/* text.c
 *
 *
 * $Id$
 *
 * ***** BEGIN GPL LICENSE BLOCK *****
 *
 * 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
 * of the License, 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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 * The Original Code is Copyright (C) 2001-2002 by NaN Holding BV.
 * All rights reserved.
 *
 * The Original Code is: all of this file.
 *
 * Contributor(s): none yet.
 *
 * ***** END GPL LICENSE BLOCK *****
 */

#include <string.h> /* strstr */

#include "MEM_guardedalloc.h"

#include "BLI_blenlib.h"

#include "DNA_scene_types.h"
#include "DNA_text_types.h"

#include "BKE_utildefines.h"
#include "BKE_text.h"
#include "BKE_library.h"
#include "BKE_global.h"
#include "BKE_main.h"

#include "BPY_extern.h"

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

/***************/ /*

How Texts should work
--
A text should relate to a file as follows -
(Text *)->name should be the place where the 
	file will or has been saved.
	
(Text *)->flags has the following bits
	TXT_ISDIRTY - should always be set if the file in mem. differs from
					the file on disk, or if there is no file on disk.
	TXT_ISTMP - should always be set if the (Text *)->name file has not
					been written before, and attempts to save should result
					in "Save over?"
	TXT_ISMEM - should always be set if the Text has not been mapped to
					a file, in which case (Text *)->name may be NULL or garbage.			
	TXT_ISEXT - should always be set if the Text is not to be written into
					the .blend
	TXT_ISSCRIPT - should be set if the user has designated the text
					as a script. (NEW: this was unused, but now it is needed by
					space handler script links (see header_view3d.c, for example)

->>> see also: /makesdna/DNA_text_types.h

Display
--
The st->top determines at what line the top of the text is displayed.
If the user moves the cursor the st containing that cursor should
be popped ... other st's retain their own top location.

*/ /***************/


/****************/ /*
	Undo

Undo/Redo works by storing
events in a queue, and a pointer
to the current position in the
queue...

Events are stored using an
arbitrary op-code system
to keep track of
a) the two cursors (normal and selected)
b) input (visible and control (ie backspace))

input data is stored as its
ASCII value, the opcodes are
then selected to not conflict.

opcodes with data in between are
written at the beginning and end
of the data to allow undo and redo
to simply check the code at the current
undo position

*/ /***************/

/***/

static void txt_pop_first(Text *text);
static void txt_pop_last(Text *text);
static void txt_undo_add_op(Text *text, int op);
static void txt_undo_add_block(Text *text, int op, char *buf);
static void txt_delete_line(Text *text, TextLine *line);

/***/

static char *txt_cut_buffer= NULL;
static unsigned char undoing;

/* allow to switch off undoing externally */
void txt_set_undostate(int u)
{
	undoing = u;
}

int txt_get_undostate(void)
{
	return undoing;
}

void free_text(Text *text)
{
	TextLine *tmp;

	for (tmp= text->lines.first; tmp; tmp= tmp->next) {
		MEM_freeN(tmp->line);
		if (tmp->format)
		  MEM_freeN(tmp->format);
	}
	
	BLI_freelistN(&text->lines);

	if(text->name) MEM_freeN(text->name);
	MEM_freeN(text->undo_buf);
	if (text->compiled) BPY_free_compiled_text(text);
}

Text *add_empty_text(char *name) 
{
	Text *ta;
	TextLine *tmp;
	
	ta= alloc_libblock(&G.main->text, ID_TXT, name);
	ta->id.us= 1;
	
	ta->name= NULL;

	ta->undo_pos= -1;
	ta->undo_len= TXT_INIT_UNDO;
	ta->undo_buf= MEM_mallocN(ta->undo_len, "undo buf");
		
	ta->nlines=1;
	ta->flags= TXT_ISDIRTY | TXT_ISTMP | TXT_ISMEM;

	ta->lines.first= ta->lines.last= NULL;

	tmp= (TextLine*) MEM_mallocN(sizeof(TextLine), "textline");
	tmp->line= (char*) MEM_mallocN(1, "textline_string");
	tmp->format= (char*) MEM_mallocN(2, "Syntax_format");
	
	tmp->line[0]=0;
	tmp->len= 0;
				
	tmp->next= NULL;
	tmp->prev= NULL;
				
	BLI_addhead(&ta->lines, tmp);
	
	ta->curl= ta->lines.first;
	ta->curc= 0;
	ta->sell= ta->lines.first;
	ta->selc= 0;

	return ta;
}

// this function removes any control characters from
// a textline

static void cleanup_textline(TextLine * tl)
{
	int i;

	for (i = 0; i < tl->len; i++ ) {
		if (tl->line[i] < ' ' && tl->line[i] != '\t') {
			memmove(tl->line + i, tl->line + i + 1, tl->len - i);
			tl->len--;
			i--;
		}
	}
}

int reopen_text(Text *text)
{
	FILE *fp;
	int i, llen, len;
	unsigned char *buffer;
	TextLine *tmp;
	char sdir[FILE_MAXDIR];
	char sfile[FILE_MAXFILE];
	char str[FILE_MAXDIR+FILE_MAXFILE];

	if (!text || !text->name) return 0;
	
	BLI_strncpy(str, text->name, FILE_MAXDIR+FILE_MAXFILE);
	BLI_convertstringcode(str, G.sce, G.scene->r.cfra);
	BLI_split_dirfile(str, sdir, sfile);
	
	fp= fopen(str, "r");
	if(fp==NULL) return 0;

	/* free memory: */

	for (tmp= text->lines.first; tmp; tmp= tmp->next) {
		MEM_freeN(tmp->line);
		if (tmp->format) MEM_freeN(tmp->format);
	}
	
	BLI_freelistN(&text->lines);

	text->lines.first= text->lines.last= NULL;
	text->curl= text->sell= NULL;

	/* clear undo buffer */
	MEM_freeN(text->undo_buf);
	text->undo_pos= -1;
	text->undo_len= TXT_INIT_UNDO;
	text->undo_buf= MEM_mallocN(text->undo_len, "undo buf");
	
	text->flags= TXT_ISDIRTY | TXT_ISTMP; 
	
	fseek(fp, 0L, SEEK_END);
	len= ftell(fp);
	fseek(fp, 0L, SEEK_SET);	

	text->undo_pos= -1;
	
	buffer= MEM_mallocN(len, "text_buffer");
	// under windows fread can return less then len bytes because
	// of CR stripping
	len = fread(buffer, 1, len, fp);

	fclose(fp);
	
	text->nlines=0;
	i=0;
	llen=0;
	for(i=0; i<len; i++) {
		if (buffer[i]=='\n') {
			tmp= (TextLine*) MEM_mallocN(sizeof(TextLine), "textline");
			tmp->line= (char*) MEM_mallocN(llen+1, "textline_string");
			tmp->format= (char*) MEM_mallocN(llen+2, "Syntax_format");
			
			if(llen) memcpy(tmp->line, &buffer[i-llen], llen);
			tmp->line[llen]=0;
			tmp->len= llen;
				
			cleanup_textline(tmp);

			BLI_addtail(&text->lines, tmp);
			text->nlines++;
				
			llen=0;
			continue;
		}
		llen++;
	}

	if (llen!=0 || text->nlines==0) {
		tmp= (TextLine*) MEM_mallocN(sizeof(TextLine), "textline");
		tmp->line= (char*) MEM_mallocN(llen+1, "textline_string");
		tmp->format= (char*) MEM_mallocN(llen+2, "Syntax_format");
		
		if(llen) memcpy(tmp->line, &buffer[i-llen], llen);

		tmp->line[llen]=0;
		tmp->len= llen;
		
		cleanup_textline(tmp);

		BLI_addtail(&text->lines, tmp);
		text->nlines++;
	}
	
	text->curl= text->sell= text->lines.first;
	text->curc= text->selc= 0;
	
	MEM_freeN(buffer);	
	return 1;
}

Text *add_text(char *file) 
{
	FILE *fp;
	int i, llen, len;
	unsigned char *buffer;
	TextLine *tmp;
	Text *ta;
	char sdir[FILE_MAXDIR];
	char sfile[FILE_MAXFILE];
	char str[FILE_MAXDIR+FILE_MAXFILE];

	BLI_strncpy(str, file, FILE_MAXDIR+FILE_MAXFILE);
	if (G.scene) /* can be NULL (bg mode) */
		BLI_convertstringcode(str, G.sce, G.scene->r.cfra);
	BLI_split_dirfile(str, sdir, sfile);
	
	fp= fopen(str, "r");
	if(fp==NULL) return NULL;
	
	ta= alloc_libblock(&G.main->text, ID_TXT, sfile);
	ta->id.us= 1;

	ta->lines.first= ta->lines.last= NULL;
	ta->curl= ta->sell= NULL;

