/*
--------------------------------------------------------------------------------
This source file is part of SkyX.
Visit http://www.paradise-studios.net/products/skyx/

Copyright (C) 2009-2011 Xavier Verguín González <xavyiy@gmail.com>

This program 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; either version 2 of the License, or (at your option) any later
version.

This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along with
this program; if not, write to the Free Software Foundation, Inc., 59 Temple
Place - Suite 330, Boston, MA 02111-1307, USA, or go to
http://www.gnu.org/copyleft/lesser.txt.
--------------------------------------------------------------------------------
*/

#include "MoonManager.h"

#include "SkyX.h"

namespace SkyX
{
	MoonManager::MoonManager(SkyX *s)
		: mSkyX(s)
		, mMoonBillboard(0)
		, mMoonSceneNode(0)
		, mCreated(false)
		, mMoonSize(0.225f)
		, mMoonHaloIntensity(0.4f)
		, mMoonHaloStrength(0.9f)
	{
	}

	MoonManager::~MoonManager()
	{
		remove();
	}

	void MoonManager::create()
	{
		if (mCreated)
		{
			return;
		}

		mMoonSceneNode = mSkyX->getSceneManager()->getRootSceneNode()->createChildSceneNode();

		mMoonBillboard = mSkyX->getSceneManager()->createBillboardSet("SkyXMoonBillboardSet", 1);
        mMoonBillboard->setMaterialName(mSkyX->getGPUManager()->getMoonMaterialName());
		mMoonBillboard->setBillboardType(Ogre::BBT_ORIENTED_COMMON);
		mMoonBillboard->setRenderQueueGroup(Ogre::RENDER_QUEUE_SKIES_EARLY+1);
		mMoonBillboard->setCastShadows(false);

		mMoonBillboard->createBillboard(Ogre::Vector3(0,0,0));

		mMoonSceneNode->attachObject(mMoonBillboard);

		mCreated = true;
	}

	void MoonManager::remove()
	{
		if (!mCreated)
		{
			return;
		}

		mMoonSceneNode->detachAllObjects();
		mMoonSceneNode->getParentSceneNode()->removeAndDestroyChild(mMoonSceneNode->getName());
		mMoonSceneNode = 0;

		mSkyX->getSceneManager()->destroyBillboardSet(mMoonBillboard);
		mMoonBillboard = 0;

		mCreated = false;
	}

	void MoonManager::updateMoonPhase(const Ogre::Real& phase)
	{
		Ogre::Real center = 0, radius = 0, radius_add = 0, interpolation = 0, halo_flip = 0;

		Ogre::Vector3 halo1, halo2;

		// [-1, 0]
		if (phase < 0)
		{
			// [-1, -0.5]
			if (phase < -0.5)
			{
				center = (1+phase)/2;
				radius = 0.25;

				interpolation = center*4;

				if (interpolation < 1.0f/3)
				{
					interpolation /= 1.0f/3;
					halo1 = Ogre::Vector3(0.25, 0.5, (1-interpolation)*interpolation);
					halo2 = Ogre::Vector3(0.25, 0.5, interpolation);
				}
				else if (interpolation < 2.0f/3)
				{
					interpolation -= 1.0f/3;
					interpolation /= 1.0f/3;
					halo1 = Ogre::Vector3(0.25, 0.5, 1-interpolation);
					halo2 = Ogre::Vector3(0.0, 0.5, interpolation);
				}
				else
				{
					interpolation -= 2.0f/3;
					interpolation /= 1.0f/3;
					halo1 = Ogre::Vector3(0.0, 0.5, 1-interpolation);
					halo2 = Ogre::Vector3(0.75, 0.0, interpolation);
				}

				radius_add =  0.1*center/(0.25001-center);

				radius += radius_add;
				center += radius_add;
			}
			// [-0.5, 0]
			else
			{
				center = (-phase)/2;
				radius = 0.25;

				interpolation = 1-center*4;

				if (interpolation < 1.0f/3)
				{
					interpolation /= 1.0f/3;
					halo1 = Ogre::Vector3(0.75, 0.0, 1-interpolation);
					halo2 = Ogre::Vector3(0.5, 0.0, interpolation);
				}
				else if (interpolation < 2.0f/3)
				{
					interpolation -= 1.0f/3;
					interpolation /= 1.0f/3;
					halo1 = Ogre::Vector3(0.5, 0.0, 1-interpolation);
					halo2 = Ogre::Vector3(0.25, 0.0, interpolation);
				}
				else
				{
					interpolation -= 2.0f/3;
					interpolation /= 1.0f/3;
					halo1 = Ogre::Vector3(0.25, 0.0, 1-interpolation);
					halo2 = Ogre::Vector3(0.00, 0.0, interpolation);
				}

				radius_add =  0.1*center/(0.25001-center);

				radius += radius_add;
				center += radius_add;

				radius = -radius;
				center = -center;
			}
		}
		// [0, 1]
		else
		{
			halo_flip = 1;

