//===-- rosa/support/csv/CSVWriter.hpp --------------------------*- C++ -*-===//
//
//                                 The RoSA Framework
//
// Distributed under the terms and conditions of the Boost Software License 1.0.
// See accompanying file LICENSE.
//
// If you did not receive a copy of the license file, see
// http://www.boost.org/LICENSE_1_0.txt.
//
//===----------------------------------------------------------------------===//
///
/// \file rosa/support/csv/CSVWriter.hpp
///
/// \authors David Juhasz    (david.juhasz@tuwien.ac.at)
///          Edwin Willegger (edwin.willegger@tuwien.ac.at)
///
/// \date 2017-2020
///
/// \brief Facitilities to write CSV files.
///
//===----------------------------------------------------------------------===//

#ifndef ROSA_SUPPORT_CSV_CSVWRITER_HPP
#define ROSA_SUPPORT_CSV_CSVWRITER_HPP

#include <iostream>
#include <ostream>

#include <array>
#include <tuple>
#include <vector>

#include "rosa/support/log.h"

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
  /// \param          Delimiter is the separator between the values of
  /// the csv file.
  ///
  /// \note The writer operates on non-binary outputs as long as \p S is in
  /// good state.
  CSVWriter(std::ostream &S, const char Delimiter = ',')
      : Str(S.good() && !(S.flags() & std::ios::binary) ? &S : nullptr),
        Delimiter(Delimiter), 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 << Delimiter;
      } else {
        IsFirst = false;
      }
      *Str << PRINTABLE(V);
      if (!Str->good()) {
        Str = nullptr;
      }
    }
  }

  /// Set the delimiter used in the csv file.
  /// \param Separator the character which separates the values in the csv file.
  inline void setDelimiter(char Separator) noexcept {
    this->Delimiter = Separator;
  }

  /// get the delimiter currently set to separate the values in the csv file.
  /// \return the current character, which is used to separte teh values in the
  /// csv file.
  inline char getDelimiter() const noexcept { return this->Delimiter; }

private:
  std::ostream *Str; ///< Output stream to write to.
  char Delimiter;    ///< The separator between the data entries.
  bool IsFirst;      ///< Denotes if the next write would be the first one.
};

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

public:
  //    typedef <Ts...> value_type ;  ///< Type of values written.
  typedef std::tuple<Ts...> value_type;

  /// Creates a new instance.
  ///
  /// \param [in,out] S output stream to write to
  /// \param          Delimiter is the separator between the values of
  /// the csv file.
  ///
  /// \note The writer operates on non-binary outputs as long as \p S is in
  /// good state.
  CSVTupleWriter(std::ostream &S, const char Delimiter = ',')
      : Str(S.good() && !(S.flags() & std::ios::binary) ? &S : nullptr),
        Delimiter(Delimiter), IsHeaderWritten(false), IsDataWritten(false) {}

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

  /// Write the values of a tuple to a CSV file with \c
  /// rosa::csv::CSVTupleWriter.
  ///
  /// \see rosa::csv::CSVTupleWriter
  ///
  ///
  /// \param [in,out] values tuple, which values are written in a recusive
  /// fashion into a stream.
  template <size_t i = 0> void write(const std::tuple<Ts...> &values) {
    constexpr size_t size = sizeof...(Ts);
    const auto value = PRINTABLE(std::get<i>(values));

    LOG_TRACE_STREAM << "Writing tuple values into file \n";
    LOG_TRACE_STREAM << " Tuple has " << std::to_string(size)
                     << " elements. \n";

    LOG_TRACE_STREAM << " Value is " << value;

    if (Str) {
      /// Write the current element of the tuple into the stream and add a
      /// separtor after it, and call the function for the next element in the
      /// tuple.
      if constexpr (i + 1 != sizeof...(Ts)) {
        *Str << value << Delimiter;
        write<i + 1>(values);
        /// If the last element is written into the stream than begin a new
        /// line.
      } else if constexpr (i + 1 == sizeof...(Ts)) {
        *Str << value << '\n';
        /// every time the last data value of a line is written, the flag
        /// indicates that data was already written into the file.
        IsDataWritten = true;
      }
    }
  }

  /// Write the header values to a CSV file with \c rosa::csv::CSVTupleWriter.
  ///
  /// \note The function has no effect if anything has already been written
  /// to the output stream either by \c
  /// rosa::csv::CSVTupleWriter::writeHeader() or \c
  /// rosa::csv::CSVTupleWriter::write().
  ///
  /// \see rosa::csv::CSVTupleWriter
  ///
  /// \param header the content of the header line.
  void writeHeader(const std::array<std::string, sizeof...(Ts)> &header) {
    size_t index = 0;
    /// write into the stream only, if it is not a nullptr, and if no data and
    /// no header was already written into it.
    if (Str && IsDataWritten == false && IsHeaderWritten == false) {
      index = 0;
      for (auto i = header.begin(); i != header.end(); ++i) {
        index = index + 1;
        /// write into the stream every entry with a delimiter, in this case ",
        /// " until the last entry
        if (index != header.size()) {
          *Str << *i << Delimiter;
          /// write the last entry into the stream, without any delimiter
        } else {
          *Str << *i;
        }
      }
      /// finish the header line and start a new line.
      *Str << '\n';
      /// now it is not possible to write additional header lines.
      IsHeaderWritten = true;
    }
  }

  /// Set the delimiter used in the csv file.
  /// \param Separator the character which separates the values in the csv file.
  inline void setDelimiter(char Separator) noexcept {
    this->Delimiter = Separator;
  }

  /// get the delimiter currently set to separate the values in the csv file.
  /// \return the current character, which is used to separte teh values in the
  /// csv file.
  inline char getDelimiter() const noexcept { return this->Delimiter; }

private:
  std::ostream *Str;    ///< Output stream to write to.
  char Delimiter;       ///< The separator between the data entries.
  bool IsHeaderWritten; ///< If an header line was already written into the
                        ///< stream. If set than no additional header could be
                        ///< written.
  bool IsDataWritten; ///< If one line of data has already been written into the
                      ///< stream, than no headerline could be added.
};

/// Writes all values of a tuple to a CSV file with \c
/// rosa::csv::CSVTupleWriter.
///
/// \see rosa::csv::CSVTupleWriter
///
/// \tparam Ts types of values to write
///
/// \param [in,out] W object to write with
/// \param V values to write
///
/// \return \p W after writing \p V with it
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