AtomicGameEngine/Source/ThirdParty/TurboBadger/tb_style_edit.cpp

// ================================================================================
// ==      This file is a part of Turbo Badger. (C) 2011-2014, Emil Segerås      ==
// ==                     See tb_core.h for more information.                    ==
// ================================================================================

#include "tb_style_edit.h"
#include "tb_widgets_common.h"
#include "tb_style_edit_content.h"
#include "tb_system.h"
#include "tb_tempbuffer.h"
#include "tb_font_renderer.h"
#include "utf8/utf8.h"
#include <assert.h>

namespace tb {

#if 0 // Enable for some graphical debugging
#define TMPDEBUG(expr) expr
#define nTMPDEBUG(expr)
#else
#define TMPDEBUG(expr) 
#define nTMPDEBUG(expr) expr
#endif

const int TAB_SPACE = 4;

const char *special_char_newln = "¶";		// 00B6 PILCROW SIGN
const char *special_char_space = "·";		// 00B7 MIDDLE DOT
const char *special_char_tab = "»";		// 00BB RIGHT-POINTING DOUBLE ANGLE QUOTATION MARK
const char *special_char_password = "•";	// 2022 BULLET

static bool is_space(int8 c)
{
	switch(c)
	{
		case ' ':
			return true;
	}
	return false;
}

static bool is_linebreak(int8 c)
{
	switch(c)
	{
		case '\n':
		case '\r':
		case 0:
			return true;
	}
	return false;
}

static bool is_wordbreak(int8 c)
{
	switch(c)
	{
		case 0:
		case '\n':
		case '\r':
		case '-':
		case '\t':
		case '\"':
		case '(':
		case ')':
		case '/':
		case '\\':
		case '*':
		case '+':
		case ',':
		case '.':
		case ';':
		case ':':
		case '>':
		case '<':
		case '&':
		case '#':
		case '!':
		case '=':
		case '[':
		case ']':
		case '{':
		case '}':
		case '^':
			return true;
	}
	return is_space(c);
}

/** Check if no line wrapping is allowed before the character at the given offset.
	The string must be null terminated. */
static bool is_never_break_before(const char *str, int ofs)
{
	switch (str[ofs])
	{
	case '\n':
	case '\r':
	case ' ':
	case '-':
	case '.':
	case ',':
	case ':':
	case ';':
	case '!':
	case '?':
	case ')':
	case ']':
	case '}':
	case '>':
		return true;
	case '\'':
	case '"':
		// Simple test if it's the first quote in a word surrounded by space.
		if (ofs > 0 && !is_space(str[ofs - 1]))
			return true;
	default:
		return false;
	}
}

/** Check if no line wrapping is allowed after the character at the given offset.
	The string must be null terminated. */
static bool is_never_break_after(const char *str, int ofs)
{
	switch (str[ofs])
	{
	case '(':
	case '[':
	case '{':
	case '<':
		return true;
	case '\'':
	case '"':
		// Simple test if it's the last quote in a word surrounded by space.
		if (!is_space(str[ofs+ 1]))
			return true;
	default:
		return false;
	}
}

static bool GetNextFragment(const char *text, TBTextFragmentContentFactory *content_factory, int *frag_len, bool *is_embed)
{
	if (text[0] == '\t')
	{
		*frag_len = 1;
		return text[1] != 0;
	}
	else if (text[0] == 0) // happens when not setting text and maby when setting ""
	{
		*frag_len = 0;
		return false;
	}
	else if (text[0] == '\r' || text[0] == '\n')
	{
		int len = (text[0] == '\r' && text[1] == '\n') ? 2 : 1;
		*frag_len = len;
		return false;
	}
	else if (content_factory)
	{
		if (int content_len = content_factory->GetContent(text))
		{
			*frag_len = content_len;
			*is_embed = true;
			return text[content_len] != 0;
		}
	}
	int i = 0;
	while (!is_wordbreak(text[i]))
		i++;
	if (i == 0)
		if (is_wordbreak(text[i]))
			i++;
	*frag_len = i;
	if (text[i] == 0)
		return false;
	return true;
}

// == TBSelection ==================================================

TBSelection::TBSelection(TBStyleEdit *styledit)
	: styledit(styledit)
{
}

void TBSelection::CorrectOrder()
{
	if (start.block == stop.block && start.ofs == stop.ofs)
		SelectNothing();
	else
	{
		if ((start.block == stop.block && start.ofs > stop.ofs) ||
			(start.block != stop.block && start.block->ypos > stop.block->ypos))
		{
			TBTextOfs tmp = start;
			start = stop;
			stop = tmp;
		}
	}
}

void TBSelection::CopyToClipboard()
{
	if (IsSelected())
	{
		TBStr text;
		if (GetText(text))
			TBClipboard::SetText(text);
	}
}

void TBSelection::Invalidate() const
{
	TBBlock *block = start.block;
	while (block)
	{
		block->Invalidate();
		if (block == stop.block)
			break;
		block = block->GetNext();
	}
}

void TBSelection::Select(const TBTextOfs &new_start, const TBTextOfs &new_stop)
{
	Invalidate();
	start.Set(new_start);
	stop.Set(new_stop);
	CorrectOrder();
	Invalidate();
}

void TBSelection::Select(const TBPoint &from, const TBPoint &to)
{
	Invalidate();
	styledit->caret.Place(from);
	start.Set(styledit->caret.pos);
	styledit->caret.Place(to);
	stop.Set(styledit->caret.pos);
	CorrectOrder();
	Invalidate();
	styledit->caret.UpdateWantedX();
}

void TBSelection::Select(int glob_ofs_from, int glob_ofs_to)
{
	TBTextOfs ofs1, ofs2;
	ofs1.SetGlobalOfs(styledit, glob_ofs_from);
	ofs2.SetGlobalOfs(styledit, glob_ofs_to);
	Select(ofs1, ofs2);
}

void TBSelection::SelectToCaret(TBBlock *old_caret_block, int32 old_caret_ofs)
{
	Invalidate();
	if (!start.block)
	{
		start.Set(old_caret_block, old_caret_ofs);
		stop.Set(styledit->caret.pos);
	}
	else
	{
		if (start.block == old_caret_block && start.ofs == old_caret_ofs)
			start.Set(styledit->caret.pos);
		else
			stop.Set(styledit->caret.pos);
	}
	CorrectOrder();
	Invalidate();
}

void TBSelection::SelectAll()
{
	start.Set(styledit->blocks.GetFirst(), 0);
	stop.Set(styledit->blocks.GetLast(), styledit->blocks.GetLast()->str_len);
	Invalidate();
}

void TBSelection::SelectNothing()
{
	Invalidate();
	start.Set(nullptr, 0);
	stop.Set(nullptr, 0);
}

bool TBSelection::IsBlockSelected(TBBlock *block) const
{
	if (!IsSelected())
		return false;
	return block->ypos >= start.block->ypos && block->ypos <= stop.block->ypos;
}

bool TBSelection::IsFragmentSelected(TBTextFragment *elm) const
{
	if (!IsSelected())
		return false;
	if (start.block == stop.block)
	{
		if (elm->block != start.block)
			return false;
		if (start.ofs < elm->ofs + elm->len && stop.ofs >= elm->ofs)
			return true;
		return false;
	}
	if (elm->block->ypos > start.block->ypos && elm->block->ypos < stop.block->ypos)
		return true;
	if (elm->block->ypos == start.block->ypos && elm->ofs + elm->len > start.ofs)
		return true;
	if (elm->block->ypos == stop.block->ypos && elm->ofs < stop.ofs)
		return true;
	return false;
}

bool TBSelection::IsSelected() const
{
	return start.block ? true : false;
}

void TBSelection::RemoveContent()
{
	if (!IsSelected())
		return;
	styledit->BeginLockScrollbars();
	if (start.block == stop.block)
	{
        if (!styledit->undoredo.applying)
            styledit->undoredo.Commit(styledit, start.GetGlobalOfs(styledit), stop.ofs - start.ofs, start.block->str.CStr() + start.ofs, false);
		start.block->RemoveContent(start.ofs, stop.ofs - start.ofs);
	}
	else
	{
		// Remove text in first block
		TBTempBuffer commit_string;
		int32 start_gofs = 0;
		if (!styledit->undoredo.applying)
		{
			start_gofs = start.GetGlobalOfs(styledit);
			commit_string.Append(start.block->str.CStr() + start.ofs, start.block->str_len - start.ofs);
		}
		start.block->RemoveContent(start.ofs, start.block->str_len - start.ofs);

