/**************************************************************************
 *   cut.c  --  This file is part of GNU nano.                            *
 *                                                                        *
 *   Copyright (C) 1999-2011, 2013-2018 Free Software Foundation, Inc.    *
 *   Copyright (C) 2014 Mark Majeres                                      *
 *   Copyright (C) 2016 Benno Schulenberg                                 *
 *                                                                        *
 *   GNU nano 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 nano 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, see http://www.gnu.org/licenses/.  *
 *                                                                        *
 **************************************************************************/

#include "proto.h"

#include <string.h>

static bool keep_cutbuffer = FALSE;
		/* Should we keep the contents of the cutbuffer? */

/* Indicate that we should no longer keep the contents of the cutbuffer. */
void cutbuffer_reset(void)
{
	keep_cutbuffer = FALSE;
}

/* Return the status of cutbuffer preservation. */
inline bool keeping_cutbuffer(void)
{
	return keep_cutbuffer;
}

/* If we aren't on the last line of the file, move all the text of the
 * current line, plus the newline at the end, into the cutbuffer.  If we
 * are, move all of the text of the current line into the cutbuffer.  In
 * both cases, set the current place we want to the beginning of the
 * current line. */
void cut_line(void)
{
	if (openfile->current != openfile->filebot)
		extract_buffer(&cutbuffer, &cutbottom, openfile->current, 0,
				openfile->current->next, 0);
	else
		extract_buffer(&cutbuffer, &cutbottom, openfile->current, 0,
				openfile->current, strlen(openfile->current->data));
	openfile->placewewant = 0;
}

#ifndef NANO_TINY
/* Move all currently marked text into the cutbuffer, and set the
 * current place we want to where the text used to start. */
void cut_marked(bool *right_side_up)
{
	filestruct *top, *bot;
	size_t top_x, bot_x;

	mark_order((const filestruct **)&top, &top_x,
				(const filestruct **)&bot, &bot_x, right_side_up);

	extract_buffer(&cutbuffer, &cutbottom, top, top_x, bot, bot_x);
	openfile->placewewant = xplustabs();
}

/* If we aren't at the end of the current line, move all the text from
 * the current cursor position to the end of the current line, not
 * counting the newline at the end, into the cutbuffer.  If we are, and
 * we're not on the last line of the file, move the newline at the end
 * into the cutbuffer, and set the current place we want to where the
 * newline used to be. */
void cut_to_eol(void)
{
	size_t data_len = strlen(openfile->current->data);

	if (openfile->current_x < data_len)
		/* If we're not at the end of the line, move all the text from
		 * the current position up to it, not counting the newline at
		 * the end, into the cutbuffer. */
		extract_buffer(&cutbuffer, &cutbottom, openfile->current,
				openfile->current_x, openfile->current, data_len);
	else if (openfile->current != openfile->filebot) {
		/* If we're at the end of the line, and it isn't the last line
		 * of the file, move all the text from the current position up
		 * to the beginning of the next line, i.e. the newline at the
		 * end, into the cutbuffer. */
		extract_buffer(&cutbuffer, &cutbottom, openfile->current,
				openfile->current_x, openfile->current->next, 0);
		openfile->placewewant = xplustabs();
	}
}

/* Move all the text from the current cursor position to the end of the
 * file into the cutbuffer. */
void cut_to_eof(void)
{
	extract_buffer(&cutbuffer, &cutbottom,
				openfile->current, openfile->current_x,
				openfile->filebot, strlen(openfile->filebot->data));
}
#endif /* !NANO_TINY */

/* Move text from the current buffer into the cutbuffer.  If
 * copy_text is TRUE, copy the text back into the buffer afterward.
 * If cut_till_eof is TRUE, move all text from the current cursor
 * position to the end of the file into the cutbuffer. */
void do_cut_text(bool copy_text, bool cut_till_eof)
{
#ifndef NANO_TINY
	filestruct *cb_save = NULL;
		/* The current end of the cutbuffer, before we add text to it. */
	size_t cb_save_len = 0;
		/* The length of the string at the current end of the cutbuffer,
		 * before we add text to it. */
	bool old_no_newlines = ISSET(NO_NEWLINES);
	bool right_side_up = TRUE;
		/* There *is* no region, *or* it is marked forward. */
#endif
	size_t was_totsize = openfile->totsize;

	/* If a chain of cuts was broken, empty the cutbuffer. */
	if (!keep_cutbuffer) {
		free_filestruct(cutbuffer);
		cutbuffer = NULL;
		/* Indicate that future cuts should add to the cutbuffer. */
		keep_cutbuffer = TRUE;
	}

