// DatasetMergeResult.h

#ifndef dset__DatasetMergeResult_H
#define dset__DatasetMergeResult_H

// David Adams
// April 2004
//
// This class holds the reult of a dataset merge.
//
// None of the datasets are managed here.

#include <string>
#include <iosfwd>
#include <memory>
#include "dataset_base/Dataset.h"

class XmlElement;

namespace dset {

class DatasetMergeResult {

private:  // data

  bool m_valid;
  int m_err;
  DatasetList m_input_dsts;
  DatasetList m_merged_dsts;
  DatasetList m_rejected_dsts;
  const Dataset* m_pdst;

public:  // Constructors and destructor.

  // Constructor for invalid state.
  explicit DatasetMergeResult(int err =0);

  // Constructor for a valid result.
  DatasetMergeResult(const DatasetList& input_dsts,
                     const DatasetList& merged_datasets,
                     const DatasetList& rejected_datasets,
                     const Dataset* pdst);

public:  // Const methods

  // Validity.
  bool is_valid() const { return m_valid; }

  // Error code for invalid result.
  int error() const { return m_err; }

  // Is up to date.
  bool is_up_to_date() const {
    return merged_datasets().size() == input_datasets().size();
  }

  // Return the list of input datasets.
  // Does not include those rejected by append(...).
  const DatasetList& input_datasets() const { return m_input_dsts; }

  // Return the list of datasets included in the last call to dataset().
  const DatasetList& merged_datasets() const { return m_merged_dsts; }

  // Return the list of datasets rejected after their append(...).
  const DatasetList& rejected_datasets() const { return m_rejected_dsts; }

  // Return the merged dataset.
  // This dataset should not change and should not be deleted
  // until the next call to update(). After that, all bets are off.
  // It is not required that all input datasets be merged; instead
  // this corresponds to the list of merged datasets.
  const Dataset* dataset() const { return m_pdst; }

};

}  // end namespace dset

// Free functions.
std::ostream&
operator<<(std::ostream& lhs, const dset::DatasetMergeResult& rhs);

// Equality.
bool operator==(const dset::DatasetMergeResult& lhs,
                const dset::DatasetMergeResult& rhs);

// Inequality.
bool operator!=(const dset::DatasetMergeResult& lhs,
                const dset::DatasetMergeResult& rhs);

#endif