/* readline.c --- line editing support for Guile */

/*	Copyright (C) 1997 Free Software Foundation, Inc.
 * 
 * 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 software; see the file COPYING.  If not, write to
 * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 * As a special exception, the Free Software Foundation gives permission
 * for additional uses of the text contained in its release of GUILE.
 *
 * The exception is that, if you link the GUILE library with other files
 * to produce an executable, this does not by itself cause the
 * resulting executable to be covered by the GNU General Public License.
 * Your use of that executable is in no way restricted on account of
 * linking the GUILE library code into it.
 *
 * This exception does not however invalidate any other reasons why
 * the executable file might be covered by the GNU General Public License.
 *
 * This exception applies only to the code released by the
 * Free Software Foundation under the name GUILE.  If you copy
 * code from other Free Software Foundation releases into a copy of
 * GUILE, as the General Public License permits, the exception does
 * not apply to the code that you add in this way.  To avoid misleading
 * anyone as to the status of such modified files, you must delete
 * this exception notice from them.
 *
 * If you write modifications of your own for GUILE, it is your choice
 * whether to permit this exception to apply to your modifications.
 * If you do not wish that, delete this exception notice.  
 */


#include "_scm.h"
#if defined (HAVE_RL_GETC_FUNCTION)
#include <libguile.h>
#include <readline.h>
#include <gh.h>
#include <readline/readline.h>
#include <readline/history.h>

#ifndef HAVE_STRDUP
static char *
strdup (char *s)
{
  int len = strlen (s);
  char *new = malloc (len + 1);
  strcpy (new, s);
  return new;
}
#endif /* HAVE_STRDUP */

#ifndef HAVE_RL_CLEANUP_AFTER_SIGNAL

/* These are readline functions added in release 2.3.  They will work
 * together with readline-2.1 and 2.2.  (The readline interface is
 * disabled for earlier releases.)
 * They are declared static; if we want to use them elsewhere, then
 * we need external declarations for them, but at the moment, I don't
 * think anything else in Guile ought to use these.
 */

extern void _rl_clean_up_for_exit ();
extern void _rl_kill_kbd_macro ();
extern int _rl_init_argument ();

static void
rl_cleanup_after_signal ()
{
#ifdef HAVE_RL_CLEAR_SIGNALS
  _rl_clean_up_for_exit ();
#endif
  (*rl_deprep_term_function) ();
#ifdef HAVE_RL_CLEAR_SIGNALS
  rl_clear_signals ();
#endif
  rl_pending_input = 0;
}

static void
rl_free_line_state ()
{
  register HIST_ENTRY *entry;
   
  free_undo_list ();

  entry = current_history ();
  if (entry)
    entry->data = (char *)NULL; 
  
  _rl_kill_kbd_macro ();
  rl_clear_message ();
  _rl_init_argument ();
}

#endif /* !HAVE_RL_CLEANUP_AFTER_SIGNAL */

static int promptp;
static SCM input_port;
static SCM before_read;

static int
current_input_getc (FILE *in)
{
  SCM ans;
  if (promptp && SCM_NIMP (before_read))
    {
      scm_apply (before_read, SCM_EOL, SCM_EOL);
      promptp = 0;
    }
  ans = scm_getc (input_port);
  return ans;
}

static void
redisplay ()
{
  rl_redisplay ();
  /* promptp = 1; */
}

SCM_PROC (s_readline, "readline", 0, 4, 0, scm_readline);

int in_readline = 0;
#ifdef USE_THREADS
scm_mutex_t reentry_barrier_mutex;
#endif

static void
reentry_barrier ()
{
  int reentryp = 0;
#ifdef USE_THREADS
  /* We should rather use scm_mutex_try_lock when it becomes available */
  scm_mutex_lock (&reentry_barrier_mutex);
#endif
  if (in_readline)
    reentryp = 1;
  else
    ++in_readline;
#ifdef USE_THREADS
  scm_mutex_unlock (&reentry_barrier_mutex);
#endif
  if (reentryp)
    scm_misc_error (s_readline, "readline is not reentrant", SCM_EOL);
}

static SCM
handle_error (void *data, SCM tag, SCM args)
{
  rl_free_line_state ();
  rl_cleanup_after_signal ();
  --in_readline;
  scm_handle_by_throw (data, tag, args);
  return SCM_UNSPECIFIED; /* never reached */
}

static SCM
internal_readline (SCM text)
{
  SCM ret;
  char *s;
  char *prompt = SCM_UNBNDP (text) ? "" : SCM_CHARS (text);