		// Remove text in all block in between start and stop
		TBBlock *block = start.block->GetNext();
		while (block != stop.block)
		{
			if (!styledit->undoredo.applying)
				commit_string.Append(block->str, block->str_len);

			TBBlock *next = block->GetNext();
			styledit->blocks.Delete(block);
			block = next;
		}

		// Remove text in last block
		if (!styledit->undoredo.applying)
		{
			commit_string.Append(stop.block->str, stop.ofs);
			styledit->undoredo.Commit(styledit, start_gofs, commit_string.GetAppendPos(), commit_string.GetData(), false);
		}
		stop.block->RemoveContent(0, stop.ofs);
	}
	stop.block->Merge();
	start.block->Merge();
	styledit->caret.Place(start.block, start.ofs);
	styledit->caret.UpdateWantedX();
	SelectNothing();
	styledit->EndLockScrollbars();

    if (styledit->text_change_listener)
        styledit->text_change_listener->OnChange(styledit);

}

bool TBSelection::GetText(TBStr &text) const
{
	if (!IsSelected())
	{
		text.Clear();
		return true;
	}
	if (start.block == stop.block)
		text.Append(start.block->str.CStr() + start.ofs, stop.ofs - start.ofs);
	else
	{
		TBTempBuffer buf;
		buf.Append(start.block->str.CStr() + start.ofs, start.block->str_len - start.ofs);
		TBBlock *block = start.block->GetNext();
		while (block != stop.block)
		{
			buf.Append(block->str, block->str_len);
			block = block->GetNext();
		}
		// FIX: Add methods to change data owner from temp buffer to string!
		buf.Append(stop.block->str, stop.ofs);
		text.Set((char*)buf.GetData(), buf.GetAppendPos());
	}
	return true;
}

// == TBTextOfs =========================================================================

int32 TBTextOfs::GetGlobalOfs(TBStyleEdit *se) const
{
	int32 gofs = 0;
	TBBlock *b = se->blocks.GetFirst();
	while (b && b != block)
	{
		gofs += b->str_len;
		b = b->GetNext();
	}
	gofs += ofs;
	return gofs;
}

bool TBTextOfs::SetGlobalOfs(TBStyleEdit *se, int32 gofs)
{
	TBBlock *b = se->blocks.GetFirst();
	while (b)
	{
		int b_len = b->str_len;
        if (gofs < b_len)
		{
			block = b;
			ofs = gofs;
			return true;
		}
        gofs -= b_len;
        if (!gofs && !b->GetNext())
        {
            block = b;
            ofs = b->str.Length() + 1;
            return true;
        }
		b = b->GetNext();
	}
	assert(!"out of range! not a valid global offset!");
	return false;
}

// == TBCaret ============================================================================

TBCaret::TBCaret(TBStyleEdit *styledit)
	: styledit(styledit)
	, x(0)
	, y(0)
	, width(2)
	, height(0)
	, wanted_x(0)
	, on(false)
	, prefer_first(true)
{
}

void TBCaret::Invalidate()
{
	if (styledit->listener)
		styledit->listener->Invalidate(TBRect(x - styledit->scroll_x, y - styledit->scroll_y, width, height));
}

void TBCaret::UpdatePos()
{
	Invalidate();
	TBTextFragment *fragment = GetFragment();
	x = fragment->xpos + fragment->GetCharX(styledit->font, pos.ofs - fragment->ofs);
	y = fragment->ypos + pos.block->ypos;
	height = fragment->GetHeight(styledit->font);
	if (!height)
	{
		// If we don't have height, we're probably inside a style switch embed.
		y = fragment->line_ypos + pos.block->ypos;
		height = fragment->line_height;
	}
	Invalidate();
}

bool TBCaret::Move(bool forward, bool word)
{
	// Make it stay on the same line if it reach the wrap point.
	prefer_first = forward;
	if (this->styledit->packed.password_on)
		word = false;

	int len = pos.block->str_len;
	if (word && !(forward && pos.ofs == len) && !(!forward && pos.ofs == 0))
	{
		const char *str = pos.block->str;
		if (forward)
		{
			if (is_linebreak(str[pos.ofs]))
			{
				pos.ofs++;
			}
			else if (is_wordbreak(str[pos.ofs]))
			{
				while (pos.ofs < len && is_wordbreak(str[pos.ofs]) && !is_linebreak(str[pos.ofs]))
					pos.ofs++;
			}
			else
			{
				while (pos.ofs < len && !is_wordbreak(str[pos.ofs]))
					pos.ofs++;

                // This is causing trailing space to be selected
                // on double click of text fragment
                // I seem to remember disabling this once before
                // and having an issue, so leaving it here for reference
                //while (pos.ofs < len && is_space(str[pos.ofs]))
                    //pos.ofs++;
			}
		}
		else if (pos.ofs > 0)
		{
			while (pos.ofs > 0 && is_space(str[pos.ofs - 1]))
				pos.ofs--;
			if (pos.ofs > 0 && is_wordbreak(str[pos.ofs - 1]))
			{
				while (pos.ofs > 0 && is_wordbreak(str[pos.ofs - 1]))
					pos.ofs--;
			}
			else
			{
				while (pos.ofs > 0 && !is_wordbreak(str[pos.ofs - 1]))
					pos.ofs--;
			}
		}
	}
	else
	{
		if (forward && pos.ofs >= pos.block->str_len && pos.block->GetNext())
		{
			pos.block = pos.block->GetNext();
			pos.ofs = 0;
		}
		else if (!forward && pos.ofs <= 0 && pos.block->prev)
		{
			pos.block = pos.block->GetPrev();
			pos.ofs = pos.block->str_len;
		}
		else
		{
			int i = pos.ofs;
			if (forward)
				utf8::move_inc(pos.block->str, &i, pos.block->str_len);
			else
				utf8::move_dec(pos.block->str, &i);
			pos.ofs = i;
		}
	}
	return Place(pos.block, pos.ofs, true, forward);
}

bool TBCaret::Place(const TBPoint &point)
{
	TBBlock *block = styledit->FindBlock(point.y);
	TBTextFragment *fragment = block->FindFragment(point.x, point.y - block->ypos);
	int ofs = fragment->ofs + fragment->GetCharOfs(styledit->font, point.x - fragment->xpos);

	if (Place(block, ofs))
	{
		if (GetFragment() != fragment)
		{
			prefer_first = !prefer_first;
			Place(block, ofs);
		}
		return true;
	}
	return false;
}

void TBCaret::Place(TB_CARET_POS place)
{
	if (place == TB_CARET_POS_BEGINNING)
		Place(styledit->blocks.GetFirst(), 0);
	else if (place == TB_CARET_POS_END)
		Place(styledit->blocks.GetLast(), styledit->blocks.GetLast()->str_len);
}

bool TBCaret::Place(TBBlock *block, int ofs, bool allow_snap, bool snap_forward)
{
	if (block)
	{
		while (block->GetNext() && ofs > block->str_len)
		{
			ofs -= block->str_len;
			block = block->GetNext();
		}
		while (block->prev && ofs < 0)
		{
			block = block->GetPrev();
			ofs += block->str_len;
		}
		if (ofs < 0)
			ofs = 0;
		if (ofs > block->str_len)
			ofs = block->str_len;

		// Avoid being inside linebreak
		if (allow_snap)
		{
			TBTextFragment *fragment = block->FindFragment(ofs);
			if (ofs > fragment->ofs && fragment->IsBreak())
			{
				if (snap_forward && block->GetNext())
				{
					block = block->GetNext();
					ofs = 0;
				}
				else
					ofs = fragment->ofs;
			}
		}
	}

	bool changed = (pos.block != block || pos.ofs != ofs);
	pos.Set(block, ofs);

	if (block)
		UpdatePos();

	return changed;
}

void TBCaret::AvoidLineBreak()
{
	TBTextFragment *fragment = GetFragment();
	if (pos.ofs > fragment->ofs && fragment->IsBreak())
		pos.ofs = fragment->ofs;
	UpdatePos();
}

void TBCaret::Paint(int32 translate_x, int32 translate_y)
{
//	if (on && !(styledit->select_state && styledit->selection.IsSelected()))
	if (on || styledit->select_state)
	{
		styledit->listener->DrawCaret(TBRect(translate_x + x, translate_y + y, width, height));
	}
}

void TBCaret::ResetBlink()
{
	styledit->listener->CaretBlinkStop();
	on = true;
	styledit->listener->CaretBlinkStart();
}

void TBCaret::UpdateWantedX()
{
	wanted_x = x;
}

TBTextFragment *TBCaret::GetFragment()
{
	return pos.block->FindFragment(pos.ofs, prefer_first);
}

void TBCaret::SwitchBlock(bool second)
{
}

void TBCaret::SetGlobalOfs(int32 gofs, bool allow_snap, bool snap_forward)
{
	TBTextOfs ofs;
	if (ofs.SetGlobalOfs(styledit, gofs))
		Place(ofs.block, ofs.ofs, allow_snap, snap_forward);
}

