/**
 * @file llgltfasset.cpp
 * @brief LL GLTF Implementation
 *
 * $LicenseInfo:firstyear=2024&license=viewergpl$
 *
 * Copyright (c) 2024, Linden Research, Inc.
 *
 * Second Life Viewer Source Code
 * The source code in this file ("Source Code") is provided by Linden Lab
 * to you under the terms of the GNU General Public License, version 2.0
 * ("GPL"), unless you have obtained a separate licensing agreement
 * ("Other License"), formally executed by you and Linden Lab.  Terms of
 * the GPL can be found in doc/GPL-license.txt in this distribution, or
 * online at http://secondlifegrid.net/programs/open_source/licensing/gplv2
 *
 * There are special exceptions to the terms and conditions of the GPL as
 * it is applied to this Source Code. View the full text of the exception
 * in the file doc/FLOSS-exception.txt in this software distribution, or
 * online at
 * http://secondlifegrid.net/programs/open_source/licensing/flossexception
 *
 * 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.
 *
 * ALL LINDEN LAB SOURCE CODE IS PROVIDED "AS IS." LINDEN LAB MAKES NO
 * WARRANTIES, EXPRESS, IMPLIED OR OTHERWISE, REGARDING ITS ACCURACY,
 * COMPLETENESS OR PERFORMANCE.
 * $/LicenseInfo$
 */

#include "linden_common.h"

#include "tinygltf/tiny_gltf.h"

#include "llgltfasset.h"

#include "llgltfaccessor.h"
#include "llshadermgr.h"
#include "llvolumeoctree.h"

// Global variable defined in newview (llappviewer.h)
extern F32 gFrameTimeSeconds;
// External functions from LLFetchedGLTFMaterial. HB
extern LLGLTFMaterial* create_fetch_material();
extern void bind_fetched_material(LLGLTFMaterial* matp);
// External function from LLTinyGLTFHelper. HB
extern void get_material_from_model(const std::string& filename,
									const tinygltf::Model& model, S32 mat_idx,
									LLGLTFMaterial* matp,
									std::string& mat_name, bool flip);

using namespace LLGLTF;

///////////////////////////////////////////////////////////////////////////////
// LLGLTF::Node class
///////////////////////////////////////////////////////////////////////////////

Node::Node()
:	mParent(INVALID_INDEX),
	mMesh(INVALID_INDEX),
	mSkin(INVALID_INDEX),
	mMatrixValid(false),
	mTRSValid(false),
	mNeedsApplyMatrix(false)
{
}

void Node::updateRenderTransforms(Asset& asset, const LLMatrix4a& modelview)
{
	mRenderMatrix.matMul(mMatrix, modelview);

	for (auto& idx : mChildren)
	{
		Node& child = asset.mNodes[idx];
		child.updateRenderTransforms(asset, mRenderMatrix);
	}
}

void Node::updateTransforms(Asset& asset, const LLMatrix4a& parent_mat)
{
	makeMatrixValid();
	mAssetMatrix.matMul(mMatrix, parent_mat);

	mAssetMatrixInv = mAssetMatrix;
	mAssetMatrixInv.invert();

	S32 my_index = this - &asset.mNodes[0];

	for (auto& idx : mChildren)
	{
		Node& child = asset.mNodes[idx];
		child.mParent = my_index;
		child.updateTransforms(asset, mAssetMatrix);
	}
}

void Node::makeMatrixValid()
{
	if (!mMatrixValid && mTRSValid)
	{
		// t = sc * rot * trans;
		// t = trans * rot * sc; // Best so far, still wrong on negative scale
		// t = sc * trans * rot;
		glh::matrix4f rot, trans, sc;
		mRotation.get_value(rot);
		trans.set_translate(mTranslation);
		sc.set_scale(mScale);
		glh::matrix4f t = trans * sc * rot;
		mMatrix.loadu(t.m);
		mMatrixValid = true;
	}
}

void Node::makeTRSValid()
{
	if (!mTRSValid && mMatrixValid)
	{
		glh::matrix4f t(mMatrix.getF32ptr());
		glh::vec4f p = t.get_column(3);
		mTranslation.set_value(p.v[0], p.v[1], p.v[2]);

		mScale.set_value(t.get_column(0).length(), t.get_column(1).length(),
						 t.get_column(2).length());

