/*
Open Asset Import Library (ASSIMP)
----------------------------------------------------------------------

Copyright (c) 2006-2010, ASSIMP Development Team
All rights reserved.

Redistribution and use of this software in source and binary forms, 
with or without modification, are permitted provided that the 
following conditions are met:

* Redistributions of source code must retain the above
  copyright notice, this list of conditions and the
  following disclaimer.

* Redistributions in binary form must reproduce the above
  copyright notice, this list of conditions and the
  following disclaimer in the documentation and/or other
  materials provided with the distribution.

* Neither the name of the ASSIMP team, nor the names of its
  contributors may be used to endorse or promote products
  derived from this software without specific prior
  written permission of the ASSIMP Development Team.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 
OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

----------------------------------------------------------------------
*/

/** @file  LWOAnimation.cpp
 *  @brief LWOAnimationResolver utility class 
 *
 *  It's a very generic implementation of LightWave's system of
 *  componentwise-animated stuff. The one and only fully free
 *  implementation of LightWave envelopes of which I know.
*/

#include "AssimpPCH.h"
#if (!defined ASSIMP_BUILD_NO_LWO_IMPORTER) && (!defined ASSIMP_BUILD_NO_LWS_IMPORTER)

// internal headers
#include "LWOFileData.h"

using namespace Assimp;
using namespace Assimp::LWO;

// ------------------------------------------------------------------------------------------------
// Construct an animation resolver from a given list of envelopes
AnimResolver::AnimResolver(std::list<Envelope>& _envelopes,double tick)
	: envelopes   (_envelopes)
	, sample_rate (0.)
{
	trans_x = trans_y = trans_z = NULL;
	rotat_x = rotat_y = rotat_z = NULL;
	scale_x = scale_y = scale_z = NULL;

	first = last = 150392.;

	// find transformation envelopes
	for (std::list<LWO::Envelope>::iterator it = envelopes.begin(); it != envelopes.end(); ++it) {

		(*it).old_first = 0;
		(*it).old_last  = (*it).keys.size()-1;

		if ((*it).keys.empty()) continue;
		switch ((*it).type) {

			// translation
			case LWO::EnvelopeType_Position_X:
				trans_x = &*it;break;
			case LWO::EnvelopeType_Position_Y:
				trans_y = &*it;break;
			case LWO::EnvelopeType_Position_Z:
				trans_z = &*it;break;

				// rotation
			case LWO::EnvelopeType_Rotation_Heading:
				rotat_x = &*it;break;
			case LWO::EnvelopeType_Rotation_Pitch:
				rotat_y = &*it;break;
			case LWO::EnvelopeType_Rotation_Bank:
				rotat_z = &*it;break;

				// scaling
			case LWO::EnvelopeType_Scaling_X:
				scale_x = &*it;break;
			case LWO::EnvelopeType_Scaling_Y:
				scale_y = &*it;break;
			case LWO::EnvelopeType_Scaling_Z:
				scale_z = &*it;break;
			default:
				continue;
		};

		// convert from seconds to ticks
		for (std::vector<LWO::Key>::iterator d = (*it).keys.begin(); d != (*it).keys.end(); ++d)
			(*d).time *= tick;

		// set default animation range (minimum and maximum time value for which we have a keyframe)
		first = std::min(first, (*it).keys.front().time );
		last  = std::max(last,  (*it).keys.back().time );
	}

	// deferred setup of animation range to increase performance.
	// typically the application will want to specify its own.
	need_to_setup = true;
}

// ------------------------------------------------------------------------------------------------
// Reset all envelopes to their original contents
void AnimResolver::ClearAnimRangeSetup()
{
	for (std::list<LWO::Envelope>::iterator it = envelopes.begin(); it != envelopes.end(); ++it) {
		
		(*it).keys.erase((*it).keys.begin(),(*it).keys.begin()+(*it).old_first);
		(*it).keys.erase((*it).keys.begin()+(*it).old_last+1,(*it).keys.end());
	}
}

// ------------------------------------------------------------------------------------------------
// Insert additional keys to match LWO's pre& post behaviours.
void AnimResolver::UpdateAnimRangeSetup()
{
	// XXX doesn't work yet (hangs if more than one envelope channels needs to be interpolated)

	for (std::list<LWO::Envelope>::iterator it = envelopes.begin(); it != envelopes.end(); ++it) {
		if ((*it).keys.empty()) continue;
	
		const double my_first = (*it).keys.front().time;
		const double my_last  = (*it).keys.back().time;

		const double delta = my_last-my_first;
		const size_t old_size = (*it).keys.size();

		const float value_delta = (*it).keys.back().value - (*it).keys.front().value; 

		// NOTE: We won't handle reset, linear and constant here.
		// See DoInterpolation() for their implementation.

