// octave-hist.cc                                        -*- C++ -*-
/*

Copyright (C) 1992, 1993, 1994, 1995 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 2, 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, write to the Free
Software Foundation, 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

The functions listed below were adapted from similar functions from
GNU Bash, the Bourne Again SHell, copyright (C) 1987, 1989, 1991 Free
Software Foundation, Inc.

  do_history         edit_history_readline
  do_edit_history    edit_history_add_hist

*/

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

#include <sys/types.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <fstream.h>
#include <strstream.h>

#include "statdefs.h"
#include "utils.h"
#include "error.h"
#include "input.h"
#include "pager.h"
#include "octave.h"
#include "oct-obj.h"
#include "user-prefs.h"
#include "unwind-prot.h"
#include "octave-hist.h"
#include "sighandlers.h"
#include "defun.h"

extern "C"
{
#include <readline/history.h>
}

// Nonzero means input is coming from temporary history file.
int input_from_tmp_history_file = 0;

// Nonzero means we are saving history lines.
int saving_history = 1;

// The number of lines to save in the history file.
static int octave_hist_size = 1024;

// The name of the history file.
static char *octave_hist_file;

// The number of hisory lines we read from the history file.
static int history_lines_in_file = 0;

// The number of history lines we've saved so far.
static int history_lines_this_session = 0;

// Get some default values, possibly reading them from the
// environment.

static int
default_history_size (void)
{
  int size = 1024;
  char *env_size = getenv ("OCTAVE_HISTSIZE");
  if (env_size)
    {
      int val;
      if (sscanf (env_size, "%d", &val) == 1)
	size = val > 0 ? val : 0;
    }
  return size;
}

static char *
default_history_file (void)
{
  char *file = 0;

  char *env_file = getenv ("OCTAVE_HISTFILE");
  if (env_file)
    {
      fstream f (env_file, (ios::in | ios::out));
      if (f)
	{
	  file = strsave (env_file);
	  f.close ();
	}
    }

  if (! file && home_directory)
    file = strconcat (home_directory, "/.octave_hist");

  return file;
}

// Prime the history list.

void
initialize_history (void)
{
  octave_hist_file = default_history_file ();
  octave_hist_size = default_history_size ();

  read_history (octave_hist_file);
  using_history ();
  history_lines_in_file = where_history ();
}

void
clean_up_history (void)
{
  stifle_history (octave_hist_size);
  write_history (octave_hist_file);
}

void
maybe_save_history (char *s)
{
  if (saving_history)
    {
      add_history (s);
      history_lines_this_session++;
    }
}

// Display, save, or load history.  Stolen and modified from bash.
//
// Arg of -w FILENAME means write file, arg of -r FILENAME
// means read file, arg of -q means don't number lines.  Arg of N
// means only display that many items. 

void
do_history (int argc, char **argv)
{
  HIST_ENTRY **hlist;

  int numbered_output = 1;

  while (--argc > 0)
    {
      argv++;

      if (*argv[0] == '-' && strlen (*argv) == 2
	  && ((*argv)[1] == 'r' || (*argv)[1] == 'w'
	      || (*argv)[1] == 'a' || (*argv)[1] == 'n'))
	{
	  char *file;
	  int result = 0;

	  if (argc > 1)
	    file = *(argv+1);
	  else
	    file = octave_hist_file;

	  switch ((*argv)[1])
	    {
	    case 'a':		// Append `new' lines to file.
	      {
		if (history_lines_this_session)
		  {
		    if (history_lines_this_session < where_history ())
		      {
// If the filename was supplied, then create it if it doesn't already
// exist.
			if (file)
			  {
			    struct stat buf;

			    if (stat (file, &buf) == -1)
			      {
				int tem;

				tem = open (file, O_CREAT, 0666);
				close (tem);
			      }
			  }

			result =
			  append_history (history_lines_this_session, file);
			history_lines_in_file += history_lines_this_session;
			history_lines_this_session = 0;
		      }
		  }
	      }
	      break;

	    case 'w':		// Write entire history.
	      result = write_history (file);
	      break;

	    case 'r':		// Read entire file.
	      result = read_history (file);
	      break;

	    case 'n':		// Read `new' history from file.
// Read all of the lines in the file that we haven't already read.
	      using_history ();
	      result = read_history_range (file, history_lines_in_file, -1);
	      using_history ();
	      history_lines_in_file = where_history ();
	      break;
	    }
	  return;
	}
      else if (strcmp (*argv, "-q") == 0)
	numbered_output = 0;
      else if (strcmp (*argv, "--") == 0)
	{
	  argc--;
	  argv++;
	  break;
	}
      else
	break;
    }

  int limited = 0;
  int limit = 0;

  if (argc > 0)
    {
      limited = 1;
      if (sscanf (*argv, "%d", &limit) != 1)
        {
	  if (*argv[0] == '-')
	    error ("history: unrecognized option `%s'", *argv);
	  else
	    error ("history: bad non-numeric arg `%s'", *argv);
	  return;
        }
    }

  hlist = history_list ();

  if (hlist)
    {
      for (int i = 0; hlist[i]; i++)
	; // Do nothing.

