override;

  /**
   * Callback registered with the VariableArraySelection.
   */
  static void SelectionModifiedCallback(
    vtkObject* caller, unsigned long eid, void* clientdata, void* calldata);

  /**
   * Convenience function for getting a string that describes a set of
   * dimensions.
   */
  vtkStdString DescribeDimensions(int ncFD, const int* dimIds, int numDims);

  /**
   * Reads meta data and populates ivars.  Returns 1 on success, 0 on failure.
   */
  virtual int ReadMetaData(int ncFD);

  /**
   * Fills the VariableDimensions array.
   */
  virtual int FillVariableDimensions(int ncFD);

  /**
   * Determines whether the given variable is a time dimension.  The default
   * implementation bases the decision on the name of the variable.  Subclasses
   * should override this function if there is a more specific way to identify
   * the time variable.  This method is always called after ReadMetaData for
   * a given file.
   */
  virtual int IsTimeDimension(int ncFD, int dimId);

  /**
   * Given a dimension already determined to be a time dimension (via a call to
   * IsTimeDimension) returns an array with time values.  The default
   * implementation just uses the time index for the time value.  Subclasses
   * should override this function if there is a convention that identifies time
   * values.  This method returns 0 on error, 1 otherwise.
   */
  virtual vtkSmartPointer<vtkDoubleArray> GetTimeValues(int ncFD, int dimId);

  /**
   * Called internally to determine whether a variable with the given set of
   * dimensions should be loaded as point data (return true) or cell data
   * (return false).  The implementation in this class always returns true.
   * Subclasses should override to load cell data for some or all variables.
   */
  virtual bool DimensionsAreForPointData(vtkIntArray* vtkNotUsed(dimensions)) { return true; }

  /**
   * Retrieves the update extent for the output object.  The default
   * implementation just gets the update extent from the object as you would
   * expect.  However, if a subclass is loading an unstructured data set, this
   * gives it a chance to set the range of values to read.
   */
  virtual void GetUpdateExtentForOutput(vtkDataSet* output, int extent[6]);

  /**
   * Load the variable at the given time into the given data set.  Return 1
   * on success and 0 on failure.
   */
  virtual int LoadVariable(int ncFD, const char* varName, double time, vtkDataSet* output);

private:
  vtkNetCDFReader(const vtkNetCDFReader&) = delete;
  void operator=(const vtkNetCDFReader&) = delete;

  int UpdateExtent[6];
  char* TimeUnits;
  char* Calendar;
  vtkNetCDFReaderPrivate* Private;
};

#endif // vtkNetCDFReader_h