/* 	ta->flags= TXT_ISTMP | TXT_ISEXT; */
	ta->flags= TXT_ISTMP;
	
	fseek(fp, 0L, SEEK_END);
	len= ftell(fp);
	fseek(fp, 0L, SEEK_SET);	

	ta->name= MEM_mallocN(strlen(file)+1, "text_name");
	strcpy(ta->name, file);

	ta->undo_pos= -1;
	ta->undo_len= TXT_INIT_UNDO;
	ta->undo_buf= MEM_mallocN(ta->undo_len, "undo buf");
	
	buffer= MEM_mallocN(len, "text_buffer");
	// under windows fread can return less then len bytes because
	// of CR stripping
	len = fread(buffer, 1, len, fp);

	fclose(fp);
	
	ta->nlines=0;
	i=0;
	llen=0;
	for(i=0; i<len; i++) {
		if (buffer[i]=='\n') {
			tmp= (TextLine*) MEM_mallocN(sizeof(TextLine), "textline");
			tmp->line= (char*) MEM_mallocN(llen+1, "textline_string");
			tmp->format= (char*) MEM_mallocN(llen+2, "Syntax_format");
			
			if(llen) memcpy(tmp->line, &buffer[i-llen], llen);
			tmp->line[llen]=0;
			tmp->len= llen;
			
			cleanup_textline(tmp);

			BLI_addtail(&ta->lines, tmp);
			ta->nlines++;
				
			llen=0;
			continue;
		}
		llen++;
	}

	if (llen!=0 || ta->nlines==0) {
		tmp= (TextLine*) MEM_mallocN(sizeof(TextLine), "textline");
		tmp->line= (char*) MEM_mallocN(llen+1, "textline_string");
		tmp->format= (char*) MEM_mallocN(llen+2, "Syntax_format");
		
		if(llen) memcpy(tmp->line, &buffer[i-llen], llen);

		tmp->line[llen]=0;
		tmp->len= llen;
		
		cleanup_textline(tmp);

		BLI_addtail(&ta->lines, tmp);
		ta->nlines++;
	}
	
	ta->curl= ta->sell= ta->lines.first;
	ta->curc= ta->selc= 0;
	
	MEM_freeN(buffer);	

	return ta;
}

Text *copy_text(Text *ta)
{
	Text *tan;
	TextLine *line, *tmp;
	
	tan= copy_libblock(ta);
	
	tan->name= MEM_mallocN(strlen(ta->name)+1, "text_name");
	strcpy(tan->name, ta->name);
	
	tan->flags = ta->flags | TXT_ISDIRTY | TXT_ISTMP;
	
	tan->lines.first= tan->lines.last= NULL;
	tan->curl= tan->sell= NULL;
	
	tan->nlines= ta->nlines;

	line= ta->lines.first;	
	/* Walk down, reconstructing */
	while (line) {
		tmp= (TextLine*) MEM_mallocN(sizeof(TextLine), "textline");
		tmp->line= MEM_mallocN(line->len+1, "textline_string");
		tmp->format= MEM_mallocN(line->len+2, "Syntax_format");
		
		strcpy(tmp->line, line->line);

		tmp->len= line->len;
		
		BLI_addtail(&tan->lines, tmp);
		
		line= line->next;
	}

	tan->curl= tan->sell= tan->lines.first;
	tan->curc= tan->selc= 0;

	return tan;
}

/*****************************/
/* Editing utility functions */
/*****************************/

static void make_new_line (TextLine *line, char *newline, char *newformat) 
{
	if (line->line) MEM_freeN(line->line);
	if (line->format) MEM_freeN(line->format);
	
	line->line= newline;
	line->len= strlen(newline);
	line->format= newformat;
}

static TextLine *txt_new_line(char *str)
{
	TextLine *tmp;

	if(!str) str= "";
	
	tmp= (TextLine *) MEM_mallocN(sizeof(TextLine), "textline");
	tmp->line= MEM_mallocN(strlen(str)+1, "textline_string");
	tmp->format= MEM_mallocN(strlen(str)+2, "Syntax_format");
	
	strcpy(tmp->line, str);
	
	tmp->len= strlen(str);
	tmp->next= tmp->prev= NULL;
	
	return tmp;
}

static TextLine *txt_new_linen(char *str, int n)
{
	TextLine *tmp;

	if(!str) str= "";
	
	tmp= (TextLine *) MEM_mallocN(sizeof(TextLine), "textline");
	tmp->line= MEM_mallocN(n+1, "textline_string");
	tmp->format= MEM_mallocN(n+2, "Syntax_format");
	
	BLI_strncpy(tmp->line, str, n+1);
	
	tmp->len= strlen(tmp->line);
	tmp->next= tmp->prev= NULL;
	
	return tmp;
}

void txt_clean_text (Text *text) 
{	
	TextLine **top, **bot;
	
	if (!text) return;
	
	if (!text->lines.first) {
		if (text->lines.last) text->lines.first= text->lines.last;
		else text->lines.first= text->lines.last= txt_new_line(NULL);
	} 
	
	if (!text->lines.last) text->lines.last= text->lines.first;

	top= (TextLine **) &text->lines.first;
	bot= (TextLine **) &text->lines.last;
	
	while ((*top)->prev) *top= (*top)->prev;
	while ((*bot)->next) *bot= (*bot)->next;

	if(!text->curl) {
		if(text->sell) text->curl= text->sell;
		else text->curl= text->lines.first;
		text->curc= 0;
	}

	if(!text->sell) {
		text->sell= text->curl;
		text->selc= 0;
	}
}

int txt_get_span (TextLine *from, TextLine *to)
{
	int ret=0;
	TextLine *tmp= from;

	if (!to || !from) return 0;
	if (from==to) return 0;

	/* Look forwards */
	while (tmp) {
		if (tmp == to) return ret;
		ret++;
		tmp= tmp->next;
	}

	/* Look backwards */
	if (!tmp) {
		tmp= from;
		ret=0;
		while(tmp) {
			if (tmp == to) break;
			ret--;
			tmp= tmp->prev;
		}
		if(!tmp) ret=0;
	}

	return ret;	
}

static void txt_make_dirty (Text *text)
{
	text->flags |= TXT_ISDIRTY;
	if (text->compiled) BPY_free_compiled_text(text);
}

/****************************/
/* Cursor utility functions */
/****************************/

static void txt_curs_cur (Text *text, TextLine ***linep, int **charp)
{
	*linep= &text->curl; *charp= &text->curc;
}

static void txt_curs_sel (Text *text, TextLine ***linep, int **charp)
{
	*linep= &text->sell; *charp= &text->selc;
}

static void txt_curs_first (Text *text, TextLine **linep, int *charp)
{
	if (text->curl==text->sell) {
		*linep= text->curl;
		if (text->curc<text->selc) *charp= text->curc;
		else *charp= text->selc;
	} else if (txt_get_span(text->lines.first, text->curl)<txt_get_span(text->lines.first, text->sell)) {
		*linep= text->curl;
		*charp= text->curc;
	} else {
		*linep= text->sell;
		*charp= text->selc;		
	}
}

