/*****************************************************************************************
 *                                                                                       *
 * OpenSpace                                                                             *
 *                                                                                       *
 * Copyright (c) 2014-2015                                                               *
 *                                                                                       *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of this  *
 * software and associated documentation files (the "Software"), to deal in the Software *
 * without restriction, including without limitation the rights to use, copy, modify,    *
 * merge, publish, distribute, sublicense, and/or sell copies of the Software, and to    *
 * permit persons to whom the Software is furnished to do so, subject to the following   *
 * conditions:                                                                           *
 *                                                                                       *
 * The above copyright notice and this permission notice shall be included in all copies *
 * or substantial portions of the Software.                                              *
 *                                                                                       *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,   *
 * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A         *
 * PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT    *
 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF  *
 * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE  *
 * OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                                         *
 ****************************************************************************************/

#include <modules/newhorizons/rendering/renderablefov.h>

#include <openspace/engine/configurationmanager.h>
#include <openspace/engine/openspaceengine.h>
#include <openspace/util/constants.h>
#include <openspace/util/spicemanager.h>

#include <modules/newhorizons/util/imagesequencer.h>
#include <openspace/util/time.h>


#include <ghoul/io/texture/texturereader.h>
#include <ghoul/opengl/textureunit.h>
#include <ghoul/filesystem/filesystem.h>

#include <openspace/query/query.h>

#include <openspace/util/spicemanager.h>
#include <iomanip>
#include <utility>   
#include <chrono>

namespace {
	const std::string _loggerCat              = "RenderableFov";
	//constants
	const std::string keyBody                 = "Body";
	const std::string keyFrame                = "Frame";
	const std::string keyPathModule           = "ModulePath";
	const std::string keyColor                = "RGB";
	const std::string keyInstrument           = "Instrument.Name";
	const std::string keyInstrumentMethod     = "Instrument.Method";
	const std::string keyInstrumentAberration = "Instrument.Aberration";
    const std::string keyPotentialTargets     = "PotentialTargets";

    // colors, move later
    glm::vec4 col_sq;
    glm::vec4 c_project;
    glm::vec4 col_end;
    glm::vec4 blue;
    glm::vec4 col_gray;
    glm::vec4 col_start;
}

namespace openspace {

RenderableFov::RenderableFov(const ghoul::Dictionary& dictionary)
    : Renderable(dictionary)
    , _lineWidth("lineWidth", "Line Width", 1.f, 1.f, 20.f)
    , _drawSolid("solidDraw", "Draw as Quads", false)
    , _programObject(nullptr)
    , _texture(nullptr)
    , _mode(GL_LINES)
{
    bool success = dictionary.getValue(keyBody, _spacecraft);
    ghoul_assert(success, "");

    success = dictionary.getValue(keyFrame, _frame);
    ghoul_assert(success, "");

    success = dictionary.getValue(keyInstrument, _instrumentID);
    ghoul_assert(success, "");

    success = dictionary.getValue(keyInstrumentMethod, _method);
    ghoul_assert(success, "");

    success = dictionary.getValue(keyInstrumentAberration, _aberrationCorrection);
    ghoul_assert(success, "");

    ghoul::Dictionary potentialTargets;
    success = dictionary.getValue(keyPotentialTargets, potentialTargets);
    ghoul_assert(success, "");

    _potentialTargets.resize(potentialTargets.size());
    for (int i = 0; i < potentialTargets.size(); ++i) {
        std::string target;
        potentialTargets.getValue(std::to_string(i + 1), target);
        _potentialTargets[i] = target;
    }

    addProperty(_lineWidth);
	addProperty(_drawSolid);
}

void RenderableFov::allocateData() { 
	int points = 20;
	_stride[0] = points;
	_isize[0]  = points;
	_iarray1[0] = new int[_isize[0]];
	for (int i = 0; i < points; i++){
		for (int j = 0; j < 4; j++){
			_varray1.push_back(0); // pos
		}
		for (int j = 0; j < 4; j++){
			_varray1.push_back(0); // col
		}
		_iarray1[0][i] = i;
	}