  promptp = 1;
  s = readline (prompt);
  if (s)
    ret = scm_makfrom0str (s);
  else 
    ret = SCM_EOF_VAL;

  free (s);

  return ret;
}

SCM
scm_readline (SCM text, SCM inp, SCM outp, SCM read_hook)
{
  SCM ans;
  
  reentry_barrier ();
  
  before_read = SCM_BOOL_F;

  if (!SCM_UNBNDP (text))
    {
      if (!(SCM_NIMP (text) && SCM_STRINGP (text)))
	{
	  --in_readline;
	  scm_wrong_type_arg (s_readline, SCM_ARG1, text);
	}
      SCM_COERCE_SUBSTR (text);
    }
  
  if (SCM_UNBNDP (inp))
    inp = scm_cur_inp;
  
  if (SCM_UNBNDP (outp))
    outp = scm_cur_outp;
  
  if (!(SCM_UNBNDP (read_hook) || SCM_FALSEP (read_hook)))
    {
      if (!(SCM_NFALSEP (scm_thunk_p (read_hook))))
	{
	  --in_readline;
	  scm_wrong_type_arg (s_readline, SCM_ARG4, read_hook);
	}
      before_read = read_hook;
    }
  
  if (!(SCM_NIMP (inp) && SCM_OPINFPORTP (inp)))
    {
      --in_readline;
      scm_misc_error (s_readline,
		      "Input port is not open or not a file port",
		      SCM_EOL);
    }
  if (!(SCM_NIMP (outp) && SCM_OPOUTFPORTP (outp)))
    {
      --in_readline;
      scm_misc_error (s_readline,
		      "Output port is not open or not a file port",
		      SCM_EOL);
    }

  input_port = inp;
  rl_instream = (FILE *) SCM_STREAM (inp);
  rl_outstream = (FILE *) SCM_STREAM (outp);

  ans = scm_internal_catch (SCM_BOOL_T,
			    (scm_catch_body_t) internal_readline,
			    (void *) text,
			    handle_error, 0);
  --in_readline;
  return ans;
}

SCM_PROC (s_add_history, "add-history", 1, 0, 0, scm_add_history);

SCM
scm_add_history (SCM text)
{
  char* s;
  SCM_ASSERT ((SCM_NIMP(text) && SCM_STRINGP(text)), text, SCM_ARG1,
	      s_add_history);
  SCM_COERCE_SUBSTR (text);

  s = SCM_CHARS (text);
  add_history (strdup (s));

  return SCM_UNSPECIFIED;
}


SCM_PROC (s_filename_completion_function, "filename-completion-function", 2, 0, 0, scm_filename_completion_function);

SCM
scm_filename_completion_function (SCM text, SCM continuep)
{
  char *s;
  SCM ans;
  SCM_ASSERT (SCM_NIMP (text) && SCM_STRINGP (text),
	      text,
	      SCM_ARG1,
	      s_filename_completion_function);
  SCM_COERCE_SUBSTR (text);
  s = filename_completion_function (SCM_CHARS (text), SCM_NFALSEP (continuep));
  ans = scm_makfrom0str (s);
  free (s);
  return ans;
}

/*
 * The following has been modified from code contributed by
 * Andrew Archibald <aarchiba@undergrad.math.uwaterloo.ca>
 */

SCM scm_readline_completion_function_var;

static char *
completion_function (char *text, int continuep)
{
  SCM compfunc = SCM_CDR (scm_readline_completion_function_var);
  SCM res;

  if (SCM_FALSEP (compfunc))
    return NULL; /* #f => completion disabled */
  else
    {
      SCM t = scm_makfrom0str (text);
      SCM c = continuep ? SCM_BOOL_T : SCM_BOOL_F;
      res = scm_apply (compfunc, SCM_LIST2 (t, c), SCM_EOL);
  
      if (SCM_FALSEP (res))
	return NULL;
  
      if (!(SCM_NIMP (res) && SCM_STRINGP (res)))
	scm_misc_error (s_readline,
			"Completion function returned bogus value: %S",
			SCM_LIST1 (res));
      SCM_COERCE_SUBSTR (res);
      return strdup (SCM_CHARS (res));
    }
}


void
scm_init_readline ()
{
#include "readline.x"
  scm_readline_completion_function_var
    = scm_sysintern ("*readline-completion-function*", SCM_BOOL_F);
  rl_getc_function = current_input_getc;
  rl_redisplay_function = redisplay;
  rl_completion_entry_function = (Function*) completion_function;
#ifdef USE_THREADS
  scm_mutex_init (&reentry_barrier_mutex);
#endif
  scm_add_feature ("readline");
}

#endif