// Copyright (C) 2002-2012 Nikolaus Gebhardt
// This file is part of the "Irrlicht Engine".
// For conditions of distribution and use, see copyright notice in irrlicht.h

#include "CGUIScrollBar.h"

#include "IGUISkin.h"
#include "IGUIEnvironment.h"
#include "IVideoDriver.h"
#include "CGUIButton.h"
#include "IGUIFont.h"
#include "IGUIFontBitmap.h"
#include "os.h"

namespace irr
{
namespace gui
{


//! constructor
CGUIScrollBar::CGUIScrollBar(bool horizontal, IGUIEnvironment* environment,
				IGUIElement* parent, s32 id,
				core::rect<s32> rectangle, bool noclip)
	: IGUIScrollBar(environment, parent, id, rectangle), UpButton(0),
	DownButton(0), Dragging(false), Horizontal(horizontal),
	DraggedBySlider(false), TrayClick(false), Pos(0), DrawPos(0),
	DrawHeight(0), Min(0), Max(100), SmallStep(10), LargeStep(50), DesiredPos(0),
	LastChange(0)
{
	#ifdef _DEBUG
	setDebugName("CGUIScrollBar");
	#endif

	refreshControls();

	setNotClipped(noclip);

	// this element can be tabbed to
	setTabStop(true);
	setTabOrder(-1);

	setPos(0);
}


//! destructor
CGUIScrollBar::~CGUIScrollBar()
{
	if (UpButton)
		UpButton->drop();

	if (DownButton)
		DownButton->drop();
}


//! called if an event happened.
bool CGUIScrollBar::OnEvent(const SEvent& event)
{
	if (isEnabled())
	{

		switch(event.EventType)
		{
		case EET_KEY_INPUT_EVENT:
			if (event.KeyInput.PressedDown)
			{
				const s32 oldPos = Pos;
				bool absorb = true;
				switch (event.KeyInput.Key)
				{
				case KEY_LEFT:
				case KEY_UP:
					setPos(Pos-SmallStep);
					break;
				case KEY_RIGHT:
				case KEY_DOWN:
					setPos(Pos+SmallStep);
					break;
				case KEY_HOME:
					setPos(Min);
					break;
				case KEY_PRIOR:
					setPos(Pos-LargeStep);
					break;
				case KEY_END:
					setPos(Max);
					break;
				case KEY_NEXT:
					setPos(Pos+LargeStep);
					break;
				default:
					absorb = false;
				}

				if (Pos != oldPos)
				{
					SEvent newEvent;
					newEvent.EventType = EET_GUI_EVENT;
					newEvent.GUIEvent.Caller = this;
					newEvent.GUIEvent.Element = 0;
					newEvent.GUIEvent.EventType = EGET_SCROLL_BAR_CHANGED;
					Parent->OnEvent(newEvent);
				}
				if (absorb)
					return true;
			}
			break;
		case EET_GUI_EVENT:
			if (event.GUIEvent.EventType == EGET_BUTTON_CLICKED)
			{
				if (event.GUIEvent.Caller == UpButton)
					setPos(Pos-SmallStep);
				else
				if (event.GUIEvent.Caller == DownButton)
					setPos(Pos+SmallStep);

				SEvent newEvent;
				newEvent.EventType = EET_GUI_EVENT;
				newEvent.GUIEvent.Caller = this;
				newEvent.GUIEvent.Element = 0;
				newEvent.GUIEvent.EventType = EGET_SCROLL_BAR_CHANGED;
				Parent->OnEvent(newEvent);

				return true;
			}
			else
			if (event.GUIEvent.EventType == EGET_ELEMENT_FOCUS_LOST)
			{
				if (event.GUIEvent.Caller == this)
					Dragging = false;
			}
			break;
		case EET_MOUSE_INPUT_EVENT:
		{
			const core::position2di p(event.MouseInput.X, event.MouseInput.Y);
			bool isInside = isPointInside ( p );
			switch(event.MouseInput.Event)
			{
			case EMIE_MOUSE_WHEEL:
				if (Environment->hasFocus(this))
				{
					// thanks to a bug report by REAPER
					// thanks to tommi by tommi for another bugfix
					// everybody needs a little thanking. hallo niko!;-)
					setPos(	getPos() +
							( (event.MouseInput.Wheel < 0 ? -1 : 1) * SmallStep * (Horizontal ? 1 : -1 ) )
							);

