/** 
 * @file lltextbase.h
 * @author Martin Reddy
 * @brief The base class of text box/editor, providing Url handling support
 *
 * $LicenseInfo:firstyear=2009&license=viewerlgpl$
 * Second Life Viewer Source Code
 * Copyright (C) 2010, Linden Research, Inc.
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation;
 * version 2.1 of the License only.
 * 
 * This library 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
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 * 
 * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
 * $/LicenseInfo$
 */

#ifndef LL_LLTEXTBASE_H
#define LL_LLTEXTBASE_H

#include "v4color.h"
#include "lleditmenuhandler.h"
#include "llspellcheckmenuhandler.h"
#include "llstyle.h"
#include "llkeywords.h"
#include "llpanel.h"

#include <string>
#include <vector>
#include <set>

#include <boost/signals2.hpp>

class LLScrollContainer;
class LLContextMenu;
class LLUrlMatch;

///
/// A text segment is used to specify a subsection of a text string
/// that should be formatted differently, such as a hyperlink. It
/// includes a start/end offset from the start of the string, a
/// style to render with, an optional tooltip, etc.
///
class LLTextSegment 
:	public LLRefCount, 
	public LLMouseHandler
{
public:
	LLTextSegment(S32 start, S32 end) 
	:	mStart(start), 
		mEnd(end)
	{}
	virtual ~LLTextSegment();
	bool						getDimensions(S32 first_char, S32 num_chars, S32& width, S32& height) const;

	virtual bool				getDimensionsF32(S32 first_char, S32 num_chars, F32& width, S32& height) const;
	virtual S32					getOffset(S32 segment_local_x_coord, S32 start_offset, S32 num_chars, bool round) const;

	/**
	* Get number of chars that fit into free part of current line.
	*
	* @param num_pixels - maximum width of rect
	* @param segment_offset - symbol in segment we start processing line from
	* @param line_offset - symbol in line after which segment starts
	* @param max_chars - limit of symbols that will fit in current line
	* @param line_ind - index of not word-wrapped string inside segment for multi-line segments.
	* Two string separated by word-wrap will have same index.
	* @return number of chars that will fit into current line
	*/
	virtual S32					getNumChars(S32 num_pixels, S32 segment_offset, S32 line_offset, S32 max_chars, S32 line_ind) const;
	virtual void				updateLayout(const class LLTextBase& editor);
	virtual F32					draw(S32 start, S32 end, S32 selection_start, S32 selection_end, const LLRectf& draw_rect);
	virtual bool				canEdit() const;
	virtual void				unlinkFromDocument(class LLTextBase* editor);
	virtual void				linkToDocument(class LLTextBase* editor);

	virtual const LLColor4&		getColor() const;
	//virtual void 				setColor(const LLColor4 &color);
	virtual LLStyleConstSP		getStyle() const;
	virtual void 				setStyle(LLStyleConstSP style);
	virtual void				setToken( LLKeywordToken* token );
	virtual LLKeywordToken*		getToken() const;
	virtual void				setToolTip(const std::string& tooltip);
	virtual void				dump() const;

	// LLMouseHandler interface
	/*virtual*/ BOOL			handleMouseDown(S32 x, S32 y, MASK mask);
	/*virtual*/ BOOL			handleMouseUp(S32 x, S32 y, MASK mask);
	/*virtual*/ BOOL			handleMiddleMouseDown(S32 x, S32 y, MASK mask);
	/*virtual*/ BOOL			handleMiddleMouseUp(S32 x, S32 y, MASK mask);
	/*virtual*/ BOOL			handleRightMouseDown(S32 x, S32 y, MASK mask);
	/*virtual*/ BOOL			handleRightMouseUp(S32 x, S32 y, MASK mask);
	/*virtual*/ BOOL			handleDoubleClick(S32 x, S32 y, MASK mask);
	/*virtual*/ BOOL			handleHover(S32 x, S32 y, MASK mask);
	/*virtual*/ BOOL			handleScrollWheel(S32 x, S32 y, S32 clicks);
	/*virtual*/ BOOL			handleScrollHWheel(S32 x, S32 y, S32 clicks);
	/*virtual*/ BOOL			handleToolTip(S32 x, S32 y, MASK mask);
	/*virtual*/ const std::string&	getName() const;
	/*virtual*/ void			onMouseCaptureLost();
	/*virtual*/ void			screenPointToLocal(S32 screen_x, S32 screen_y, S32* local_x, S32* local_y) const;
	/*virtual*/ void			localPointToScreen(S32 local_x, S32 local_y, S32* screen_x, S32* screen_y) const;
	/*virtual*/ BOOL			hasMouseCapture();