/****************************/
/* Cursor movement functions */
/****************************/

void txt_move_up(Text *text, short sel)
{
	TextLine **linep;
	int *charp, old;
	
	if (!text) return;
	if(sel) txt_curs_sel(text, &linep, &charp);
	else { txt_pop_first(text); txt_curs_cur(text, &linep, &charp); }
	if (!*linep) return;
	old= *charp;

	if((*linep)->prev) {
		*linep= (*linep)->prev;
		if (*charp > (*linep)->len) {
			*charp= (*linep)->len;
			if(!undoing) txt_undo_add_toop(text, sel?UNDO_STO:UNDO_CTO, txt_get_span(text->lines.first, (*linep)->next), old, txt_get_span(text->lines.first, *linep), (unsigned short) *charp);
		} else {
			if(!undoing) txt_undo_add_op(text, sel?UNDO_SUP:UNDO_CUP);
		}
	} else {
		*charp= 0;
		if(!undoing) txt_undo_add_op(text, sel?UNDO_SUP:UNDO_CUP);
	}

	if(!sel) txt_pop_sel(text);
}

void txt_move_down(Text *text, short sel) 
{
	TextLine **linep;
	int *charp, old;
	
	if (!text) return;
	if(sel) txt_curs_sel(text, &linep, &charp);
	else { txt_pop_last(text); txt_curs_cur(text, &linep, &charp); }
	if (!*linep) return;
	old= *charp;

	if((*linep)->next) {
		*linep= (*linep)->next;
		if (*charp > (*linep)->len) {
			*charp= (*linep)->len;
			if(!undoing) txt_undo_add_toop(text, sel?UNDO_STO:UNDO_CTO, txt_get_span(text->lines.first, (*linep)->prev), old, txt_get_span(text->lines.first, *linep), (unsigned short)*charp);
		} else
			if(!undoing) txt_undo_add_op(text, sel?UNDO_SDOWN:UNDO_CDOWN);	
	} else {
		*charp= (*linep)->len;
		if(!undoing) txt_undo_add_op(text, sel?UNDO_SDOWN:UNDO_CDOWN);
	}

	if(!sel) txt_pop_sel(text);
}

void txt_move_left(Text *text, short sel) 
{
	TextLine **linep;
	int *charp, oundoing= undoing;
	
	if (!text) return;
	if(sel) txt_curs_sel(text, &linep, &charp);
	else { txt_pop_first(text); txt_curs_cur(text, &linep, &charp); }
	if (!*linep) return;

	undoing= 1;
	if (*charp== 0) {
		if ((*linep)->prev) {
			txt_move_up(text, sel);
			*charp= (*linep)->len;
		}
	} else {
		(*charp)--;
	}
	undoing= oundoing;
	if(!undoing) txt_undo_add_op(text, sel?UNDO_SLEFT:UNDO_CLEFT);
	
	if(!sel) txt_pop_sel(text);
}

void txt_move_right(Text *text, short sel) 
{
	TextLine **linep;
	int *charp, oundoing= undoing;
	
	if (!text) return;
	if(sel) txt_curs_sel(text, &linep, &charp);
	else { txt_pop_last(text); txt_curs_cur(text, &linep, &charp); }
	if (!*linep) return;

	undoing= 1;
	if (*charp== (*linep)->len) {
		if ((*linep)->next) {
			txt_move_down(text, sel);
			*charp= 0;
		}
	} else {
		(*charp)++;
	}
	undoing= oundoing;
	if(!undoing) txt_undo_add_op(text, sel?UNDO_SRIGHT:UNDO_CRIGHT);

	if(!sel) txt_pop_sel(text);
}

void txt_move_bol (Text *text, short sel) 
{
	TextLine **linep;
	int *charp, old;
	
	if (!text) return;
	if(sel) txt_curs_sel(text, &linep, &charp);
	else txt_curs_cur(text, &linep, &charp);
	if (!*linep) return;
	old= *charp;
	
	*charp= 0;

	if(!sel) txt_pop_sel(text);
	if(!undoing) txt_undo_add_toop(text, sel?UNDO_STO:UNDO_CTO, txt_get_span(text->lines.first, *linep), old, txt_get_span(text->lines.first, *linep), (unsigned short)*charp);
}

void txt_move_eol (Text *text, short sel) 
{
	TextLine **linep;
	int *charp, old;
	
	if (!text) return;
	if(sel) txt_curs_sel(text, &linep, &charp);
	else txt_curs_cur(text, &linep, &charp);
	if (!*linep) return;
	old= *charp;
		
	*charp= (*linep)->len;

	if(!sel) txt_pop_sel(text);
	if(!undoing) txt_undo_add_toop(text, sel?UNDO_STO:UNDO_CTO, txt_get_span(text->lines.first, *linep), old, txt_get_span(text->lines.first, *linep), (unsigned short)*charp);
}

void txt_move_bof (Text *text, short sel)
{
	TextLine **linep;
	int *charp, old;
	
	if (!text) return;
	if(sel) txt_curs_sel(text, &linep, &charp);
	else txt_curs_cur(text, &linep, &charp);
	if (!*linep) return;
	old= *charp;

	*linep= text->lines.first;
	*charp= 0;

	if(!sel) txt_pop_sel(text);
	if(!undoing) txt_undo_add_toop(text, sel?UNDO_STO:UNDO_CTO, txt_get_span(text->lines.first, *linep), old, txt_get_span(text->lines.first, *linep), (unsigned short)*charp);
}

void txt_move_eof (Text *text, short sel)
{
	TextLine **linep;
	int *charp, old;
	
	if (!text) return;
	if(sel) txt_curs_sel(text, &linep, &charp);
	else txt_curs_cur(text, &linep, &charp);
	if (!*linep) return;
	old= *charp;

	*linep= text->lines.last;
	*charp= (*linep)->len;

	if(!sel) txt_pop_sel(text);
	if(!undoing) txt_undo_add_toop(text, sel?UNDO_STO:UNDO_CTO, txt_get_span(text->lines.first, *linep), old, txt_get_span(text->lines.first, *linep), (unsigned short)*charp);	
}

void txt_move_toline (Text *text, unsigned int line, short sel)
{
	TextLine **linep, *oldl;
	int *charp, oldc;
	unsigned int i;
	
	if (!text) return;
	if(sel) txt_curs_sel(text, &linep, &charp);
	else txt_curs_cur(text, &linep, &charp);
	if (!*linep) return;
	oldc= *charp;
	oldl= *linep;
	
	*linep= text->lines.first;
	for (i=0; i<line; i++) {
		if ((*linep)->next) *linep= (*linep)->next;
		else break;
	}
	*charp= 0;
	
	if(!sel) txt_pop_sel(text);
	if(!undoing) txt_undo_add_toop(text, sel?UNDO_STO:UNDO_CTO, txt_get_span(text->lines.first, oldl), oldc, txt_get_span(text->lines.first, *linep), (unsigned short)*charp);	
}

/****************************/
/* Text selection functions */
/****************************/

static void txt_curs_swap (Text *text)
{
	TextLine *tmpl;
	int tmpc;
		
	tmpl= text->curl;
	text->curl= text->sell;
	text->sell= tmpl;
	
	tmpc= text->curc;
	text->curc= text->selc;
	text->selc= tmpc;
	
	if(!undoing) txt_undo_add_op(text, UNDO_SWAP);
}

static void txt_pop_first (Text *text)
{
			
	if (txt_get_span(text->curl, text->sell)<0 ||
		(text->curl==text->sell && text->curc>text->selc)) {	
		txt_curs_swap(text);
	}

	if(!undoing) txt_undo_add_toop(text, UNDO_STO,
		txt_get_span(text->lines.first, text->sell), 
		text->selc, 
		txt_get_span(text->lines.first, text->curl), 
		text->curc);		
	
	txt_pop_sel(text);
}

static void txt_pop_last (Text *text)
{
	if (txt_get_span(text->curl, text->sell)>0 ||
		(text->curl==text->sell && text->curc<text->selc)) {
		txt_curs_swap(text);
	}

	if(!undoing) txt_undo_add_toop(text, UNDO_STO,
		txt_get_span(text->lines.first, text->sell), 
		text->selc, 
		txt_get_span(text->lines.first, text->curl), 
		text->curc);		
	
	txt_pop_sel(text);
}

/* never used: CVS 1.19 */
/*  static void txt_pop_selr (Text *text) */

void txt_pop_sel (Text *text)
{
	text->sell= text->curl;
	text->selc= text->curc;	
}

void txt_order_cursors(Text *text)
{
	if (!text) return;
	if (!text->curl) return;
	if (!text->sell) return;
	