					SEvent newEvent;
					newEvent.EventType = EET_GUI_EVENT;
					newEvent.GUIEvent.Caller = this;
					newEvent.GUIEvent.Element = 0;
					newEvent.GUIEvent.EventType = EGET_SCROLL_BAR_CHANGED;
					Parent->OnEvent(newEvent);
					return true;
				}
				break;
			case EMIE_LMOUSE_PRESSED_DOWN:
			{
				if (isInside)
				{
					Dragging = true;
					DraggedBySlider = SliderRect.isPointInside(p);
					TrayClick = !DraggedBySlider;
					DesiredPos = getPosFromMousePos(p);
					return true;
				}
				break;
			}
			case EMIE_LMOUSE_LEFT_UP:
			case EMIE_MOUSE_MOVED:
			{
				if ( !event.MouseInput.isLeftPressed () )
					Dragging = false;

				if ( !Dragging )
				{
					if ( event.MouseInput.Event == EMIE_MOUSE_MOVED )
						break;
					return isInside;
				}

				if ( event.MouseInput.Event == EMIE_LMOUSE_LEFT_UP )
					Dragging = false;

				const s32 newPos = getPosFromMousePos(p);
				const s32 oldPos = Pos;

				if (!DraggedBySlider)
				{
					if ( isInside )
					{
						DraggedBySlider = SliderRect.isPointInside(p);
						TrayClick = !DraggedBySlider;
					}

					if (DraggedBySlider)
					{
						setPos(newPos);
					}
					else
					{
						TrayClick = false;
						if (event.MouseInput.Event == EMIE_MOUSE_MOVED)
							return isInside;
					}
				}

				if (DraggedBySlider)
				{
					setPos(newPos);
				}
				else
				{
					DesiredPos = newPos;
				}

				if (Pos != oldPos && Parent)
				{
					SEvent newEvent;
					newEvent.EventType = EET_GUI_EVENT;
					newEvent.GUIEvent.Caller = this;
					newEvent.GUIEvent.Element = 0;
					newEvent.GUIEvent.EventType = EGET_SCROLL_BAR_CHANGED;
					Parent->OnEvent(newEvent);
				}
				return isInside;
			} break;

			default:
				break;
			}
		} break;
		default:
			break;
		}
	}

	return IGUIElement::OnEvent(event);
}

void CGUIScrollBar::OnPostRender(u32 timeMs)
{
	if (Dragging && !DraggedBySlider && TrayClick && timeMs > LastChange + 200)
	{
		LastChange = timeMs;

		const s32 oldPos = Pos;

		if (DesiredPos >= Pos + LargeStep)
			setPos(Pos + LargeStep);
		else
		if (DesiredPos <= Pos - LargeStep)
			setPos(Pos - LargeStep);
		else
		if (DesiredPos >= Pos - LargeStep && DesiredPos <= Pos + LargeStep)
			setPos(DesiredPos);

		if (Pos != oldPos && Parent)
		{
			SEvent newEvent;
			newEvent.EventType = EET_GUI_EVENT;
			newEvent.GUIEvent.Caller = this;
			newEvent.GUIEvent.Element = 0;
			newEvent.GUIEvent.EventType = EGET_SCROLL_BAR_CHANGED;
			Parent->OnEvent(newEvent);
		}
	}

}

//! draws the element and its children
void CGUIScrollBar::draw()
{
	if (!IsVisible)
		return;

	IGUISkin* skin = Environment->getSkin();
	if (!skin)
		return;


	video::SColor iconColor = skin->getColor(isEnabled() ? EGDC_WINDOW_SYMBOL : EGDC_GRAY_WINDOW_SYMBOL);
	if ( iconColor != CurrentIconColor )
	{
		refreshControls();
	}


	SliderRect = AbsoluteRect;