// == TBTextProps =======================================================================

TBTextProps::TBTextProps(const TBFontDescription &font_desc, const TBColor &text_color)
{
	base_data.font_desc = font_desc;
	base_data.text_color = text_color;
	base_data.underline = false;
	data = &base_data;
}

TBTextProps::Data *TBTextProps::Push()
{
	if (Data *new_data = new Data)
	{
		data_list.AddLast(new_data);
		new_data->font_desc = data->font_desc;
		new_data->text_color = data->text_color;
		new_data->underline = data->underline;
		data = new_data;
		return data;
	}
	return nullptr;
}

void TBTextProps::Pop()
{
	if (!data_list.GetLast())
		return; // Unballanced or we previosly got OOM.
	data_list.Delete(data_list.GetLast());
	data = data_list.GetLast() ? data_list.GetLast() : &base_data;
}

TBFontFace *TBTextProps::GetFont()
{
	return g_font_manager->GetFontFace(data->font_desc);
}

// ============================================================================

TBBlock::TBBlock(TBStyleEdit *styledit)
	: styledit(styledit)
	, ypos(0)
	, height(0)
	, align(styledit->align)
	, line_width_max(0)
	, str_len(0)
{
}

TBBlock::~TBBlock()
{
	Clear();
}

void TBBlock::Clear()
{
	fragments.DeleteAll();
}

void TBBlock::Set(const char *newstr, int32 len)
{
	str.Set(newstr, len);
	str_len = len;
	Split();
	Layout(true, true);
}

void TBBlock::SetAlign(TB_TEXT_ALIGN align)
{
	if (this->align == align)
		return;
	this->align = align;
	Layout(false, false);
}

int32 TBBlock::InsertText(int32 ofs, const char *text, int32 len, bool allow_line_recurse)
{
	styledit->BeginLockScrollbars();
	int first_line_len = len;
	for(int i = 0; i < len; i++)
		if (text[i] == '\r' || text[i] == '\n')
		{
			first_line_len = i;
			// Include the line break too but not for single lines
			if (!styledit->packed.multiline_on)
				break;
			if (text[i] == '\r' && text[i + 1] == '\n')
				first_line_len++;
			first_line_len++;
			break;
		}

	int32 inserted_len = first_line_len;
	str.Insert(ofs, text, first_line_len);
	str_len += first_line_len;

	Split();
	Layout(true, true);

	// Add the rest which was after the linebreak.
	if (allow_line_recurse && styledit->packed.multiline_on)
	{
		// Instead of recursively calling InsertText, we will loop through them all here
		TBBlock *next_block = GetNext();
		const char *next_line_ptr = &text[first_line_len];
		int remaining = len - first_line_len;
		while (remaining > 0)
		{
			if (!next_block)
			{
				next_block = new TBBlock(styledit);
				styledit->blocks.AddLast(next_block);
			}
			int consumed = next_block->InsertText(0, next_line_ptr, remaining, false);
			next_line_ptr += consumed;
			inserted_len += consumed;
			remaining -= consumed;
			next_block = next_block->GetNext();
		}
	}
	styledit->EndLockScrollbars();

	return inserted_len;
}

void TBBlock::RemoveContent(int32 ofs, int32 len)
{
	if (!len)
		return;
	str.Remove(ofs, len);
	str_len -= len;
	Layout(true, true);
}

void TBBlock::Split()
{
	int32 len = str_len;
	int brlen = 1; // FIX: skip ending newline fragment but not if there is several newlines and check for singleline newline.
	if (len > 1 && str.CStr()[len - 2] == '\r' && str.CStr()[len - 1] == '\n')
		brlen++;
	len -= brlen;
	for(int i = 0; i < len; i++)
	{
		if (is_linebreak(str.CStr()[i]))
		{
			TBBlock *block = new TBBlock(styledit);
			if (!block)
				return;
			styledit->blocks.AddAfter(block, this);

			if (i < len - 1 && str.CStr()[i] == '\r' && str.CStr()[i + 1] == '\n')
				i++;
			i++;

			len = len + brlen - i;
			block->Set(str.CStr() + i, len);
			str.Remove(i, len);
			str_len -= len;
			break;
		}
	}
}

void TBBlock::Merge()
{
	TBBlock *next_block = GetNext();
	if (next_block && !fragments.GetLast()->IsBreak())
	{
		str.Append(GetNext()->str);
		str_len = str.Length();

		styledit->blocks.Delete(next_block);

		height = 0; // Ensure that Layout propagate height to remaining blocks.
		Layout(true, true);
	}
}

int32 TBBlock::CalculateTabWidth(TBFontFace *font, int32 xpos) const
{
	int tabsize = font->GetStringWidth("x", 1) * TAB_SPACE;
	int p2 = int(xpos / tabsize) * tabsize + tabsize;
	return p2 - xpos;
}

int32 TBBlock::FirstNonTabPos() const
{
    for (int i = 0; i < str.Length(); i++)
        if (str[i] != ' ' && str[i] != '\t')
            return i;

    return 0;
}

int32 TBBlock::CalculateStringWidth(TBFontFace *font, const char *str, int len) const
{
	if (styledit->packed.password_on)
	{
		// Convert the length in number or characters, since that's what matters for password width.
		len = utf8::count_characters(str, len);
		return font->GetStringWidth(special_char_password) * len;
	}
	return font->GetStringWidth(str, len);
}

int32 TBBlock::CalculateLineHeight(TBFontFace *font) const
{
	return font->GetHeight();
}

int32 TBBlock::CalculateBaseline(TBFontFace *font) const
{
	return font->GetAscent();
}

int TBBlock::GetStartIndentation(TBFontFace *font, int first_line_len) const
{
	// Lines beginning with whitespace or list points, should
	// indent to the same as the beginning when wrapped.
	int indentation = 0;
	int i = 0;
	while (i < first_line_len)
	{
		const char *current_str = str.CStr() + i;
		UCS4 uc = utf8::decode_next(str, &i, first_line_len);
		switch (uc)
		{
		case '\t':
			indentation += CalculateTabWidth(font, indentation);
			continue;
		case ' ':
		case '-':
		case '*':
			indentation += CalculateStringWidth(font, current_str, 1);
			continue;
		case 0x2022: // BULLET
			indentation += CalculateStringWidth(font, current_str, 3);
			continue;
		};
		break;
	}
	return indentation;
}

void TBBlock::Layout(bool update_fragments, bool propagate_height)
{
	// Create fragments from the word fragments
	if (update_fragments || !fragments.GetFirst())
	{
		Clear();

		int ofs = 0;
		const char *text = str;
		while (true)
		{
			int frag_len;
			bool is_embed = false;
			bool more = GetNextFragment(&text[ofs], styledit->packed.styling_on ? styledit->content_factory : nullptr, &frag_len, &is_embed);

			TBTextFragment *fragment = new TBTextFragment();
			if (!fragment)
				break;

			fragment->Init(this, ofs, frag_len);

			if (is_embed)
				fragment->content = styledit->content_factory->CreateFragmentContent(&text[ofs], frag_len);

			fragments.AddLast(fragment);
			ofs += frag_len;

			if (!more)
				break;
		}
	}

	// Layout

	if (styledit->layout_width <= 0 && styledit->GetSizeAffectsLayout())
		// Don't layout if we have no space. This will happen when setting text
		// before the widget has been layouted. We will relayout when we are resized.
		return;

	int old_line_width_max = line_width_max;
	line_width_max = 0;
	int line_ypos = 0;
	int first_line_indentation = 0;
	TBTextFragment *first_fragment_on_line = fragments.GetFirst();

	while (first_fragment_on_line)
	{
		int line_width = 0;

		// Get the last fragment that should be laid out on the line while
		// calculating line width and preliminary x positions for the fragments.