	S32						getStart() const 					{ return mStart; }
	void					setStart(S32 start)					{ mStart = start; }
	S32						getEnd() const						{ return mEnd; }
	void					setEnd( S32 end )					{ mEnd = end; }

protected:
	S32				mStart;
	S32				mEnd;
};

class LLNormalTextSegment : public LLTextSegment
{
public:
	LLNormalTextSegment( LLStyleConstSP style, S32 start, S32 end, LLTextBase& editor );
	LLNormalTextSegment( const LLColor4& color, S32 start, S32 end, LLTextBase& editor, BOOL is_visible = TRUE);
	virtual ~LLNormalTextSegment();

	/*virtual*/ bool				getDimensionsF32(S32 first_char, S32 num_chars, F32& width, S32& height) const;
	/*virtual*/ S32					getOffset(S32 segment_local_x_coord, S32 start_offset, S32 num_chars, bool round) const;
	/*virtual*/ S32					getNumChars(S32 num_pixels, S32 segment_offset, S32 line_offset, S32 max_chars, S32 line_ind) const;
	/*virtual*/ F32					draw(S32 start, S32 end, S32 selection_start, S32 selection_end, const LLRectf& draw_rect);
	/*virtual*/ bool				canEdit() const { return true; }
	/*virtual*/ const LLColor4&		getColor() const					{ return mStyle->getColor(); }
	/*virtual*/ LLStyleConstSP		getStyle() const					{ return mStyle; }
	/*virtual*/ void 				setStyle(LLStyleConstSP style)	{ mStyle = style; }
	/*virtual*/ void				setToken( LLKeywordToken* token )	{ mToken = token; }
	/*virtual*/ LLKeywordToken*		getToken() const					{ return mToken; }
	/*virtual*/ BOOL				getToolTip( std::string& msg ) const;
	/*virtual*/ void				setToolTip(const std::string& tooltip);
	/*virtual*/ void				dump() const;

	/*virtual*/ BOOL				handleHover(S32 x, S32 y, MASK mask);
	/*virtual*/ BOOL				handleRightMouseDown(S32 x, S32 y, MASK mask);
	/*virtual*/ BOOL				handleMouseDown(S32 x, S32 y, MASK mask);
	/*virtual*/ BOOL				handleMouseUp(S32 x, S32 y, MASK mask);
	/*virtual*/ BOOL				handleToolTip(S32 x, S32 y, MASK mask);

protected:
	F32					drawClippedSegment(S32 seg_start, S32 seg_end, S32 selection_start, S32 selection_end, LLRectf rect);

	virtual		const LLWString&	getWText()	const;
	virtual		const S32			getLength()	const;

protected:
	class LLTextBase&	mEditor;
	LLStyleConstSP		mStyle;
	S32					mFontHeight;
	LLKeywordToken* 	mToken;
	std::string     	mTooltip;
	boost::signals2::connection mImageLoadedConnection;
};

// This text segment is the same as LLNormalTextSegment, the only difference
// is that LLNormalTextSegment draws value of LLTextBase (LLTextBase::getWText()),
// but LLLabelTextSegment draws label of the LLTextBase (LLTextBase::mLabel)
class LLLabelTextSegment : public LLNormalTextSegment
{
public:
	LLLabelTextSegment( LLStyleConstSP style, S32 start, S32 end, LLTextBase& editor );
	LLLabelTextSegment( const LLColor4& color, S32 start, S32 end, LLTextBase& editor, BOOL is_visible = TRUE);

protected:

	/*virtual*/	const LLWString&	getWText()	const;
	/*virtual*/	const S32			getLength()	const;
};

// Text segment that represents a single emoji character that has a different style (=font size) than the rest of
// the document it belongs to
class LLEmojiTextSegment : public LLNormalTextSegment
{
public:
	LLEmojiTextSegment(LLStyleConstSP style, S32 start, S32 end, LLTextBase& editor);
	LLEmojiTextSegment(const LLColor4& color, S32 start, S32 end, LLTextBase& editor, BOOL is_visible = TRUE);

	bool canEdit() const override { return false; }
	BOOL handleToolTip(S32 x, S32 y, MASK mask) override;
};

// Text segment that changes it's style depending of mouse pointer position ( is it inside or outside segment)
class LLOnHoverChangeableTextSegment : public LLNormalTextSegment
{
public:
	LLOnHoverChangeableTextSegment( LLStyleConstSP style, LLStyleConstSP normal_style, S32 start, S32 end, LLTextBase& editor );
	/*virtual*/ F32 draw(S32 start, S32 end, S32 selection_start, S32 selection_end, const LLRectf& draw_rect);
	/*virtual*/ BOOL handleHover(S32 x, S32 y, MASK mask);
protected:
	// Style used for text when mouse pointer is over segment
	LLStyleConstSP		mHoveredStyle;
	// Style used for text when mouse pointer is outside segment
	LLStyleConstSP		mNormalStyle;

};

class LLIndexSegment : public LLTextSegment
{
public:
	LLIndexSegment() : LLTextSegment(0, 0) {}
};

class LLInlineViewSegment : public LLTextSegment
{
public:
	struct Params : public LLInitParam::Block<Params>
	{
		Mandatory<LLView*>		view;
		Optional<bool>			force_newline;
		Optional<S32>			left_pad,
								right_pad,
								bottom_pad,
								top_pad;
	};

	LLInlineViewSegment(const Params& p, S32 start, S32 end);
	~LLInlineViewSegment();
	/*virtual*/ bool		getDimensionsF32(S32 first_char, S32 num_chars, F32& width, S32& height) const;
	/*virtual*/ S32			getNumChars(S32 num_pixels, S32 segment_offset, S32 line_offset, S32 max_chars, S32 line_ind) const;
	/*virtual*/ void		updateLayout(const class LLTextBase& editor);
	/*virtual*/ F32			draw(S32 start, S32 end, S32 selection_start, S32 selection_end, const LLRectf& draw_rect);
	/*virtual*/ bool		canEdit() const { return false; }
	/*virtual*/ void		unlinkFromDocument(class LLTextBase* editor);
	/*virtual*/ void		linkToDocument(class LLTextBase* editor);

private:
	S32 mLeftPad;
	S32 mRightPad;
	S32 mTopPad;
	S32 mBottomPad;
	LLView* mView;
	bool	mForceNewLine;
};

class LLLineBreakTextSegment : public LLTextSegment
{
public:

	LLLineBreakTextSegment(LLStyleConstSP style,S32 pos);
	LLLineBreakTextSegment(S32 pos);
	~LLLineBreakTextSegment();
	/*virtual*/ bool		getDimensionsF32(S32 first_char, S32 num_chars, F32& width, S32& height) const;
	S32			getNumChars(S32 num_pixels, S32 segment_offset, S32 line_offset, S32 max_chars, S32 line_ind) const;
	F32			draw(S32 start, S32 end, S32 selection_start, S32 selection_end, const LLRectf& draw_rect);

private:
	S32			mFontHeight;
};

class LLImageTextSegment : public LLTextSegment
{
public:
	LLImageTextSegment(LLStyleConstSP style,S32 pos,class LLTextBase& editor);
	~LLImageTextSegment();
	/*virtual*/ bool		getDimensionsF32(S32 first_char, S32 num_chars, F32& width, S32& height) const;
	S32			getNumChars(S32 num_pixels, S32 segment_offset, S32 char_offset, S32 max_chars, S32 line_ind) const;
	F32			draw(S32 start, S32 end, S32 selection_start, S32 selection_end, const LLRectf& draw_rect);