	// draws the background
	skin->draw2DRectangle(this, skin->getColor(EGDC_SCROLLBAR), SliderRect, &AbsoluteClippingRect);

	if ( core::isnotzero ( range() ) )
	{
		// recalculate slider rectangle
		if (Horizontal)
		{
			SliderRect.UpperLeftCorner.X = AbsoluteRect.UpperLeftCorner.X + DrawPos + RelativeRect.getHeight() - DrawHeight/2;
			SliderRect.LowerRightCorner.X = SliderRect.UpperLeftCorner.X + DrawHeight;
		}
		else
		{
			SliderRect.UpperLeftCorner.Y = AbsoluteRect.UpperLeftCorner.Y + DrawPos + RelativeRect.getWidth() - DrawHeight/2;
			SliderRect.LowerRightCorner.Y = SliderRect.UpperLeftCorner.Y + DrawHeight;
		}

		skin->draw3DButtonPaneStandard(this, SliderRect, &AbsoluteClippingRect);
	}

	// draw buttons
	IGUIElement::draw();
}


void CGUIScrollBar::updateAbsolutePosition()
{
	IGUIElement::updateAbsolutePosition();
	// todo: properly resize
	refreshControls();
	setPos ( Pos );
}

//!
s32 CGUIScrollBar::getPosFromMousePos(const core::position2di &pos) const
{
	f32 w, p;
	if (Horizontal)
	{
		w = RelativeRect.getWidth() - f32(RelativeRect.getHeight())*3.0f;
		p = pos.X - AbsoluteRect.UpperLeftCorner.X - RelativeRect.getHeight()*1.5f;
	}
	else
	{
		w = RelativeRect.getHeight() - f32(RelativeRect.getWidth())*3.0f;
		p = pos.Y - AbsoluteRect.UpperLeftCorner.Y - RelativeRect.getWidth()*1.5f;
	}
	return (s32) ( p/w * range() ) + Min;
}


//! sets the position of the scrollbar
void CGUIScrollBar::setPos(s32 pos)
{
	Pos = core::s32_clamp ( pos, Min, Max );

	if ( core::isnotzero ( range() ) )
	{
		if (Horizontal)
		{
			f32 f = (RelativeRect.getWidth() - ((f32)RelativeRect.getHeight()*3.0f)) / range();
			DrawPos = (s32)( ( ( Pos - Min ) * f) + ((f32)RelativeRect.getHeight() * 0.5f));
			DrawHeight = RelativeRect.getHeight();
		}
		else
		{
			f32 f = (RelativeRect.getHeight() - ((f32)RelativeRect.getWidth()*3.0f)) / range();

			DrawPos = (s32)( ( ( Pos - Min ) * f) + ((f32)RelativeRect.getWidth() * 0.5f));
			DrawHeight = RelativeRect.getWidth();
		}
	}
}


//! gets the small step value
s32 CGUIScrollBar::getSmallStep() const
{
	return SmallStep;
}


//! sets the small step value
void CGUIScrollBar::setSmallStep(s32 step)
{
	if (step > 0)
		SmallStep = step;
	else
		SmallStep = 10;
}


//! gets the small step value
s32 CGUIScrollBar::getLargeStep() const
{
	return LargeStep;
}


//! sets the small step value
void CGUIScrollBar::setLargeStep(s32 step)
{
	if (step > 0)
		LargeStep = step;
	else
		LargeStep = 50;
}


//! gets the maximum value of the scrollbar.
s32 CGUIScrollBar::getMax() const
{
	return Max;
}


//! sets the maximum value of the scrollbar.
void CGUIScrollBar::setMax(s32 max)
{
	Max = max;
	if ( Min > Max )
		Min = Max;

	bool enable = core::isnotzero ( range() );
	UpButton->setEnabled(enable);
	DownButton->setEnabled(enable);
	setPos(Pos);
}

//! gets the minimum value of the scrollbar.
s32 CGUIScrollBar::getMin() const
{
	return Min;
}


//! sets the minimum value of the scrollbar.
void CGUIScrollBar::setMin(s32 min)
{
	Min = min;
	if ( Max < Min )
		Max = Min;


	bool enable = core::isnotzero ( range() );
	UpButton->setEnabled(enable);
	DownButton->setEnabled(enable);
	setPos(Pos);
}


//! gets the current position of the scrollbar
s32 CGUIScrollBar::getPos() const
{
	return Pos;
}


//! refreshes the position and text on child buttons
void CGUIScrollBar::refreshControls()
{
	CurrentIconColor = video::SColor(255,255,255,255);

