/*

Copyright (C) 1996-2018 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
<https://www.gnu.org/licenses/>.

*/

#if defined (HAVE_CONFIG_H)
#  include "config.h"
#endif

#include <cstring>

#include <fstream>
#include <sstream>
#include <string>

#include "cmd-edit.h"
#include "cmd-hist.h"
#include "file-ops.h"
#include "lo-error.h"
#include "singleton-cleanup.h"
#include "str-vec.h"

#if defined (USE_READLINE)
#include <cstdlib>

#include "oct-rl-hist.h"

#include "file-stat.h"
#endif

namespace octave
{
  command_history *command_history::instance = nullptr;

#if defined (USE_READLINE)

  class
  gnu_history : public command_history
  {
  public:

    gnu_history (void)
      : command_history (), mark (0) { }

    ~gnu_history (void) = default;

    void do_process_histcontrol (const std::string&);

    std::string do_histcontrol (void) const;

    bool do_add (const std::string&);

    void do_remove (int);

    void do_clear (void);

    int do_where (void) const;

    int do_length (void) const;

    int do_max_input_history (void) const;

    int do_base (void) const;

    int do_current_number (void) const;

    void do_stifle (int);

    int do_unstifle (void);

    int do_is_stifled (void) const;

    void do_set_mark (int);

    int do_goto_mark (void);

    void do_read (const std::string&, bool);

    void do_read_range (const std::string&, int, int, bool);

    void do_write (const std::string&) const;

    void do_append (const std::string&);

    void do_truncate_file (const std::string&, int) const;

    string_vector do_list (int, bool) const;

    std::string do_get_entry (int) const;

    void do_replace_entry (int, const std::string&);

    void do_clean_up_and_save (const std::string&, int);

  private:

    int mark;
  };

  void
  gnu_history::do_process_histcontrol (const std::string& control_arg)
  {
    history_control = 0;

    size_t len = control_arg.length ();
    size_t beg = 0;

    while (beg < len)
      {
        if (control_arg[beg] == ':')
          beg++;
        else
          {
            size_t end = control_arg.find (':', beg);

            if (end == std::string::npos)
              end = len;

            std::string tmp = control_arg.substr (beg, end-beg);

            if (tmp == "erasedups")
              history_control |= HC_ERASEDUPS;
            else if (tmp == "ignoreboth")
              history_control |= (HC_IGNDUPS | HC_IGNSPACE);
            else if (tmp == "ignoredups")
              history_control |= HC_IGNDUPS;
            else if (tmp == "ignorespace")
              history_control |= HC_IGNSPACE;
            else
              (*current_liboctave_warning_with_id_handler)
                ("Octave:history-control",
                 "unknown histcontrol directive %s", tmp.c_str ());

            if (end != std::string::npos)
              beg = end + 1;
          }
      }
  }

  std::string
  gnu_history::do_histcontrol (void) const
  {
    // FIXME: instead of reconstructing this value, should we just save
    // the string we were given when constructing the command_history object?

    std::string retval;

    if (history_control & HC_IGNSPACE)
      retval.append ("ignorespace");

    if (history_control & HC_IGNDUPS)
      {
        if (retval.length () > 0)
          retval += ':';

        retval.append ("ignoredups");
      }

    if (history_control & HC_ERASEDUPS)
      {
        if (retval.length () > 0)
          retval += ':';

        retval.append ("erasedups");
      }

    return retval;
  }

  bool
  gnu_history::do_add (const std::string& s)
  {
    if (! do_ignoring_entries ())
      {
        if (s.empty ()
            || (s.length () == 1 && (s[0] == '\r' || s[0] == '\n')))
          return false;

        // Strip newline before adding to list
        std::string stmp = s;
        if (stmp.back () == '\n')
          stmp.pop_back ();

        int added = ::octave_add_history (stmp.c_str (), history_control);
        lines_this_session += added;
        return (added > 0) ? true : false;
      }
    return false;
  }

  void
  gnu_history::do_remove (int n)
  {
    ::octave_remove_history (n);
  }

  void
  gnu_history::do_clear (void)
  {
    ::octave_clear_history ();
  }

  int
  gnu_history::do_where (void) const
  {
    return ::octave_where_history ();
  }

  int
  gnu_history::do_length (void) const
  {
    return ::octave_history_length ();
  }

  int
  gnu_history::do_max_input_history (void) const
  {
    return ::octave_max_input_history ();
  }

  int
  gnu_history::do_base (void) const
  {
    return ::octave_history_base ();
  }

  int
  gnu_history::do_current_number (void) const
  {
    return (xsize > 0) ? do_base () + do_where () : -1;
  }

  void
  gnu_history::do_stifle (int n)
  {
    ::octave_stifle_history (n);
  }

  int
  gnu_history::do_unstifle (void)
  {
    return ::octave_unstifle_history ();
  }

  int
  gnu_history::do_is_stifled (void) const
  {
    return ::octave_history_is_stifled ();
  }

  void
  gnu_history::do_set_mark (int n)
  {
    mark = n;
  }

  int
  gnu_history::do_goto_mark (void)
  {
    if (mark)
      {
        char *line = ::octave_history_goto_mark (mark);

        if (line)
          {
            command_editor::insert_text (line);

            command_editor::clear_undo_list ();
          }
      }

    mark = 0;