		// process pre behaviour
		switch ((*it).pre) {
			case LWO::PrePostBehaviour_OffsetRepeat:
			case LWO::PrePostBehaviour_Repeat:
			case LWO::PrePostBehaviour_Oscillate:
				{
				const double start_time = delta - fmod(my_first-first,delta);
				std::vector<LWO::Key>::iterator n = std::find_if((*it).keys.begin(),(*it).keys.end(), 
					std::bind1st(std::greater<double>(),start_time)),m;

				size_t ofs = 0;
				if (n != (*it).keys.end()) {
					// copy from here - don't use iterators, insert() would invalidate them
					ofs = (*it).keys.end()-n;
					(*it).keys.insert((*it).keys.begin(),ofs,LWO::Key());

					std::copy((*it).keys.end()-ofs,(*it).keys.end(),(*it).keys.begin());
				}

				// do full copies. again, no iterators
				const unsigned int num = (unsigned int)((my_first-first) / delta);
				(*it).keys.resize((*it).keys.size() + num*old_size);

				n = (*it).keys.begin()+ofs;
				bool reverse = false;
				for (unsigned int i = 0; i < num; ++i) {
					m = n+old_size*(i+1);
					std::copy(n,n+old_size,m);

					if ((*it).pre == LWO::PrePostBehaviour_Oscillate && (reverse = !reverse))
						std::reverse(m,m+old_size-1);
				}

				// update time values 
				n = (*it).keys.end() - (old_size+1);
				double cur_minus = delta;
				unsigned int tt = 1;
				for (const double tmp =  delta*(num+1);cur_minus <= tmp;cur_minus += delta,++tt) {
					m = (delta == tmp ? (*it).keys.begin() :  n - (old_size+1));
					for (;m != n; --n) {
						(*n).time -= cur_minus;
					
						// offset repeat? add delta offset to key value
						if ((*it).pre == LWO::PrePostBehaviour_OffsetRepeat) {
							(*n).value += tt * value_delta;
						}
					}
				}
				break;
				}
			default:
				// silence compiler warning
				break;
		}

		// process post behaviour
		switch ((*it).post) {
			
			case LWO::PrePostBehaviour_OffsetRepeat:
			case LWO::PrePostBehaviour_Repeat:
			case LWO::PrePostBehaviour_Oscillate:

				break;

			default:
				// silence compiler warning
				break;
		}
	}
}

// ------------------------------------------------------------------------------------------------
// Extract bind pose matrix
void AnimResolver::ExtractBindPose(aiMatrix4x4& out)
{
	// If we have no envelopes, return identity
	if (envelopes.empty()) {
		out = aiMatrix4x4();
		return;
	}
	aiVector3D angles, scaling(1.f,1.f,1.f), translation;

	if (trans_x) translation.x = trans_x->keys[0].value;
	if (trans_y) translation.y = trans_y->keys[0].value;
	if (trans_z) translation.z = trans_z->keys[0].value;

	if (rotat_x) angles.x = rotat_x->keys[0].value;
	if (rotat_y) angles.y = rotat_y->keys[0].value;
	if (rotat_z) angles.z = rotat_z->keys[0].value;

	if (scale_x) scaling.x = scale_x->keys[0].value;
	if (scale_y) scaling.y = scale_y->keys[0].value;
	if (scale_z) scaling.z = scale_z->keys[0].value;