	IGUISkin* skin = Environment->getSkin();
	IGUISpriteBank* sprites = 0;

	if (skin)
	{
		sprites = skin->getSpriteBank();
		CurrentIconColor = skin->getColor(isEnabled() ? EGDC_WINDOW_SYMBOL : EGDC_GRAY_WINDOW_SYMBOL);
	}

	if (Horizontal)
	{
		const s32 h = RelativeRect.getHeight();
		const s32 w = (h < RelativeRect.getWidth() / 2) ? h : RelativeRect.getWidth() / 2;
		if (!UpButton)
		{
			UpButton = new CGUIButton(Environment, this, -1, core::rect<s32>(0,0, w, h), NoClip);
			UpButton->setSubElement(true);
			UpButton->setTabStop(false);
		}
		if (sprites)
		{
			UpButton->setSpriteBank(sprites);
			UpButton->setSprite(EGBS_BUTTON_UP, skin->getIcon(EGDI_CURSOR_LEFT), CurrentIconColor);
			UpButton->setSprite(EGBS_BUTTON_DOWN, skin->getIcon(EGDI_CURSOR_LEFT), CurrentIconColor);
		}
		UpButton->setRelativePosition(core::rect<s32>(0,0, w, h));
		UpButton->setAlignment(EGUIA_UPPERLEFT, EGUIA_UPPERLEFT, EGUIA_UPPERLEFT, EGUIA_LOWERRIGHT);
		if (!DownButton)
		{
			DownButton = new CGUIButton(Environment, this, -1, core::rect<s32>(RelativeRect.getWidth()-w, 0, RelativeRect.getWidth(), h), NoClip);
			DownButton->setSubElement(true);
			DownButton->setTabStop(false);
		}
		if (sprites)
		{
			DownButton->setSpriteBank(sprites);
			DownButton->setSprite(EGBS_BUTTON_UP, skin->getIcon(EGDI_CURSOR_RIGHT), CurrentIconColor);
			DownButton->setSprite(EGBS_BUTTON_DOWN, skin->getIcon(EGDI_CURSOR_RIGHT), CurrentIconColor);
		}
		DownButton->setRelativePosition(core::rect<s32>(RelativeRect.getWidth()-w, 0, RelativeRect.getWidth(), h));
		DownButton->setAlignment(EGUIA_LOWERRIGHT, EGUIA_LOWERRIGHT, EGUIA_UPPERLEFT, EGUIA_LOWERRIGHT);
	}
	else
	{
		const s32 w = RelativeRect.getWidth();
		const s32 h = (w < RelativeRect.getHeight() / 2) ? w : RelativeRect.getHeight() / 2;
		if (!UpButton)
		{
			UpButton = new CGUIButton(Environment, this, -1, core::rect<s32>(0,0, w, h), NoClip);
			UpButton->setSubElement(true);
			UpButton->setTabStop(false);
		}
		if (sprites)
		{
			UpButton->setSpriteBank(sprites);
			UpButton->setSprite(EGBS_BUTTON_UP, skin->getIcon(EGDI_CURSOR_UP), CurrentIconColor);
			UpButton->setSprite(EGBS_BUTTON_DOWN, skin->getIcon(EGDI_CURSOR_UP), CurrentIconColor);
		}
		UpButton->setRelativePosition(core::rect<s32>(0,0, w, h));
		UpButton->setAlignment(EGUIA_UPPERLEFT, EGUIA_LOWERRIGHT, EGUIA_UPPERLEFT, EGUIA_UPPERLEFT);
		if (!DownButton)
		{
			DownButton = new CGUIButton(Environment, this, -1, core::rect<s32>(0,RelativeRect.getHeight()-h, w, RelativeRect.getHeight()), NoClip);
			DownButton->setSubElement(true);
			DownButton->setTabStop(false);
		}
		if (sprites)
		{
			DownButton->setSpriteBank(sprites);
			DownButton->setSprite(EGBS_BUTTON_UP, skin->getIcon(EGDI_CURSOR_DOWN), CurrentIconColor);
			DownButton->setSprite(EGBS_BUTTON_DOWN, skin->getIcon(EGDI_CURSOR_DOWN), CurrentIconColor);
		}
		DownButton->setRelativePosition(core::rect<s32>(0,RelativeRect.getHeight()-h, w, RelativeRect.getHeight()));
		DownButton->setAlignment(EGUIA_UPPERLEFT, EGUIA_LOWERRIGHT, EGUIA_LOWERRIGHT, EGUIA_LOWERRIGHT);
	}
}

} // end namespace gui
} // end namespace irr
