//===-- rosa/support/csv/CSVWriter.hpp --------------------------*- C++ -*-===//
//
//                                 The RoSA Framework
//
//===----------------------------------------------------------------------===//
///
/// \file rosa/support/csv/CSVWriter.hpp
///
/// \authors David Juhasz (david.juhasz@tuwien.ac.at)
///          Edwin Willegger (edwin.willegger@tuwien.ac.at)
///
/// \date 2017-2019
///
/// \brief Facitilities to write CSV files.
///
//===----------------------------------------------------------------------===//

#ifndef ROSA_SUPPORT_CSV_CSVWRITER_HPP
#define ROSA_SUPPORT_CSV_CSVWRITER_HPP

#include <iostream>
#include <ostream>

#include <tuple>
#include <vector>

namespace rosa {
namespace csv {

/// Provides facilities to write values into a CSV file.
///
/// The writer emits a comma, the character `,`, between each written values.
/// The resulted stream is a flat CSV file as it consists of onlyone row, no new
/// line is emitted.
///
/// \tparam T type of values to write
template <typename T>
class CSVWriter {
public:
  /// Creates a new instance.
  ///
  /// \param [in,out] S output stream to write to
  ///
  /// \note The writer operates on non-binary outputs as long as \p S is in
  /// good state.
  CSVWriter(std::ostream &S)
      : Str(S.good() && !(S.flags() & std::ios::binary) ? &S : nullptr),
        IsFirst(true) {}

  /// Tells if the last operation was successful.
  ///
  /// \return if the last operation was successful
  bool good(void) const noexcept {
    return Str != nullptr;
  }

  /// Writes an entry to the output stream.
  ///
  /// The implementation does anything only if the last operation was
  /// successful. If so, \p V is written to \c rosa::csv::CSVWriter::Str.
  /// The emitted value is preceded with a comma if the actual call is not the
  /// first one for \p this object. Success of the operation is checked at the
  /// end.
  ///
  /// \param V value to write
  void write(const T &V) {
    if (Str) {
      if (!IsFirst) {
        *Str << ',';
      } else {
        IsFirst = false;
      }
      *Str << V;
      if (!Str->good()) {
        Str = nullptr;
      }
    }
  }

private:
  std::ostream *Str; ///< Output stream to write to.
  bool IsFirst;      ///< Denotes if the next write would be the first one.
};

/// Writes a tuple of values into a CSV file
///
/// \tparam Ts tpyes of values to write
template <typename... Ts> class CSVTupleWriter {

public:
    /// Creates a new instance.
    ///
    /// \param [in,out] S output stream to write to
    ///
    /// \note The writer operates on non-binary outputs as long as \p S is in
    /// good state.
    CSVTupleWriter(std::ostream &S)
        : Str(S.good() && !(S.flags() & std::ios::binary) ? &S : nullptr),
          IsFirst(true) {}

    /// Tells if the last operation was successful.
    ///
    /// \return if the last operation was successful
    bool good(void) const noexcept {
      return Str != nullptr;
    }

    template<size_t i = 0>
    void write(std::tuple<Ts...> values) {
        size_t size = 0;
        std::cout << "Writing tuple values into file" << std::endl;
        std::cout << "Tuple has ";
        std::cout << std::tuple_size<decltype (values)>::value;
        std::cout << " elements." << std::endl;
        size = std::tuple_size<decltype (values)>::value;

        std::cout << std::get<i>(values) << std::endl;

        if(Str){
            if constexpr(i+1 != sizeof...(Ts)){
                *Str << std::get<i>(values) << ", ";
                write<i+1>(values);
            }else if constexpr(i + 1 == sizeof...(Ts)){
                *Str << std::get<i>(values) << '\n';
            }
        }
    }

    void writeHeader(std::vector<std::string> header){
        size_t index = 0;
        if(Str){
            index = 0;
            for (auto i = header.begin(); i != header.end(); ++i){
                index = index + 1;
                if(index != header.size()){
                    *Str << *i << ", ";
                }else {
                    *Str << *i;
                }
            }
            *Str << '\n';
        }
    }

private:
    std::ostream *Str; ///< Output stream to write to.
    bool IsFirst;      ///< Denotes if the next write would be the first one.

};

template <typename... Ts>
CSVTupleWriter<Ts...> &operator<<(CSVTupleWriter<Ts...> &W, const std::tuple<Ts...> V)
{
    W.write(V);
    return W;
}

/// Writes a value to a CSV file with \c rosa::csv::CSVWriter.
///
/// \see rosa::csv::CSVWriter
///
/// \tparam T type of value to write
///
/// \param [in,out] W object to write with
/// \param V value to write
///
/// \return \p W after writing \p V with it
template <typename T>
CSVWriter<T> &operator<<(CSVWriter<T> &W, const T& V) {
  W.write(V);
  return W;
}

} // End namespace csv
} // End namespace rosa

#endif // ROSA_SUPPORT_CSV_CSVWRITER_HPP