/* m-x.c -- Meta-X minibuffer reader. */

/* This file is part of GNU Info, a program for reading online documentation
   stored in Info format.

   Copyright (C) 1993 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 program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

   Written by Brian Fox (bfox@ai.mit.edu). */

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

#include "info.h"

/* **************************************************************** */
/*								    */
/*		       Reading Named Commands			    */
/*								    */
/* **************************************************************** */

/* Read the name of an Info function in the echo area and return the
   name.  A return value of NULL indicates that no function name could
   be read. */
char *
read_function_name (prompt, window)
     char *prompt;
     WINDOW *window;
{
  register int i;
  char *line;
  REFERENCE **array = (REFERENCE **)NULL;
  int array_index = 0, array_slots = 0;

  /* Make an array of REFERENCE which actually contains the names of
     the functions available in Info. */
  for (i = 0; function_doc_array[i].func; i++)
    {
      REFERENCE *entry;

      entry = (REFERENCE *)xmalloc (sizeof (REFERENCE));
      entry->label = savestring (function_doc_array[i].func_name);
      entry->nodename = (char *)NULL;
      entry->filename = (char *)NULL;

      add_pointer_to_array
	(entry, array_index, array, array_slots, 200, REFERENCE *);
    }

  line = info_read_completing_in_echo_area (window, prompt, array);

  info_free_references (array);

  if (!echo_area_is_active)
    window_clear_echo_area ();

  return (line);
}

DECLARE_INFO_COMMAND (describe_command,
   "Read the name of an Info command and describe it")
{
  char *line;

  line = read_function_name ("Describe command: ", window);

  if (!line)
    {
      info_abort_key (active_window, count, key);
      return;
    }

  /* Describe the function named in "LINE". */
  if (*line)
    {
      char *fundoc;
      VFunction *fun;

      fun = named_function (line);

      if (!fun)
	return;

      window_message_in_echo_area ("%s: %s.",
				   line, function_documentation (fun));
    }
  free (line);
}

DECLARE_INFO_COMMAND (info_execute_command,
   "Read a command name in the echo area and execute it")
{
  char *line;

  /* Ask the completer to read a reference for us. */
  if (info_explicit_arg || count != 1)
    {
      char *prompt;

      prompt = (char *)xmalloc (20);
      sprintf (prompt, "%d M-x ", count);
      line = read_function_name (prompt, window);
    }
  else
    line = read_function_name ("M-x ", window);

  /* User aborted? */
  if (!line)
    {
      info_abort_key (active_window, count, key);
      return;
    }

  /* User accepted "default"?  (There is none.) */
  if (!*line)
    {
      free (line);
      return;
    }

  /* User wants to execute a named command.  Do it. */
  {
    VFunction *function;

    if ((active_window != the_echo_area) &&
	(strncmp (line, "echo-area-", 10) == 0))
      {
	free (line);
	info_error ("Cannot execute an `echo-area' command here.");
	return;
      }

    function = named_function (line);
    free (line);

    if (!function)
      return;

    (*function) (active_window, count, 0);
  }
}

/* Okay, now that we have M-x, let the user set the screen height. */
DECLARE_INFO_COMMAND (set_screen_height,
  "Set the height of the displayed window")
{
  int new_height;

  if (info_explicit_arg || count != 1)
    new_height = count;
  else
    {
      char prompt[80];
      char *line;

      new_height = screenheight;

      sprintf (prompt, "Set screen height to (%d): ", new_height);

      line = info_read_in_echo_area (window, prompt);

      /* If the user aborted, do that now. */
      if (!line)
	{
	  info_abort_key (active_window, count, 0);
	  return;
	}

      /* Find out what the new height is supposed to be. */
      if (*line)
	new_height = atoi (line);

      /* Clear the echo area if it isn't active. */
      if (!echo_area_is_active)
	window_clear_echo_area ();

      free (line);
    }

  terminal_clear_screen ();
  display_clear_display (the_display);
  screenheight = new_height;
  display_initialize_display (screenwidth, screenheight);
  window_new_screen_size (screenwidth, screenheight);
}