		/* Flip so text->curl is before text->sell */
	if (txt_get_span(text->curl, text->sell)<0 ||
			(text->curl==text->sell && text->curc>text->selc))
		txt_curs_swap(text);
}

int txt_has_sel(Text *text)
{
	return ((text->curl!=text->sell) || (text->curc!=text->selc));
}

static void txt_delete_sel (Text *text)
{
	TextLine *tmpl;
	char *buf, *format;
	
	if (!text) return;
	if (!text->curl) return;
	if (!text->sell) return;

	if (!txt_has_sel(text)) return;
	
	txt_order_cursors(text);

	if(!undoing) {
		buf= txt_sel_to_buf(text);
		txt_undo_add_block(text, UNDO_DBLOCK, buf);
		MEM_freeN(buf);
	}

	buf= MEM_mallocN(text->curc+(text->sell->len - text->selc)+1, "textline_string");
	format= MEM_mallocN(text->curc+(text->sell->len - text->selc)+2, "Syntax_format");
	
	strncpy(buf, text->curl->line, text->curc);
	strcpy(buf+text->curc, text->sell->line + text->selc);
	buf[text->curc+(text->sell->len - text->selc)]=0;

	make_new_line(text->curl, buf, format);
	
	tmpl= text->sell;
	while (tmpl != text->curl) {
		tmpl= tmpl->prev;
		if (!tmpl) break;
		
		txt_delete_line(text, tmpl->next);
	}
	
	text->sell= text->curl;
	text->selc= text->curc;
}

void txt_sel_all (Text *text)
{
	if (!text) return;

	text->curl= text->lines.first;
	text->curc= 0;
	
	text->sell= text->lines.last;
	text->selc= text->sell->len;
}

void txt_sel_line (Text *text)
{
	if (!text) return;
	if (!text->curl) return;
	
	text->curc= 0;
	text->sell= text->curl;
	text->selc= text->sell->len;
}

/***************************/
/* Cut and paste functions */
/***************************/

void txt_print_cutbuffer (void) 
{
	printf ("Cut buffer\n--\n%s\n--\n", txt_cut_buffer);	
}

char *txt_to_buf (Text *text)
{
	int length;
	TextLine *tmp, *linef, *linel;
	int charf, charl;
	char *buf;
	
	if (!text) return NULL;
	if (!text->curl) return NULL;
	if (!text->sell) return NULL;
		
	linef= text->lines.first;
	charf= 0;
		
	linel= text->lines.last;
	charl= linel->len;

	if (linef == text->lines.last) {
		length= charl-charf;

		buf= MEM_mallocN(length+2, "text buffer");
		
		BLI_strncpy(buf, linef->line + charf, length+1);
		buf[length]=0;
	} else {
		length= linef->len - charf;
		length+= charl;
		length+= 2; /* For the 2 '\n' */
		
		tmp= linef->next;
		while (tmp && tmp!= linel) {
			length+= tmp->len+1;
			tmp= tmp->next;
		}
		
		buf= MEM_mallocN(length+1, "cut buffer");

		strncpy(buf, linef->line + charf, linef->len-charf);
		length= linef->len - charf;
		
		buf[length++]='\n';
		
		tmp= linef->next;
		while (tmp && tmp!=linel) {
			strncpy(buf+length, tmp->line, tmp->len);
			length+= tmp->len;
			
			buf[length++]='\n';			
			
			tmp= tmp->next;
		}
		strncpy(buf+length, linel->line, charl);
		length+= charl;
		
		/* python compiler wants an empty end line */
		buf[length++]='\n';			
		buf[length]=0;
	}
	
	return buf;
}

int txt_find_string(Text *text, char *findstr)
{
	TextLine *tl, *startl;
	char *s= NULL;

	if (!text || !text->curl || !text->sell) return 0;
	
	txt_order_cursors(text);

	tl= startl= text->sell;
	
	s= strstr(&tl->line[text->selc], findstr);
	while (!s) {
		tl= tl->next;
		if (!tl)
			tl= text->lines.first;

		s= strstr(tl->line, findstr);
		if (tl==startl)
			break;
	}
	
	if (s) {
		text->curl= text->sell= tl;
		text->curc= (int) (s-tl->line);
		text->selc= text->curc + strlen(findstr);
		
		return 1;				
	} else
		return 0;
}

void txt_cut_sel (Text *text)
{
	txt_copy_sel(text);
	
	txt_delete_sel(text);
	txt_make_dirty(text);
}

char *txt_sel_to_buf (Text *text)
{
	char *buf;
	int length=0;
	TextLine *tmp, *linef, *linel;
	int charf, charl;
	
	if (!text) return NULL;
	if (!text->curl) return NULL;
	if (!text->sell) return NULL;
	
	if (text->curl==text->sell) {
		linef= linel= text->curl;
		
		if (text->curc < text->selc) {
			charf= text->curc;
			charl= text->selc;
		} else{
			charf= text->selc;
			charl= text->curc;
		}
	} else if (txt_get_span(text->curl, text->sell)<0) {
		linef= text->sell;
		linel= text->curl;

		charf= text->selc;		
		charl= text->curc;
	} else {
		linef= text->curl;
		linel= text->sell;
		
		charf= text->curc;
		charl= text->selc;
	}

	if (linef == linel) {
		length= charl-charf;

		buf= MEM_mallocN(length+1, "sel buffer");
		
		BLI_strncpy(buf, linef->line + charf, length+1);
	} else {
		length+= linef->len - charf;
		length+= charl;
		length++; /* For the '\n' */
		
		tmp= linef->next;
		while (tmp && tmp!= linel) {
			length+= tmp->len+1;
			tmp= tmp->next;
		}
		
		buf= MEM_mallocN(length+1, "sel buffer");
		
		strncpy(buf, linef->line+ charf, linef->len-charf);
		length= linef->len-charf;
		
		buf[length++]='\n';
		
		tmp= linef->next;
		while (tmp && tmp!=linel) {
			strncpy(buf+length, tmp->line, tmp->len);
			length+= tmp->len;
			
			buf[length++]='\n';			
			
			tmp= tmp->next;
		}
		strncpy(buf+length, linel->line, charl);
		length+= charl;
		
		buf[length]=0;
	}	

	return buf;
}

void txt_copy_sel (Text *text)
{
	int length=0;
	TextLine *tmp, *linef, *linel;
	int charf, charl;
	
	if (!text) return;
	if (!text->curl) return;
	if (!text->sell) return;

	if (!txt_has_sel(text)) return;
	
	if (txt_cut_buffer) MEM_freeN(txt_cut_buffer);
	txt_cut_buffer= NULL;
	
	if (text->curl==text->sell) {
		linef= linel= text->curl;
		
		if (text->curc < text->selc) {
			charf= text->curc;
			charl= text->selc;
		} else{
			charf= text->selc;
			charl= text->curc;
		}
	} else if (txt_get_span(text->curl, text->sell)<0) {
		linef= text->sell;
		linel= text->curl;

		charf= text->selc;		
		charl= text->curc;
	} else {
		linef= text->curl;
		linel= text->sell;
		
		charf= text->curc;
		charl= text->selc;
	}

	if (linef == linel) {
		length= charl-charf;

		txt_cut_buffer= MEM_mallocN(length+1, "cut buffera");
		
		BLI_strncpy(txt_cut_buffer, linef->line + charf, length+1);
	} else {
		length+= linef->len - charf;
		length+= charl;
		length++; /* For the '\n' */
		
		tmp= linef->next;
		while (tmp && tmp!= linel) {
			length+= tmp->len+1;
			tmp= tmp->next;
		}
		
		txt_cut_buffer= MEM_mallocN(length+1, "cut bufferb");
		
		strncpy(txt_cut_buffer, linef->line+ charf, linef->len-charf);
		length= linef->len-charf;
		
		txt_cut_buffer[length++]='\n';
		
		tmp= linef->next;
		while (tmp && tmp!=linel) {
			strncpy(txt_cut_buffer+length, tmp->line, tmp->len);
			length+= tmp->len;
			
			txt_cut_buffer[length++]='\n';			
			
			tmp= tmp->next;
		}
		strncpy(txt_cut_buffer+length, linel->line, charl);
		length+= charl;
		
		txt_cut_buffer[length]=0;
	}
}

void txt_insert_buf(Text *text, char *in_buffer)
{
	int i=0, l=0, j, u, len;
	TextLine *add;

	if (!text) return;
	if (!in_buffer) return;

	txt_delete_sel(text);
	
	if(!undoing) txt_undo_add_block (text, UNDO_IBLOCK, in_buffer); 	

	u= undoing;
	undoing= 1;

	/* Read the first line (or as close as possible */
	while (in_buffer[i] && in_buffer[i]!='\n') {
		txt_add_char(text, in_buffer[i]);
		i++;
	}
	
	if (in_buffer[i]=='\n') txt_split_curline(text);
	else { undoing = u; return; }
	i++;