	/*virtual*/ BOOL	handleToolTip(S32 x, S32 y, MASK mask);
	/*virtual*/ void	setToolTip(const std::string& tooltip);

private:
	class LLTextBase&	mEditor;
	LLStyleConstSP	mStyle;

protected:
	std::string		mTooltip;
};

typedef LLPointer<LLTextSegment> LLTextSegmentPtr;

///
/// The LLTextBase class provides a base class for all text fields, such
/// as LLTextEditor and LLTextBox. It implements shared functionality
/// such as Url highlighting and opening.
///
class LLTextBase 
:	public LLUICtrl,
	protected LLEditMenuHandler,
	public LLSpellCheckMenuHandler,
	public ll::ui::SearchableControl
{
public:
	friend class LLTextSegment;
	friend class LLNormalTextSegment;
	friend class LLUICtrlFactory;

	typedef boost::signals2::signal<bool (const LLUUID& user_id)> is_friend_signal_t;
	typedef boost::signals2::signal<bool (const LLUUID& blocked_id, const std::string from)> is_blocked_signal_t;

	struct LineSpacingParams : public LLInitParam::ChoiceBlock<LineSpacingParams>
	{
		Alternative<F32>	multiple;
		Alternative<S32>	pixels;
		LineSpacingParams();
	};

	struct Params : public LLInitParam::Block<Params, LLUICtrl::Params>
	{
		Optional<LLUIColor>		cursor_color,
								text_color,
								text_readonly_color,
								text_tentative_color,
								bg_readonly_color,
								bg_writeable_color,
								bg_focus_color,
								text_selected_color,
								bg_selected_color;

		Optional<bool>			bg_visible,
								border_visible,
								track_end,
								read_only,
								skip_link_underline,
								spellcheck,
								allow_scroll,
								plain_text,
								wrap,
								use_ellipses,
								use_color,
								parse_urls,
								force_urls_external,
								parse_highlights,
								clip,
								clip_partial,
								trusted_content,
								always_show_icons;
								
		Optional<S32>			v_pad,
								h_pad;


		Optional<LineSpacingParams>
								line_spacing;

		Optional<S32>			max_text_length;

		Optional<LLFontGL::ShadowType>	font_shadow;

		Optional<LLFontGL::VAlign> text_valign;

		Params();
	};

	// LLMouseHandler interface
	/*virtual*/ BOOL		handleMouseDown(S32 x, S32 y, MASK mask);
	/*virtual*/ BOOL		handleMouseUp(S32 x, S32 y, MASK mask);
	/*virtual*/ BOOL		handleMiddleMouseDown(S32 x, S32 y, MASK mask);
	/*virtual*/ BOOL		handleMiddleMouseUp(S32 x, S32 y, MASK mask);
	/*virtual*/ BOOL		handleRightMouseDown(S32 x, S32 y, MASK mask);
	/*virtual*/ BOOL		handleRightMouseUp(S32 x, S32 y, MASK mask);
	/*virtual*/ BOOL		handleDoubleClick(S32 x, S32 y, MASK mask);
	/*virtual*/ BOOL		handleHover(S32 x, S32 y, MASK mask);
	/*virtual*/ BOOL		handleScrollWheel(S32 x, S32 y, S32 clicks);
	/*virtual*/ BOOL		handleToolTip(S32 x, S32 y, MASK mask);

	// LLView interface
	/*virtual*/ void		reshape(S32 width, S32 height, BOOL called_from_parent = TRUE);
	/*virtual*/ void		draw();

	// LLUICtrl interface
	/*virtual*/ BOOL		acceptsTextInput() const { return !mReadOnly; }
	/*virtual*/ void		setColor( const LLColor4& c );
	virtual     void 		setReadOnlyColor(const LLColor4 &c);
	virtual	    void		onVisibilityChange( BOOL new_visibility );

	/*virtual*/ void		setValue(const LLSD& value );
	/*virtual*/ LLTextViewModel* getViewModel() const;