	// build the final matrix
	aiMatrix4x4 s,r,t;
	
	r.FromEulerAnglesXYZ(angles);
	//aiMatrix4x4::RotationY(angles.y,r);
	// fixme: make FromEulerAngles static, too
	aiMatrix4x4::Translation(translation,t);
	aiMatrix4x4::Scaling(scaling,s);
	out = s*r*t;
}

// ------------------------------------------------------------------------------------------------
// Do a single interpolation on a channel 
void AnimResolver::DoInterpolation(std::vector<LWO::Key>::const_iterator cur, 
	LWO::Envelope* envl,double time, float& fill)
{
	if (envl->keys.size() == 1) {
		fill = envl->keys[0].value;
		return;
	}

	// check whether we're at the beginning of the animation track
	if (cur == envl->keys.begin()) {
	
		// ok ... this depends on pre behaviour now
		// we don't need to handle repeat&offset repeat&oszillate here, see UpdateAnimRangeSetup()
		switch (envl->pre)
		{
		case LWO::PrePostBehaviour_Linear:
			DoInterpolation2(cur,cur+1,time,fill);
			return;

		case LWO::PrePostBehaviour_Reset:
			fill = 0.f;
			return;

		default : //case LWO::PrePostBehaviour_Constant:
			fill = (*cur).value;
			return;
		}
	}
	// check whether we're at the end of the animation track
	else if (cur == envl->keys.end()-1 && time > envl->keys.rbegin()->time) {
		// ok ... this depends on post behaviour now
		switch (envl->post)
		{
		case LWO::PrePostBehaviour_Linear:
			DoInterpolation2(cur,cur-1,time,fill);
			return;

		case LWO::PrePostBehaviour_Reset:
			fill = 0.f;
			return;

		default : //case LWO::PrePostBehaviour_Constant:
			fill = (*cur).value;
			return;
		}
	}

	// Otherwise do a simple interpolation
	DoInterpolation2(cur-1,cur,time,fill);
}

// ------------------------------------------------------------------------------------------------
// Almost the same, except we won't handle pre/post conditions here
void AnimResolver::DoInterpolation2(std::vector<LWO::Key>::const_iterator beg, 
	std::vector<LWO::Key>::const_iterator end,double time, float& fill)
{
	switch ((*end).inter) {
		
		case LWO::IT_STEP:
			// no interpolation at all - take the value of the last key
			fill = (*beg).value;
			return;
		default:

			// silence compiler warning
			break;
	}
	// linear interpolation - default
	fill = (*beg).value + ((*end).value - (*beg).value)*(float)(((time - (*beg).time) / ((*end).time - (*beg).time)));
}

// ------------------------------------------------------------------------------------------------
// Subsample animation track by given key values
void AnimResolver::SubsampleAnimTrack(std::vector<aiVectorKey>& /*out*/,
	double /*time*/ ,double /*sample_delta*/ )
{
	//ai_assert(out.empty() && sample_delta);

	//const double time_start = out.back().mTime;
//	for ()
}

// ------------------------------------------------------------------------------------------------
// Track interpolation
void AnimResolver::InterpolateTrack(std::vector<aiVectorKey>& out,aiVectorKey& fill,double time)
{
	// subsample animation track?
	if (flags & AI_LWO_ANIM_FLAG_SAMPLE_ANIMS) {
		SubsampleAnimTrack(out,time, sample_delta);
	}

	fill.mTime = time;

	// get x
	if ((*cur_x).time == time) {
		fill.mValue.x = (*cur_x).value;

		if (cur_x != envl_x->keys.end()-1) /* increment x */
			++cur_x;
		else end_x = true;
	}
	else DoInterpolation(cur_x,envl_x,time,(float&)fill.mValue.x);

	// get y
	if ((*cur_y).time == time) {
		fill.mValue.y = (*cur_y).value;

		if (cur_y != envl_y->keys.end()-1) /* increment y */
			++cur_y;
		else end_y = true;
	}
	else DoInterpolation(cur_y,envl_y,time,(float&)fill.mValue.y);

	// get z
	if ((*cur_z).time == time) {
		fill.mValue.z = (*cur_z).value;

		if (cur_z != envl_z->keys.end()-1) /* increment z */
			++cur_z;
		else end_x = true;
	}
	else DoInterpolation(cur_z,envl_z,time,(float&)fill.mValue.z);
}