	/* Read as many full lines as we can */
	len= strlen(in_buffer);

	while (i<len) {
		l=0;

		while (in_buffer[i] && in_buffer[i]!='\n') {
			i++; l++;
		}
	
		if(in_buffer[i]=='\n') {
			add= txt_new_linen(in_buffer +(i-l), l);
			BLI_insertlinkbefore(&text->lines, text->curl, add);
			i++;
		} else {
			for (j= i-l; j<i && j<(int)strlen(in_buffer); j++) {
				txt_add_char(text, in_buffer[j]);
			}
			break;
		}
	}
	
	undoing= u;
}

void txt_free_cut_buffer(void) 
{
	if (txt_cut_buffer) MEM_freeN(txt_cut_buffer);
}

void txt_paste(Text *text)
{
	txt_insert_buf(text, txt_cut_buffer);
}

/******************/
/* Undo functions */
/******************/

#define MAX_UNDO_TEST(x) \
	while (text->undo_pos+x >= text->undo_len) { \
		if(text->undo_len*2 > TXT_MAX_UNDO) { \
			error("Undo limit reached, buffer cleared\n"); \
			MEM_freeN(text->undo_buf); \
			text->undo_len= TXT_INIT_UNDO; \
			text->undo_buf= MEM_mallocN(text->undo_len, "undo buf"); \
			text->undo_pos=-1; \
			return; \
		} else { \
			void *tmp= text->undo_buf; \
			text->undo_buf= MEM_callocN(text->undo_len*2, "undo buf"); \
			memcpy(text->undo_buf, tmp, text->undo_len); \
			text->undo_len*=2; \
			MEM_freeN(tmp); \
		} \
	}

static void dump_buffer(Text *text) 
{
	int i= 0;
	
	while (i++<text->undo_pos) printf("%d: %d %c\n", i, text->undo_buf[i], text->undo_buf[i]);
}

void txt_print_undo(Text *text)
{
	int i= 0;
	int op;
	char *ops;
	int linep, charp;
	
	dump_buffer(text);
	
	printf ("---< Undo Buffer >---\n");
	
	printf ("UndoPosition is %d\n", text->undo_pos);
	
	while (i<=text->undo_pos) {
		op= text->undo_buf[i];
		
		if (op==UNDO_CLEFT) {
			ops= "Cursor left";
		} else if (op==UNDO_CRIGHT) {
			ops= "Cursor right";
		} else if (op==UNDO_CUP) {
			ops= "Cursor up";
		} else if (op==UNDO_CDOWN) {
			ops= "Cursor down";
		} else if (op==UNDO_SLEFT) {
			ops= "Selection left";
		} else if (op==UNDO_SRIGHT) {
			ops= "Selection right";
		} else if (op==UNDO_SUP) {
			ops= "Selection up";
		} else if (op==UNDO_SDOWN) {
			ops= "Selection down";
		} else if (op==UNDO_STO) {
			ops= "Selection ";
		} else if (op==UNDO_CTO) {
			ops= "Cursor ";
		} else if (op==UNDO_INSERT) {
			ops= "Insert";
		} else if (op==UNDO_BS) {
			ops= "Backspace";
		} else if (op==UNDO_DEL) {
			ops= "Delete";
		} else if (op==UNDO_SWAP) {
			ops= "Cursor swap";
		} else if (op==UNDO_DBLOCK) {
			ops= "Delete text block";
		} else if (op==UNDO_IBLOCK) {
			ops= "Insert text block";
		} else if (op==UNDO_INDENT) {
			ops= "Indent ";
		} else if (op==UNDO_UNINDENT) {
			ops= "Unindent ";
		} else if (op==UNDO_COMMENT) {
			ops= "Comment ";
		} else if (op==UNDO_UNCOMMENT) {
			ops= "Uncomment ";
		} else {
			ops= "Unknown";
		}
		
		printf ("Op (%o) at %d = %s", op, i, ops);
		if (op==UNDO_INSERT || op==UNDO_BS || op==UNDO_DEL) {
			i++;
			printf (" - Char is %c", text->undo_buf[i]);  
			i++;
		} else if (op==UNDO_STO || op==UNDO_CTO) {
			i++;

			charp= text->undo_buf[i]; i++;
			charp= charp+(text->undo_buf[i]<<8); i++;

			linep= text->undo_buf[i]; i++;
			linep= linep+(text->undo_buf[i]<<8); i++;
			linep= linep+(text->undo_buf[i]<<16); i++;
			linep= linep+(text->undo_buf[i]<<24); i++;
			
			printf ("to <%d, %d> ", linep, charp);

			charp= text->undo_buf[i]; i++;
			charp= charp+(text->undo_buf[i]<<8); i++;

			linep= text->undo_buf[i]; i++;
			linep= linep+(text->undo_buf[i]<<8); i++;
			linep= linep+(text->undo_buf[i]<<16); i++;
			linep= linep+(text->undo_buf[i]<<24); i++;
			
			printf ("from <%d, %d>", linep, charp);
		} else if (op==UNDO_DBLOCK || op==UNDO_IBLOCK) {
			i++;

			linep= text->undo_buf[i]; i++;
			linep= linep+(text->undo_buf[i]<<8); i++;
			linep= linep+(text->undo_buf[i]<<16); i++;
			linep= linep+(text->undo_buf[i]<<24); i++;
			
			printf (" (length %d) <", linep);
			
			while (linep>0) {
				putchar(text->undo_buf[i]);
				linep--; i++;
			}
			
			linep= text->undo_buf[i]; i++;
			linep= linep+(text->undo_buf[i]<<8); i++;
			linep= linep+(text->undo_buf[i]<<16); i++;
			linep= linep+(text->undo_buf[i]<<24); i++;
			printf ("> (%d)", linep);
		} else if (op==UNDO_INDENT || op==UNDO_UNINDENT) {
			i++;

			charp= text->undo_buf[i]; i++;
			charp= charp+(text->undo_buf[i]<<8); i++;

			linep= text->undo_buf[i]; i++;
			linep= linep+(text->undo_buf[i]<<8); i++;
			linep= linep+(text->undo_buf[i]<<16); i++;
			linep= linep+(text->undo_buf[i]<<24); i++;
			
			printf ("to <%d, %d> ", linep, charp);

			charp= text->undo_buf[i]; i++;
			charp= charp+(text->undo_buf[i]<<8); i++;

			linep= text->undo_buf[i]; i++;
			linep= linep+(text->undo_buf[i]<<8); i++;
			linep= linep+(text->undo_buf[i]<<16); i++;
			linep= linep+(text->undo_buf[i]<<24); i++;
			
			printf ("from <%d, %d>", linep, charp);
		}
		
		printf (" %d\n",  i);
		i++;
	}
}

static void txt_undo_add_op(Text *text, int op)
{
	//XXX MAX_UNDO_TEST(2);
	
	text->undo_pos++;
	text->undo_buf[text->undo_pos]= op;
	text->undo_buf[text->undo_pos+1]= 0;
}

static void txt_undo_add_block(Text *text, int op, char *buf)
{
	int length;
	
	length= strlen(buf);
	
	//XXX MAX_UNDO_TEST(length+11);

	text->undo_pos++;
	text->undo_buf[text->undo_pos]= op;
	
	text->undo_pos++;
	text->undo_buf[text->undo_pos]= (length)&0xff;
	text->undo_pos++;
	text->undo_buf[text->undo_pos]= (length>>8)&0xff;
	text->undo_pos++;
	text->undo_buf[text->undo_pos]= (length>>16)&0xff;
	text->undo_pos++;
	text->undo_buf[text->undo_pos]= (length>>24)&0xff;

	text->undo_pos++;
	strncpy(text->undo_buf+text->undo_pos, buf, length);
	text->undo_pos+=length;

	text->undo_buf[text->undo_pos]= (length)&0xff;
	text->undo_pos++;
	text->undo_buf[text->undo_pos]= (length>>8)&0xff;
	text->undo_pos++;
	text->undo_buf[text->undo_pos]= (length>>16)&0xff;
	text->undo_pos++;
	text->undo_buf[text->undo_pos]= (length>>24)&0xff;

	text->undo_pos++;
	text->undo_buf[text->undo_pos]= op;
	
	text->undo_buf[text->undo_pos+1]= 0;
}

void txt_undo_add_toop(Text *text, int op, unsigned int froml, unsigned short fromc, unsigned int tol, unsigned short toc)
{
	//XXX MAX_UNDO_TEST(15);

	if (froml==tol && fromc==toc) return;

	text->undo_pos++;
	text->undo_buf[text->undo_pos]= op;

	text->undo_pos++;
	text->undo_buf[text->undo_pos]= (fromc)&0xff;
	text->undo_pos++;
	text->undo_buf[text->undo_pos]= (fromc>>8)&0xff;

	text->undo_pos++;
	text->undo_buf[text->undo_pos]= (froml)&0xff;
	text->undo_pos++;
	text->undo_buf[text->undo_pos]= (froml>>8)&0xff;
	text->undo_pos++;
	text->undo_buf[text->undo_pos]= (froml>>16)&0xff;
	text->undo_pos++;
	text->undo_buf[text->undo_pos]= (froml>>24)&0xff;

	text->undo_pos++;
	text->undo_buf[text->undo_pos]= (toc)&0xff;
	text->undo_pos++;
	text->undo_buf[text->undo_pos]= (toc>>8)&0xff;