			// [0, 0.5]
			if (phase < 0.5)
			{
				center = phase/2;
				radius = 0.25;

				interpolation = center*4;

				if (interpolation < 1.0f/3)
				{
					interpolation /= 1.0f/3;
					halo1 = Ogre::Vector3(0.00, 0.0, 1-interpolation);
					halo2 = Ogre::Vector3(0.25, 0.0, interpolation);
				}
				else if (interpolation < 2.0f/3)
				{
					interpolation -= 1.0f/3;
					interpolation /= 1.0f/3;
					halo1 = Ogre::Vector3(0.25, 0.0, 1-interpolation);
					halo2 = Ogre::Vector3(0.5, 0.0, interpolation);
				}
				else
				{
					interpolation -= 2.0f/3;
					interpolation /= 1.0f/3;
					halo1 = Ogre::Vector3(0.5, 0.0, 1-interpolation);
					halo2 = Ogre::Vector3(0.75, 0.0, interpolation);
				}

				radius_add =  0.1*center/(0.25001-center);

				radius += radius_add;
				center += radius_add;

				radius = -radius;
				center = center;
			}
			// [0.5, 1]
			else
			{
				center = (1-phase)/2;
				radius = 0.25;

				interpolation = 1-center*4;

				if (interpolation < 1.0f/3)
				{
					interpolation /= 1.0f/3;
					halo1 = Ogre::Vector3(0.75, 0.0, 1-interpolation);
					halo2 = Ogre::Vector3(0.0, 0.5, interpolation);
				}
				else if (interpolation < 2.0f/3)
				{
					interpolation -= 1.0f/3;
					interpolation /= 1.0f/3;
					halo1 = Ogre::Vector3(0.0, 0.5, 1-interpolation);
					halo2 = Ogre::Vector3(0.25, 0.5, interpolation);
				}
				else
				{
					interpolation -= 2.0f/3;
					interpolation /= 1.0f/3;
					halo1 = Ogre::Vector3(0.25, 0.5, 1-interpolation);
					halo2 = Ogre::Vector3(0.25, 0.5, (1-interpolation)*interpolation);
				}

				radius_add =  0.1*center/(0.25001-center);

				radius += radius_add;
				center += radius_add;

				center = -center;
			}
		}

		static_cast<Ogre::MaterialPtr>(
			Ogre::MaterialManager::getSingleton().getByName("SkyX_Moon"))
				->getTechnique(0)->getPass(0)->getFragmentProgramParameters()->setNamedConstant("uMoonPhase", Ogre::Vector3(radius, center + 0.5f, mMoonHaloStrength));

		halo1.z *= mMoonHaloIntensity;
		halo2.z *= mMoonHaloIntensity;

		static_cast<Ogre::MaterialPtr>(
			Ogre::MaterialManager::getSingleton().getByName("SkyX_Moon"))
				->getTechnique(0)->getPass(0)->getFragmentProgramParameters()->setNamedConstant("uMoonHalo1", halo1);
		static_cast<Ogre::MaterialPtr>(
			Ogre::MaterialManager::getSingleton().getByName("SkyX_Moon"))
				->getTechnique(0)->getPass(0)->getFragmentProgramParameters()->setNamedConstant("uMoonHalo2", halo2);
		static_cast<Ogre::MaterialPtr>(
			Ogre::MaterialManager::getSingleton().getByName("SkyX_Moon"))
				->getTechnique(0)->getPass(0)->getFragmentProgramParameters()->setNamedConstant("uMoonHaloFlip", halo_flip);
	}

	void MoonManager::updateGeometry(Ogre::Camera* c)
	{
		if (!mCreated)
		{
			return;
		}

    // Handling infinite far clip
    Ogre::Real cameraCurrentFarClipDistance = c->getFarClipDistance();
    if(cameraCurrentFarClipDistance == 0)
      cameraCurrentFarClipDistance = SKYX_INFINITE_FAR_CLIP_DEFAULT_DISTANCE;

		float radius = cameraCurrentFarClipDistance*0.95f,
              size = radius*mMoonSize;

		mMoonBillboard->setCommonDirection((mSkyX->getController()->getMoonDirection()).normalisedCopy().perpendicular());

		Ogre::Vector3 moonRelativePos = mSkyX->getController()->getMoonDirection()*
			Ogre::Math::Cos(Ogre::Math::ASin((size/2)/radius))*radius;

		mMoonSceneNode->setPosition(c->getDerivedPosition() + moonRelativePos);

		if (moonRelativePos.y < -size/2)
		{
			mMoonSceneNode->setVisible(false);
		}
		else
		{
			mMoonSceneNode->setVisible(mSkyX->isVisible());

			static_cast<Ogre::MaterialPtr>(Ogre::MaterialManager::getSingleton().getByName("SkyX_Moon"))->getTechnique(0)->getPass(0)
				->getVertexProgramParameters()->setNamedConstant("uSkydomeCenter", c->getDerivedPosition());
		}

		if (mMoonBillboard->getBoundingBox().getMaximum().x != size)
		{
			_updateMoonBounds(c);
		}
	}

	void MoonManager::_updateMoonBounds(Ogre::Camera* c)
	{
    // Handling infinite far clip
    Ogre::Real cameraCurrentFarClipDistance = c->getFarClipDistance();
    if(cameraCurrentFarClipDistance == 0)
      cameraCurrentFarClipDistance = SKYX_INFINITE_FAR_CLIP_DEFAULT_DISTANCE;

		float radius = cameraCurrentFarClipDistance*0.95f,
              size = radius*mMoonSize;

		mMoonBillboard->setDefaultDimensions(size, size);
		mMoonBillboard->setBounds(Ogre::AxisAlignedBox(-size/2, -size/2, -size/2,
														size/2,  size/2,  size/2), 1);
		mMoonSceneNode->_updateBounds();
	}
}