	// LLEditMenuHandler interface
	/*virtual*/ BOOL		canDeselect() const;
	/*virtual*/ void		deselect();

	virtual void	onFocusReceived();
	virtual void	onFocusLost();

    void        setParseHTML(bool parse_html) { mParseHTML = parse_html; }

	// LLSpellCheckMenuHandler overrides
	/*virtual*/ bool		getSpellCheck() const;

	/*virtual*/ const std::string& getSuggestion(U32 index) const;
	/*virtual*/ U32			getSuggestionCount() const;
	/*virtual*/ void		replaceWithSuggestion(U32 index);

	/*virtual*/ void		addToDictionary();
	/*virtual*/ bool		canAddToDictionary() const;

	/*virtual*/ void		addToIgnore();
	/*virtual*/ bool		canAddToIgnore() const;

	// Spell checking helper functions
	std::string				getMisspelledWord(U32 pos) const;
	bool					isMisspelledWord(U32 pos) const;
	void					onSpellCheckSettingsChange();
	virtual void			onSpellCheckPerformed(){}

	// used by LLTextSegment layout code
	bool					getWordWrap() { return mWordWrap; }
	bool					getUseEllipses() { return mUseEllipses; }
	bool					getUseColor() { return mUseColor; }
	bool					truncate(); // returns true of truncation occurred

	bool					isContentTrusted() {return mTrustedContent;}
	void					setContentTrusted(bool trusted_content) { mTrustedContent = trusted_content; }

	// TODO: move into LLTextSegment?
	void					createUrlContextMenu(S32 x, S32 y, const std::string &url); // create a popup context menu for the given Url

	// Text accessors
	// TODO: add optional style parameter
	virtual void			setText(const LLStringExplicit &utf8str , const LLStyle::Params& input_params = LLStyle::Params()); // uses default style
	virtual std::string		getText() const;
	void					setMaxTextLength(S32 length) { mMaxTextByteLength = length; }
	S32						getMaxTextLength() { return mMaxTextByteLength; }

	// wide-char versions
	void					setWText(const LLWString& text);
	const LLWString&       	getWText() const;

	void					appendText(const std::string &new_text, bool prepend_newline, const LLStyle::Params& input_params = LLStyle::Params());

	void					setLabel(const LLStringExplicit& label);
	virtual BOOL			setLabelArg(const std::string& key, const LLStringExplicit& text );

	const	std::string& 	getLabel()	{ return mLabel.getString(); }
	const	LLWString&		getWlabel() { return mLabel.getWString();}

	void					setLastSegmentToolTip(const std::string &tooltip);

	/**
	 * If label is set, draws text label (which is LLLabelTextSegment)
	 * that is visible when no user text provided
	 */
	void					resetLabel();

	void					setFont(const LLFontGL* font);

	// force reflow of text
	void					needsReflow(S32 index = 0);

	S32						getLength() const { return getWText().length(); }
	S32						getLineCount() const { return mLineInfoList.size(); }
	S32						removeFirstLine(); // returns removed length

	void					addDocumentChild(LLView* view);
	void					removeDocumentChild(LLView* view);
	const LLView*			getDocumentView() const { return mDocumentView; }
	LLRect					getVisibleTextRect() const { return mVisibleTextRect; }
	LLRect					getTextBoundingRect();
	LLRect					getVisibleDocumentRect() const;

	S32						getVPad() { return mVPad; }
	S32						getHPad() { return mHPad; }
	F32						getLineSpacingMult() { return mLineSpacingMult; }
	S32						getLineSpacingPixels() { return mLineSpacingPixels; } // only for multiline

	S32						getDocIndexFromLocalCoord( S32 local_x, S32 local_y, BOOL round, bool hit_past_end_of_line = true) const;
	LLRect					getLocalRectFromDocIndex(S32 pos) const;
	LLRect					getDocRectFromDocIndex(S32 pos) const;

	void					setReadOnly(bool read_only) { mReadOnly = read_only; }
	bool					getReadOnly() { return mReadOnly; }

	void					setSkipLinkUnderline(bool skip_link_underline) { mSkipLinkUnderline = skip_link_underline; }
	bool					getSkipLinkUnderline() { return mSkipLinkUnderline;  }

    void					setParseURLs(bool parse_urls) { mParseHTML = parse_urls; }

	void					setPlainText(bool value) { mPlainText = value;}
	bool					getPlainText() const { return mPlainText; }

