/* Simple built-in editing commands.
   Copyright (C) 1985, 1993, 1994, 1995, 1996, 1997, 1998, 2001, 2002,
                 2003, 2004, 2005, 2006, 2007, 2008, 2009
                 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 3 of the License, 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.  If not, see <http://www.gnu.org/licenses/>.  */


#include <config.h>
#include "lisp.h"
#include "commands.h"
#include "buffer.h"
#include "character.h"
#include "syntax.h"
#include "window.h"
#include "keyboard.h"
#include "keymap.h"
#include "dispextern.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;
extern Lisp_Object Vtranslation_table_for_input;

DEFUN ("forward-point", Fforward_point, Sforward_point, 1, 1, 0,
       doc: /* Return buffer position N characters after (before if N negative) point.  */)
     (n)
     Lisp_Object n;
{
  CHECK_NUMBER (n);

  return make_number (PT + XINT (n));
}

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

  /* 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 = PT + XINT (n);

    if (new_point < BEGV)
      {
	SET_PT (BEGV);
	xsignal0 (Qbeginning_of_buffer);
      }
    if (new_point > ZV)
      {
	SET_PT (ZV);
	xsignal0 (Qend_of_buffer);
      }

    SET_PT (new_point);
  }

  return Qnil;
}

DEFUN ("backward-char", Fbackward_char, Sbackward_char, 0, 1, "^p",
       doc: /* Move point left N characters (right if N is negative).
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);

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

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

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

  if (count <= 0)
    shortage = scan_newline (PT, PT_BYTE, BEGV, BEGV_BYTE, count - 1, 1);
  else
    shortage = scan_newline (PT, PT_BYTE, ZV, ZV_BYTE, count, 1);

  /* Since scan_newline does TEMP_SET_PT_BOTH,
     and we want to set PT "for real",
     go back to the old point and then come back here.  */
  pos = PT;
  pos_byte = PT_BYTE;
  TEMP_SET_PT_BOTH (opoint, opoint_byte);
  SET_PT_BOTH (pos, pos_byte);

  if (shortage > 0
      && (count <= 0
	  || (ZV > BEGV
	      && PT != opoint
	      && (FETCH_BYTE (PT_BYTE - 1) != '\n'))))
    shortage--;

  return make_number (count <= 0 ? - shortage : shortage);
}

DEFUN ("beginning-of-line", Fbeginning_of_line, Sbeginning_of_line, 0, 1, "^p",
       doc: /* Move point to beginning of current line.
With argument N not nil or 1, move forward N - 1 lines first.
If point reaches the beginning or end of buffer, it stops there.

This function constrains point to the current field unless this moves
point to a different line than the original, unconstrained result.  If
N is nil or 1, and a front-sticky field starts at point, the point
does not move.  To ignore field boundaries bind
`inhibit-field-text-motion' to t, or use the `forward-line' function
instead.  For instance, `(forward-line 0)' does the same thing as
`(beginning-of-line)', except that it ignores field boundaries.  */)
     (n)
     Lisp_Object n;
{
  if (NILP (n))
    XSETFASTINT (n, 1);
  else
    CHECK_NUMBER (n);

  SET_PT (XINT (Fline_beginning_position (n)));

  return Qnil;
}

DEFUN ("end-of-line", Fend_of_line, Send_of_line, 0, 1, "^p",
       doc: /* Move point to end of current line.
With argument N not nil or 1, move forward N - 1 lines first.
If point reaches the beginning or end of buffer, it stops there.
To ignore intangibility, bind `inhibit-point-motion-hooks' to t.

This function constrains point to the current field unless this moves
point to a different line than the original, unconstrained result.  If
N is nil or 1, and a rear-sticky field ends at point, the point does
not move.  To ignore field boundaries bind `inhibit-field-text-motion'
to t.  */)
     (n)
     Lisp_Object n;
{
  int newpos;

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

  while (1)
    {
      newpos = XINT (Fline_end_position (n));
      SET_PT (newpos);

      if (PT > newpos
	  && FETCH_CHAR (PT - 1) == '\n')
	{
	  /* If we skipped over a newline that follows
	     an invisible intangible run,
	     move back to the last tangible position
	     within the line.  */

	  SET_PT (PT - 1);
	  break;
	}
      else if (PT > newpos && PT < ZV
	       && FETCH_CHAR (PT) != '\n')
	/* If we skipped something intangible
	   and now we're not really at eol,
	   keep going.  */
	n = make_number (1);
      else
	break;
    }

  return Qnil;
}

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

  CHECK_NUMBER (n);

  pos = PT + XINT (n);
  if (NILP (killflag))
    {
      if (XINT (n) < 0)
	{
	  if (pos < BEGV)
	    xsignal0 (Qbeginning_of_buffer);
	  else
	    del_range (pos, PT);
	}
      else
	{
	  if (pos > ZV)
	    xsignal0 (Qend_of_buffer);
	  else
	    del_range (PT, pos);
	}
    }
  else
    {
      call1 (Qkill_forward_chars, n);
    }
  return Qnil;
}