// ------------------------------------------------------------------------------------------------
// Build linearly subsampled keys from three single envelopes, one for each component (x,y,z)
void AnimResolver::GetKeys(std::vector<aiVectorKey>& out, 
	LWO::Envelope* _envl_x,
	LWO::Envelope* _envl_y,
	LWO::Envelope* _envl_z,
	unsigned int _flags)
{
	envl_x = _envl_x;
	envl_y = _envl_y;
	envl_z = _envl_z;
	flags  = _flags;

	// generate default channels if none are given
	LWO::Envelope def_x, def_y, def_z;
	LWO::Key key_dummy;
	key_dummy.time = 0.f;
	if ((envl_x && envl_x->type == LWO::EnvelopeType_Scaling_X) ||
		(envl_y && envl_y->type == LWO::EnvelopeType_Scaling_Y) || 
		(envl_z && envl_z->type == LWO::EnvelopeType_Scaling_Z)) {
		key_dummy.value = 1.f;
	}
	else key_dummy.value = 0.f;

	if (!envl_x) {
		envl_x = &def_x;
		envl_x->keys.push_back(key_dummy);
	}
	if (!envl_y) {
		envl_y = &def_y;
		envl_y->keys.push_back(key_dummy);
	}
	if (!envl_z) {
		envl_z = &def_z;
		envl_z->keys.push_back(key_dummy);
	}

	// guess how many keys we'll get
	size_t reserve;
	double sr = 1.;
	if (flags & AI_LWO_ANIM_FLAG_SAMPLE_ANIMS) {
		if (!sample_rate)
			sr = 100.f;
		else sr = sample_rate;
		sample_delta = 1.f / sr; 

		reserve = (size_t)(
			std::max( envl_x->keys.rbegin()->time,
			std::max( envl_y->keys.rbegin()->time, envl_z->keys.rbegin()->time )) * sr);
	}
	else reserve = std::max(envl_x->keys.size(),std::max(envl_x->keys.size(),envl_z->keys.size()));
	out.reserve(reserve+(reserve>>1));

	// Iterate through all three arrays at once - it's tricky, but 
	// rather interesting to implement.
	double lasttime = std::min(envl_x->keys[0].time,std::min(envl_y->keys[0].time,envl_z->keys[0].time));
	
	cur_x = envl_x->keys.begin();
	cur_y = envl_y->keys.begin();
	cur_z = envl_z->keys.begin();

	end_x = end_y = end_z = false;
	while (1) {

		aiVectorKey fill;

		if ((*cur_x).time == (*cur_y).time && (*cur_x).time == (*cur_z).time ) {

			// we have a keyframe for all of them defined .. great,
			// we don't need to fucking interpolate here ...
			fill.mTime = (*cur_x).time;

			fill.mValue.x = (*cur_x).value;
			fill.mValue.y = (*cur_y).value;
			fill.mValue.z = (*cur_z).value;

			// subsample animation track
			if (flags & AI_LWO_ANIM_FLAG_SAMPLE_ANIMS) {
				//SubsampleAnimTrack(out,cur_x, cur_y, cur_z, d, sample_delta);
			}
		}

		// Find key with lowest time value
		else if ((*cur_x).time <= (*cur_y).time && !end_x) {

			if ((*cur_z).time <= (*cur_x).time && !end_z) {
				InterpolateTrack(out,fill,(*cur_z).time);
			}
			else {
				InterpolateTrack(out,fill,(*cur_x).time);
			}
		}
		else if ((*cur_z).time <= (*cur_y).time && !end_y)	{
			InterpolateTrack(out,fill,(*cur_y).time);
		}
		else if (!end_y) {
			// welcome on the server, y
			InterpolateTrack(out,fill,(*cur_y).time);
		}
		else {
			// we have reached the end of at least 2 channels,
			// only one is remaining. Extrapolate the 2.
			if (end_y) {
				InterpolateTrack(out,fill,(end_x ? (*cur_z) : (*cur_x)).time);
			}
			else if (end_x) {
				InterpolateTrack(out,fill,(end_z ? (*cur_y) : (*cur_z)).time);
			}
			else { // if (end_z) 
				InterpolateTrack(out,fill,(end_y ? (*cur_x) : (*cur_y)).time);
			}
		}
		lasttime = fill.mTime;
		out.push_back(fill);