		mRotation.set_value(t);
		mTRSValid = true;
	}
}

void Node::setRotation(const glh::quaternionf& q)
{
	makeTRSValid();
	mRotation = q;
	mMatrixValid = false;
}

void Node::setTranslation(const glh::vec3f& t)
{
	makeTRSValid();
	mTranslation = t;
	mMatrixValid = false;
}

void Node::setScale(const glh::vec3f& s)
{
	makeTRSValid();
	mScale = s;
	mMatrixValid = false;
}

const Node& Node::operator=(const tinygltf::Node& src)
{
	F32* dst_mat = mMatrix.getF32ptr();

	if (src.matrix.size() == 16)
	{
		// Node has a transformation matrix, just copy it
		for (U32 i = 0; i < 16; ++i)
		{
			dst_mat[i] = (F32)src.matrix[i];
		}

		mMatrixValid = true;
	}
	else if (!src.rotation.empty() || !src.translation.empty() ||
			 !src.scale.empty())
	{
		// Node has rotation/translation/scale, convert to matrix
		if (src.rotation.size() == 4)
		{
			mRotation = glh::quaternionf((F32)src.rotation[0],
										 (F32)src.rotation[1],
										 (F32)src.rotation[2],
										 (F32)src.rotation[3]);
		}

		if (src.translation.size() == 3)
		{
			mTranslation = glh::vec3f((F32)src.translation[0],
									  (F32)src.translation[1],
									  (F32)src.translation[2]);
		}

		glh::vec3f scale;
		if (src.scale.size() == 3)
		{
			mScale = glh::vec3f((F32)src.scale[0], (F32)src.scale[1],
								(F32)src.scale[2]);
		}
		else
		{
			mScale.set_value(1.f, 1.f, 1.f);
		}

		mTRSValid = true;
	}
	else
	{
		// Node specifies no transformation, set to identity
		mMatrix.setIdentity();
	}

	mChildren = src.children;
	mMesh = src.mesh;
	mSkin = src.skin;
	mName = src.name;

	return *this;
}

///////////////////////////////////////////////////////////////////////////////
// LLGLTF::Asset class
///////////////////////////////////////////////////////////////////////////////

Asset::Asset()
{
	mLastUpdateTime = gFrameTimeSeconds;
}

void Asset::updateTransforms()
{
	for (auto& scene : mScenes)
	{
		scene.updateTransforms(*this);
	}
}

void Asset::updateRenderTransforms(const LLMatrix4a& modelview)
{
#if 0
	// Traverse hierarchy and update render transforms from scratch
	for (auto& scene : mScenes)
	{
		scene.updateRenderTransforms(*this, modelview);
	}
#else
	// Use mAssetMatrix to update render transforms from node list
	for (auto& node : mNodes)
	{
		//if (node.mMesh != INVALID_INDEX)
		{
			node.mRenderMatrix.matMul(node.mAssetMatrix, modelview);
		}
	}
#endif
}

S32 Asset::lineSegmentIntersect(const LLVector4a& start, const LLVector4a& end,
								LLVector4a* intersectp, LLVector2* tcoordp,
								LLVector4a* normalp, LLVector4a* tangentp,
								S32* prim_hitp)
{
	S32 node_hit = -1;
	S32 primitive_hit = -1;

	LLVector4a p, local_start, local_end;
	LLVector4a asset_end = end;
	for (auto& node : mNodes)
	{
		if (node.mMesh != INVALID_INDEX)
		{
			bool new_hit = false;

			// Transform start and end to this node's local space
			node.mAssetMatrixInv.affineTransform(start, local_start);
			node.mAssetMatrixInv.affineTransform(asset_end, local_end);

			Mesh& mesh = mMeshes[node.mMesh];
			for (auto& primitive : mesh.mPrimitives)
			{
				const LLVolumeTriangle* tri =
					primitive.lineSegmentIntersect(local_start, local_end, &p,
												   tcoordp, normalp, tangentp);
				if (tri)
				{
					new_hit = true;
					local_end = p;

					// Pointer math to get the node index
					node_hit = &node - &mNodes[0];
					llassert(&mNodes[node_hit] == &node);

					// Pointer math to get the primitive index
					primitive_hit = &primitive - &mesh.mPrimitives[0];
					llassert(&mesh.mPrimitives[primitive_hit] == &primitive);
				}
			}

			if (new_hit)
			{
				// Shorten line segment on hit
				node.mAssetMatrix.affineTransform(p, asset_end);

