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

  Program:   Visualization Toolkit
  Module:    vtkSQLiteToTableReader.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.

=========================================================================*/
#include "vtkDoubleArray.h"
#include "vtkInformation.h"
#include "vtkInformationVector.h"
#include "vtkIntArray.h"
#include "vtkObjectFactory.h"
#include "vtkSQLiteDatabase.h"
#include "vtkSQLiteQuery.h"
#include "vtkSmartPointer.h"
#include "vtkStreamingDemandDrivenPipeline.h"
#include "vtkStringArray.h"
#include "vtkTable.h"

#include "vtkSQLiteToTableReader.h"

//----------------------------------------------------------------------------
vtkStandardNewMacro(vtkSQLiteToTableReader);

//----------------------------------------------------------------------------
vtkSQLiteToTableReader::vtkSQLiteToTableReader() = default;

//----------------------------------------------------------------------------
vtkSQLiteToTableReader::~vtkSQLiteToTableReader() = default;

//----------------------------------------------------------------------------
int vtkSQLiteToTableReader::RequestData(vtkInformation *,
                                      vtkInformationVector **,
                                      vtkInformationVector *outputVector)
{
  //Make sure we have all the information we need to provide a vtkTable
  if(!this->Database)
  {
    vtkErrorMacro(<<"No open database connection");
    return 1;
  }
  if(!this->Database->IsA("vtkSQLiteDatabase"))
  {
    vtkErrorMacro(<<"Wrong type of database for this reader");
    return 1;
  }
  if(this->TableName.empty())
  {
    vtkErrorMacro(<<"No table selected");
    return 1;
  }

  vtkInformation *outInfo = outputVector->GetInformationObject(0);

  // Return all data in the first piece ...
  if(outInfo->Get(vtkStreamingDemandDrivenPipeline::UPDATE_PIECE_NUMBER()) > 0)
  {
    return 1;
  }

  vtkTable* const output = vtkTable::SafeDownCast(
      outInfo->Get(vtkDataObject::DATA_OBJECT()));

  //perform a query to get the names and types of the columns
  std::string queryStr = "pragma table_info(";
  queryStr += this->TableName;
  queryStr += ")";
  vtkSQLiteQuery *query =
    static_cast<vtkSQLiteQuery*>(this->Database->GetQueryInstance());
  query->SetQuery(queryStr.c_str());
  if(!query->Execute())
  {
    vtkErrorMacro(<<"Error performing 'pragma' query");
  }

  //use the results of the query to create columns of the proper name & type
  std::vector<std::string> columnTypes;
  while(query->NextRow())
  {
    std::string columnName = query->DataValue(1).ToString();
    std::string columnType = query->DataValue(2).ToString();
    columnTypes.push_back(columnType);
    if(columnType == "INTEGER")
    {
      vtkSmartPointer<vtkIntArray> column =
        vtkSmartPointer<vtkIntArray>::New();
      column->SetName(columnName.c_str());
      output->AddColumn(column);
    }
    else if(columnType == "REAL")
    {
      vtkSmartPointer<vtkDoubleArray> column =
        vtkSmartPointer<vtkDoubleArray>::New();
      column->SetName(columnName.c_str());
      output->AddColumn(column);
    }
    else
    {
      vtkSmartPointer<vtkStringArray> column =
        vtkSmartPointer<vtkStringArray>::New();
      column->SetName(columnName.c_str());
      output->AddColumn(column);
    }
  }

  //do a query to get the contents of the SQLite table
  queryStr = "SELECT * FROM ";
  queryStr += this->TableName;
  query->SetQuery(queryStr.c_str());
  if(!query->Execute())
  {
    vtkErrorMacro(<<"Error performing 'select all' query");
  }

  //use the results of the query to populate the columns
  while(query->NextRow())
  {
    for(int col = 0; col < query->GetNumberOfFields(); ++ col)
    {
      if(columnTypes[col] == "INTEGER")
      {
        vtkIntArray *column =
          static_cast<vtkIntArray*>(output->GetColumn(col));
        column->InsertNextValue(query->DataValue(col).ToInt());
      }
      else if(columnTypes[col] == "REAL")
      {
        vtkDoubleArray *column =
          static_cast<vtkDoubleArray*>(output->GetColumn(col));
        column->InsertNextValue(query->DataValue(col).ToDouble());
      }
      else
      {
        vtkStringArray *column =
          static_cast<vtkStringArray*>(output->GetColumn(col));
        column->InsertNextValue(query->DataValue(col).ToString());
      }
    }
  }

  query->Delete();
  return 1;
}

//----------------------------------------------------------------------------
void vtkSQLiteToTableReader::PrintSelf(ostream& os, vtkIndent indent)
{
  this->Superclass::PrintSelf(os,indent);
}