	text->undo_pos++;
	text->undo_buf[text->undo_pos]= (tol)&0xff;
	text->undo_pos++;
	text->undo_buf[text->undo_pos]= (tol>>8)&0xff;
	text->undo_pos++;
	text->undo_buf[text->undo_pos]= (tol>>16)&0xff;
	text->undo_pos++;
	text->undo_buf[text->undo_pos]= (tol>>24)&0xff;

	text->undo_pos++;
	text->undo_buf[text->undo_pos]= op;

	text->undo_buf[text->undo_pos+1]= 0;
}

static void txt_undo_add_charop(Text *text, int op, char c)
{
	//XXX MAX_UNDO_TEST(4);

	text->undo_pos++;
	text->undo_buf[text->undo_pos]= op;
	text->undo_pos++;
	text->undo_buf[text->undo_pos]= c;
	text->undo_pos++;
	text->undo_buf[text->undo_pos]= op;
	text->undo_buf[text->undo_pos+1]= 0;
}

void txt_do_undo(Text *text)
{
	int op= text->undo_buf[text->undo_pos];
	unsigned int linep, i;
	unsigned short charp;
	TextLine *holdl;
	int holdc, holdln;
	char *buf;
	
	if (text->undo_pos<0) {
		return;
	}

	text->undo_pos--;

	undoing= 1;
	
	switch(op) {
		case UNDO_CLEFT:
			txt_move_right(text, 0);
			break;
			
		case UNDO_CRIGHT:
			txt_move_left(text, 0);
			break;
			
		case UNDO_CUP:
			txt_move_down(text, 0);
			break;
			
		case UNDO_CDOWN:
			txt_move_up(text, 0);
			break;

		case UNDO_SLEFT:
			txt_move_right(text, 1);
			break;

		case UNDO_SRIGHT:
			txt_move_left(text, 1);
			break;

		case UNDO_SUP:
			txt_move_down(text, 1);
			break;

		case UNDO_SDOWN:
			txt_move_up(text, 1);
			break;
		
		case UNDO_CTO:
		case UNDO_STO:
			text->undo_pos--;
			text->undo_pos--;
			text->undo_pos--;
			text->undo_pos--;
		
			text->undo_pos--;
			text->undo_pos--;
		
			linep= text->undo_buf[text->undo_pos]; text->undo_pos--;
			linep= (linep<<8)+text->undo_buf[text->undo_pos]; text->undo_pos--;
			linep= (linep<<8)+text->undo_buf[text->undo_pos]; text->undo_pos--;
			linep= (linep<<8)+text->undo_buf[text->undo_pos]; text->undo_pos--;

			charp= text->undo_buf[text->undo_pos]; text->undo_pos--;
			charp= (charp<<8)+text->undo_buf[text->undo_pos]; text->undo_pos--;
			
			if (op==UNDO_CTO) {
				txt_move_toline(text, linep, 0);
				text->curc= charp;
				txt_pop_sel(text);
			} else {
				txt_move_toline(text, linep, 1);
				text->selc= charp;
			}
			
			text->undo_pos--;
			break;
			
		case UNDO_INSERT:
			txt_backspace_char(text);
			text->undo_pos--;
			text->undo_pos--;
			break;

		case UNDO_BS:
			txt_add_char(text, text->undo_buf[text->undo_pos]);
			text->undo_pos--;
			text->undo_pos--;
			break;

		case UNDO_DEL:
			txt_add_char(text, text->undo_buf[text->undo_pos]);
			txt_move_left(text, 0);
			text->undo_pos--;
			text->undo_pos--;
			break;

		case UNDO_SWAP:
			txt_curs_swap(text);
			txt_do_undo(text); /* swaps should appear transparent */
			break;

		case UNDO_DBLOCK:
			linep= text->undo_buf[text->undo_pos]; text->undo_pos--;
			linep= (linep<<8)+text->undo_buf[text->undo_pos]; text->undo_pos--;
			linep= (linep<<8)+text->undo_buf[text->undo_pos]; text->undo_pos--;
			linep= (linep<<8)+text->undo_buf[text->undo_pos]; text->undo_pos--;

			buf= MEM_mallocN(linep+1, "dblock buffer");
			for (i=0; i < linep; i++){
				buf[(linep-1)-i]= text->undo_buf[text->undo_pos]; 
				text->undo_pos--;
			}
			buf[i]= 0;
			
			txt_curs_first(text, &holdl, &holdc);
			holdln= txt_get_span(text->lines.first, holdl);
			
			txt_insert_buf(text, buf);			
			MEM_freeN(buf);

			text->curl= text->lines.first;
			while (holdln>0) {
				if(text->curl->next)
					text->curl= text->curl->next;
					
				holdln--;
			}
			text->curc= holdc;

			linep= text->undo_buf[text->undo_pos]; text->undo_pos--;
			linep= (linep<<8)+text->undo_buf[text->undo_pos]; text->undo_pos--;
			linep= (linep<<8)+text->undo_buf[text->undo_pos]; text->undo_pos--;
			linep= (linep<<8)+text->undo_buf[text->undo_pos]; text->undo_pos--;

			text->undo_pos--;
			
			break;

		case UNDO_IBLOCK:
			linep= text->undo_buf[text->undo_pos]; text->undo_pos--;
			linep= (linep<<8)+text->undo_buf[text->undo_pos]; text->undo_pos--;
			linep= (linep<<8)+text->undo_buf[text->undo_pos]; text->undo_pos--;
			linep= (linep<<8)+text->undo_buf[text->undo_pos]; text->undo_pos--;

			txt_delete_sel(text);
			while (linep>0) {
				txt_backspace_char(text);
				text->undo_pos--;
				linep--;
			}

			text->undo_pos--;
			text->undo_pos--;
			text->undo_pos--; 
			text->undo_pos--;
			
			text->undo_pos--;

			break;
		case UNDO_INDENT:
		case UNDO_UNINDENT:
		case UNDO_COMMENT:
		case UNDO_UNCOMMENT:
			linep= text->undo_buf[text->undo_pos]; text->undo_pos--;
			linep = (linep<<8)+text->undo_buf[text->undo_pos]; text->undo_pos--;
			linep = (linep<<8)+text->undo_buf[text->undo_pos]; text->undo_pos--;
			linep = (linep<<8)+text->undo_buf[text->undo_pos]; text->undo_pos--;
			//linep is now the end line of the selection
			
			charp = text->undo_buf[text->undo_pos]; text->undo_pos--;
			charp = (charp<<8)+text->undo_buf[text->undo_pos]; text->undo_pos--;
			//charp is the last char selected or text->line->len
			//set the selcetion for this now
			text->selc = charp;
			text->sell = text->lines.first;
			for (i= 0; i < linep; i++) {
				text->sell = text->sell->next;
			}

			linep= text->undo_buf[text->undo_pos]; text->undo_pos--;
			linep = (linep<<8)+text->undo_buf[text->undo_pos]; text->undo_pos--;
			linep = (linep<<8)+text->undo_buf[text->undo_pos]; text->undo_pos--;
			linep = (linep<<8)+text->undo_buf[text->undo_pos]; text->undo_pos--;
			//first line to be selected
			
			charp = text->undo_buf[text->undo_pos]; text->undo_pos--;
			charp = (charp<<8)+text->undo_buf[text->undo_pos]; text->undo_pos--;
			//first postion to be selected
			text->curc = charp;
			text->curl = text->lines.first;
			for (i = 0; i < linep; i++) {
				text->curl = text->curl->next;
			}

			
			if (op==UNDO_INDENT) {
				unindent(text);
			} else if (op== UNDO_UNINDENT) {
				indent(text);
			} else if (op == UNDO_COMMENT) {
				uncomment(text);
			} else if (op == UNDO_UNCOMMENT) {
				comment(text);
			}

			text->undo_pos--;
			break;
		default:
			//XXX error("Undo buffer error - resetting");
			text->undo_pos= -1;
			
			break;
	}
	
	undoing= 0;	
}

void txt_do_redo(Text *text)
{
	char op;
	unsigned int linep, i;
	unsigned short charp;
	char *buf;
	
	text->undo_pos++;	
	op= text->undo_buf[text->undo_pos];
	
	if (!op) {
		text->undo_pos--;
		return;
	}
	
	undoing= 1;

	switch(op) {
		case UNDO_CLEFT:
			txt_move_left(text, 0);
			break;
			
		case UNDO_CRIGHT:
			txt_move_right(text, 0);
			break;
			