    // FIXME: for operate_and_get_next.
    command_editor::remove_startup_hook (command_history::goto_mark);

    return 0;
  }

  void
  gnu_history::do_read (const std::string& f, bool must_exist)
  {
    if (! f.empty ())
      {
        int status = ::octave_read_history (f.c_str ());

        if (status != 0 && must_exist)
          {
            std::string msg = "reading file '" + f + "'";

            error (status, msg);
          }
        else
          {
            lines_in_file = do_where ();

            ::octave_using_history ();
          }
      }
    else
      error ("gnu_history::read: missing filename");
  }

  void
  gnu_history::do_read_range (const std::string& f, int from, int to,
                              bool must_exist)
  {
    if (from < 0)
      from = lines_in_file;

    if (! f.empty ())
      {
        int status = ::octave_read_history_range (f.c_str (), from, to);

        if (status != 0 && must_exist)
          {
            std::ostringstream buf;
            buf << "reading lines " << from << " to " << to
                << " from file '" << f << "'";

            error (status, buf.str ());
          }
        else
          {
            lines_in_file = do_where ();

            ::octave_using_history ();
          }
      }
    else
      error ("gnu_history::read_range: missing filename");
  }

  void
  gnu_history::do_write (const std::string& f_arg) const
  {
    if (initialized)
      {
        std::string f = f_arg;

        if (f.empty ())
          f = xfile;

        if (! f.empty ())
          {
            int status = ::octave_write_history (f.c_str ());

            if (status != 0)
              {
                std::string msg = "writing file '" + f + "'";

                error (status, msg);
              }
          }
        else
          error ("gnu_history::write: missing filename");
      }
  }

  void
  gnu_history::do_append (const std::string& f_arg)
  {
    if (initialized)
      {
        if (lines_this_session)
          {
            if (lines_this_session < do_where ())
              {
                // Create file if it doesn't already exist.

                std::string f = f_arg;

                if (f.empty ())
                  f = xfile;

                if (! f.empty ())
                  {
                    sys::file_stat fs (f);

                    if (! fs)
                      {
                        std::fstream tmp (f, std::ios::out);
                        tmp.close ();
                      }

                    int status
                      = ::octave_append_history (lines_this_session, f.c_str ());

                    if (status != 0)
                      {
                        std::string msg = "appending to file '" + f_arg + "'";

                        error (status, msg);
                      }
                    else
                      lines_in_file += lines_this_session;

                    lines_this_session = 0;
                  }
                else
                  error ("gnu_history::append: missing filename");
              }
          }
      }
  }

  void
  gnu_history::do_truncate_file (const std::string& f_arg, int n) const
  {
    if (initialized)
      {
        std::string f = f_arg;

        if (f.empty ())
          f = xfile;

        if (! f.empty ())
          ::octave_history_truncate_file (f.c_str (), n);
        else
          error ("gnu_history::truncate_file: missing filename");
      }
  }

  string_vector
  gnu_history::do_list (int limit, bool number_lines) const
  {
    string_vector retval;

    if (limit)
      retval = ::octave_history_list (limit, number_lines);

    return retval;
  }

  std::string
  gnu_history::do_get_entry (int n) const
  {
    std::string retval;

    char *line = ::octave_history_get (do_base () + n);

    if (line)
      retval = line;

    return retval;
  }

  void
  gnu_history::do_replace_entry (int which, const std::string& line)
  {
    ::octave_replace_history_entry (which, line.c_str ());
  }

  void
  gnu_history::do_clean_up_and_save (const std::string& f_arg, int n)
  {
    if (initialized)
      {
        std::string f = f_arg;

        if (f.empty ())
          f = xfile;

        if (! f.empty ())
          {
            if (n < 0)
              n = xsize;

            stifle (n);

            do_write (f.c_str ());
          }
        else
          error ("gnu_history::clean_up_and_save: missing filename");
      }
  }

