/*

Copyright (C) 1996-2015 John W. Eaton

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
<http://www.gnu.org/licenses/>.

*/

// Author: John W. Eaton.

#ifdef HAVE_CONFIG_H
#  include <config.h>
#endif

#include <cstring>
#include <cctype>

#include <fstream>
#include <iomanip>
#include <iostream>
#include <sstream>
#include <string>

#include "byte-swap.h"
#include "data-conv.h"
#include "file-ops.h"
#include "glob-match.h"
#include "lo-mappers.h"
#include "mach-info.h"
#include "oct-env.h"
#include "oct-time.h"
#include "quit.h"
#include "str-vec.h"

#include "Cell.h"
#include "defun.h"
#include "error.h"
#include "errwarn.h"
#include "load-save.h"
#include "ls-ascii-helper.h"
#include "ls-oct-text.h"
#include "ovl.h"
#include "oct-map.h"
#include "ov-cell.h"
#include "pager.h"
#include "pt-exp.h"
#include "unwind-prot.h"
#include "utils.h"
#include "variables.h"
#include "version.h"
#include "dMatrix.h"

// The number of decimal digits to use when writing ascii data.
static int Vsave_precision = 16;

// Functions for reading octave format text data.

// Extract a KEYWORD and its value from stream IS, returning the
// associated value in a new string.
//
// Input should look something like:
//
//  [%#][ \t]*keyword[ \t]*:[ \t]*string-value[ \t]*\n

std::string
extract_keyword (std::istream& is, const char *keyword, const bool next_only)
{
  std::string retval;

  int ch = is.peek ();
  if (next_only && ch != '%' && ch != '#')
    return retval;

  char c;
  while (is.get (c))
    {
      if (c == '%' || c == '#')
        {
          std::ostringstream buf;

          while (is.get (c) && (c == ' ' || c == '\t' || c == '%' || c == '#'))
            ; // Skip whitespace and comment characters.

          if (isalpha (c))
            buf << c;

          while (is.get (c) && isalpha (c))
            buf << c;

          std::string tmp = buf.str ();
          bool match = (tmp.substr (0, strlen (keyword)) == keyword);

          if (match)
            {
              std::ostringstream value;
              while (is.get (c) && (c == ' ' || c == '\t' || c == ':'))
                ; // Skip whitespace and the colon.

              is.putback (c);
              retval = read_until_newline (is, false);
              break;
            }
          else if (next_only)
            break;
          else
            skip_until_newline (is, false);
        }
    }

  int len = retval.length ();

  if (len > 0)
    {
      while (len)
        {
          c = retval[len-1];

          if (c == ' ' || c == '\t')
            len--;
          else
            {
              retval.resize (len);
              break;
            }
        }
    }

  return retval;
}

// Extract one value (scalar, matrix, string, etc.) from stream IS and
// place it in TC, returning the name of the variable.  If the value
// is tagged as global in the file, return TRUE in GLOBAL.
//
// Each type supplies its own function to load the data, and so this
// function is extensible.
//
// FILENAME is used for error messages.
//
// The data is expected to be in the following format:
//
// The input file must have a header followed by some data.
//
// All lines in the header must begin with a '#' character.
//
// The header must contain a list of keyword and value pairs with the
// keyword and value separated by a colon.
//
// Keywords must appear in the following order:
//
// # name: <name>
// # type: <type>
// # <info>
//
// Where, for the built in types are:
//
//  <name> : a valid identifier
//
//  <type> : <typename>
//         | global <typename>
//
//  <typename> : scalar
//             | complex scalar
//             | matrix
//             | complex matrix
//             | bool
//             | bool matrix
//             | string
//             | range
//
//  <info> : <matrix info>
//         | <string info>
//
//  <matrix info> : # rows: <integer>
//                : # columns: <integer>
//
//  <string info> : # elements: <integer>
//                : # length: <integer> (once before each string)
//
//  For backward compatibility the type "string array" is treated as a
// "string" type. Also "string" can have a single element with no elements
// line such that
//
//  <string info> : # length: <integer>
//
// Formatted ASCII data follows the header.
//
// Example:
//
//  # name: foo
//  # type: matrix
//  # rows: 2
//  # columns: 2
//    2  4
//    1  3
//
// Example:
//
//  # name: foo
//  # type: string
//  # elements: 5
//  # length: 4
//  this
//  # length: 2
//  is
//  # length: 1
//  a
//  # length: 6
//  string
//  # length: 5
//  array
//
// FIXME: This format is fairly rigid, and doesn't allow for arbitrary comments.
// Someone should fix that.  It does allow arbitrary types however.

