/* Simple built-in editing commands.
   Copyright (C) 1985, 93, 94, 95, 1996 Free Software Foundation, Inc.

This file is part of GNU Emacs.

GNU Emacs 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.

GNU Emacs 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 GNU Emacs; see the file COPYING.  If not, write to
the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.  */


#include <config.h>
#include "lisp.h"
#include "commands.h"
#include "buffer.h"
#include "syntax.h"
#include "window.h"
#include "keyboard.h"

Lisp_Object Qkill_forward_chars, Qkill_backward_chars, Vblink_paren_function;

/* A possible value for a buffer's overwrite-mode variable.  */
Lisp_Object Qoverwrite_mode_binary;

/* Non-nil means put this face on the next self-inserting character.  */
Lisp_Object Vself_insert_face;

/* This is the command that set up Vself_insert_face.  */
Lisp_Object Vself_insert_face_command;

extern Lisp_Object Qface;

DEFUN ("forward-char", Fforward_char, Sforward_char, 0, 1, "p",
  "Move point right N characters (left if N is negative).\n\
On reaching end of buffer, stop and signal error.")
  (n)
     Lisp_Object n;
{
  if (NILP (n))
    XSETFASTINT (n, 1);
  else
    CHECK_NUMBER (n, 0);

  /* This used to just set point to point + XINT (n), and then check
     to see if it was within boundaries.  But now that SET_PT can
     potentially do a lot of stuff (calling entering and exiting
     hooks, etcetera), that's not a good approach.  So we validate the
     proposed position, then set point.  */
  {
    int new_point = point + XINT (n);

    if (new_point < BEGV)
      {
	SET_PT (BEGV);
	Fsignal (Qbeginning_of_buffer, Qnil);
      }
    if (new_point > ZV)
      {
	SET_PT (ZV);
	Fsignal (Qend_of_buffer, Qnil);
      }

    SET_PT (new_point);
  }

  return Qnil;
}

DEFUN ("backward-char", Fbackward_char, Sbackward_char, 0, 1, "p",
  "Move point left N characters (right if N is negative).\n\
On attempt to pass beginning or end of buffer, stop and signal error.")
  (n)
     Lisp_Object n;
{
  if (NILP (n))
    XSETFASTINT (n, 1);
  else
    CHECK_NUMBER (n, 0);

  XSETINT (n, - XINT (n));
  return Fforward_char (n);
}

DEFUN ("forward-line", Fforward_line, Sforward_line, 0, 1, "p",
  "Move N lines forward (backward if N is negative).\n\
Precisely, if point is on line I, move to the start of line I + N.\n\
If there isn't room, go as far as possible (no error).\n\
Returns the count of lines left to move.  If moving forward,\n\
that is N - number of lines moved; if backward, N + number moved.\n\
With positive N, a non-empty line at the end counts as one line\n\
  successfully moved (for the return value).")
  (n)
     Lisp_Object n;
{
  int pos2 = point;
  int pos;
  int count, shortage, negp;

  if (NILP (n))
    count = 1;
  else
    {
      CHECK_NUMBER (n, 0);
      count = XINT (n);
    }

  negp = count <= 0;
  pos = scan_buffer ('\n', pos2, 0, count - negp, &shortage, 1);
  if (shortage > 0
      && (negp
	  || (ZV > BEGV
	      && pos != pos2
	      && FETCH_CHAR (pos - 1) != '\n')))
    shortage--;
  SET_PT (pos);
  return make_number (negp ? - shortage : shortage);
}

DEFUN ("beginning-of-line", Fbeginning_of_line, Sbeginning_of_line,
  0, 1, "p",
  "Move point to beginning of current line.\n\
With argument N not nil or 1, move forward N - 1 lines first.\n\
If scan reaches end of buffer, stop there without error.")
  (n)
     Lisp_Object n;
{
  if (NILP (n))
    XSETFASTINT (n, 1);
  else
    CHECK_NUMBER (n, 0);

  Fforward_line (make_number (XINT (n) - 1));
  return Qnil;
}

DEFUN ("end-of-line", Fend_of_line, Send_of_line,
  0, 1, "p",
  "Move point to end of current line.\n\
With argument N not nil or 1, move forward N - 1 lines first.\n\
If scan reaches end of buffer, stop there without error.")
  (n)
     Lisp_Object n;
{
  register int pos;
  register int stop;

  if (NILP (n))
    XSETFASTINT (n, 1);
  else
    CHECK_NUMBER (n, 0);