#endif

  bool
  command_history::instance_ok (void)
  {
    bool retval = true;

    if (! instance)
      {
        make_command_history ();

        if (instance)
          singleton_cleanup_list::add (cleanup_instance);
      }

    if (! instance)
      (*current_liboctave_error_handler)
        ("unable to create command history object!");

    return retval;
  }

  void
  command_history::make_command_history (void)
  {
#if defined (USE_READLINE)
    instance = new gnu_history ();
#else
    instance = new command_history ();
#endif
  }

  void
  command_history::initialize (bool read_history_file,
                               const std::string& f_arg, int sz,
                               const std::string & control_arg)
  {
    if (instance_ok ())
      instance->do_initialize (read_history_file, f_arg, sz, control_arg);
  }

  bool
  command_history::is_initialized (void)
  {
    // We just want to check the status of an existing instance, not
    // create one.
    return instance && instance->do_is_initialized ();
  }

  void
  command_history::set_file (const std::string& f_arg)
  {
    if (instance_ok ())
      {
        std::string f = sys::file_ops::tilde_expand (f_arg);

        instance->do_set_file (f);
      }
  }

  std::string
  command_history::file (void)
  {
    return (instance_ok ())
      ? instance->do_file () : "";
  }

  void
  command_history::process_histcontrol (const std::string& control_arg)
  {
    if (instance_ok ())
      instance->do_process_histcontrol (control_arg);
  }

  std::string
  command_history::histcontrol (void)
  {
    return (instance_ok ())
      ? instance->do_histcontrol () : "";
  }

  void
  command_history::set_size (int n)
  {
    if (instance_ok ())
      instance->do_set_size (n);
  }

  int
  command_history::size (void)
  {
    return (instance_ok ())
      ? instance->do_size () : 0;
  }

  void
  command_history::ignore_entries (bool flag)
  {
    if (instance_ok ())
      instance->do_ignore_entries (flag);
  }

  bool
  command_history::ignoring_entries (void)
  {
    return (instance_ok ())
      ? instance->do_ignoring_entries () : false;
  }

  bool
  command_history::add (const std::string& s)
  {
    if (instance_ok ())
      return instance->do_add (s);
    return false;
  }

  void
  command_history::remove (int n)
  {
    if (instance_ok ())
      instance->do_remove (n);
  }

  void
  command_history::clear (void)
  {
    if (instance_ok ())
      instance->do_clear ();
  }

  int
  command_history::where (void)
  {
    return (instance_ok ())
      ? instance->do_where () : 0;
  }

  int
  command_history::length (void)
  {
    return (instance_ok ())
      ? instance->do_length () : 0;
  }

  int
  command_history::max_input_history (void)
  {
    return (instance_ok ())
      ? instance->do_max_input_history () : 0;
  }

  int
  command_history::base (void)
  {
    return (instance_ok ())
      ? instance->do_base () : 0;
  }

  int
  command_history::current_number (void)
  {
    return (instance_ok ())
      ? instance->do_current_number () : 0;
  }

  void
  command_history::stifle (int n)
  {
    if (instance_ok ())
      instance->do_stifle (n);
  }

  int
  command_history::unstifle (void)
  {
    return (instance_ok ())
      ? instance->do_unstifle () : 0;
  }

  int
  command_history::is_stifled (void)
  {
    return (instance_ok ())
      ? instance->do_is_stifled () : 0;
  }

  void
  command_history::set_mark (int n)
  {
    if (instance_ok ())
      instance->do_set_mark (n);
  }

  int
  command_history::goto_mark (void)
  {
    return (instance_ok ())
      ? instance->do_goto_mark () : 0;
  }

  void
  command_history::read (bool must_exist)
  {
    read (file (), must_exist);
  }

  void
  command_history::read (const std::string& f, bool must_exist)
  {
    if (instance_ok ())
      instance->do_read (f, must_exist);
  }

  void
  command_history::read_range (int from, int to, bool must_exist)
  {
    read_range (file (), from, to, must_exist);
  }

  void
  command_history::read_range (const std::string& f, int from, int to,
                               bool must_exist)
  {
    if (instance_ok ())
      instance->do_read_range (f, from, to, must_exist);
  }

  void
  command_history::write (const std::string& f)
  {
    if (instance_ok ())
      instance->do_write (f);
  }

  void
  command_history::append (const std::string& f)
  {
    if (instance_ok ())
      instance->do_append (f);
  }

  void
  command_history::truncate_file (const std::string& f, int n)
  {
    if (instance_ok ())
      instance->do_truncate_file (f, n);
  }

  string_vector
  command_history::list (int limit, bool number_lines)
  {
    return (instance_ok ())
      ? instance->do_list (limit, number_lines) : string_vector ();
  }

