////////////////////////////////////////////////////////////////////////
//
// Copyright (C) 1996-2022 The Octave Project Developers
//
// See the file COPYRIGHT.md in the top-level directory of this
// distribution or <https://octave.org/copyright/>.
//
// This file is part of Octave.
//
// Octave 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 3 of the License, or
// (at your option) any later version.
//
// Octave 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 Octave; see the file COPYING.  If not, see
// <https://www.gnu.org/licenses/>.
//
////////////////////////////////////////////////////////////////////////

#if ! defined (octave_oct_stream_h)
#define octave_oct_stream_h 1

#include "octave-config.h"

#include <ios>
#include <iosfwd>
#include <list>
#include <map>
#include <memory>
#include <string>

#include "oct-string.h"

// These only appear as reference arguments or return values.

class Cell;
class octave_value;
class octave_value_list;
class string_vector;

#include "Array-fwd.h"
#include "data-conv.h"
#include "mach-info.h"

OCTAVE_BEGIN_NAMESPACE(octave)

  class interpreter;

  // These are only needed as arguments to private functions, so they
  // are also treated as private.

  class scanf_format_elt;
  class scanf_format_list;

  class printf_format_elt;
  class printf_format_list;

  // Provide an interface for Octave streams.

  class
  OCTINTERP_API
  base_stream
  {
    friend class stream;

  public:

    base_stream (std::ios::openmode arg_md = std::ios::in | std::ios::out,
                 mach_info::float_format ff = mach_info::native_float_format (),
                 const std::string& encoding = "utf-8")
      : m_mode (arg_md), m_flt_fmt (ff), m_encoding (encoding),
        m_conv_ostream (nullptr), m_fail (false), m_open_state (true),
        m_errmsg ()
    { }

    // No copying!

    base_stream (const base_stream&) = delete;

    base_stream& operator = (const base_stream&) = delete;

    virtual ~base_stream (void) = default;

    // The remaining functions are not specific to input or output only,
    // and must be provided by the derived classes.

    // Position a stream at OFFSET relative to ORIGIN.

    virtual int seek (off_t offset, int origin) = 0;

    // Return current stream position.

    virtual off_t tell (void) = 0;

    // Return TRUE if EOF has been reached on this stream.

    virtual bool eof (void) const = 0;

    // The name of the file.

    virtual std::string name (void) const = 0;

    // If the derived class provides this function and it returns a
    // pointer to a valid istream, scanf(), read(), getl(), and gets()
    // will automatically work for this stream.

    virtual std::istream * input_stream (void) { return nullptr; }

    // If the derived class provides this function and it returns a
    // pointer to a valid ostream, flush(), write(), and printf() will
    // automatically work for this stream.

    virtual std::ostream * output_stream (void) { return nullptr; }

    // Return either the original output stream or one wrapped with the
    // encoding facet.

    std::ostream * preferred_output_stream (void)
    {
      if (! m_encoding.compare ("utf-8"))
        return output_stream ();

      if (m_conv_ostream)
        return m_conv_ostream;

      // wrap the output stream with encoding conversion facet
      std::ostream *os = output_stream ();
      if (os && *os)
      {
        convfacet_u8 *facet = new convfacet_u8 (m_encoding);
        std::wbuffer_convert<convfacet_u8, char> *converter
          = new std::wbuffer_convert<convfacet_u8, char> (os->rdbuf (),
                                                          facet);
        m_conv_ostream = new std::ostream (converter);
      }

      return (m_conv_ostream ? m_conv_ostream : output_stream ());
    }

    // Return TRUE if this stream is open.

    bool is_open (void) const { return m_open_state; }

    virtual void do_close (void) { }

    void close (void)
    {
      if (is_open ())
        {
          m_open_state = false;
          do_close ();
        }
    }

    virtual int file_number (void) const
    {
      // Kluge alert!

      if (name () == "stdin")
        return 0;
      else if (name () == "stdout")
        return 1;
      else if (name () == "stderr")
        return 2;
      else
        return -1;
    }

    bool ok (void) const { return ! m_fail; }

    // Return current error message for this stream.

    std::string error (bool clear, int& err_num);

  protected:

    int mode (void) const { return m_mode; }

    mach_info::float_format float_format (void) const { return m_flt_fmt; }

    std::string encoding (void) const { return m_encoding; }

    // Set current error state and set fail to TRUE.

    OCTINTERP_API void error (const std::string& msg);
    OCTINTERP_API void error (const std::string& who, const std::string& msg);

    // Clear any error message and set fail to FALSE.

    OCTINTERP_API void clear (void);

    // Clear stream state.

