// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
// Mobius Forensic Toolkit
// Copyright (C) 2008,2009,2010,2011,2012,2013,2014,2015,2016,2017,2018,2019,2020,2021,2022 Eduardo Aguiar
//
// This program is free software; you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by the
// Free Software Foundation; either version 2, or (at your option) any later
// version.
//
// This program is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General
// Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
#include "line_reader.h"

namespace mobius
{
namespace io
{
namespace
{
// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
//! \brief Detect line separator
//! \param s String
//! \return Separator string or "" if not found
// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
static std::string
_detect_separator (const std::string& s)
{
  char last_c = 0;
  
  for (const auto& c : s)
    {
      if (c == '\n' && last_c == '\r')
        return "\r\n";
      
      else if (c == '\n')
        return "\n";
      
      else if (last_c == '\r')
        return "\r";
      
      last_c = c;
    }
    
  return {};
}

} // namespace

// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
//! \brief Constructor
//! \param text_reader Text reader object
//! \param separator Line separator
// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
line_reader::line_reader (
  const mobius::io::text_reader& text_reader,
  const std::string& separator
)
 : text_reader_ (text_reader),
   separator_ (separator)
{
}

// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
//! \brief Constructor
//! \param reader Reader object
//! \param encoding Charset encoding
//! \param separator Line separator
// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
line_reader::line_reader (
  const mobius::io::reader& reader,
  const std::string& encoding,
  const std::string& separator
)
 : text_reader_ (text_reader (reader, encoding)),
   separator_ (separator)
{
}

// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
//! \brief Read line
//! \param line Reference to line
//! \return <i>true</i> if line has been read, <i>false</i> otherwise
// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
bool
line_reader::read (std::string& line)
{
  // detect separator, if not set
  while (separator_.empty ())
    {
      auto data = text_reader_.read (65536);

      if (data.empty ())
        {
          if (buffer_.empty ())
            return false;

          line = buffer_;
          buffer_.clear ();
          return true;
        }

      buffer_ += data;
      separator_ = _detect_separator (buffer_);
    }

  // search for separator
  auto pos = buffer_.find (separator_);

  while (pos == std::string::npos)
    {
      auto data = text_reader_.read (65536);

      if (data.empty ())
        {
          if (buffer_.empty ())
            return false;

          line = buffer_;
          buffer_.clear ();
          return true;
        }

      buffer_ += data;
      pos = buffer_.find (separator_);
    }

  // if separator found, return line up to separator
  if (pos != std::string::npos)
    {
      line = buffer_.substr (0, pos);
      buffer_ = buffer_.erase (0, pos + separator_.size ());
      return true;
    }

  return false;
}

} // namespace io
} // namespace mobius