  SET_PT (find_before_next_newline (PT, 0, XINT (n) - (XINT (n) <= 0)));

  return Qnil;
}

DEFUN ("delete-char", Fdelete_char, Sdelete_char, 1, 2, "p\nP",
  "Delete the following N characters (previous if N is negative).\n\
Optional second arg KILLFLAG non-nil means kill instead (save in kill ring).\n\
Interactively, N is the prefix arg, and KILLFLAG is set if\n\
N was explicitly specified.")
  (n, killflag)
     Lisp_Object n, killflag;
{
  CHECK_NUMBER (n, 0);

  if (NILP (killflag))
    {
      if (XINT (n) < 0)
	{
	  if (point + XINT (n) < BEGV)
	    Fsignal (Qbeginning_of_buffer, Qnil);
	  else
	    del_range (point + XINT (n), point);
	}
      else
	{
	  if (point + XINT (n) > ZV)
	    Fsignal (Qend_of_buffer, Qnil);
	  else
	    del_range (point, point + XINT (n));
	}
    }
  else
    {
      call1 (Qkill_forward_chars, n);
    }
  return Qnil;
}

DEFUN ("delete-backward-char", Fdelete_backward_char, Sdelete_backward_char,
  1, 2, "p\nP",
  "Delete the previous N characters (following if N is negative).\n\
Optional second arg KILLFLAG non-nil means kill instead (save in kill ring).\n\
Interactively, N is the prefix arg, and KILLFLAG is set if\n\
N was explicitly specified.")
  (n, killflag)
     Lisp_Object n, killflag;
{
  Lisp_Object value;
  int deleted_tab = 0;
  int i;

  CHECK_NUMBER (n, 0);

  /* See if we are about to delete a tab backwards.  */
  for (i = 0; i < XINT (n); i++)
    {
      if (point - i < BEGV)
	break;
      if (FETCH_CHAR (point - i) == '\t')
	{
	  deleted_tab = 1;
	  break;
	}
    }

  value = Fdelete_char (make_number (-XINT (n)), killflag);

  /* In overwrite mode, back over columns while clearing them out,
     unless at end of line.  */
  if (XINT (n) > 0
      && ! NILP (current_buffer->overwrite_mode)
      && ! deleted_tab
      && ! (point == ZV || FETCH_CHAR (point) == '\n'))
    {
      Finsert_char (make_number (' '), XINT (n));
      SET_PT (point - XINT (n));
    }

  return value;
}

DEFUN ("self-insert-command", Fself_insert_command, Sself_insert_command, 1, 1, "p",
  "Insert the character you type.\n\
Whichever character you type to run this command is inserted.")
  (n)
     Lisp_Object n;
{
  CHECK_NUMBER (n, 0);

  /* Barf if the key that invoked this was not a character.  */
  if (!INTEGERP (last_command_char))
    bitch_at_user ();
  else if (XINT (n) >= 2 && NILP (current_buffer->overwrite_mode))
    {
      XSETFASTINT (n, XFASTINT (n) - 2);
      /* The first one might want to expand an abbrev.  */
      internal_self_insert (XINT (last_command_char), 1);
      /* The bulk of the copies of this char can be inserted simply.
	 We don't have to handle a user-specified face specially
	 because it will get inherited from the first char inserted.  */
      Finsert_char (last_command_char, n, Qt);
      /* The last one might want to auto-fill.  */
      internal_self_insert (XINT (last_command_char), 0);
    }
  else
    while (XINT (n) > 0)
      {
	/* Ok since old and new vals both nonneg */
	XSETFASTINT (n, XFASTINT (n) - 1);
	internal_self_insert (XINT (last_command_char), XFASTINT (n) != 0);
      }

  return Qnil;
}

/* Insert character C1.  If NOAUTOFILL is nonzero, don't do autofill
   even if it is enabled.

   If this insertion is suitable for direct output (completely simple),
   return 0.  A value of 1 indicates this *might* not have been simple.
   A value of 2 means this did things that call for an undo boundary.  */

internal_self_insert (c1, noautofill)
     /* This has to be unsigned char; when it is char,
	some compilers sign-extend it in SYNTAX_ENTRY, despite
	the casts to unsigned char there.  */
     unsigned char c1;
     int noautofill;
{
  extern Lisp_Object Fexpand_abbrev ();
  int hairy = 0;
  Lisp_Object tem;
  register enum syntaxcode synt;
  register int c = c1;
  Lisp_Object overwrite;

  overwrite = current_buffer->overwrite_mode;
  if (!NILP (Vbefore_change_function) || !NILP (Vafter_change_function)
      || !NILP (Vbefore_change_functions) || !NILP (Vafter_change_functions))
    hairy = 1;