	_stride[0] = 8;
	_vsize[0] = static_cast<unsigned int>(_varray1.size());
	_vtotal[0] = static_cast<int>(_vsize[0] / _stride[0]);

	// allocate second vbo data 
	int cornerPoints = 12;
	_isize[1] = cornerPoints;
	_iarray1[1] = new int[_isize[1]];
	for (unsigned int i = 0; i < _isize[1]; i++){
		_iarray1[1][i] = i;
	}
	_varray2.resize(40);
	_vsize[1] = 40;
	_vtotal[1] = 5;
	_isteps = 10;
}

RenderableFov::~RenderableFov() {
	delete[] _iarray1[0];
	delete[] _iarray1[1];
	deinitialize();
}

bool RenderableFov::initialize() {
	bool completeSuccess = true;
    if (_programObject == nullptr) {
        _programObject = ghoul::opengl::ProgramObject::Build("FovProgram",
            "${MODULE_NEWHORIZONS}/shaders/fov_vs.glsl",
            "${MODULE_NEWHORIZONS}/shaders/fov_fs.glsl");
        if (!_programObject)
            return false;
    }

	allocateData();
	sendToGPU();

	return completeSuccess;
}

bool RenderableFov::deinitialize() {
	return true;
}

bool RenderableFov::isReady() const {
	return _programObject != nullptr;
}

void RenderableFov::sendToGPU() {
	// Initialize and upload to graphics card
	glGenVertexArrays(1, &_vaoID[0]);
	glGenBuffers(1, &_vboID[0]);
	glGenBuffers(1, &_iboID[0]);

	glBindVertexArray(_vaoID[0]);
	glBindBuffer(GL_ARRAY_BUFFER, _vboID[0]);
	glBufferData(GL_ARRAY_BUFFER, _vsize[0] * sizeof(GLfloat), NULL, GL_STATIC_DRAW); // orphaning the buffer, sending NULL data.
	glBufferSubData(GL_ARRAY_BUFFER, 0, _vsize[0] * sizeof(GLfloat), &_varray1[0]);

	GLsizei st = sizeof(GLfloat) * _stride[0];

	glEnableVertexAttribArray(0);
	glEnableVertexAttribArray(1);
	glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, st, (void*)0);
	glVertexAttribPointer(1, 4, GL_FLOAT, GL_FALSE, st, (void*)(4 * sizeof(GLfloat)));

	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, _iboID[0]);
	glBufferData(GL_ELEMENT_ARRAY_BUFFER, _isize[0] * sizeof(int), _iarray1, GL_STATIC_DRAW);
	glBindVertexArray(0);

	// second vbo
	glGenVertexArrays(1, &_vaoID[1]);
	glGenBuffers(1, &_vboID[1]);
	glGenBuffers(1, &_iboID[1]);

	glBindVertexArray(_vaoID[1]);
	glBindBuffer(GL_ARRAY_BUFFER, _vboID[1]);
	glBufferData(GL_ARRAY_BUFFER, _vsize[1] * sizeof(GLfloat), NULL, GL_STATIC_DRAW); // orphaning the buffer, sending NULL data.
	glBufferSubData(GL_ARRAY_BUFFER, 0, _vsize[1] * sizeof(GLfloat), &_varray2[0]);

	glEnableVertexAttribArray(0);
	glEnableVertexAttribArray(1);
	glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, st, (void*)0);
	glVertexAttribPointer(1, 4, GL_FLOAT, GL_FALSE, st, (void*)(4 * sizeof(GLfloat)));

	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, _iboID[1]);
	glBufferData(GL_ELEMENT_ARRAY_BUFFER, _isize[1] * sizeof(int), _iarray1[1], GL_STATIC_DRAW);
	glBindVertexArray(0);
}
// various helper methods

void RenderableFov::insertPoint(std::vector<float>& arr, psc p, glm::vec4 c) {
	for (int i = 0; i < 4; i++){
		arr.push_back(p[i]);
	}
	for (int i = 0; i < 4; i++){
		arr.push_back(c[i]);
	}
	_nrInserted++;
}