// Ugh.  The signature of the compare method is not standard in older
// versions of the GNU libstdc++.  Do this instead:

#define SUBSTRING_COMPARE_EQ(s, pos, n, t) (s.substr (pos, n) == t)

std::string
read_text_data (std::istream& is, const std::string& filename, bool& global,
                 octave_value& tc, octave_idx_type count)
{
  // Read name for this entry or break on EOF.

  std::string name = extract_keyword (is, "name");

  if (name.empty ())
    {
      if (count == 0)
        error ("load: empty name keyword or no data found in file '%s'",
               filename.c_str ());

      return "";
    }

  if (! (name == ".nargin." || name == ".nargout."
         || name == CELL_ELT_TAG || valid_identifier (name)))
    error ("load: invalid identifier '%s' found in file '%s'",
           name.c_str (), filename.c_str ());

  // Look for type keyword.

  std::string tag = extract_keyword (is, "type");

  if (tag.empty ())
    error ("load: failed to extract keyword specifying value type");

  std::string typ;
  size_t pos = tag.rfind (' ');

  if (pos != std::string::npos)
    {
      global = SUBSTRING_COMPARE_EQ (tag, 0, 6, "global");

      typ = global ? tag.substr (7) : tag;
    }
  else
    typ = tag;

  // Special case for backward compatibility.  A small bit of cruft
  if (SUBSTRING_COMPARE_EQ (typ, 0, 12, "string array"))
    tc = charMatrix ();
  else
    tc = octave_value_typeinfo::lookup_type (typ);

  if (! tc.load_ascii (is))
    error ("load: trouble reading ascii file '%s'", filename.c_str ());

  return name;
}

// Save the data from TC along with the corresponding NAME, and global
// flag MARK_AS_GLOBAL on stream OS in the plain text format described
// above for load_text_data.  If NAME is empty, the name: line is not
// generated.  PRECISION specifies the number of decimal digits to print.
//
// Assumes ranges and strings cannot contain Inf or NaN values.
//
// Returns 1 for success and 0 for failure.

// FIXME: should probably write the help string here too.

bool
save_text_data (std::ostream& os, const octave_value& val_arg,
                const std::string& name, bool mark_as_global,
                int precision)
{
  bool success = true;

  if (! name.empty ())
    os << "# name: " << name << "\n";

  octave_value val = val_arg;

  if (mark_as_global)
    os << "# type: global " << val.type_name () << "\n";
  else
    os << "# type: " << val.type_name () << "\n";

  if (! precision)
    precision = Vsave_precision;

  long old_precision = os.precision ();
  os.precision (precision);

  success = val.save_ascii (os);

  // Insert an extra pair of newline characters after the data so that
  // multiple data elements may be handled separately by gnuplot (see
  // the description of the index qualifier for the plot command in the
  // gnuplot documentation).
  os << "\n\n";

  os.precision (old_precision);

  return (os && success);
}

bool
save_text_data_for_plotting (std::ostream& os, const octave_value& t,
                             const std::string& name)
{
  return save_text_data (os, t, name, false, 6);
}

// Maybe this should be a static function in tree-plot.cc?

// If TC is matrix, save it on stream OS in a format useful for
// making a 3-D plot with gnuplot.  If PARAMETRIC is TRUE,
// assume a parametric 3-D plot will be generated.

bool
save_three_d (std::ostream& os, const octave_value& tc, bool parametric)
{
  bool fail = false;

  octave_idx_type nr = tc.rows ();
  octave_idx_type nc = tc.columns ();

  if (! tc.is_real_matrix ())
    error ("for now, I can only save real matrices in 3-D format");

  os << "# 3-D data...\n"
     << "# type: matrix\n"
     << "# total rows: " << nr << "\n"
     << "# total columns: " << nc << "\n";

  long old_precision = os.precision ();
  os.precision (6);

  if (parametric)
    {
      octave_idx_type extras = nc % 3;
      if (extras)
        warning ("ignoring last %d columns", extras);

      Matrix tmp = tc.matrix_value ();
      nr = tmp.rows ();

      for (octave_idx_type i = 0; i < nc-extras; i += 3)
        {
          os << tmp.extract (0, i, nr-1, i+2);
          if (i+3 < nc-extras)
            os << "\n";
        }
    }
  else
    {
      Matrix tmp = tc.matrix_value ();
      nr = tmp.rows ();

      for (octave_idx_type i = 0; i < nc; i++)
        {
          os << tmp.extract (0, i, nr-1, i);
          if (i+1 < nc)
            os << "\n";
        }
    }

  os.precision (old_precision);

  return (os && ! fail);
}

DEFUN (save_precision, args, nargout,
       "-*- texinfo -*-\n\
@deftypefn  {} {@var{val} =} save_precision ()\n\
@deftypefnx {} {@var{old_val} =} save_precision (@var{new_val})\n\
@deftypefnx {} {} save_precision (@var{new_val}, \"local\")\n\
Query or set the internal variable that specifies the number of digits to\n\
keep when saving data in text format.\n\
\n\
When called from inside a function with the @qcode{\"local\"} option, the\n\
variable is changed locally for the function and any subroutines it calls.\n\
The original variable value is restored when exiting the function.\n\
@end deftypefn")
{
  return SET_INTERNAL_VARIABLE_WITH_LIMITS (save_precision, -1,
                                            std::numeric_limits<int>::max ());
}