		case UNDO_CUP:
			txt_move_up(text, 0);
			break;
			
		case UNDO_CDOWN:
			txt_move_down(text, 0);
			break;

		case UNDO_SLEFT:
			txt_move_left(text, 1);
			break;

		case UNDO_SRIGHT:
			txt_move_right(text, 1);
			break;

		case UNDO_SUP:
			txt_move_up(text, 1);
			break;

		case UNDO_SDOWN:
			txt_move_down(text, 1);
			break;
		
		case UNDO_INSERT:
			text->undo_pos++;
			txt_add_char(text, text->undo_buf[text->undo_pos]);
			text->undo_pos++;
			break;

		case UNDO_BS:
			text->undo_pos++;
			txt_backspace_char(text);
			text->undo_pos++;
			break;

		case UNDO_DEL:
			text->undo_pos++;
			txt_delete_char(text);
			text->undo_pos++;
			break;

		case UNDO_SWAP:
			txt_curs_swap(text);
			txt_do_undo(text); /* swaps should appear transparent a*/
			break;
			
		case UNDO_CTO:
		case UNDO_STO:
			text->undo_pos++;
			text->undo_pos++;

			text->undo_pos++;
			text->undo_pos++;
			text->undo_pos++;
			text->undo_pos++;

			text->undo_pos++;

			charp= text->undo_buf[text->undo_pos];
			text->undo_pos++;
			charp= charp+(text->undo_buf[text->undo_pos]<<8);

			text->undo_pos++;
			linep= text->undo_buf[text->undo_pos]; text->undo_pos++;
			linep= linep+(text->undo_buf[text->undo_pos]<<8); text->undo_pos++;
			linep= linep+(text->undo_buf[text->undo_pos]<<16); text->undo_pos++;
			linep= linep+(text->undo_buf[text->undo_pos]<<24); text->undo_pos++;
			
			if (op==UNDO_CTO) {
				txt_move_toline(text, linep, 0);
				text->curc= charp;
				txt_pop_sel(text);
			} else {
				txt_move_toline(text, linep, 1);
				text->selc= charp;
			}

			break;

		case UNDO_DBLOCK:
			text->undo_pos++;
			linep= text->undo_buf[text->undo_pos]; text->undo_pos++;
			linep= linep+(text->undo_buf[text->undo_pos]<<8); text->undo_pos++;
			linep= linep+(text->undo_buf[text->undo_pos]<<16); text->undo_pos++;
			linep= linep+(text->undo_buf[text->undo_pos]<<24); text->undo_pos++;

			txt_delete_sel(text);
			text->undo_pos+=linep;

			text->undo_pos++;
			text->undo_pos++;
			text->undo_pos++; 
			text->undo_pos++;
			
			break;

		case UNDO_IBLOCK:
			text->undo_pos++;
			linep= text->undo_buf[text->undo_pos]; text->undo_pos++;
			linep= linep+(text->undo_buf[text->undo_pos]<<8); text->undo_pos++;
			linep= linep+(text->undo_buf[text->undo_pos]<<16); text->undo_pos++;
			linep= linep+(text->undo_buf[text->undo_pos]<<24); text->undo_pos++;

			buf= MEM_mallocN(linep+1, "iblock buffer");
			memcpy (buf, &text->undo_buf[text->undo_pos], linep);
			text->undo_pos+= linep;
			buf[linep]= 0;
			
			txt_insert_buf(text, buf);			
			MEM_freeN(buf);

			linep= text->undo_buf[text->undo_pos]; text->undo_pos++;
			linep= linep+(text->undo_buf[text->undo_pos]<<8); text->undo_pos++;
			linep= linep+(text->undo_buf[text->undo_pos]<<16); text->undo_pos++;
			linep= linep+(text->undo_buf[text->undo_pos]<<24); text->undo_pos++;

			break;
		case UNDO_INDENT:
		case UNDO_UNINDENT:
		case UNDO_COMMENT:
		case UNDO_UNCOMMENT:
			text->undo_pos++;
			charp = text->undo_buf[text->undo_pos]; text->undo_pos++;
			charp = charp+(text->undo_buf[text->undo_pos]<<8); text->undo_pos++;
			//charp is the first char selected or 0
			
			linep= text->undo_buf[text->undo_pos]; text->undo_pos++;
			linep = linep+(text->undo_buf[text->undo_pos]<<8); text->undo_pos++;
			linep = linep+(text->undo_buf[text->undo_pos]<<16); text->undo_pos++;
			linep = linep+(text->undo_buf[text->undo_pos]<<24); text->undo_pos++;
			//linep is now the first line of the selection			
			//set the selcetion for this now
			text->curc = charp;
			text->curl = text->lines.first;
			for (i= 0; i < linep; i++) {
				text->curl = text->curl->next;
			}
			
			charp = text->undo_buf[text->undo_pos]; text->undo_pos++;
			charp = charp+(text->undo_buf[text->undo_pos]<<8); text->undo_pos++;
			//last postion to be selected
			linep= text->undo_buf[text->undo_pos]; text->undo_pos++;
			linep = linep+(text->undo_buf[text->undo_pos]<<8); text->undo_pos++;
			linep = linep+(text->undo_buf[text->undo_pos]<<16); text->undo_pos++;
			linep = linep+(text->undo_buf[text->undo_pos]<<24); text->undo_pos++;
			//Last line to be selected
			
			text->selc = charp;
			text->sell = text->lines.first;
			for (i = 0; i < linep; i++) {
				text->sell = text->sell->next;
			}

			if (op==UNDO_INDENT) {
				indent(text);
			} else if (op== UNDO_UNINDENT) {
				unindent(text);
			} else if (op == UNDO_COMMENT) {
				comment(text);
			} else if (op == UNDO_UNCOMMENT) {
				uncomment(text);
			}
			break;
		default:
			//XXX error("Undo buffer error - resetting");
			text->undo_pos= -1;

			break;
	}
	
	undoing= 0;	
}

/**************************/
/* Line editing functions */ 
/**************************/

void txt_split_curline (Text *text) 
{
	TextLine *ins;
	char *left, *right, *fleft, *fright;
	
	if (!text) return;
	if (!text->curl) return;

	txt_delete_sel(text);	

	/* Make the two half strings */

	left= MEM_mallocN(text->curc+1, "textline_string");
	fleft= MEM_mallocN(text->curc+2, "Syntax_format");
	if (text->curc) memcpy(left, text->curl->line, text->curc);
	left[text->curc]=0;
	
	right= MEM_mallocN(text->curl->len - text->curc+1, "textline_string");
	fright= MEM_mallocN(text->curl->len - text->curc+2, "Syntax_format");
	if (text->curl->len - text->curc) memcpy(right, text->curl->line+text->curc, text->curl->len-text->curc);
	right[text->curl->len - text->curc]=0;

	MEM_freeN(text->curl->line);
	if (text->curl->format) MEM_freeN(text->curl->format);

	/* Make the new TextLine */
	
	ins= MEM_mallocN(sizeof(TextLine), "textline");
	ins->line= left;
	ins->format= fleft;
	ins->len= text->curc;
	
	text->curl->line= right;
	text->curl->format= fright;
	text->curl->len= text->curl->len - text->curc;
	
	BLI_insertlinkbefore(&text->lines, text->curl, ins);	
	
	text->curc=0;
	
	txt_make_dirty(text);
	txt_clean_text(text);
	
	txt_pop_sel(text);
	if(!undoing) txt_undo_add_charop(text, UNDO_INSERT, '\n');
}

static void txt_delete_line (Text *text, TextLine *line) 
{
	if (!text) return;
	if (!text->curl) return;

	BLI_remlink (&text->lines, line);
	
	if (line->line) MEM_freeN(line->line);
	if (line->format) MEM_freeN(line->format);