		TBTextFragment *last_fragment_on_line = fragments.GetLast();
		if (styledit->packed.wrapping)
		{
			// If we should wrap, search for the last allowed break point before the overflow.
			TBTextFragment *allowed_last_fragment = nullptr;

			int line_xpos = first_line_indentation;
			for (TBTextFragment *fragment = first_fragment_on_line; fragment; fragment = fragment->GetNext())
			{
				// Give the fragment the current x. Then tab widths are calculated properly in GetWidth.
				fragment->xpos = line_xpos;
				int fragment_w = fragment->GetWidth(styledit->font);

				// Check if we overflow
				bool overflow = line_xpos + fragment_w > styledit->layout_width;

				if (overflow && allowed_last_fragment)
				{
					last_fragment_on_line = allowed_last_fragment;
					break;
				}

				// Check if this is a allowed break position
				if (fragment->GetAllowBreakAfter())
				{
					if (!fragment->GetNext() || fragment->GetNext()->GetAllowBreakBefore())
					{
						allowed_last_fragment = fragment;
						line_width = line_xpos + fragment_w;
					}
				}

				line_xpos += fragment_w;
			}
			if (!allowed_last_fragment)
				line_width = line_xpos;
		}
		else
		{
			// When wrapping is off, just measure and set pos.
			line_width = first_line_indentation;
			for (TBTextFragment *fragment = first_fragment_on_line; fragment; fragment = fragment->GetNext())
			{
				fragment->xpos = line_width;
				line_width += fragment->GetWidth(styledit->font);
			}
		}

		// Commit line - Layout each fragment on the line.

		int line_height = 0;
		int line_baseline = 0;
		TBTextFragment *fragment = first_fragment_on_line;
		while (fragment)
		{
			line_height = MAX(fragment->GetHeight(styledit->font), line_height);
			line_baseline = MAX(fragment->GetBaseline(styledit->font), line_baseline);

			// These positions are not final. Will be adjusted below.
			fragment->ypos = line_ypos;

			if (fragment == last_fragment_on_line)
				break;
			fragment = fragment->GetNext();
		}

		// Adjust the position of fragments on the line - now when we know the line totals.
		// x change because of alignment, y change because of fragment baseline vs line baseline.

		int32 xofs = 0;
		if (align == TB_TEXT_ALIGN_RIGHT)
			xofs = styledit->layout_width - line_width;
		else if (align == TB_TEXT_ALIGN_CENTER)
			xofs = (styledit->layout_width - line_width) / 2;

		int adjusted_line_height = line_height;
		fragment = first_fragment_on_line;
		while (fragment)
		{
			// The fragment need to know these later.
			fragment->line_ypos = line_ypos;
			fragment->line_height = line_height;

			// Adjust the position
			fragment->ypos += line_baseline - fragment->GetBaseline(styledit->font);
			fragment->xpos += xofs;

			// We now know the final position so update content.
			fragment->UpdateContentPos();

			// Total line height may now have changed a bit.
			adjusted_line_height = MAX(line_baseline - fragment->GetBaseline(styledit->font) + fragment->GetHeight(styledit->font), adjusted_line_height);

			if (fragment == last_fragment_on_line)
				break;
			fragment = fragment->GetNext();
		}

		// Update line_height set on fragments if needed
		if (line_height != adjusted_line_height)
		{
			for (fragment = first_fragment_on_line; fragment != last_fragment_on_line->GetNext(); fragment = fragment->GetNext())
				fragment->line_height = adjusted_line_height;
		}

		line_width_max = MAX(line_width_max, line_width);

		// This was the first line so calculate the indentation to use for the other lines.
		if (styledit->packed.wrapping && first_fragment_on_line == fragments.GetFirst())
			first_line_indentation = GetStartIndentation(styledit->font, last_fragment_on_line->ofs + last_fragment_on_line->len);

		// Consume line

		line_ypos += adjusted_line_height;

		first_fragment_on_line = last_fragment_on_line->GetNext();
	}

	ypos = GetPrev() ? GetPrev()->ypos + GetPrev()->height : 0;
	SetSize(old_line_width_max, line_width_max, line_ypos, propagate_height);

	Invalidate();
}

void TBBlock::SetSize(int32 old_w, int32 new_w, int32 new_h, bool propagate_height)
{
	// Later: could optimize with Scroll here.
	int32 dh = new_h - height;
	height = new_h;
	if (dh != 0 && propagate_height)
	{
		TBBlock *block = GetNext();
		while (block)
		{
			block->ypos = block->GetPrev()->ypos + block->GetPrev()->height;
			block->Invalidate();
			block = block->GetNext();
		}
	}

	// Update content_width and content_height
	// content_width can only be calculated in constant time if we grow larger.
	// If we shrink our width and where equal to content_width, we don't know
	// how wide the widest block is and we set a flag to update it when needed.

	if (!styledit->packed.wrapping && !styledit->packed.multiline_on)
		styledit->content_width = new_w;
	else if (new_w > styledit->content_width)
		styledit->content_width = new_w;
	else if (new_w < old_w && old_w == styledit->content_width)
		styledit->packed.calculate_content_width_needed = 1;

	styledit->content_height = styledit->blocks.GetLast()->ypos + styledit->blocks.GetLast()->height;

	if (styledit->listener && styledit->packed.lock_scrollbars_counter == 0 && propagate_height)
		styledit->listener->UpdateScrollbars();
}

TBTextFragment *TBBlock::FindFragment(int32 ofs, bool prefer_first) const
{
	TBTextFragment *fragment = fragments.GetFirst();
	while (fragment)
	{
		if (prefer_first && ofs <= fragment->ofs + fragment->len)
			return fragment;
		if (!prefer_first && ofs < fragment->ofs + fragment->len)
			return fragment;
		fragment = fragment->GetNext();
	}
	return fragments.GetLast();
}

TBTextFragment *TBBlock::FindFragment(int32 x, int32 y) const
{
	TBTextFragment *fragment = fragments.GetFirst();
	while (fragment)
	{
		if (y < fragment->line_ypos + fragment->line_height)
		{
			if (x < fragment->xpos + fragment->GetWidth(styledit->font))
				return fragment;
			if (fragment->GetNext() && fragment->GetNext()->line_ypos > fragment->line_ypos)
				return fragment;
		}
		fragment = fragment->GetNext();
	}
	return fragments.GetLast();
}

void TBBlock::Invalidate()
{
	if (styledit->listener)
		styledit->listener->Invalidate(TBRect(0, - styledit->scroll_y + ypos, styledit->layout_width, height));
}

void TBBlock::BuildSelectionRegion(int32 translate_x, int32 translate_y, TBTextProps *props,
	TBRegion &bg_region, TBRegion &fg_region)
{
	if (!styledit->selection.IsBlockSelected(this))
		return;

	TBTextFragment *fragment = fragments.GetFirst();
	while (fragment)
	{
		fragment->BuildSelectionRegion(translate_x, translate_y + ypos, props, bg_region, fg_region);
		fragment = fragment->GetNext();
	}
}

void TBBlock::Paint(int32 translate_x, int32 translate_y, TBTextProps *props)
{
	TMPDEBUG(styledit->listener->DrawRect(TBRect(translate_x, translate_y + ypos, styledit->layout_width, height), TBColor(255, 200, 0, 128)));

	TBTextFragment *fragment = fragments.GetFirst();
	while (fragment)
	{
		fragment->Paint(translate_x, translate_y + ypos, props);
		fragment = fragment->GetNext();
	}
}

// == TBTextFragment =========================================================================

TBTextFragment::~TBTextFragment()
{
	delete content;
}

void TBTextFragment::Init(TBBlock *block, uint16 ofs, uint16 len)
{
	this->block = block; this->ofs = ofs; this->len = len;
}

void TBTextFragment::UpdateContentPos()
{
	if (content)
		content->UpdatePos(xpos, ypos + block->ypos);
}

void TBTextFragment::BuildSelectionRegion(int32 translate_x, int32 translate_y, TBTextProps *props,
	TBRegion &bg_region, TBRegion &fg_region)
{
	if (!block->styledit->selection.IsFragmentSelected(this))
		return;

	int x = translate_x + xpos;
	int y = translate_y + ypos;
	TBFontFace *font = props->GetFont();

	if (content)
	{
		// Selected embedded content should add to the foreground region.
		fg_region.IncludeRect(TBRect(x, y, GetWidth(font), GetHeight(font)));
		return;
	}