				// Transform results back to asset space
				if (intersectp)
				{
					*intersectp = asset_end;
				}

				if (normalp || tangentp)
				{
					LLMatrix4 normal_mat4(node.mAssetMatrixInv.getF32ptr());
					normal_mat4.transpose();

					LLMatrix4a norm_mat;
					norm_mat.loadu(normal_mat4.getF32ptr());

					if (normalp)
					{
						LLVector4a n = *normalp;
						F32 w = n.getF32ptr()[3];
						n.getF32ptr()[3] = 0.0f;

						norm_mat.affineTransform(n, *normalp);
						normalp->getF32ptr()[3] = w;
					}

					if (tangentp)
					{
						LLVector4a t = *tangentp;
						F32 w = t.getF32ptr()[3];
						t.getF32ptr()[3] = 0.0f;

						norm_mat.affineTransform(t, *tangentp);
						tangentp->getF32ptr()[3] = w;
					}
				}
			}
		}
	}

	if (node_hit != -1)
	{
		if (prim_hitp)
		{
			*prim_hitp = primitive_hit;
		}
	}

	return node_hit;
}

void Asset::render(bool opaque, bool rigged)
{
	if (rigged)
	{
		gGL.loadIdentity();
	}

	for (auto& node : mNodes)
	{
		if (node.mSkin != INVALID_INDEX)
		{
			if (rigged)
			{
				Skin& skin = mSkins[node.mSkin];
				skin.uploadMatrixPalette(*this, node);
			}
			else
			{
				// Skip static nodes if we are rendering rigged
				continue;
			}
		}
		else if (rigged)
		{
			// Skip rigged nodes if we are not rendering rigged
			continue;
		}


		if (node.mMesh != INVALID_INDEX)
		{
			Mesh& mesh = mMeshes[node.mMesh];
			for (auto& primitive : mesh.mPrimitives)
			{
				if (!rigged)
				{
					gGL.loadMatrix((F32*)node.mRenderMatrix.mMatrix);
				}
				bool cull = true;
				if (primitive.mMaterial != INVALID_INDEX)
				{
					Material& material = mMaterials[primitive.mMaterial];

					if ((material.mMaterial->mAlphaMode ==
							LLGLTFMaterial::ALPHA_MODE_BLEND) == opaque)
					{
						continue;
					}
					bind_fetched_material(material.mMaterial);
					cull = !material.mMaterial->mDoubleSided;
				}
				else
				{
					if (!opaque)
					{
						continue;
					}
					bind_fetched_material(NULL);
				}

				LLVertexBuffer* buffp = primitive.mVertexBuffer;
				if (!buffp) continue;

				LLGLDisable cull_face(!cull ? GL_CULL_FACE : 0);

				buffp->setBuffer();
				U32 num_indices = buffp->getNumIndices();
				if (num_indices > 0)
				{
					buffp->draw(primitive.mGLMode, num_indices, 0);
				}
				else
				{
					buffp->drawArrays(primitive.mGLMode, 0,
									  buffp->getNumVerts());
				}
			}
		}
	}
}

void Asset::renderOpaque()
{
	render(true);
}

void Asset::renderTransparent()
{
	render(false);
}

void Asset::update()
{
	F32 dt = gFrameTimeSeconds - mLastUpdateTime;
	if (dt <= 0.f)
	{
		return;
	}
	mLastUpdateTime = gFrameTimeSeconds;

	if (mAnimations.size() > 0)
	{
#if 0	// For now, these settings are not even listed in LL's viewer
		// app_settings/settings.xml, so they default to 0 and 1.f
		// respectively. If configuration is ever to be provided, just use
		// static variables in the LLGLTF::Asset class and setter methods to
		// set them on viewer launch from llappviewer.cpp, and on change from
		// llviewercontrol.cpp... HB
		static LLCachedControl<U32> anim_idx(gSavedSettings,
											 "GLTFAnimationIndex", 0);
		static LLCachedControl<F32> anim_speed(gSavedSettings,
											   "GLTFAnimationSpeed", 1.f);
		U32 idx = llclamp(anim_idx(), 0U, mAnimations.size() - 1);
#else
		constexpr U32 idx = 0;
		constexpr F32 anim_speed = 1.f;
#endif
		mAnimations[idx].update(*this, dt * anim_speed);
	}

	updateTransforms();
}

bool Asset::allocateGLResources(const std::string& filename,
								const tinygltf::Model& model)
{
	// Do images first as materials may depend on images
	for (auto& image : mImages)
	{
		image.allocateGLResources();
	}

