#include "MantidMDAlgorithms/DivideMD.h"
#include "MantidKernel/System.h"
#include "MantidDataObjects/MDEventFactory.h"
#include "MantidDataObjects/MDEventWorkspace.h"
#include "MantidDataObjects/MDBoxBase.h"
#include "MantidDataObjects/MDBox.h"

using namespace Mantid::Kernel;
using namespace Mantid::API;
using namespace Mantid::DataObjects;

namespace Mantid {
namespace MDAlgorithms {

// Register the algorithm into the AlgorithmFactory
DECLARE_ALGORITHM(DivideMD)

//----------------------------------------------------------------------------------------------
/** Constructor
 */
DivideMD::DivideMD() {}

//----------------------------------------------------------------------------------------------
/** Destructor
 */
DivideMD::~DivideMD() {}

//----------------------------------------------------------------------------------------------
/// Algorithm's name for identification. @see Algorithm::name
const std::string DivideMD::name() const { return "DivideMD"; }

/// Algorithm's version for identification. @see Algorithm::version
int DivideMD::version() const { return 1; }

//----------------------------------------------------------------------------------------------

//----------------------------------------------------------------------------------------------
/// Is the operation commutative?
bool DivideMD::commutative() const { return false; }

//----------------------------------------------------------------------------------------------
/// Check the inputs and throw if the algorithm cannot be run
void DivideMD::checkInputs() {
  if (m_rhs_event)
    throw std::runtime_error("Cannot divide by a MDEventWorkspace on the RHS.");
  if (m_lhs_event && !m_rhs_scalar)
    throw std::runtime_error(
        "A MDEventWorkspace can only be divided by a scalar.");
}

//----------------------------------------------------------------------------------------------
/** Perform the operation with MDEventWorkpsace as LHS and a scalar as RHS
 * Will do "ws /= scalar"
 * @param ws ::  MDEventWorkspace being modified
 */
template <typename MDE, size_t nd>
void DivideMD::execEventScalar(typename MDEventWorkspace<MDE, nd>::sptr ws) {
  // Get the scalar multiplying
  float scalar = float(m_rhs_scalar->dataY(0)[0]);
  float scalarError = float(m_rhs_scalar->dataE(0)[0]);
  float scalarRelativeErrorSquared =
      (scalarError * scalarError) / (scalar * scalar);

  // Get all the MDBoxes contained
  MDBoxBase<MDE, nd> *parentBox = ws->getBox();
  std::vector<API::IMDNode *> boxes;
  parentBox->getBoxes(boxes, 1000, true);

  bool fileBackedTarget(false);
  Kernel::DiskBuffer *dbuff(NULL);
  if (ws->isFileBacked()) {
    fileBackedTarget = true;
    dbuff = ws->getBoxController()->getFileIO();
  }

  for (size_t i = 0; i < boxes.size(); i++) {
    MDBox<MDE, nd> *box = dynamic_cast<MDBox<MDE, nd> *>(boxes[i]);
    if (box) {
      size_t ic(0);
      typename std::vector<MDE> &events = box->getEvents();
      typename std::vector<MDE>::iterator it = events.begin();
      typename std::vector<MDE>::iterator it_end = events.end();
      for (; it != it_end; it++) {
        // Multiply weight by a scalar, propagating error
        float oldSignal = it->getSignal();
        float signal = oldSignal / scalar;
        float errorSquared =
            signal * signal * (it->getErrorSquared() / (oldSignal * oldSignal) +
                               scalarRelativeErrorSquared);
        it->setSignal(signal);
        it->setErrorSquared(errorSquared);
        ic++;
      }

      box->releaseEvents();
      if (fileBackedTarget && ic > 0) {
        Kernel::ISaveable *const pSaver(box->getISaveable());
        dbuff->toWrite(pSaver);
      }
    }
  }
  // Recalculate the totals
  ws->refreshCache();
  // Mark file-backed workspace as dirty
  ws->setFileNeedsUpdating(true);
}

//----------------------------------------------------------------------------------------------
/// Run the algorithm with an MDEventWorkspace as output
void DivideMD::execEvent() {
  if (m_lhs_event && !m_rhs_scalar)
    throw std::runtime_error(
        "A MDEventWorkspace can only be divided by a scalar.");
  if (!m_out_event)
    throw std::runtime_error(
        "DivideMD::execEvent(): Error creating output MDEventWorkspace.");
  // Call the method to do the dividing
  CALL_MDEVENT_FUNCTION(this->execEventScalar, m_out_event);
}

//----------------------------------------------------------------------------------------------
/// Run the algorithm with a MDHisotWorkspace as output and operand
void DivideMD::execHistoHisto(
    Mantid::DataObjects::MDHistoWorkspace_sptr out,
    Mantid::DataObjects::MDHistoWorkspace_const_sptr operand) {
  out->divide(*operand);
}

//----------------------------------------------------------------------------------------------
/// Run the algorithm with a MDHisotWorkspace as output, scalar and operand
void DivideMD::execHistoScalar(
    Mantid::DataObjects::MDHistoWorkspace_sptr out,
    Mantid::DataObjects::WorkspaceSingleValue_const_sptr scalar) {
  out->divide(scalar->dataY(0)[0], scalar->dataE(0)[0]);
}

} // namespace Mantid
} // namespace MDAlgorithms