/**
 *
 * Copyright (c) 2021, Kitty Barnett
 *
 * The source code in this file is provided to you under the terms of the
 * GNU Lesser General Public License, version 2.1, but WITHOUT ANY WARRANTY;
 * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
 * PARTICULAR PURPOSE. Terms of the LGPL can be found in doc/LGPL-licence.txt
 * in this distribution, or online at http://www.gnu.org/licenses/lgpl-2.1.txt
 *
 * By copying, modifying or distributing this software, you acknowledge that
 * you have read and understood your obligations described above, and agree to
 * abide by those obligations.
 *
 */

#include "llviewerprecompiledheaders.h"

#include "llvisualeffect.h"

#include <boost/iterator/filter_iterator.hpp>
#include <boost/range/iterator_range.hpp>

// ============================================================================
// LLTweenableValue class
//

template<>
float LLTweenableValueLerp<float>::get()
{
	if (!m_CurValue)
	{
		float curFactor = (LLTimer::getElapsedSeconds() - m_StartTime) / m_Duration;
		if (curFactor < 1.0)
			return lerp(m_StartValue, m_EndValue, curFactor);
		m_CurValue = m_EndValue;
	}
	return m_CurValue.get();
}

template<>
LLColor3 LLTweenableValueLerp<LLColor3>::get()
{
	if (!m_CurValue)
	{
		float curFactor = (LLTimer::getElapsedSeconds() - m_StartTime) / m_Duration;
		if (curFactor < 1.0)
			return lerp(m_StartValue, m_EndValue, curFactor);
		m_CurValue = m_EndValue;
	}
	return m_CurValue.get();
}

template<>
LLVector4 LLTweenableValueLerp<LLVector4>::get()
{
	if (!m_CurValue)
	{
		float curFactor = (LLTimer::getElapsedSeconds() - m_StartTime) / m_Duration;
		if (curFactor < 1.0)
			return lerp(m_StartValue, m_EndValue, curFactor);
		m_CurValue = m_EndValue;
	}
	return m_CurValue.get();
}

// ============================================================================
// LLVfxManager class
//

LLVfxManager::LLVfxManager()
{
}

bool LLVfxManager::addEffect(LLVisualEffect* pEffectInst)
{
	// Effect IDs can be reused across effects but should be unique for all effect instances sharing the same effect code
	auto itEffect = std::find_if(m_Effects.begin(), m_Effects.end(), [pEffectInst](const LLVisualEffect* pEffect) { return pEffect->getCode() == pEffectInst->getCode() && pEffect->getId() == pEffectInst->getId(); });
	llassert(m_Effects.end() == itEffect);
	if (m_Effects.end() != itEffect)
		return false;

	m_Effects.insert(std::upper_bound(m_Effects.begin(), m_Effects.end(), pEffectInst, cmpEffect), pEffectInst);
	return true;
}

LLVisualEffect* LLVfxManager::getEffect(EVisualEffect eCode, const LLUUID& idEffect) const
{
	auto itEffect = std::find_if(m_Effects.begin(), m_Effects.end(), [eCode, &idEffect](const LLVisualEffect* pEffect) { return pEffect->getCode() == eCode && pEffect->getId() == idEffect; });
	return (m_Effects.end() != itEffect) ? *itEffect : nullptr;
}

bool LLVfxManager::getEffects(std::list<LLVisualEffect*>& effectList, std::function<bool(const LLVisualEffect*)> fnFilter)
{
	effectList.clear();

	auto itEffect  = boost::make_filter_iterator(fnFilter, m_Effects.begin(), m_Effects.end()),
	     endEffect = boost::make_filter_iterator(fnFilter, m_Effects.end(), m_Effects.end());
	while (itEffect != endEffect)
	{
		effectList.push_back(*itEffect++);
	}

	return effectList.size();
}

bool LLVfxManager::removeEffect(EVisualEffect eCode, const LLUUID& idEffect)
{
	auto itEffect = std::find_if(m_Effects.begin(), m_Effects.end(), [eCode, &idEffect](const LLVisualEffect* pEffect) { return pEffect->getCode() == eCode && pEffect->getId() == idEffect; });
	if (m_Effects.end() == itEffect)
		return false;

	delete *itEffect;
	m_Effects.erase(itEffect);
	return true;
}

void LLVfxManager::runEffect(EVisualEffect eCode, LLVisualEffectParams* pParams)
{
	runEffect([eCode](const LLVisualEffect* pEffect) { return pEffect->getCode() == eCode; }, pParams);
}

void LLVfxManager::runEffect(EVisualEffectType eType, LLVisualEffectParams* pParams)
{
	runEffect([eType](const LLVisualEffect* pEffect) { return pEffect->getType() == eType; }, pParams);
}

void LLVfxManager::runEffect(std::function<bool(const LLVisualEffect*)> predicate, LLVisualEffectParams* pParams)
{
	// *TODO-Catz: once we're done, check whether iterating over the entire list still has negliable impact
	auto itEffect  = boost::make_filter_iterator(predicate, m_Effects.begin(), m_Effects.end()),
	     endEffect = boost::make_filter_iterator(predicate, m_Effects.end(), m_Effects.end());
	while (itEffect != endEffect)
	{
		LLVisualEffect* pEffect = *itEffect++;
		if (pEffect->getEnabled())
		{
			if (pParams)
				pParams->step(itEffect == endEffect);
			pEffect->run(pParams);
		}
	}
}

void  LLVfxManager::updateEffect(LLVisualEffect* pEffect, bool fEnabled, U32 nPriority)
{
	llassert(m_Effects.end() != std::find(m_Effects.begin(), m_Effects.end(), pEffect));

	if ( (pEffect->getEnabled() != fEnabled) || (pEffect->getPriority() != nPriority) )
	{
		pEffect->setEnabled(fEnabled);
		pEffect->setPriority(nPriority);
		std::sort(m_Effects.begin(), m_Effects.end(), cmpEffect);
	}
}

// static
bool LLVfxManager::cmpEffect(const LLVisualEffect* pLHS, const LLVisualEffect* pRHS)
{
	if (pLHS && pRHS)
	{
		// Sort by code, then priority, then memory address
		return (pLHS->getCode() == pRHS->getCode()) ? (pLHS->getPriority() == pRHS->getPriority() ? pLHS < pRHS
		                                                                                          : pLHS->getPriority() > pRHS->getPriority())
			                                        : pLHS->getCode() < pRHS->getCode();
	}
	return (pLHS);
}

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