	// cursor manipulation
	bool					setCursor(S32 row, S32 column);
	bool					setCursorPos(S32 cursor_pos, bool keep_cursor_offset = false);
	void					startOfLine();
	void					endOfLine();
	void					startOfDoc();
	void					endOfDoc();
	void					changePage( S32 delta );
	void					changeLine( S32 delta );

	bool					scrolledToStart();
	bool					scrolledToEnd();

	const LLFontGL*			getFont() const					{ return mFont; }

	virtual void			appendLineBreakSegment(const LLStyle::Params& style_params);
	virtual void			appendImageSegment(const LLStyle::Params& style_params);
	virtual void			appendWidget(const LLInlineViewSegment::Params& params, const std::string& text, bool allow_undo);
	boost::signals2::connection setURLClickedCallback(const commit_signal_t::slot_type& cb);
	boost::signals2::connection setIsFriendCallback(const is_friend_signal_t::slot_type& cb);
	boost::signals2::connection setIsObjectBlockedCallback(const is_blocked_signal_t::slot_type& cb);

	void					setWordWrap(bool wrap);
	LLScrollContainer*		getScrollContainer() const { return mScroller; }

protected:
	// protected member variables
	// List of offsets and segment index of the start of each line.  Always has at least one node (0).
	struct line_info
	{
		line_info(S32 index_start, S32 index_end, LLRect rect, S32 line_num);
		S32 mDocIndexStart;
		S32 mDocIndexEnd;
		LLRect mRect;
		S32 mLineNum; // actual line count (ignoring soft newlines due to word wrap)
	};
	typedef std::vector<line_info> line_list_t;
	
	// helper structs
	struct compare_bottom
	{
		bool operator()(const S32& a, const line_info& b) const;
		bool operator()(const line_info& a, const S32& b) const;
		bool operator()(const line_info& a, const line_info& b) const;
	};
	struct compare_top
	{
		bool operator()(const S32& a, const line_info& b) const;
		bool operator()(const line_info& a, const S32& b) const;
		bool operator()(const line_info& a, const line_info& b) const;
	};
	struct line_end_compare;
	typedef std::vector<LLTextSegmentPtr> segment_vec_t;

	// Abstract inner base class representing an undoable editor command.
	// Concrete sub-classes can be defined for operations such as insert, remove, etc.
	// Used as arguments to the execute() method below.
	class TextCmd
	{
	public:
		TextCmd( S32 pos, BOOL group_with_next, LLTextSegmentPtr segment = LLTextSegmentPtr() ) 
		:	mPos(pos), 
			mGroupWithNext(group_with_next)
		{
			if (segment.notNull())
			{
				mSegments.push_back(segment);
			}
		}
		virtual			~TextCmd() {}
		virtual BOOL	execute(LLTextBase* editor, S32* delta) = 0;
		virtual S32		undo(LLTextBase* editor) = 0;
		virtual S32		redo(LLTextBase* editor) = 0;
		virtual BOOL	canExtend(S32 pos) const { return FALSE; }
		virtual void	blockExtensions() {}
		virtual BOOL	extendAndExecute( LLTextBase* editor, S32 pos, llwchar c, S32* delta ) { llassert(0); return 0; }
		virtual BOOL	hasExtCharValue( llwchar value ) const { return FALSE; }

		// Defined here so they can access protected LLTextEditor editing methods
		S32				insert(LLTextBase* editor, S32 pos, const LLWString &wstr) { return editor->insertStringNoUndo( pos, wstr, &mSegments ); }
		S32 			remove(LLTextBase* editor, S32 pos, S32 length) { return editor->removeStringNoUndo( pos, length ); }
		S32				overwrite(LLTextBase* editor, S32 pos, llwchar wc) { return editor->overwriteCharNoUndo(pos, wc); }
		