#ifndef NANO_TINY
	if (copy_text) {
		/* If the cutbuffer isn't empty, remember where it currently ends. */
		if (cutbuffer != NULL) {
			cb_save = cutbottom;
			cb_save_len = strlen(cutbottom->data);
		}
		/* Don't add a magicline when moving text to the cutbuffer. */
		SET(NO_NEWLINES);
	}

	if (cut_till_eof) {
		/* Move all text up to the end of the file into the cutbuffer. */
		cut_to_eof();
	} else if (openfile->mark) {
		/* Move the marked text to the cutbuffer, and turn the mark off. */
		cut_marked(&right_side_up);
		openfile->mark = NULL;
	} else if (ISSET(CUT_FROM_CURSOR))
		/* Move all text up to the end of the line into the cutbuffer. */
		cut_to_eol();
	else
#endif
		/* Move the entire line into the cutbuffer. */
		cut_line();

#ifndef NANO_TINY
	if (copy_text) {
		/* Copy the text that is in the cutbuffer (starting at its saved end,
		 * if there is one) back into the current buffer.  This effectively
		 * uncuts the text we just cut. */
		if (cutbuffer != NULL) {
			if (cb_save != NULL) {
				cb_save->data += cb_save_len;
				copy_from_buffer(cb_save);
				cb_save->data -= cb_save_len;
			} else
				copy_from_buffer(cutbuffer);

			/* If the copied region was marked forward, put the new desired
			 * x position at its end; otherwise, leave it at its beginning. */
			if (right_side_up)
				openfile->placewewant = xplustabs();
		}
		/* Restore the magicline behavior now that we're done fiddling. */
		if (!old_no_newlines)
			UNSET(NO_NEWLINES);
	} else
#endif /* !NANO_TINY */
	/* Only set the modification flag if actually something was cut. */
	if (openfile->totsize != was_totsize)
		set_modified();

	refresh_needed = TRUE;

#ifdef DEBUG
	dump_filestruct(cutbuffer);
#endif
}

/* Move text from the current buffer into the cutbuffer. */
void do_cut_text_void(void)
{
#ifndef NANO_TINY
	add_undo(CUT);
#endif
	do_cut_text(FALSE, FALSE);
#ifndef NANO_TINY
	update_undo(CUT);
#endif
}

#ifndef NANO_TINY
/* Move text from the current buffer into the cutbuffer, and copy it
 * back into the buffer afterward.  If the mark is set or the cursor
 * was moved, blow away previous contents of the cutbuffer. */
void do_copy_text(void)
{
	static struct filestruct *next_contiguous_line = NULL;
	bool mark_is_set = (openfile->mark != NULL);

	/* Remember the current viewport and cursor position. */
	ssize_t is_edittop_lineno = openfile->edittop->lineno;
	size_t is_firstcolumn = openfile->firstcolumn;
	ssize_t is_current_lineno = openfile->current->lineno;
	size_t is_current_x = openfile->current_x;

	if (mark_is_set || openfile->current != next_contiguous_line)
		cutbuffer_reset();

	do_cut_text(TRUE, FALSE);

	/* If the mark was set, blow away the cutbuffer on the next copy. */
	next_contiguous_line = (mark_is_set ? NULL : openfile->current);

	/* If the mark was set, restore the viewport and cursor position. */
	if (mark_is_set) {
		openfile->edittop = fsfromline(is_edittop_lineno);
		openfile->firstcolumn = is_firstcolumn;
		openfile->current = fsfromline(is_current_lineno);
		openfile->current_x = is_current_x;
	}
}

/* Cut from the current cursor position to the end of the file. */
void do_cut_till_eof(void)
{
	add_undo(CUT_TO_EOF);
	do_cut_text(FALSE, TRUE);
	update_undo(CUT_TO_EOF);
}
#endif /* !NANO_TINY */

/* Copy text from the cutbuffer into the current buffer. */
void do_uncut_text(void)
{
	ssize_t was_lineno = openfile->current->lineno;
		/* The line number where we started the paste. */
	size_t was_leftedge = 0;
		/* The leftedge where we started the paste. */

	/* If the cutbuffer is empty, there is nothing to do. */
	if (cutbuffer == NULL)
		return;

#ifndef NANO_TINY
	add_undo(PASTE);

	if (ISSET(SOFTWRAP))
		was_leftedge = leftedge_for(xplustabs(), openfile->current);
#endif

	/* Add a copy of the text in the cutbuffer to the current buffer
	 * at the current cursor position. */
	copy_from_buffer(cutbuffer);

#ifndef NANO_TINY
	update_undo(PASTE);
#endif

	/* If we pasted less than a screenful, don't center the cursor. */
	if (less_than_a_screenful(was_lineno, was_leftedge))
		focusing = FALSE;

	/* Set the desired x position to where the pasted text ends. */
	openfile->placewewant = xplustabs();

	set_modified();
	refresh_needed = TRUE;
}