		if (lasttime >= (*cur_x).time) {
			if (cur_x != envl_x->keys.end()-1)
				++cur_x;
			else end_x = true;
		}
		if (lasttime >= (*cur_y).time) {
			if (cur_y != envl_y->keys.end()-1)
				++cur_y;
			else end_y = true;
		}
		if (lasttime >= (*cur_z).time) {
			if (cur_z != envl_z->keys.end()-1)
				++cur_z;
			else end_z = true;
		}

		if( end_x && end_y && end_z ) /* finished? */
			break;
	}

	if (flags & AI_LWO_ANIM_FLAG_START_AT_ZERO) {
		for (std::vector<aiVectorKey>::iterator it = out.begin(); it != out.end(); ++it)
			(*it).mTime -= first;
	}
}

// ------------------------------------------------------------------------------------------------
// Extract animation channel
void AnimResolver::ExtractAnimChannel(aiNodeAnim** out, unsigned int flags /*= 0*/)
{
	*out = NULL;


	//FIXME: crashes if more than one component is animated at different timings, to be resolved.
	
	// If we have no envelopes, return NULL
	if (envelopes.empty()) {
		return;
	}

	// We won't spawn an animation channel if we don't have at least one envelope with more than one keyframe defined.
	const bool trans = ((trans_x && trans_x->keys.size() > 1) || (trans_y && trans_y->keys.size() > 1) || (trans_z && trans_z->keys.size() > 1));
	const bool rotat = ((rotat_x && rotat_x->keys.size() > 1) || (rotat_y && rotat_y->keys.size() > 1) || (rotat_z && rotat_z->keys.size() > 1));
	const bool scale = ((scale_x && scale_x->keys.size() > 1) || (scale_y && scale_y->keys.size() > 1) || (scale_z && scale_z->keys.size() > 1));
	if (!trans && !rotat && !scale)
		return;

	// Allocate the output animation 
	aiNodeAnim* anim = *out = new aiNodeAnim();

	// Setup default animation setup if necessary
	if (need_to_setup) {
		UpdateAnimRangeSetup();
		need_to_setup = false;
	}

	// copy translation keys
	if (trans) {
		std::vector<aiVectorKey> keys;
		GetKeys(keys,trans_x,trans_y,trans_z,flags);

		anim->mPositionKeys = new aiVectorKey[ anim->mNumPositionKeys = keys.size() ];
		std::copy(keys.begin(),keys.end(),anim->mPositionKeys);
	}

	// copy rotation keys
	if (rotat) {
		std::vector<aiVectorKey> keys;
		GetKeys(keys,rotat_x,rotat_y,rotat_z,flags);

		anim->mRotationKeys = new aiQuatKey[ anim->mNumRotationKeys = keys.size() ];
		
		// convert heading, pitch, bank to quaternion
		// mValue.x=Heading=Rot(Y), mValue.y=Pitch=Rot(X), mValue.z=Bank=Rot(Z)
		// Lightwave's rotation order is ZXY
		aiVector3D X(1.0,0.0,0.0);
		aiVector3D Y(0.0,1.0,0.0);
		aiVector3D Z(0.0,0.0,1.0);
		for (unsigned int i = 0; i < anim->mNumRotationKeys; ++i) {
			aiQuatKey& qk = anim->mRotationKeys[i];
			qk.mTime  = keys[i].mTime;
			qk.mValue = aiQuaternion(Y,keys[i].mValue.x)*aiQuaternion(X,keys[i].mValue.y)*aiQuaternion(Z,keys[i].mValue.z);
		}
	}

	// copy scaling keys
	if (scale) {
		std::vector<aiVectorKey> keys;
		GetKeys(keys,scale_x,scale_y,scale_z,flags);

		anim->mScalingKeys = new aiVectorKey[ anim->mNumScalingKeys = keys.size() ];
		std::copy(keys.begin(),keys.end(),anim->mScalingKeys);
	}
}


#endif // no lwo or no lws