		S32				getPosition() const { return mPos; }
		BOOL			groupWithNext() const { return mGroupWithNext; }
		
	protected:
		const S32			mPos;
		BOOL				mGroupWithNext;
		segment_vec_t		mSegments;
	};

	struct compare_segment_end
	{
		bool operator()(const LLTextSegmentPtr& a, const LLTextSegmentPtr& b) const;
	};
	typedef std::multiset<LLTextSegmentPtr, compare_segment_end> segment_set_t;

	// member functions
	LLTextBase(const Params &p);
	virtual ~LLTextBase();
	void							initFromParams(const Params& p);
    virtual void					beforeValueChange();
	virtual void					onValueChange(S32 start, S32 end);
    virtual bool                    useLabel() const;

	// draw methods
	virtual void					drawSelectionBackground(); // draws the black box behind the selected text
	void							drawCursor();
	void							drawText();

	// modify contents
	S32								insertStringNoUndo(S32 pos, const LLWString &wstr, segment_vec_t* segments = NULL); // returns num of chars actually inserted
	S32 							removeStringNoUndo(S32 pos, S32 length);
	S32								overwriteCharNoUndo(S32 pos, llwchar wc);
	void							appendAndHighlightText(const std::string &new_text, S32 highlight_part, const LLStyle::Params& stylep, bool underline_on_hover_only = false);


	// manage segments 
	void                			getSegmentAndOffset( S32 startpos, segment_set_t::const_iterator* seg_iter, S32* offsetp ) const;
	void                			getSegmentAndOffset( S32 startpos, segment_set_t::iterator* seg_iter, S32* offsetp );
	LLTextSegmentPtr    			getSegmentAtLocalPos( S32 x, S32 y, bool hit_past_end_of_line = true);
	segment_set_t::iterator			getEditableSegIterContaining(S32 index);
	segment_set_t::const_iterator	getEditableSegIterContaining(S32 index) const;
	segment_set_t::iterator			getSegIterContaining(S32 index);
	segment_set_t::const_iterator	getSegIterContaining(S32 index) const;
	void                			clearSegments();
	void							createDefaultSegment();
	virtual void					updateSegments();
	void							insertSegment(LLTextSegmentPtr segment_to_insert);
	const LLStyle::Params&			getStyleParams();

	//  manage lines
	S32								getLineStart( S32 line ) const;
	S32								getLineEnd( S32 line ) const;
	S32								getLineNumFromDocIndex( S32 doc_index, bool include_wordwrap = true) const;
	S32								getLineOffsetFromDocIndex( S32 doc_index, bool include_wordwrap = true) const;
	S32								getFirstVisibleLine() const;
	std::pair<S32, S32>				getVisibleLines(bool fully_visible = false);
	S32								getLeftOffset(S32 width);
	void							reflow();

	// cursor
	void							updateCursorXPos();
	void							setCursorAtLocalPos( S32 local_x, S32 local_y, bool round, bool keep_cursor_offset=false );
	S32								getEditableIndex(S32 index, bool increasing_direction); // constraint cursor to editable segments of document
	void							resetCursorBlink() { mCursorBlinkTimer.reset(); }
	void							updateScrollFromCursor();

	// text selection
	bool							hasSelection() const { return (mSelectionStart !=mSelectionEnd); }
	void 							startSelection();
	void 							endSelection();

	// misc
	void							updateRects();
	void							needsScroll() { mScrollNeeded = TRUE; }

	struct URLLabelCallback;
	// Replace a URL with a new icon and label, for example, when
	// avatar names are looked up.
	void replaceUrl(const std::string &url, const std::string &label, const std::string& icon);
	
	void							appendTextImpl(const std::string &new_text, const LLStyle::Params& input_params = LLStyle::Params());
	void							appendAndHighlightTextImpl(const std::string &new_text, S32 highlight_part, const LLStyle::Params& style_params, bool underline_on_hover_only = false);
	S32 normalizeUri(std::string& uri);
	
protected:
	virtual std::string _getSearchText() const
	{
		return mLabel.getString() + getToolTip();
	}

    std::vector<LLRect> getSelectionRects();

protected:
	// text segmentation and flow
	segment_set_t       		mSegments;
	line_list_t					mLineInfoList;
	LLRect						mVisibleTextRect;			// The rect in which text is drawn.  Excludes borders.
	LLRect						mTextBoundingRect;