    OCTINTERP_API void clearerr (void);

  private:

    // The permission bits for the file.  Should be some combination of
    // std::ios::open_mode bits.
    int m_mode;

    // Data format.
    mach_info::float_format m_flt_fmt;

    // Code page
    std::string m_encoding;

    // encoding conversion facet
    typedef string::deletable_facet<string::codecvt_u8> convfacet_u8;

    // FIXME: Identified by compiler as unused private field.
    // Commented out 10/29/2022.
    // If there are no repercussions, delete entirely.
    // std::wbuffer_convert<convfacet_u8, char> *m_converter;

    // wrappers for encoding conversion
    // std::istream *m_conv_istream;

    std::ostream *m_conv_ostream;

    // TRUE if an error has occurred.
    bool m_fail;

    // TRUE if this stream is open.
    bool m_open_state;

    // Should contain error message if fail is TRUE.
    std::string m_errmsg;

    // Functions that are defined for all input streams (input streams
    // are those that define is).

    OCTINTERP_API std::string
    do_gets (octave_idx_type max_len, bool& err, bool strip_newline,
             const std::string& who /* = "gets" */);

    OCTINTERP_API std::string
    getl (octave_idx_type max_len, bool& err,
          const std::string& who /* = "getl" */);
    OCTINTERP_API std::string
    gets (octave_idx_type max_len, bool& err,
          const std::string& who /* = "gets" */);
    OCTINTERP_API off_t
    skipl (off_t count, bool& err, const std::string& who /* = "skipl" */);

    OCTINTERP_API octave_value
    do_scanf (scanf_format_list& fmt_list, octave_idx_type nr,
              octave_idx_type nc, bool one_elt_size_spec,
              octave_idx_type& count, const std::string& who /* = "scanf" */);

    OCTINTERP_API octave_value
    scanf (const std::string& fmt, const Array<double>& size,
           octave_idx_type& count, const std::string& who /* = "scanf" */);

    OCTINTERP_API bool
    do_oscanf (const scanf_format_elt *elt, octave_value&,
               const std::string& who /* = "scanf" */);

    OCTINTERP_API octave_value_list
    oscanf (const std::string& fmt, const std::string& who /* = "scanf" */);

    OCTINTERP_API octave_value
    do_textscan (const std::string& fmt, octave_idx_type ntimes,
                 const octave_value_list& options,
                 const std::string& who, octave_idx_type& count);

    // Functions that are defined for all output streams (output streams
    // are those that define os).

    OCTINTERP_API int flush (void);

    OCTINTERP_API int
    do_numeric_printf_conv (std::ostream& os, const printf_format_elt *elt,
                            int nsa, int sa_1, int sa_2,
                            const octave_value& val,
                            const std::string& who);

    OCTINTERP_API void field_width_error (const std::string& who) const;

    OCTINTERP_API int
    do_printf (printf_format_list& fmt_list, const octave_value_list& args,
               const std::string& who /* = "printf" */);

    OCTINTERP_API int
    printf (const std::string& fmt, const octave_value_list& args,
            const std::string& who /* = "printf" */);

    OCTINTERP_API int
    puts (const std::string& s, const std::string& who /* = "puts" */);

    // We can always do this in terms of seek(), so the derived class
    // only has to provide that.

    OCTINTERP_API void
    invalid_operation (const std::string& who, const char *rw);
  };

  class
  OCTINTERP_API
  stream
  {
  public:

    // BS must be allocated with new or nullptr.
    stream (base_stream *bs = nullptr) : m_rep (bs) { }

    stream (const stream&) = default;

    stream& operator = (const stream&) = default;

    ~stream (void) = default;

    OCTINTERP_API int flush (void);

    OCTINTERP_API std::string
    getl (octave_idx_type max_len, bool& err,
          const std::string& who /* = "getl" */);

    OCTINTERP_API std::string
    getl (const octave_value& max_len, bool& err,
          const std::string& who /* = "getl" */);

    OCTINTERP_API std::string
    gets (octave_idx_type max_len, bool& err,
          const std::string& who /* = "gets" */);

    OCTINTERP_API std::string
    gets (const octave_value& max_len, bool& err,
          const std::string& who /* = "gets" */);

    OCTINTERP_API off_t
    skipl (off_t count, bool& err, const std::string& who /* = "skipl" */);

    OCTINTERP_API off_t
    skipl (const octave_value& count, bool& err,
           const std::string& who /* = "skipl" */);

    OCTINTERP_API int seek (off_t offset, int origin);

    OCTINTERP_API int
    seek (const octave_value& offset, const octave_value& origin);

    OCTINTERP_API off_t tell (void);

    OCTINTERP_API int rewind (void);

    OCTINTERP_API bool is_open (void) const;

    OCTINTERP_API void close (void);

    OCTINTERP_API octave_value
    read (const Array<double>& size, octave_idx_type block_size,
          oct_data_conv::data_type input_type,
          oct_data_conv::data_type output_type,
          octave_idx_type skip, mach_info::float_format flt_fmt,
          octave_idx_type& count);

    OCTINTERP_API octave_idx_type
    write (const octave_value& data, octave_idx_type block_size,
           oct_data_conv::data_type output_type,
           octave_idx_type skip, mach_info::float_format flt_fmt);

    OCTINTERP_API bool write_bytes (const void *data, std::size_t n_elts);

    OCTINTERP_API bool skip_bytes (std::size_t n_elts);

    template <typename T>
    OCTINTERP_API octave_idx_type
    write (const Array<T>& data, octave_idx_type block_size,
           oct_data_conv::data_type output_type,
           octave_idx_type skip, mach_info::float_format flt_fmt);