	// Selected text should add to the backgroud region.
	TBSelection *sel = &block->styledit->selection;

	int sofs1 = sel->start.block == block ? sel->start.ofs : 0;
	int sofs2 = sel->stop.block == block ? sel->stop.ofs : block->str_len;
	sofs1 = MAX(sofs1, (int)ofs);
	sofs2 = MIN(sofs2, (int)(ofs + len));

	int s1x = GetStringWidth(font, block->str.CStr() + ofs, sofs1 - ofs);
	int s2x = GetStringWidth(font, block->str.CStr() + sofs1, sofs2 - sofs1);

	bg_region.IncludeRect(TBRect(x + s1x, y, s2x, GetHeight(font)));
}

void TBTextFragment::Paint(int32 translate_x, int32 translate_y, TBTextProps *props)
{
	TBStyleEditListener *listener = block->styledit->listener;

	int x = translate_x + xpos;
	int y = translate_y + ypos;
	TBColor color = props->data->text_color;
	TBFontFace *font = props->GetFont();

    if (block->styledit->text_theme)
        color = block->styledit->text_theme->themeColors[themeColor];

	if (content)
	{
		content->Paint(this, translate_x, translate_y, props);
		return;
	}
	TMPDEBUG(listener->DrawRect(TBRect(x, y, GetWidth(font), GetHeight(font)), TBColor(255, 255, 255, 128)));

	if (block->styledit->packed.password_on)
	{
		int cw = block->CalculateStringWidth(font, special_char_password);
		int num_char = utf8::count_characters(Str(), len);
		for(int i = 0; i < num_char; i++)
			listener->DrawString(x + i * cw, y, font, color, special_char_password);
	}
	else if (block->styledit->packed.show_whitespace)
	{
		if (IsTab())
			listener->DrawString(x, y, font, color, special_char_tab);
		else if (IsBreak())
			listener->DrawString(x, y, font, color, special_char_newln);
		else if (IsSpace())
			listener->DrawString(x, y, font, color, special_char_space);
		else
			listener->DrawString(x, y, font, color, Str(), len);
	}
	else if (!IsTab() && !IsBreak() && !IsSpace())
		listener->DrawString(x, y, font, color, Str(), len);

	if (props->data->underline)
	{
		int line_h = font->GetHeight() / 16;
		line_h = MAX(line_h, 1);
		listener->DrawRectFill(TBRect(x, y + GetBaseline(font) + 1, GetWidth(font), line_h), color);
	}
}

void TBTextFragment::Click(int button, uint32 modifierkeys)
{
	if (content)
		content->Click(this, button, modifierkeys);
}

int32 TBTextFragment::GetWidth(TBFontFace *font)
{
	if (content)
		return content->GetWidth(font, this);
	if (IsBreak())
		return 0;
	if (IsTab())
		return block->CalculateTabWidth(font, xpos);
	return block->CalculateStringWidth(font, block->str.CStr() + ofs, len);
}

int32 TBTextFragment::GetHeight(TBFontFace *font)
{
	if (content)
		return content->GetHeight(font, this);
	return block->CalculateLineHeight(font);
}

int32 TBTextFragment::GetBaseline(TBFontFace *font)
{
	if (content)
		return content->GetBaseline(font, this);
	return block->CalculateBaseline(font);
}

int32 TBTextFragment::GetCharX(TBFontFace *font, int32 ofs)
{
	assert(ofs >= 0 && ofs <= len);

	if (IsEmbedded() || IsTab())
		return ofs == 0 ? 0 :  GetWidth(font);
	if (IsBreak())
		return 0;

	return block->CalculateStringWidth(font, block->str.CStr() + this->ofs, ofs);
}

int32 TBTextFragment::GetCharOfs(TBFontFace *font, int32 x)
{
	if (IsEmbedded() || IsTab())
		return x > GetWidth(font) / 2 ? 1 : 0;
	if (IsBreak())
		return 0;

	const char *str = block->str.CStr() + ofs;
	int i = 0;
	while (i < len)
	{
		int pos = i;
		utf8::move_inc(str, &i, len);
		int last_char_len = i - pos;
		// Always measure from the beginning of the fragment because of eventual kerning & text shaping etc.
		int width_except_last_char = block->CalculateStringWidth(font, str, i - last_char_len);
		int width = block->CalculateStringWidth(font, str, i);
		if (x < width - (width - width_except_last_char) / 2)
			return pos;
	}
	return len;
}

int32 TBTextFragment::GetGlobalOfs() const
{
    int32 gofs = 0;
    TBBlock *b = block->styledit->blocks.GetFirst();
    while (b && b != block)
    {
        gofs += b->str_len;
        b = b->GetNext();
    }
    gofs += ofs;
    return gofs;
}


int32 TBTextFragment::GetStringWidth(TBFontFace *font, const char *str, int len)
{
	if (IsTab())
		return len == 0 ? 0 : block->CalculateTabWidth(font, xpos);
	if (IsBreak())
		return len == 0 ? 0 : 8;
	return block->CalculateStringWidth(font, str, len);
}

bool TBTextFragment::IsBreak() const
{
	return Str()[0] == '\r' || Str()[0] == '\n';
}

bool TBTextFragment::IsSpace() const
{
	return is_space(Str()[0]);
}

bool TBTextFragment::IsTab() const
{
	return Str()[0] == '\t';
}

bool TBTextFragment::GetAllowBreakBefore() const
{
	if (content)
		return content->GetAllowBreakBefore();
	if (len && !is_never_break_before(block->str.CStr(), ofs))
		return true;
	return false;
}

bool TBTextFragment::GetAllowBreakAfter() const
{
	if (content)
		return content->GetAllowBreakAfter();
	if (len && !is_never_break_after(block->str.CStr(), ofs + len - 1))
		return true;
	return false;
}

// ============================================================================

TBStyleEdit::TBStyleEdit()
	: listener(nullptr)    
	, content_factory(&default_content_factory)
    , text_change_listener(nullptr)
    , text_theme(nullptr)
	, layout_width(0)
	, layout_height(0)
	, content_width(0)
	, content_height(0)
	, caret(nullptr)
	, selection(nullptr)
	, scroll_x(0)
	, scroll_y(0)
	, select_state(0)
	, mousedown_fragment(nullptr)
	, font(nullptr)
	, align(TB_TEXT_ALIGN_LEFT)
	, packed_init(0)
{
	caret.styledit = this;
	selection.styledit = this;
	TMPDEBUG(packed.show_whitespace = true);

	font_desc = g_font_manager->GetDefaultFontDescription();
	font = g_font_manager->GetFontFace(font_desc);

#ifdef TB_TARGET_WINDOWS
	packed.win_style_br = 1;
#endif
	packed.selection_on = 1;

	Clear();
}

TBStyleEdit::~TBStyleEdit()
{
	listener->CaretBlinkStop();
	Clear(false);
}

void TBStyleEdit::SetListener(TBStyleEditListener *listener)
{
	this->listener = listener;
}

void TBStyleEdit::SetContentFactory(TBTextFragmentContentFactory *content_factory)
{
	if (content_factory)
		this->content_factory = content_factory;
	else
		this->content_factory = &default_content_factory;
}

void TBStyleEdit::SetFont(const TBFontDescription &font_desc)
{
	if (this->font_desc == font_desc)
		return;
	this->font_desc = font_desc;
	font = g_font_manager->GetFontFace(font_desc);
	Reformat(true);
}

void TBStyleEdit::Clear(bool init_new)
{
	undoredo.Clear(true, true);
	selection.SelectNothing();

	if (init_new && blocks.GetFirst() && IsEmpty())
		return;

	for (TBBlock *block = blocks.GetFirst(); block; block = block->GetNext())
		block->Invalidate();
	blocks.DeleteAll();

	if (init_new)
	{
		blocks.AddLast(new TBBlock(this));
		blocks.GetFirst()->Set("", 0);
	}

	caret.Place(blocks.GetFirst(), 0);
	caret.UpdateWantedX();
}

void TBStyleEdit::ScrollIfNeeded(bool x, bool y)
{
	if (layout_width <= 0 || layout_height <= 0)
		return; // This is likely during construction before layout.