	MEM_freeN(line);

	txt_make_dirty(text);
	txt_clean_text(text);
}

static void txt_combine_lines (Text *text, TextLine *linea, TextLine *lineb)
{
	char *tmp, *format;
	
	if (!text) return;
	
	if(!linea || !lineb) return;
	
	tmp= MEM_mallocN(linea->len+lineb->len+1, "textline_string");
	format= MEM_mallocN(linea->len+lineb->len+1, "Syntax_format");
	
	strcpy(tmp, linea->line);
	strcat(tmp, lineb->line);

	make_new_line(linea, tmp, format);
	
	txt_delete_line(text, lineb); 
	
	txt_make_dirty(text);
	txt_clean_text(text);
}

void txt_delete_char (Text *text) 
{
	char c='\n';
	
	if (!text) return;
	if (!text->curl) return;

	if (txt_has_sel(text)) { /* deleting a selection */
	  txt_delete_sel(text);
	}
	else if (text->curc== text->curl->len) { /* Appending two lines */
		if (text->curl->next) {
			txt_combine_lines(text, text->curl, text->curl->next);
			txt_pop_sel(text);
		}
	} else { /* Just deleting a char */
		int i= text->curc;
		
		c= text->curl->line[i];
		while(i< text->curl->len) {
			text->curl->line[i]= text->curl->line[i+1];
			i++;
		}
		text->curl->len--;

		txt_pop_sel(text);
	}

	txt_make_dirty(text);
	txt_clean_text(text);
	
	if(!undoing) txt_undo_add_charop(text, UNDO_DEL, c);
}

void txt_backspace_char (Text *text) 
{
	char c='\n';
	
	if (!text) return;
	if (!text->curl) return;
	
	if (txt_has_sel(text)) { /* deleting a selection */
	  txt_delete_sel(text);
	}
	else if (text->curc==0) { /* Appending two lines */
	    if (text->curl->prev) {
	      text->curl= text->curl->prev;
	      text->curc= text->curl->len;
			
	      txt_combine_lines(text, text->curl, text->curl->next);
	      txt_pop_sel(text);
	    }
	} 
	else { /* Just backspacing a char */
	  int i= text->curc-1;
		
	  c= text->curl->line[i];
	  while(i< text->curl->len) {
	    text->curl->line[i]= text->curl->line[i+1];
	    i++;
	  }
	  text->curl->len--;
	  text->curc--;
		
	  txt_pop_sel(text);
	}

	txt_make_dirty(text);
	txt_clean_text(text);
	
	if(!undoing) txt_undo_add_charop(text, UNDO_BS, c);
}

int txt_add_char (Text *text, char add) 
{
	int len;
	char *tmp, *format;
	
	if (!text) return 0;
	if (!text->curl) return 0;

	if (add=='\n') {
		txt_split_curline(text);
		return 1;
	}
	
	txt_delete_sel(text);
	
	tmp= MEM_mallocN(text->curl->len+2, "textline_string");
	format= MEM_mallocN(text->curl->len+4, "Syntax_format");
	
	if(text->curc) memcpy(tmp, text->curl->line, text->curc);
	tmp[text->curc]= add;
	
	len= text->curl->len - text->curc;
	if(len>0) memcpy(tmp+text->curc+1, text->curl->line+text->curc, len);
	tmp[text->curl->len+1]=0;
	make_new_line(text->curl, tmp, format);
		
	text->curc++;

	txt_pop_sel(text);
	
	txt_make_dirty(text);
	txt_clean_text(text);

	if(!undoing) txt_undo_add_charop(text, UNDO_INSERT, add);
	return 1;
}

void indent(Text *text)
{
	int len, num;
	char *tmp, *format;
	char add = '\t';
	
	if (!text) return;
	if (!text->curl) return;
	if (!text->sell) return;

	num = 0;
	while (TRUE)
	{
		tmp= MEM_mallocN(text->curl->len+2, "textline_string");
		format= MEM_mallocN(text->curl->len+3, "Syntax_format");
		
		text->curc = 0; 
		if(text->curc) memcpy(tmp, text->curl->line, text->curc);
		tmp[text->curc]= add;
		
		len= text->curl->len - text->curc;
		if(len>0) memcpy(tmp+text->curc+1, text->curl->line+text->curc, len);
		tmp[text->curl->len+1]=0;

		make_new_line(text->curl, tmp, format);
			
		text->curc++;
		
		txt_make_dirty(text);
		txt_clean_text(text);
		
		if(text->curl == text->sell) 
		{
			text->selc = text->sell->len;
			break;
		} else {
			text->curl = text->curl->next;
			num++;
		}
	}
	text->curc = 0;
	while( num > 0 )
	{
		text->curl = text->curl->prev;
		num--;
	}
	
	if(!undoing) 
	{
		txt_undo_add_toop(text, UNDO_INDENT, txt_get_span(text->lines.first, text->curl), text->curc, txt_get_span(text->lines.first, text->sell), text->selc);
	}
}

void unindent(Text *text)
{
	int num = 0;
	char remove = '\t';
	
	if (!text) return;
	if (!text->curl) return;
	if (!text->sell) return;

	while(TRUE)
	{
		int i = 0;
		
		if (text->curl->line[i] == remove)
		{
			while(i< text->curl->len) {
				text->curl->line[i]= text->curl->line[i+1];
				i++;
			}
			text->curl->len--;
		}
			 
	
		txt_make_dirty(text);
		txt_clean_text(text);
		
		if(text->curl == text->sell) 
		{
			text->selc = text->sell->len;
			break;
		} else {
			text->curl = text->curl->next;
			num++;
		}
		
	}
	text->curc = 0;
	while( num > 0 )
	{
		text->curl = text->curl->prev;
		num--;
	}
	
	if(!undoing) 
	{
		txt_undo_add_toop(text, UNDO_UNINDENT, txt_get_span(text->lines.first, text->curl), text->curc, txt_get_span(text->lines.first, text->sell), text->selc);
	}
}

void comment(Text *text)
{
	int len, num;
	char *tmp, *format;
	char add = '#';
	
	if (!text) return;
	if (!text->curl) return;
	if (!text->sell) return;// Need to change this need to check if only one line is selected ot more then one

	num = 0;
	while (TRUE)
	{
		tmp= MEM_mallocN(text->curl->len+2, "textline_string");
		format = MEM_mallocN(text->curl->len+3, "Syntax_format");
		
		text->curc = 0; 
		if(text->curc) memcpy(tmp, text->curl->line, text->curc);
		tmp[text->curc]= add;
		
		len= text->curl->len - text->curc;
		if(len>0) memcpy(tmp+text->curc+1, text->curl->line+text->curc, len);
		tmp[text->curl->len+1]=0;

		make_new_line(text->curl, tmp, format);
			
		text->curc++;
		
		txt_make_dirty(text);
		txt_clean_text(text);
		
		if(text->curl == text->sell) 
		{
			text->selc = text->sell->len;
			break;
		} else {
			text->curl = text->curl->next;
			num++;
		}
	}
	text->curc = 0;
	while( num > 0 )
	{
		text->curl = text->curl->prev;
		num--;
	}
	
	if(!undoing) 
	{
		txt_undo_add_toop(text, UNDO_COMMENT, txt_get_span(text->lines.first, text->curl), text->curc, txt_get_span(text->lines.first, text->sell), text->selc);
	}
}

void uncomment(Text *text)
{
	int num = 0;
	char remove = '#';
	
	if (!text) return;
	if (!text->curl) return;
	if (!text->sell) return;

	while(TRUE)
	{
		int i = 0;
		
		if (text->curl->line[i] == remove)
		{
			while(i< text->curl->len) {
				text->curl->line[i]= text->curl->line[i+1];
				i++;
			}
			text->curl->len--;
		}
			 
	
		txt_make_dirty(text);
		txt_clean_text(text);
		
		if(text->curl == text->sell) 
		{
			text->selc = text->sell->len;
			break;
		} else {
			text->curl = text->curl->next;
			num++;
		}
		
	}
	text->curc = 0;
	while( num > 0 )
	{
		text->curl = text->curl->prev;
		num--;
	}
	
	if(!undoing) 
	{
		txt_undo_add_toop(text, UNDO_UNCOMMENT, txt_get_span(text->lines.first, text->curl), text->curc, txt_get_span(text->lines.first, text->sell), text->selc);
	}
}

int setcurr_tab (Text *text)
{
	int i = 0;
	int test = 0;
	char *word = ":";
	char *comm = "#";
	char back_words[3][7] = {"return", "break", "pass"};
	if (!text) return 0;
	if (!text->curl) return 0;
	
	while (text->curl->line[i] == '\t')
	{
		//we only count thos tabs that are before any text or before the curs;
		if (i == text->curc)
		{
			return i;
		} else {
			i++;
		}
	}
	if(strstr(text->curl->line, word))
	{
		//if we find a : then add a tab but not if it is in a comment
		if(strcspn(text->curl->line, word) < strcspn(text->curl->line, comm))
		{
			i++;

		}
	}

	while(test < 3)
	{
		//if there are these 3 key words then remove a tab because we are done with the block
		if(strstr(text->curl->line, back_words[test]) && i > 0)
		{
			if(strcspn(text->curl->line, back_words[test]) < strcspn(text->curl->line, comm))
			{
				i--;
			}
		}
		test++;
	}
	return i;
}