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

  CHECK_NUMBER (n);

  /* See if we are about to delete a tab or newline backwards.  */
  pos = PT;
  pos_byte = PT_BYTE;
  for (i = 0; i < XINT (n) && pos_byte > BEGV_BYTE; i++)
    {
      int c;

      DEC_BOTH (pos, pos_byte);
      c = FETCH_BYTE (pos_byte);
      if (c == '\t' || c == '\n')
	{
	  deleted_special = 1;
	  break;
	}
    }

  /* 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_special
      && ! (PT == ZV || FETCH_BYTE (PT_BYTE) == '\n'))
    {
      int column = (int) current_column (); /* iftc */

      value = Fdelete_char (make_number (-XINT (n)), killflag);
      i = column - (int) current_column (); /* iftc */
      Finsert_char (make_number (' '), make_number (i), Qnil);
      /* Whitespace chars are ASCII chars, so we can simply subtract.  */
      SET_PT_BOTH (PT - i, PT_BYTE - i);
    }
  else
    value = Fdelete_char (make_number (-XINT (n)), killflag);

  return value;
}

/* Note that there's code in command_loop_1 which typically avoids
   calling this.  */
DEFUN ("self-insert-command", Fself_insert_command, Sself_insert_command, 1, 1, "p",
       doc: /* Insert the character you type.
Whichever character you type to run this command is inserted.  */)
     (n)
     Lisp_Object n;
{
  CHECK_NUMBER (n);

  /* Barf if the key that invoked this was not a character.  */
  if (!CHARACTERP (last_command_event))
    bitch_at_user ();
  {
    int character = translate_char (Vtranslation_table_for_input,
				    XINT (last_command_event));
    if (XINT (n) >= 2 && NILP (current_buffer->overwrite_mode))
      {
	int modified_char = character;
	/* Add the offset to the character, for Finsert_char.
	   We pass internal_self_insert the unmodified character
	   because it itself does this offsetting.  */
	if (! NILP (current_buffer->enable_multibyte_characters))
	  modified_char = unibyte_char_to_multibyte (modified_char);

	XSETFASTINT (n, XFASTINT (n) - 2);
	/* The first one might want to expand an abbrev.  */
	internal_self_insert (character, 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 (make_number (modified_char), n, Qt);
	/* The last one might want to auto-fill.  */
	internal_self_insert (character, 0);
      }
    else
      while (XINT (n) > 0)
	{
	  /* Ok since old and new vals both nonneg */
	  XSETFASTINT (n, XFASTINT (n) - 1);
	  internal_self_insert (character, XFASTINT (n) != 0);
	}
  }

  return Qnil;
}

/* Insert character C.  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.  */

static Lisp_Object Qexpand_abbrev;

int
internal_self_insert (c, noautofill)
     int c;
     int noautofill;
{
  int hairy = 0;
  Lisp_Object tem;
  register enum syntaxcode synt;
  Lisp_Object overwrite, string;
  /* Length of multi-byte form of C.  */
  int len;
  /* Working buffer and pointer for multi-byte form of C.  */
  unsigned char str[MAX_MULTIBYTE_LENGTH];
  int chars_to_delete = 0;
  int spaces_to_insert = 0;

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

  /* At first, get multi-byte form of C in STR.  */
  if (!NILP (current_buffer->enable_multibyte_characters))
    {
      len = CHAR_STRING (c, str);
      if (len == 1)
	/* If C has modifier bits, this makes C an appropriate
           one-byte char.  */
	c = *str;
    }
  else
    {
      str[0] = (SINGLE_BYTE_CHAR_P (c)
		? c
		: multibyte_char_to_unibyte (c, Qnil));
      len = 1;
    }
  if (!NILP (overwrite)
      && PT < ZV)
    {
      /* In overwrite-mode, we substitute a character at point (C2,
	 hereafter) by C.  For that, we delete C2 in advance.  But,
	 just substituting C2 by C may move a remaining text in the
	 line to the right or to the left, which is not preferable.
	 So we insert more spaces or delete more characters in the
	 following cases: if C is narrower than C2, after deleting C2,
	 we fill columns with spaces, if C is wider than C2, we delete
	 C2 and several characters following C2.  */

      /* This is the character after point.  */
      int c2 = FETCH_CHAR (PT_BYTE);

      /* Column the cursor should be placed at after this insertion.
         The correct value should be calculated only when necessary.  */
      int target_clm = 0;