	// Do materials before meshes as meshes may depend on materials
	for (size_t i = 0, count = mMaterials.size(); i < count; ++i)
	{
		mMaterials[i].allocateGLResources(*this);
		get_material_from_model(filename, model, i, mMaterials[i].mMaterial,
								mMaterials[i].mName, true);
	}

	for (auto& mesh : mMeshes)
	{
		if (!mesh.allocateGLResources(*this))
		{
			// Too many vertice: aborted !  HB
			return false;
		}
	}

	for (auto& animation : mAnimations)
	{
		animation.allocateGLResources(*this);
	}

	for (auto& skin : mSkins)
	{
		skin.allocateGLResources(*this);
	}

	return true;
}

const Asset& Asset::operator=(const tinygltf::Model& src)
{
	size_t count = src.scenes.size();
	mScenes.resize(count);
	for (size_t i = 0; i < count; ++i)
	{
		mScenes[i] = src.scenes[i];
	}

	count = src.nodes.size();
	mNodes.resize(count);
	for (size_t i = 0; i < count; ++i)
	{
		mNodes[i] = src.nodes[i];
	}

	count = src.meshes.size();
	mMeshes.resize(count);
	for (size_t i = 0; i < count; ++i)
	{
		mMeshes[i] = src.meshes[i];
	}

	count = src.materials.size();
	mMaterials.resize(count);
	for (size_t i = 0; i < count; ++i)
	{
		mMaterials[i] = src.materials[i];
	}

	count = src.buffers.size();
	mBuffers.resize(count);
	for (size_t i = 0; i < count; ++i)
	{
		mBuffers[i] = src.buffers[i];
	}

	count = src.bufferViews.size();
	mBufferViews.resize(count);
	for (size_t i = 0; i < count; ++i)
	{
		mBufferViews[i] = src.bufferViews[i];
	}

	count = src.textures.size();
	mTextures.resize(count);
	for (size_t i = 0; i < count; ++i)
	{
		mTextures[i] = src.textures[i];
	}

	count = src.samplers.size();
	mSamplers.resize(count);
	for (size_t i = 0; i < count; ++i)
	{
		mSamplers[i] = src.samplers[i];
	}

	count = src.images.size();
	mImages.resize(count);
	for (size_t i = 0; i < count; ++i)
	{
		mImages[i] = src.images[i];
	}

	count = src.accessors.size();
	mAccessors.resize(count);
	for (size_t i = 0; i < count; ++i)
	{
		mAccessors[i] = src.accessors[i];
	}

	count = src.animations.size();
	mAnimations.resize(count);
	for (size_t i = 0; i < count; ++i)
	{
		mAnimations[i] = src.animations[i];
	}

	count = src.skins.size();
	mSkins.resize(count);
	for (size_t i = 0; i < count; ++i)
	{
		mSkins[i] = src.skins[i];
	}

	return *this;
}

///////////////////////////////////////////////////////////////////////////////
// LLGLTF::Material class
///////////////////////////////////////////////////////////////////////////////

const Material& Material::operator=(const tinygltf::Material& src)
{
	mName = src.name;
	return *this;
}

void Material::allocateGLResources(Asset& asset)
{
	// Allocate material
	mMaterial = create_fetch_material();
}

///////////////////////////////////////////////////////////////////////////////
// LLGLTF::Mesh class
///////////////////////////////////////////////////////////////////////////////

const Mesh& Mesh::operator=(const tinygltf::Mesh& src)
{
	size_t count = src.primitives.size();
	mPrimitives.resize(count);
	for (size_t i = 0; i < count; ++i)
	{
		mPrimitives[i] = src.primitives[i];
	}

	mWeights = src.weights;
	mName = src.name;

	return *this;
}

bool Mesh::allocateGLResources(Asset& asset)
{
	for (auto& primitive : mPrimitives)
	{
		if (!primitive.allocateGLResources(asset))
		{
			// Too many vertice: aborted !  HB
			return false;
		}
	}
	return true;
}