	int32 newx = scroll_x, newy = scroll_y;
	if (x)
	{
		if (caret.x - scroll_x < 0)
			newx = caret.x;
		if (caret.x + caret.width - scroll_x > layout_width)
			newx = caret.x + caret.width - layout_width;
	}
	if (y)
	{
		if (caret.y - scroll_y < 0)
			newy = caret.y;
		if (caret.y + caret.height - scroll_y > layout_height)
			newy = caret.y + caret.height - layout_height;
	}
	SetScrollPos(newx, newy);
}

void TBStyleEdit::SetScrollPos(int32 x, int32 y)
{
	x = MIN(x, GetContentWidth() - layout_width);
	y = MIN(y, GetContentHeight() - layout_height);
	x = MAX(x, 0);
	y = MAX(y, 0);
	if (!packed.multiline_on)
		y = 0;
	int dx = scroll_x - x;
	int dy = scroll_y - y;
	if (dx || dy)
	{
		scroll_x = x;
		scroll_y = y;
		listener->Scroll(dx, dy);
	}
}

void TBStyleEdit::BeginLockScrollbars()
{
	packed.lock_scrollbars_counter++;
}

void TBStyleEdit::EndLockScrollbars()
{
	packed.lock_scrollbars_counter--;
	if (listener && packed.lock_scrollbars_counter == 0)
		listener->UpdateScrollbars();
}

void TBStyleEdit::SetLayoutSize(int32 width, int32 height, bool is_virtual_reformat)
{
	if (width == layout_width && height == layout_height)
		return;

	bool reformat = layout_width != width;
	layout_width = width;
	layout_height = height;

	if (reformat && GetSizeAffectsLayout())
		Reformat(false);

	caret.UpdatePos();
	caret.UpdateWantedX();

	if (!is_virtual_reformat)
		SetScrollPos(scroll_x, scroll_y); ///< Trig a bounds check (scroll if outside)
}

bool TBStyleEdit::GetSizeAffectsLayout() const
{
	if (packed.wrapping || align != TB_TEXT_ALIGN_LEFT)
		return true;
	return false;
}

void TBStyleEdit::Reformat(bool update_fragments)
{
	int ypos = 0;
	BeginLockScrollbars();
	TBBlock *block = blocks.GetFirst();
	while (block)
	{
		// Update ypos directly instead of using "propagate_height" since propagating
		// would iterate forward through all remaining blocks and we're going to visit
		// them all anyway.
		block->ypos = ypos;
		block->Layout(update_fragments, false);
		ypos += block->height;
		block = block->GetNext();
	}
	EndLockScrollbars();
	listener->Invalidate(TBRect(0, 0, layout_width, layout_height));
}

int32 TBStyleEdit::GetContentWidth()
{
	if (packed.calculate_content_width_needed)
	{
		packed.calculate_content_width_needed = 0;
		content_width = 0;
		TBBlock *block = blocks.GetFirst();
		while (block)
		{
			content_width = MAX(content_width, block->line_width_max);
			block = block->GetNext();
		}
	}
	return content_width;
}

int32 TBStyleEdit::GetContentHeight() const
{
	return content_height;
}

void TBStyleEdit::Paint(const TBRect &rect, const TBFontDescription &font_desc, const TBColor &text_color)
{
	TBTextProps props(font_desc, text_color);

	// Find the first visible block
	TBBlock *first_visible_block = blocks.GetFirst();
	while (first_visible_block)
	{
		if (first_visible_block->ypos + first_visible_block->height - scroll_y >= 0)
			break;
		first_visible_block = first_visible_block->GetNext();
	}

	// Get the selection region for all visible blocks
	TBRegion bg_region, fg_region;
	if (selection.IsSelected())
	{
		TBBlock *block = first_visible_block;
		while (block)
		{
			if (block->ypos - scroll_y > rect.y + rect.h)
				break;
			block->BuildSelectionRegion(-scroll_x, -scroll_y, &props, bg_region, fg_region);
			block = block->GetNext();
		}

		// Paint bg selection
		for (int i = 0; i < bg_region.GetNumRects(); i++)
			listener->DrawTextSelectionBg(bg_region.GetRect(i));
	}

	// Paint the content
	TBBlock *block = first_visible_block;
	while (block)
	{
		if (block->ypos - scroll_y > rect.y + rect.h)
			break;
		block->Paint(-scroll_x, -scroll_y, &props);
		block = block->GetNext();
	}

	// Paint fg selection
	for (int i = 0; i < fg_region.GetNumRects(); i++)
		listener->DrawTextSelectionBg(fg_region.GetRect(i));

	// Paint caret
	caret.Paint(- scroll_x, - scroll_y);
}

void TBStyleEdit::InsertBreak()
{
	if (!packed.multiline_on)
		return;

	const char *new_line_str = packed.win_style_br ? "\r\n" : "\n";

	// If we stand at the end and don't have any ending break, we're standing at the last line and
	// should insert breaks twice. One to end the current line, and one for the new empty line.
	if (caret.pos.ofs == caret.pos.block->str_len && !caret.pos.block->fragments.GetLast()->IsBreak())
		new_line_str = packed.win_style_br ? "\r\n\r\n" : "\n\n";

    TBStr indent_str;

    for (int i = 0; i < caret.pos.block->str_len; i++)
    {
        if (caret.pos.block->str[i] == '\t')
            indent_str.Append("\t", 1);
        else if (caret.pos.block->str[i] == ' ')
            indent_str.Append(" ", 1);
        else
            break;
    }

	InsertText(new_line_str);

	caret.AvoidLineBreak();
	if (caret.pos.block->GetNext())
    {
		caret.Place(caret.pos.block->GetNext(), 0);

        if (indent_str.Length())
        {
            InsertText(indent_str);
            caret.Place(TBPoint(32000, caret.y));
        }
    }

    if (text_change_listener)
        text_change_listener->OnChange(this);

}

void TBStyleEdit::InsertText(const char *text, int32 len, bool after_last, bool clear_undo_redo)
{
	if (len == TB_ALL_TO_TERMINATION)
		len = strlen(text);

    bool selected = selection.IsSelected();

	selection.RemoveContent();

	if (after_last)
		caret.Place(blocks.GetLast(), blocks.GetLast()->str_len, false);

	int32 len_inserted = caret.pos.block->InsertText(caret.pos.ofs, text, len, true);
	if (clear_undo_redo)
		undoredo.Clear(true, true);
    else
    {
        TBUndoEvent* uevent = undoredo.Commit(this, caret.GetGlobalOfs(), len_inserted, text, true);
        if (selected)
            uevent->chain = true;
    }

	caret.Place(caret.pos.block, caret.pos.ofs + len, false);
	caret.UpdatePos();
	caret.UpdateWantedX();

    if (selected)
        selection.SelectNothing();

    if (text_change_listener)
        text_change_listener->OnChange(this);

}

TBBlock *TBStyleEdit::FindBlock(int32 y) const
{
	TBBlock *block = blocks.GetFirst();
	while (block)
	{
		if (y < block->ypos + block->height)
			return block;
		block = block->GetNext();
	}
	return blocks.GetLast();
}

bool TBStyleEdit::KeyDown(int key, SPECIAL_KEY special_key, MODIFIER_KEYS modifierkeys)
{
	if (select_state)
		return false;

	bool handled = true;
	bool move_caret = special_key == TB_KEY_LEFT || special_key == TB_KEY_RIGHT ||
						special_key == TB_KEY_UP || special_key == TB_KEY_DOWN ||
						special_key == TB_KEY_HOME || special_key == TB_KEY_END ||
						special_key == TB_KEY_PAGE_UP || special_key == TB_KEY_PAGE_DOWN;

	if (!(modifierkeys & TB_SHIFT) && move_caret)
		selection.SelectNothing();

    bool superDown = (modifierkeys & TB_SUPER);
    bool ctrlOrSuper = ((modifierkeys & TB_CTRL) || superDown);