      if (limit < 0)
	limit = -limit;

      if (!limited)
	i = 0;
      else
	if ((i -= limit) < 0)
	  i = 0;

      ostrstream output_buf;

      while (hlist[i])
	{
//	  QUIT;  // in bash: (interrupt_state) throw_to_top_level ();

	  if (numbered_output)
	    output_buf.form ("%5d%c", i + history_base,
			     hlist[i]->data ? '*' : ' '); 
	  output_buf << hlist[i]->line << "\n";
	  i++;
	}

      output_buf << ends;
      maybe_page_output (output_buf);
    }
}

// Read the edited history lines from STREAM and return them
// one at a time.  This can read unlimited length lines.  The
//  caller should free the storage.

static char *
edit_history_readline (fstream& stream)
{
  char c;
  int line_len = 128;
  int lindex = 0;
  char *line = new char [line_len];
  line[0] = '\0';

  while (stream.get (c))
    {
      if (lindex + 2 >= line_len)
	{
	  char *tmp_line = new char [line_len += 128];
	  strcpy (tmp_line, line);
	  delete [] line;
	  line = tmp_line;
	}

      if (c == '\n')
	{
	  line[lindex++] = '\n';
	  line[lindex++] = '\0';
	  return line;
	}
      else
	line[lindex++] = c;
    }

  if (! lindex)
    {
      delete [] line;
      return 0;
    }

  if (lindex + 2 >= line_len)
    {
      char *tmp_line = new char [lindex+3];
      strcpy (tmp_line, line);
      delete [] line;
      line = tmp_line;
    }

// Finish with newline if none in file.

  line[lindex++] = '\n';
  line[lindex++] = '\0';
  return line;
}

extern "C"
{
  HIST_ENTRY *history_get ();
}

// Use `command' to replace the last entry in the history list, which,
// by this time, is `run_history blah...'.  The intent is that the
// new command become the history entry, and that `fc' should never
// appear in the history list.  This way you can do `run_history' to
// your heart's content.

static void
edit_history_repl_hist (char *command)
{
  if (! command || ! *command)
    return;

  HIST_ENTRY **hlist = history_list ();

  if (! hlist)
    return;

  for (int i = 0; hlist[i]; i++)
    ; // Count 'em.
  i--;

// History_get () takes a parameter that should be offset by history_base.

// Don't free this.
  HIST_ENTRY *histent = history_get (history_base + i);
  if (! histent)
    return;

  char *data = 0;
  if (histent->data)
    {
      int len = strlen (histent->data);
      data = (char *) malloc (len);
      strcpy (data, histent->data);
    }

  int n = strlen (command);

  if (command[n - 1] == '\n')
    command[n - 1] = '\0';

  if (command && *command)
    {
      HIST_ENTRY *discard = replace_history_entry (i, command, data);
      if (discard)
	{
	  if (discard->line)
	    free (discard->line);

	  free ((char *) discard);
	}
    }
}

static void
edit_history_add_hist (char *line)
{
  if (line)
    {
      int len = strlen (line);
      if (len > 0 && line[len-1] == '\n')
	line[len-1] = '\0';

      if (line[0] != '\0')
	add_history (line);
    }
}

#define histline(i) (hlist[(i)]->line)

static char *
mk_tmp_hist_file (int argc, char **argv, int insert_curr, char *warn_for)
{
  HIST_ENTRY **hlist;

  hlist = history_list ();

  int hist_count = 0;

  while (hlist[hist_count++])
    ; // Find the number of items in the history list.