	// default text style
	LLStyle::Params				mStyle;
	bool						mStyleDirty;
	const LLFontGL*				mFont;
	const LLFontGL::ShadowType	mFontShadow;

	// colors
	LLUIColor					mCursorColor;
	LLUIColor					mFgColor;
	LLUIColor					mReadOnlyFgColor;
	LLUIColor					mTentativeFgColor;
	LLUIColor					mWriteableBgColor;
	LLUIColor					mReadOnlyBgColor;
	LLUIColor					mFocusBgColor;
	LLUIColor					mTextSelectedColor;
	LLUIColor					mSelectedBGColor;

	// cursor
	S32							mCursorPos;			// I-beam is just after the mCursorPos-th character.
	S32							mDesiredXPixel;		// X pixel position where the user wants the cursor to be
	LLFrameTimer				mCursorBlinkTimer;  // timer that controls cursor blinking

	// selection
	S32							mSelectionStart;
	S32							mSelectionEnd;
	LLTimer		                mTripleClickTimer;
	
	BOOL						mIsSelecting;		// Are we in the middle of a drag-select? 

	// spell checking
	bool						mSpellCheck;
	S32							mSpellCheckStart;
	S32							mSpellCheckEnd;
	LLTimer						mSpellCheckTimer;
	std::list<std::pair<U32, U32> > mMisspellRanges;
	std::vector<std::string>		mSuggestionList;

	// configuration
	S32							mHPad;				// padding on left of text
	S32							mVPad;				// padding above text
	LLFontGL::HAlign			mHAlign;			// horizontal alignment of the document in its entirety
	LLFontGL::VAlign			mVAlign;			// vertical alignment of the document in its entirety
	LLFontGL::VAlign			mTextVAlign;		// vertical alignment of a text segment within a single line of text
	F32							mLineSpacingMult;	// multiple of line height used as space for a single line of text (e.g. 1.5 to get 50% padding)
	S32							mLineSpacingPixels;	// padding between lines
	bool						mBorderVisible;
	bool                		mParseHTML;			// make URLs interactive
	bool						mForceUrlsExternal; // URLs from this textbox will be opened in external browser
	bool						mParseHighlights;	// highlight user-defined keywords
	bool                		mWordWrap;
	bool						mUseEllipses;
	bool						mUseColor;
	bool						mTrackEnd;			// if true, keeps scroll position at end of document during resize
	bool						mReadOnly;
	bool						mBGVisible;			// render background?
	bool						mClip;				// clip text to widget rect
	bool						mClipPartial;		// false if we show lines that are partially inside bounding rect
	bool						mTrustedContent;	// if false, does not allow to execute SURL links from this editor
	bool						mPlainText;			// didn't use Image or Icon segments
	bool						mAutoIndent;
	S32							mMaxTextByteLength;	// Maximum length mText is allowed to be in bytes
	bool						mSkipTripleClick;
	bool						mAlwaysShowIcons;

	bool						mSkipLinkUnderline;

	// support widgets
	LLHandle<LLContextMenu>		mPopupMenuHandle;
	LLView*						mDocumentView;
	LLScrollContainer*			mScroller;

	// transient state
	S32							mReflowIndex;		// index at which to start reflow.  S32_MAX indicates no reflow needed.
	bool						mScrollNeeded;		// need to change scroll region because of change to cursor position
	S32							mScrollIndex;		// index of first character to keep visible in scroll region

	// Fired when a URL link is clicked
	commit_signal_t*			mURLClickSignal;

	// Used to check if user with given ID is avatar's friend
	is_friend_signal_t*         mIsFriendSignal;
	is_blocked_signal_t*        mIsObjectBlockedSignal;

	LLUIString					mLabel;	// text label that is visible when no user text provided
};

#endif