    OCTINTERP_API octave_value
    scanf (const std::string& fmt, const Array<double>& size,
           octave_idx_type& count, const std::string& who /* = "scanf" */);

    OCTINTERP_API octave_value
    scanf (const octave_value& fmt, const Array<double>& size,
           octave_idx_type& count, const std::string& who /* = "scanf" */);

    OCTINTERP_API octave_value_list
    oscanf (const std::string& fmt, const std::string& who /* = "scanf" */);

    OCTINTERP_API octave_value_list
    oscanf (const octave_value& fmt, const std::string& who /* = "scanf" */);

    OCTINTERP_API octave_value
    textscan (const std::string& fmt, octave_idx_type ntimes,
              const octave_value_list& options,
              const std::string& who, octave_idx_type& count);

    OCTINTERP_API int
    printf (const std::string& fmt, const octave_value_list& args,
            const std::string& who /* = "printf" */);

    OCTINTERP_API int
    printf (const octave_value& fmt, const octave_value_list& args,
            const std::string& who /* = "printf" */);

    OCTINTERP_API int
    puts (const std::string& s, const std::string& who /* = "puts" */);
    OCTINTERP_API int
    puts (const octave_value& s, const std::string& who /* = "puts" */);

    OCTINTERP_API bool eof (void) const;

    OCTINTERP_API std::string error (bool clear, int& err_num);

    std::string error (bool clear = false)
    {
      int err_num;
      return error (clear, err_num);
    }

    // Set the error message and state.

    void error (const std::string& msg)
    {
      if (m_rep)
        m_rep->error (msg);
    }

    void error (const char *msg) { error (std::string (msg)); }

    int file_number (void) { return m_rep ? m_rep->file_number () : -1; }

    bool is_valid (void) const { return bool (m_rep); }

    bool ok (void) const { return m_rep && m_rep->ok (); }

    operator bool () const { return ok (); }

    OCTINTERP_API std::string name (void) const;

    OCTINTERP_API int mode (void) const;

    OCTINTERP_API mach_info::float_format float_format (void) const;

    OCTINTERP_API static std::string mode_as_string (int mode);

    std::string encoding (void)
    {
      return m_rep ? m_rep->encoding () : std::string ();
    }

    std::istream * input_stream (void)
    {
      return m_rep ? m_rep->input_stream () : nullptr;
    }

    std::ostream * output_stream (void)
    {
      return (m_rep ? m_rep->preferred_output_stream () : nullptr);
    }

    void clearerr (void) { if (m_rep) m_rep->clearerr (); }

  private:

    // The actual representation of this stream.
    std::shared_ptr<base_stream> m_rep;

    bool stream_ok (bool clear = true) const
    {
      bool retval = true;

      if (m_rep)
        {
          if (clear)
            m_rep->clear ();
        }
      else
        retval = false;

      return retval;
    }

    void invalid_operation (const std::string& who, const char *rw)
    {
      if (m_rep)
        m_rep->invalid_operation (who, rw);
    }

    OCTINTERP_API octave_value
    finalize_read (std::list<void *>& input_buf_list,
                   octave_idx_type input_buf_elts,
                   octave_idx_type elts_read,
                   octave_idx_type nr, octave_idx_type nc,
                   oct_data_conv::data_type input_type,
                   oct_data_conv::data_type output_type,
                   mach_info::float_format ffmt);
  };

  class
  OCTINTERP_API
  stream_list
  {
  public:

    OCTINTERP_API stream_list (interpreter& interp);

    stream_list (const stream_list&) = delete;
    stream_list& operator = (const stream_list&) = delete;

    OCTINTERP_API ~stream_list (void);

    OCTINTERP_API int insert (stream& os);

    OCTINTERP_API stream lookup (int fid, const std::string& who = "") const;
    OCTINTERP_API stream
    lookup (const octave_value& fid, const std::string& who = "") const;

    OCTINTERP_API int remove (int fid, const std::string& who = "");
    OCTINTERP_API int remove (const octave_value& fid,
                              const std::string& who = "");

    OCTINTERP_API void clear (bool flush = true);

    OCTINTERP_API string_vector get_info (int fid) const;
    OCTINTERP_API string_vector get_info (const octave_value& fid) const;

    OCTINTERP_API std::string list_open_files (void) const;

    OCTINTERP_API octave_value open_file_numbers (void) const;

    OCTINTERP_API int get_file_number (const octave_value& fid) const;

    OCTINTERP_API octave_value stdin_file (void) const;
    OCTINTERP_API octave_value stdout_file (void) const;
    OCTINTERP_API octave_value stderr_file (void) const;

  private:

    typedef std::map<int, stream> ostrl_map;

    ostrl_map m_list;

    mutable ostrl_map::const_iterator m_lookup_cache;

    int m_stdin_file;
    int m_stdout_file;
    int m_stderr_file;
  };

OCTAVE_END_NAMESPACE(octave)

#endif