// The current command line is already part of the history list by the
// time we get to this point.  Delete it from the list.

  hist_count -= 2;
  if (! insert_curr)
    remove_history (hist_count);
  hist_count--;

// If no numbers have been specified, the default is to edit the last
// command in the history list.

  int hist_end = hist_count;
  int hist_beg = hist_count;
  int reverse = 0;

// Process options

  int usage_error = 0;
  if (argc == 3)
    {
      argv++;
      if (sscanf (*argv++, "%d", &hist_beg) != 1
	  || sscanf (*argv, "%d", &hist_end) != 1)
	usage_error = 1;
      else
	{
	  hist_beg--;
	  hist_end--;
	}
    }
  else if (argc == 2)
    {
      argv++;
      if (sscanf (*argv++, "%d", &hist_beg) != 1)
	usage_error = 1;
      else
	{
	  hist_beg--;
	  hist_end = hist_beg;
	}
    }

  if (hist_beg < 0 || hist_end < 0 || hist_beg > hist_count
      || hist_end > hist_count)
    {
      error ("%s: history specification out of range", warn_for);
      return 0;
    }

  if (usage_error)
    {
      usage ("%s [first] [last]", warn_for);
      return 0;
    }

  if (hist_end < hist_beg)
    {
      int t = hist_end;
      hist_end = hist_beg;
      hist_beg = t;
      reverse = 1;
    }

  char *name = octave_tmp_file_name ();

  fstream file (name, ios::out);

  if (! file)
    {
      error ("%s: couldn't open temporary file `%s'", warn_for, name);
      return 0;
    }

  if (reverse)
    {
      for (int i = hist_end; i >= hist_beg; i--)
	file << histline (i) << "\n";
    }
  else
    {
      for (int i = hist_beg; i <= hist_end; i++)
	file << histline (i) << "\n";
    }

  file.close ();

  return strsave (name);
}

void
do_edit_history (int argc, char **argv)
{
  char *name = mk_tmp_hist_file (argc, argv, 0, "edit_history");

  if (! name)
    return;

// Call up our favorite editor on the file of commands.

  ostrstream buf;
  buf << user_pref.editor << " " << name << ends;
  char *cmd = buf.str ();

// Ignore interrupts while we are off editing commands.  Should we
// maybe avoid using system()?

  volatile sig_handler *saved_sigint_handler = signal (SIGINT, SIG_IGN);
  system (cmd);
  signal (SIGINT, saved_sigint_handler);

// Write the commands to the history file since parse_and_execute
// disables command line history while it executes.

  fstream file (name, ios::in);

  char *line;
  int first = 1;
  while ((line = edit_history_readline (file)) != 0)
    {

// Skip blank lines

      if (line[0] == '\n')
	{
	  delete [] line;
	  continue;
	}

      if (first)
	{
	  first = 0;
	  edit_history_repl_hist (line);
	}
      else
	edit_history_add_hist (line);
    }

  file.close ();

// Turn on command echo, so the output from this will make better sense.

  begin_unwind_frame ("do_edit_history");
  unwind_protect_int (echo_input);
  unwind_protect_int (input_from_tmp_history_file);
  echo_input = 1;
  input_from_tmp_history_file = 1;

  parse_and_execute (name, 1);

  run_unwind_frame ("do_edit_history");

// Delete the temporary file.  Should probably be done with an
// unwind_protect.

  unlink (name);

  delete [] name;
}

void
do_run_history (int argc, char **argv)
{
  char *name = mk_tmp_hist_file (argc, argv, 1, "run_history");

  if (! name)
    return;

// Turn on command echo, so the output from this will make better sense.

  begin_unwind_frame ("do_run_history");
  unwind_protect_int (echo_input);
  unwind_protect_int (input_from_tmp_history_file);
  echo_input = 1;
  input_from_tmp_history_file = 1;

  parse_and_execute (name, 1);

  run_unwind_frame ("do_run_history");

// Delete the temporary file.  Should probably be done with an
// unwind_protect.

  unlink (name);

  delete [] name;
}

int
current_history_number (void)
{
  using_history ();

  if (octave_hist_size > 0)
    return history_base + where_history ();
  else
    return -1;

}

DEFUN_TEXT ("edit_history", Fedit_history, Sedit_history, -1, 1,
  "edit_history [first] [last]\n\
\n\
edit commands from the history list")
{
  Octave_object retval;

  DEFINE_ARGV("edit_history");

  do_edit_history (argc, argv);

  DELETE_ARGV;

  return retval;
}

DEFUN_TEXT ("history", Fhistory, Shistory, -1, 1,
  "history [N] [-w file] [-r file] [-q]\n\
\n\
display, save, or load command history")
{
  Octave_object retval;

  DEFINE_ARGV("history");

  do_history (argc, argv);

  DELETE_ARGV;

  return retval;
}

DEFUN_TEXT ("run_history", Frun_history, Srun_history, -1, 1,
  "run_history [first] [last]\n\
\n\
run commands from the history list")
{
  Octave_object retval;

  DEFINE_ARGV("run_history");

  do_run_history (argc, argv);

  DELETE_ARGV;

  return retval;
}

/*
;;; Local Variables: ***
;;; mode: C++ ***
;;; page-delimiter: "^/\\*" ***
;;; End: ***
*/