///////////////////////////////////////////////////////////////////////////////
// LLGLTF::Scene class
///////////////////////////////////////////////////////////////////////////////

void Scene::updateTransforms(Asset& asset)
{
	LLMatrix4a identity;
	identity.setIdentity();
	for (auto& idx : mNodes)
	{
		Node& node = asset.mNodes[idx];
		node.updateTransforms(asset, identity);
	}
}

void Scene::updateRenderTransforms(Asset& asset, const LLMatrix4a& modelview)
{
	for (auto& idx : mNodes)
	{
		Node& node = asset.mNodes[idx];
		node.updateRenderTransforms(asset, modelview);
	}
}

const Scene& Scene::operator=(const tinygltf::Scene& src)
{
	mNodes = src.nodes;
	mName = src.name;
	return *this;
}

///////////////////////////////////////////////////////////////////////////////
// LLGLTF::Texture class
///////////////////////////////////////////////////////////////////////////////

Texture::Texture()
:	mSampler(INVALID_INDEX),
	mSource(INVALID_INDEX)
{
}

const Texture& Texture::operator=(const tinygltf::Texture& src)
{
	mSampler = src.sampler;
	mSource = src.source;
	mName = src.name;
	return *this;
}

///////////////////////////////////////////////////////////////////////////////
// LLGLTF::Image class
///////////////////////////////////////////////////////////////////////////////

const Image& Image::operator=(const tinygltf::Image& src)
{
	mName = src.name;
	mUri = src.uri;
	mMimeType = src.mimeType;
	mData = src.image;
	mWidth = src.width;
	mHeight = src.height;
	mComponent = src.component;
	mBits = src.bits;
	return *this;
}

///////////////////////////////////////////////////////////////////////////////
// LLGLTF::Sampler class
///////////////////////////////////////////////////////////////////////////////

const Sampler& Sampler::operator=(const tinygltf::Sampler& src)
{
	mMagFilter = src.magFilter;
	mMinFilter = src.minFilter;
	mWrapS = src.wrapS;
	mWrapT = src.wrapT;
	mName = src.name;
	return *this;
}

///////////////////////////////////////////////////////////////////////////////
// LLGLTF::Skin class
///////////////////////////////////////////////////////////////////////////////

Skin::Skin()
:	mInverseBindMatrices(INVALID_INDEX),
	mSkeleton(INVALID_INDEX)
{
}

const Skin& Skin::operator=(const tinygltf::Skin& src)
{
	mName = src.name;
	mSkeleton = src.skeleton;
	mInverseBindMatrices = src.inverseBindMatrices;
	mJoints = src.joints;
	return *this;
}

void Skin::uploadMatrixPalette(Asset& asset, Node& node)
{
	// Prepare matrix palette

	// Model view will be applied by the shader, so assume matrix palette is in
	// asset space
	std::vector<glh::matrix4f> t_mp;

	t_mp.resize(mJoints.size());

	for (U32 i = 0; i < mJoints.size(); ++i)
	{
		Node& joint = asset.mNodes[mJoints[i]];

		//t_mp[i].set_value(joint.mRenderMatrix.getF32ptr());
		//t_mp[i] = t_mp[i] * mInverseBindMatricesData[i];

		//t_mp[i].set_value(joint.mRenderMatrix.getF32ptr());
		//t_mp[i] = mInverseBindMatricesData[i] * t_mp[i];

		t_mp[i].set_value(joint.mRenderMatrix.getF32ptr());
		t_mp[i] = t_mp[i] * mInverseBindMatricesData[i];
	}

	std::vector<F32> glmp;
	glmp.resize(mJoints.size() * 12);

	F32* mp = glmp.data();
	for (U32 i = 0; i < mJoints.size(); ++i)
	{
		F32* m = (F32*)t_mp[i].m;

		U32 idx = i * 12;

		mp[idx + 0] = m[0];
		mp[idx + 1] = m[1];
		mp[idx + 2] = m[2];
		mp[idx + 3] = m[12];

		mp[idx + 4] = m[4];
		mp[idx + 5] = m[5];
		mp[idx + 6] = m[6];
		mp[idx + 7] = m[13];

		mp[idx + 8] = m[8];
		mp[idx + 9] = m[9];
		mp[idx + 10] = m[10];
		mp[idx + 11] = m[14];
	}

	LLGLSLShader::sCurBoundShaderPtr->uniformMatrix3x4fv(LLShaderMgr::AVATAR_MATRIX,
														 mJoints.size(), GL_FALSE,
														 (F32*)glmp.data());
}