	TBTextOfs old_caret_pos = caret.pos;
	TBTextFragment *old_caret_elm = caret.GetFragment();

	if ((special_key == TB_KEY_UP || special_key == TB_KEY_DOWN) && (modifierkeys & TB_CTRL))
	{
		int32 line_height = old_caret_pos.block->CalculateLineHeight(font);
		int32 new_y = scroll_y + (special_key == TB_KEY_UP ? -line_height : line_height);
		SetScrollPos(scroll_x, new_y);
	}
    else if (special_key == TB_KEY_LEFT && !superDown)
        caret.Move(false, (modifierkeys & TB_CTRL) ? true : false);
    else if (special_key == TB_KEY_RIGHT && !superDown)
        caret.Move(true, (modifierkeys & TB_CTRL) ? true : false);
	else if (special_key == TB_KEY_UP)
		handled = caret.Place(TBPoint(caret.wanted_x, old_caret_pos.block->ypos + old_caret_elm->line_ypos - 1));
	else if (special_key == TB_KEY_DOWN)
		handled = caret.Place(TBPoint(caret.wanted_x, old_caret_pos.block->ypos + old_caret_elm->line_ypos + old_caret_elm->line_height + 1));
	else if (special_key == TB_KEY_PAGE_UP)
		caret.Place(TBPoint(caret.wanted_x, caret.y - layout_height));
	else if (special_key == TB_KEY_PAGE_DOWN)
		caret.Place(TBPoint(caret.wanted_x, caret.y + layout_height + old_caret_elm->line_height));
	else if (special_key == TB_KEY_HOME && modifierkeys & TB_CTRL)
		caret.Place(TBPoint(0, 0));
	else if (special_key == TB_KEY_END && modifierkeys & TB_CTRL)
		caret.Place(TBPoint(32000, blocks.GetLast()->ypos + blocks.GetLast()->height));
    else if (special_key == TB_KEY_HOME || ( special_key == TB_KEY_LEFT && superDown))
    {
        if (old_caret_pos.block)
        {
            int32 pos =  old_caret_pos.block->FirstNonTabPos();

            if (old_caret_pos.block->str[pos] == '\n' || old_caret_pos.block->str[pos] == '\r')
                pos = 0;

            if (old_caret_pos.ofs <= pos)
                pos = 0;

            caret.Place(old_caret_pos.block, pos);
        }
        else
            caret.Place(TBPoint(0, caret.y));
    }
    else if (special_key == TB_KEY_END || ( special_key == TB_KEY_RIGHT && superDown))
		caret.Place(TBPoint(32000, caret.y));
	else if (key == '8' && (modifierkeys & TB_CTRL))
	{
		packed.show_whitespace = !packed.show_whitespace;
		listener->Invalidate(TBRect(0, 0, layout_width, layout_height));
	}
	else if (!packed.read_only && (special_key == TB_KEY_DELETE || special_key == TB_KEY_BACKSPACE))
	{
		if (!selection.IsSelected())
		{
			caret.Move(special_key == TB_KEY_DELETE, (modifierkeys & TB_CTRL) ? true : false);
			selection.SelectToCaret(old_caret_pos.block, old_caret_pos.ofs);
		}
		selection.RemoveContent();
	}
	else if (!packed.read_only && !(modifierkeys & TB_SHIFT) && (special_key == TB_KEY_TAB && packed.multiline_on))
    {
        if (!selection.IsSelected() || selection.start.block == selection.stop.block)
        {
            InsertText("    ", 4);
        }
        else
        {
            bool chain = false;
            for (TBBlock* block = selection.start.block; block; block = block->GetNext())
            {
                if (block != selection.stop.block || selection.stop.ofs != 0)
                {
                    block->InsertText(0, "    ", 4, false);

                    TBUndoEvent* uevent = undoredo.Commit(this, block->fragments.GetFirst()->GetGlobalOfs(), 4, "    ", true);
                    uevent->chain = chain;
                    chain = true;
                }

                if (block == selection.stop.block)
                    break;
            }

            if (text_change_listener)
                text_change_listener->OnChange(this);

        }
    }
    else if (!packed.read_only && (modifierkeys & TB_SHIFT) && (special_key == TB_KEY_TAB && packed.multiline_on))
    {
        if (!selection.IsSelected() || selection.start.block == selection.stop.block)
        {
            TBBlock* block = caret.pos.block;
            if (block)
            {
                int32 start = block->FirstNonTabPos();

                if (start > 4)
                    start = 4;

                if (start)
                {
                    TBStr str;
                    for (int32 i = 0; i < start; i++)
                    {
                        str.Append(" ");
                    }

                    undoredo.Commit(this, block->fragments.GetFirst()->GetGlobalOfs(), start, str.CStr(), false);
                    block->RemoveContent(0, start);
                }

                selection.SelectNothing();
                start = block->FirstNonTabPos();
                caret.Place(block, start);

            }
        }
        else
        {
            bool chain = false;
            for (TBBlock* block = selection.start.block; block; block = block->GetNext())
            {
                if (block != selection.stop.block || selection.stop.ofs != 0)
                {
                    int32 start = block->FirstNonTabPos();

                    if (start > 4)
                        start = 4;

                    if (start)
                    {
                        TBStr str;
                        for (int32 i = 0; i < start; i++)
                        {
                            str.Append(" ");
                        }

                        TBUndoEvent* uevent = undoredo.Commit(this, block->fragments.GetFirst()->GetGlobalOfs(), start, str.CStr(), false);
                        uevent->chain = chain;
                        chain = true;
                        block->RemoveContent(0, start);
                    }
                }

                if (block == selection.stop.block)
                    break;
            }
            if (text_change_listener)
                text_change_listener->OnChange(this);

        }
    }
    else if (!packed.read_only && (special_key == TB_KEY_ENTER && packed.multiline_on) && !(ctrlOrSuper))
		InsertBreak();
    else if (!packed.read_only && (key && !(ctrlOrSuper)) && special_key != TB_KEY_ENTER)
	{
		char utf8[8];
		int len = utf8::encode(key, utf8);
        InsertText(utf8, len);
	}
	else
		handled = false;

	if ((modifierkeys & TB_SHIFT) && move_caret)
		selection.SelectToCaret(old_caret_pos.block, old_caret_pos.ofs);

	if (!(special_key == TB_KEY_UP || special_key == TB_KEY_DOWN ||
		special_key == TB_KEY_PAGE_UP || special_key == TB_KEY_PAGE_DOWN))
		caret.UpdateWantedX();

	caret.ResetBlink();

	// Hooks
	if (!move_caret && handled)
		listener->OnChange();
	if (special_key == TB_KEY_ENTER && !(modifierkeys & TB_CTRL))
	{
		if (listener->OnEnter())
			handled = true;
	}
	if (handled)
		ScrollIfNeeded();

	return handled;
}

void TBStyleEdit::Cut()
{
	if (packed.password_on)
		return;
	Copy();
	KeyDown(0, TB_KEY_DELETE, TB_MODIFIER_NONE);
}

void TBStyleEdit::Copy()
{
	if (packed.password_on)
		return;
	selection.CopyToClipboard();
}

void TBStyleEdit::Paste()
{
	TBStr text;
	if (TBClipboard::HasText() && TBClipboard::GetText(text))
	{
		InsertText(text, text.Length());
		ScrollIfNeeded(true, true);
		listener->OnChange();
        if (text_change_listener)
            text_change_listener->OnChange(this);

	}
}

void TBStyleEdit::Delete()
{
	if (selection.IsSelected())
	{
		selection.RemoveContent();
		listener->OnChange();
	}
}

void TBStyleEdit::Undo()
{
	if (CanUndo())
	{
		undoredo.Undo(this);
		listener->OnChange();
	}
}

void TBStyleEdit::Redo()
{
	if (CanRedo())
	{
		undoredo.Redo(this);
		listener->OnChange();
	}
}

bool TBStyleEdit::MouseDown(const TBPoint &point, int button, int clicks, MODIFIER_KEYS modifierkeys, bool touch)
{
	if (button != 1)
		return false;

	if (touch)
	{
		mousedown_point = TBPoint(point.x + scroll_x, point.y + scroll_y);
	}
	else if (packed.selection_on)
	{
        if (modifierkeys & TB_SHIFT) // Select to new caretpos
        {
            mousedown_fragment = nullptr;
            mousedown_point = TBPoint(point.x + scroll_x, point.y + scroll_y);
            TBTextOfs old_caret_pos = caret.pos;
            caret.Place(mousedown_point);
            selection.SelectToCaret(old_caret_pos.block, old_caret_pos.ofs);
        }
        else // Start selection
		{
			mousedown_point = TBPoint(point.x + scroll_x, point.y + scroll_y);
			selection.SelectNothing();

			// clicks is 1 to infinite, and here we support only doubleclick, so make it either single or double.
			select_state = ((clicks - 1) % 2) + 1;