      /* Overwriting in binary-mode always replaces C2 by C.
	 Overwriting in textual-mode doesn't always do that.
	 It inserts newlines in the usual way,
	 and inserts any character at end of line
	 or before a tab if it doesn't use the whole width of the tab.  */
      if (EQ (overwrite, Qoverwrite_mode_binary)
	  || (c != '\n'
	      && c2 != '\n'
	      && ! (c2 == '\t'
		    && XINT (current_buffer->tab_width) > 0
		    && XFASTINT (current_buffer->tab_width) < 20
		    && (target_clm = ((int) current_column () /* iftc */
				      + XINT (Fchar_width (make_number (c)))),
			target_clm % XFASTINT (current_buffer->tab_width)))))
	{
	  int pos = PT;
	  int pos_byte = PT_BYTE;

	  if (target_clm == 0)
	    chars_to_delete = 1;
	  else
	    {
	      /* The actual cursor position after the trial of moving
		 to column TARGET_CLM.  It is greater than TARGET_CLM
		 if the TARGET_CLM is middle of multi-column
		 character.  In that case, the new point is set after
		 that character.  */
	      int actual_clm
		= XFASTINT (Fmove_to_column (make_number (target_clm), Qnil));

	      chars_to_delete = PT - pos;

	      if (actual_clm > target_clm)
		{
		  /* We will delete too many columns.  Let's fill columns
		     by spaces so that the remaining text won't move.  */
		  spaces_to_insert = actual_clm - target_clm;
		}
	    }
	  SET_PT_BOTH (pos, pos_byte);
	  hairy = 2;
	}
      hairy = 2;
    }

  if (NILP (current_buffer->enable_multibyte_characters))
    MAKE_CHAR_MULTIBYTE (c);
  synt = SYNTAX (c);

  if (!NILP (current_buffer->abbrev_mode)
      && synt != Sword
      && NILP (current_buffer->read_only)
      && PT > BEGV
      && (!NILP (current_buffer->enable_multibyte_characters)
	  ? SYNTAX (XFASTINT (Fprevious_char ())) == Sword
	  : (SYNTAX (unibyte_char_to_multibyte (XFASTINT (Fprevious_char ())))
	     == Sword)))
    {
      int modiff = MODIFF;
      Lisp_Object sym;

      sym = call0 (Qexpand_abbrev);

      /* If we expanded an abbrev which has a hook,
	 and the hook has a non-nil `no-self-insert' property,
	 return right away--don't really self-insert.  */
      if (! NILP (sym) && ! NILP (XSYMBOL (sym)->function)
	  && SYMBOLP (XSYMBOL (sym)->function))
	{
	  Lisp_Object prop;
	  prop = Fget (XSYMBOL (sym)->function, intern ("no-self-insert"));
	  if (! NILP (prop))
	    return 1;
	}

      if (MODIFF != modiff)
	hairy = 2;
    }

  if (chars_to_delete)
    {
      string = make_string_from_bytes (str, 1, len);
      if (spaces_to_insert)
	{
	  tem = Fmake_string (make_number (spaces_to_insert),
			      make_number (' '));
	  string = concat2 (tem, string);
	}

      replace_range (PT, PT + chars_to_delete, string, 1, 1, 1);
      Fforward_char (make_number (1 + spaces_to_insert));
    }
  else
    insert_and_inherit (str, len);

  if ((CHAR_TABLE_P (Vauto_fill_chars)
       ? !NILP (CHAR_TABLE_REF (Vauto_fill_chars, c))
       : (c == ' ' || c == '\n'))
      && !noautofill
      && !NILP (current_buffer->auto_fill_function))
    {
      Lisp_Object tem;

      if (c == '\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_BOTH (PT - 1, PT_BYTE - 1);
      tem = call0 (current_buffer->auto_fill_function);
      /* Test PT < ZV in case the auto-fill-function is strange.  */
      if (c == '\n' && PT < ZV)
	SET_PT_BOTH (PT + 1, PT_BYTE + 1);
      if (!NILP (tem))
	hairy = 2;
    }

  /* If previous command specified a face to use, use it.  */
  if (!NILP (Vself_insert_face)
      && EQ (current_kboard->Vlast_command, Vself_insert_face_command))
    {
      Fput_text_property (make_number (PT - 1), make_number (PT),
			  Qface, Vself_insert_face, Qnil);
      Vself_insert_face = Qnil;
    }

  if ((synt == Sclose || synt == Smath)
      && !NILP (Vblink_paren_function) && INTERACTIVE
      && !noautofill)
    {
      call0 (Vblink_paren_function);
      hairy = 2;
    }
  return hairy;
}

/* module initialization */

void
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);

  Qexpand_abbrev = intern ("expand-abbrev");
  staticpro (&Qexpand_abbrev);

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

  DEFVAR_LISP ("self-insert-face-command", &Vself_insert_face_command,
	       doc: /* This is the command that set up `self-insert-face'.
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,
	       doc: /* Function called, if non-nil, whenever a close parenthesis is inserted.
More precisely, a char with closeparen syntax is self-inserted.  */);
  Vblink_paren_function = Qnil;

  defsubr (&Sforward_point);
  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);
}

void
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");
}

/* arch-tag: 022ba3cd-67f9-4978-9c5d-7d2b18d8644e
   (do not change this comment) */