  std::string
  command_history::get_entry (int n)
  {
    return (instance_ok ())
      ? instance->do_get_entry (n) : "";
  }

  void
  command_history::replace_entry (int which, const std::string& line)
  {
    if (instance_ok ())
      instance->do_replace_entry (which, line);
  }

  void
  command_history::clean_up_and_save (const std::string& f, int n)
  {
    if (instance_ok ())
      instance->do_clean_up_and_save (f, n);
  }

  void
  command_history::do_process_histcontrol (const std::string&)
  { }

  void
  command_history::do_initialize (bool read_history_file,
                                  const std::string& f_arg, int sz,
                                  const std::string & control_arg)
  {
    command_history::set_file (f_arg);
    command_history::set_size (sz);
    command_history::process_histcontrol (control_arg);

    if (read_history_file)
      command_history::read (false);

    initialized = true;
  }

  bool
  command_history::do_is_initialized (void) const
  {
    return initialized;
  }

  void
  command_history::do_set_file (const std::string& f)
  {
    xfile = f;
  }

  std::string
  command_history::do_file (void)
  {
    return xfile;
  }

  void
  command_history::do_set_size (int n)
  {
    xsize = n;
  }

  int
  command_history::do_size (void) const
  {
    return xsize;
  }

  void
  command_history::do_ignore_entries (bool flag)
  {
    ignoring_additions = flag;
  }

  bool
  command_history::do_ignoring_entries (void) const
  {
    return ignoring_additions;
  }

  bool
  command_history::do_add (const std::string&)
  {
    return false;
  }

  void
  command_history::do_remove (int)
  { }

  void
  command_history::do_clear (void)
  { }

  int
  command_history::do_where (void) const
  {
    return 0;
  }

  int
  command_history::do_length (void) const
  {
    return 0;
  }

  int
  command_history::do_max_input_history (void) const
  {
    return 0;
  }

  int
  command_history::do_base (void) const
  {
    return 0;
  }

  int
  command_history::do_current_number (void) const
  {
    return (xsize > 0) ? do_base () + do_where () : -1;
  }

  void
  command_history::do_stifle (int)
  { }

  int
  command_history::do_unstifle (void)
  {
    return -1;
  }

  int
  command_history::do_is_stifled (void) const
  {
    return 0;
  }

  void
  command_history::do_set_mark (int)
  { }

  int
  command_history::do_goto_mark (void)
  {
    return 0;
  }

  void
  command_history::do_read (const std::string& f, bool)
  {
    if (f.empty ())
      error ("command_history::read: missing filename");
  }

  void
  command_history::do_read_range (const std::string& f, int, int, bool)
  {
    if (f.empty ())
      error ("command_history::read_range: missing filename");
  }

  void
  command_history::do_write (const std::string& f_arg) const
  {
    if (initialized)
      {
        std::string f = f_arg;

        if (f.empty ())
          f = xfile;

        if (f.empty ())
          error ("command_history::write: missing filename");
      }
  }

  void
  command_history::do_append (const std::string& f_arg)
  {
    if (initialized)
      {
        if (lines_this_session)
          {
            if (lines_this_session < do_where ())
              {
                // Create file if it doesn't already exist.

                std::string f = f_arg;

                if (f.empty ())
                  f = xfile;

                if (f.empty ())
                  error ("command_history::append: missing filename");
              }
          }
      }
  }

  void
  command_history::do_truncate_file (const std::string& f_arg, int) const
  {
    if (initialized)
      {
        std::string f = f_arg;

        if (f.empty ())
          f = xfile;

        if (f.empty ())
          error ("command_history::truncate_file: missing filename");
      }
  }

  string_vector
  command_history::do_list (int, bool) const
  {
    return string_vector ();
  }

  std::string
  command_history::do_get_entry (int) const
  {
    return "";
  }

  void
  command_history::do_replace_entry (int, const std::string&)
  { }

  void
  command_history::do_clean_up_and_save (const std::string& f_arg, int)
  {
    if (initialized)
      {
        std::string f = f_arg;

        if (f.empty ())
          f = xfile;

        if (f.empty ())
          error ("command_history::clean_up_and_save: missing filename");
      }
  }

  void
  command_history::error (int err_num, const std::string& msg) const
  {
    if (msg.empty ())
      (*current_liboctave_error_handler) ("%s", std::strerror (err_num));
    else
      (*current_liboctave_error_handler) ("%s: %s", msg.c_str (),
                                          std::strerror (err_num));
  }

  void
  command_history::error (const std::string& s) const
  {
    (*current_liboctave_error_handler) ("%s", s.c_str ());
  }
}