			MouseMove(point);

			if (caret.pos.block)
				mousedown_fragment = caret.pos.block->FindFragment(mousedown_point.x, mousedown_point.y - caret.pos.block->ypos);
		}
		caret.ResetBlink();
	}
	return true;
}

bool TBStyleEdit::MouseUp(const TBPoint &point, int button, MODIFIER_KEYS modifierkeys, bool touch)
{
	if (button != 1)
		return false;

	if (touch && !TBWidget::cancel_click)
	{
		selection.SelectNothing();
		caret.Place(mousedown_point);
		caret.UpdateWantedX();
		caret.ResetBlink();
	}

	select_state = 0;
	if (caret.pos.block && !TBWidget::cancel_click)
	{
		TBTextFragment *fragment = caret.pos.block->FindFragment(point.x + scroll_x, point.y + scroll_y - caret.pos.block->ypos);
		if (fragment && fragment == mousedown_fragment)
			fragment->Click(button, modifierkeys);
	}
	return true;
}

bool TBStyleEdit::MouseMove(const TBPoint &point)
{
	if (select_state)
	{
		TBPoint p(point.x + scroll_x, point.y + scroll_y);
		selection.Select(mousedown_point, p);

		if (select_state == 2)
		{
			bool has_initial_selection = selection.IsSelected();

			if (has_initial_selection)
				caret.Place(selection.start.block, selection.start.ofs);
			caret.Move(false, true);
			selection.start.Set(caret.pos);

			if (has_initial_selection)
				caret.Place(selection.stop.block, selection.stop.ofs);
			caret.Move(true, true);
			selection.stop.Set(caret.pos);

			selection.CorrectOrder();
			caret.UpdateWantedX();
		}
		return true;
	}
	return false;
}

void TBStyleEdit::Focus(bool focus)
{
	if (focus)
		listener->CaretBlinkStart();
	else
		listener->CaretBlinkStop();

	caret.on = focus;
	caret.Invalidate();
	selection.Invalidate();
}

bool TBStyleEdit::SetText(const char *text, TB_CARET_POS pos)
{
	return SetText(text, strlen(text), pos);
}

bool TBStyleEdit::SetText(const char *text, int text_len, TB_CARET_POS pos)
{
	if (!text || !*text)
	{
		Clear(true);
		caret.UpdateWantedX();
		ScrollIfNeeded(true, true);
		return true;
	}

	Clear(true);
	blocks.GetFirst()->InsertText(0, text, text_len, true);

	caret.Place(blocks.GetFirst(), 0);
	caret.UpdateWantedX();
	ScrollIfNeeded(true, false);

	if (pos == TB_CARET_POS_END)
        caret.Place(blocks.GetLast(), blocks.GetLast()->str_len);

	listener->OnChange();
	return true;
}

bool TBStyleEdit::Load(const char *filename)
{
	TBFile* f = TBFile::Open(filename, TBFile::MODE_READ);
	if (!f)
		return false;
	uint32 num_bytes = f->Size();

	char *str = new char[num_bytes + 1];
	if (!str)
	{
		delete f;
		return false;
	}

	num_bytes = f->Read(str, 1, num_bytes);
	str[num_bytes] = 0;

	delete f;

	SetText(str);

	delete [] str;
	return true;
}

bool TBStyleEdit::GetText(TBStr &text)
{
	TBSelection tmp_selection(this);
	tmp_selection.SelectAll();
	return tmp_selection.GetText(text);
}

bool TBStyleEdit::IsEmpty() const
{
	return blocks.GetFirst() == blocks.GetLast() && blocks.GetFirst()->str.IsEmpty();
}

void TBStyleEdit::SetAlign(TB_TEXT_ALIGN align)
{
	this->align = align;
	// Call SetAlign on all blocks currently selected, or the block of the current caret position.
	TBBlock *start = selection.IsSelected() ? selection.start.block : caret.pos.block;
	TBBlock *stop = selection.IsSelected() ? selection.stop.block : caret.pos.block;
	while (start && start != stop->GetNext())
	{
		start->SetAlign(align);
		start = start->GetNext();
	}
}

void TBStyleEdit::SetMultiline(bool multiline)
{
	packed.multiline_on = multiline;
}

void TBStyleEdit::SetStyling(bool styling)
{
	packed.styling_on = styling;
}

void TBStyleEdit::SetReadOnly(bool readonly)
{
	packed.read_only = readonly;
}

void TBStyleEdit::SetSelection(bool selection)
{
	packed.selection_on = selection;
}

void TBStyleEdit::SetPassword(bool password)
{
	if (packed.password_on == password)
		return;
	packed.password_on = password;
	Reformat(true);
}

void TBStyleEdit::SetWrapping(bool wrapping)
{
	if (packed.wrapping == wrapping)
		return;
	packed.wrapping = wrapping;
	Reformat(false);
}

int32 TBStyleEdit::GetCaretLine()
{
    int line = 0;
    TBBlock *block = NULL;
    TBTextFragment* frag = caret.GetFragment();
    if (!frag)
        return 0;

    for (block = blocks.GetFirst(); block; block = block->GetNext())
    {
        if (frag->block == block)
            return line;
        line++;
    }

    return 0;

}

// == TBUndoRedoStack ==================================================

TBUndoRedoStack::~TBUndoRedoStack()
{
	Clear(true, true);
}

void TBUndoRedoStack::Undo(TBStyleEdit *styledit)
{
	if (!undos.GetNumItems())
		return;
	TBUndoEvent *e = undos.Remove(undos.GetNumItems() - 1);
	redos.Add(e);
	Apply(styledit, e, true);

    if (e->chain)
        Undo(styledit);
}

void TBUndoRedoStack::Redo(TBStyleEdit *styledit)
{
	if (!redos.GetNumItems())
		return;
	TBUndoEvent *e = redos.Remove(redos.GetNumItems() - 1);
	undos.Add(e);
	Apply(styledit, e, false);

    if (redos.GetNumItems())
        if (redos[0]->chain)
            Redo(styledit);
}

void TBUndoRedoStack::Apply(TBStyleEdit *styledit, TBUndoEvent *e, bool reverse)
{
	applying = true;
	if (e->insert == reverse)
	{
		styledit->selection.SelectNothing();
		styledit->caret.SetGlobalOfs(e->gofs, false);
		assert(TBTextOfs(styledit->caret.pos).GetGlobalOfs(styledit) == e->gofs);

		TBTextOfs start = styledit->caret.pos;
		styledit->caret.SetGlobalOfs(e->gofs + e->text.Length(), false);
		assert(TBTextOfs(styledit->caret.pos).GetGlobalOfs(styledit) == e->gofs + e->text.Length());

		styledit->selection.Select(start, styledit->caret.pos);
		styledit->selection.RemoveContent();
	}
	else
	{
		styledit->selection.SelectNothing();
		styledit->caret.SetGlobalOfs(e->gofs, true, true);
		styledit->InsertText(e->text);
		int text_len = e->text.Length();
		if (text_len > 1)
			styledit->selection.Select(e->gofs, e->gofs + text_len);
	}
	styledit->ScrollIfNeeded(true, true);
	applying = false;
}

void TBUndoRedoStack::Clear(bool clear_undo, bool clear_redo)
{
	assert(!applying);
	if (clear_undo)
		undos.DeleteAll();
	if (clear_redo)
		redos.DeleteAll();
}

TBUndoEvent *TBUndoRedoStack::Commit(TBStyleEdit *styledit, int32 gofs, int32 len, const char *text, bool insert)
{
	if (applying || styledit->packed.read_only)
		return nullptr;
	Clear(false, true);

	// If we're inserting a single character, check if we want to append it to the previous event.
	if (insert && undos.GetNumItems())
	{
		int num_char = utf8::count_characters(text, len);
		TBUndoEvent *e = undos[undos.GetNumItems() - 1];
		if (num_char == 1 && e->insert && e->gofs + e->text.Length() == gofs)
		{
			// Appending a space to other space(s) should append
            if ((text[0] == ' ' && !strpbrk(e->text.CStr(), "\r\n")) ||
				// But non spaces should not
				!strpbrk(e->text.CStr(), " \r\n"))
			{
				e->text.Append(text, len);
				return e;
			}
		}
	}

	// Create a new event
	if (TBUndoEvent *e = new TBUndoEvent())
	{
		e->gofs = gofs;
		e->text.Set(text, len);
		e->insert = insert;
		undos.Add(e);
		return e;
	}

	// OOM
	Clear(true, true);
	return nullptr;
}

}; // namespace tb