  if (!NILP (overwrite)
      && point < ZV
      && (EQ (overwrite, Qoverwrite_mode_binary)
	  || (c != '\n' && FETCH_CHAR (point) != '\n'))
      && (EQ (overwrite, Qoverwrite_mode_binary)
	  || FETCH_CHAR (point) != '\t'
	  || XINT (current_buffer->tab_width) <= 0
	  || XFASTINT (current_buffer->tab_width) > 20
	  || !((current_column () + 1) % XFASTINT (current_buffer->tab_width))))
    {
      del_range (point, point + 1);
      hairy = 2;
    }
  if (!NILP (current_buffer->abbrev_mode)
      && SYNTAX (c) != Sword
      && NILP (current_buffer->read_only)
      && point > BEGV && SYNTAX (FETCH_CHAR (point - 1)) == Sword)
    {
      int modiff = MODIFF;
      Fexpand_abbrev ();
      /* We can't trust the value of Fexpand_abbrev,
	 but if Fexpand_abbrev changed the buffer,
	 assume it expanded something.  */
      if (MODIFF != modiff)
	hairy = 2;
    }
  if ((c == ' ' || c == '\n')
      && !noautofill
      && !NILP (current_buffer->auto_fill_function))
    {
      insert_and_inherit (&c1, 1);
      if (c1 == '\n')
	/* After inserting a newline, move to previous line and fill */
	/* that.  Must have the newline in place already so filling and */
	/* justification, if any, know where the end is going to be. */
	SET_PT (point - 1);
      call0 (current_buffer->auto_fill_function);
      if (c1 == '\n')
	SET_PT (point + 1);
      hairy = 2;
    }
  else
    insert_and_inherit (&c1, 1);

#ifdef HAVE_FACES
  /* If previous command specified a face to use, use it.  */
  if (!NILP (Vself_insert_face)
      && EQ (current_kboard->Vlast_command, Vself_insert_face_command))
    {
      Lisp_Object before, after;
      XSETINT (before, PT - 1);
      XSETINT (after, PT);
      Fput_text_property (before, after, Qface, Vself_insert_face, Qnil);
      Vself_insert_face = Qnil;
    }
#endif
  synt = SYNTAX (c);
  if ((synt == Sclose || synt == Smath)
      && !NILP (Vblink_paren_function) && INTERACTIVE
      && !noautofill)
    {
      call0 (Vblink_paren_function);
      hairy = 2;
    }
  return hairy;
}

/* module initialization */

syms_of_cmds ()
{
  Qkill_backward_chars = intern ("kill-backward-chars");
  staticpro (&Qkill_backward_chars);

  Qkill_forward_chars = intern ("kill-forward-chars");
  staticpro (&Qkill_forward_chars);

  Qoverwrite_mode_binary = intern ("overwrite-mode-binary");
  staticpro (&Qoverwrite_mode_binary);

  DEFVAR_LISP ("self-insert-face", &Vself_insert_face,
    "If non-nil, set the face of the next self-inserting character to this.\n\
See also `self-insert-face-command'.");
  Vself_insert_face = Qnil;

  DEFVAR_LISP ("self-insert-face-command", &Vself_insert_face_command,
    "This is the command that set up `self-insert-face'.\n\
If `last-command' does not equal this value, we ignore `self-insert-face'.");
  Vself_insert_face_command = Qnil;

  DEFVAR_LISP ("blink-paren-function", &Vblink_paren_function,
    "Function called, if non-nil, whenever a close parenthesis is inserted.\n\
More precisely, a char with closeparen syntax is self-inserted.");
  Vblink_paren_function = Qnil;

  defsubr (&Sforward_char);
  defsubr (&Sbackward_char);
  defsubr (&Sforward_line);
  defsubr (&Sbeginning_of_line);
  defsubr (&Send_of_line);

  defsubr (&Sdelete_char);
  defsubr (&Sdelete_backward_char);

  defsubr (&Sself_insert_command);
}

keys_of_cmds ()
{
  int n;

  initial_define_key (global_map, Ctl ('I'), "self-insert-command");
  for (n = 040; n < 0177; n++)
    initial_define_key (global_map, n, "self-insert-command");
#ifdef MSDOS
  for (n = 0200; n < 0240; n++)
    initial_define_key (global_map, n, "self-insert-command");
#endif
  for (n = 0240; n < 0400; n++)
    initial_define_key (global_map, n, "self-insert-command");

  initial_define_key (global_map, Ctl ('A'), "beginning-of-line");
  initial_define_key (global_map, Ctl ('B'), "backward-char");
  initial_define_key (global_map, Ctl ('D'), "delete-char");
  initial_define_key (global_map, Ctl ('E'), "end-of-line");
  initial_define_key (global_map, Ctl ('F'), "forward-char");
  initial_define_key (global_map, 0177, "delete-backward-char");
}