glm::dvec3 RenderableFov::interpolate(glm::dvec3 p0, glm::dvec3 p1, float t) {
	assert(t >= 0 && t <= 1);
	float t2 = (1.f - t);
	return glm::dvec3(p0.x*t2 + p1.x*t, p0.y*t2 + p1.y*t, p0.z*t2 + p1.z*t);
}

glm::dvec3 RenderableFov::pscSlerp(glm::dvec3 p0, glm::dvec3 p1, float t){
	assert(t >= 0 && t <= 1);
	float t2 = (1.f - t);
	float omega = acosf(glm::dot(p0, p1));
	if (omega > 0.f){
		float s1 = sin(t*omega) / sin(omega);
		float s2 = sin(t2*omega) / sin(omega);
		return glm::dvec3(p0.x*s2 + p1.x*s1, p0.y*s2 + p1.y*s1, p0.z*s2 + p1.z*s1);

	}
	return p0;//tmp
}

// This method is the current bottleneck.
psc RenderableFov::checkForIntercept(glm::dvec3 ray) {
	double targetEt;
	bool intercepted = false;
    openspace::SpiceManager::ref().getSurfaceIntercept(_fovTarget, _spacecraft, _instrumentID,
																	      _frame, _method, _aberrationCorrection, 
																		  _time, targetEt, ray, ipoint, ivec, intercepted);
	ivec *= 0.9999;
	_interceptVector = PowerScaledCoordinate::CreatePowerScaledCoordinate(ivec[0], ivec[1], ivec[2]);
	_interceptVector[3] += 3;

	return _interceptVector;
}
// Orthogonal projection next to planets surface, can also be optimized. 
psc RenderableFov::orthogonalProjection(glm::dvec3 vecFov) {
	glm::dvec3 vecToTarget;
	double lt;
	SpiceManager::ref().getTargetPosition(_fovTarget, _spacecraft, _frame, _aberrationCorrection, _time, vecToTarget, lt);
	openspace::SpiceManager::ref().frameConversion(vecFov, _instrumentID, _frame, _time);
	glm::dvec3 p = openspace::SpiceManager::ref().orthogonalProjection(vecToTarget, vecFov);

	psc projection = PowerScaledCoordinate::CreatePowerScaledCoordinate(p[0], p[1], p[2]);
	projection[3] += 3;

	return projection;
}
// Bisection method, simple recurtion
glm::dvec3 RenderableFov::bisection(glm::dvec3 p1, glm::dvec3 p2, double tolerance) {
	//check if point is on surface
	double targetEt;
	glm::dvec3 half = interpolate(p1, p2, 0.5f);
	bool intercepted = false;
    openspace::SpiceManager::ref().getSurfaceIntercept(_fovTarget, _spacecraft, _instrumentID,
													                      _frame, _method, _aberrationCorrection, 
																		  _time, targetEt, half, ipoint, ivec, intercepted);
	if (glm::distance(_previousHalf, half) < tolerance){
		_previousHalf = glm::dvec3(0);
		return half;
	}
	_previousHalf = half;
	//recursive search
	if (!intercepted){
		return bisection(p1, half, tolerance);
	}else{
		return bisection(half, p2, tolerance);
	}
}

/*
	README:
	There are 4 different cases as each boundary  vector can either  have  detected
	an  intercept or is outside of the planets surface. When no such intercepts are
	detected the algorithm performs an orthogonal  projection to 'clip' the current
	fov vector next to the planets surface.  If two or more intercepts are detected
	the algorithm continues with the bisection method O(logn) for points [Pn, Pn+1]
	to locate the point Pb where  the  orthogonal  plane  meets the planets surface 
	(within  ~20  iterations this  will  narrow  down  to  centimeter  resolution). 
	Upon finding Pb a linear interpolation is performed for [Pn, Pb], at this stage 
	the points are located on a straight line between the surface intercept and the 
	surface-bound  fov-corner.  In  order  to  correctly  place these points on the 
	targets surface,  each consecutive point is queried for a surface intercept and 
	thereby moved to the hull. 
*/
void RenderableFov::fovProjection(bool H[], std::vector<glm::dvec3> bounds) {
	_nrInserted = 0;
	_varray2.clear();// empty the array

	double tolerance = 0.0000001; // very low tolerance factor
	
	glm::dvec3 mid; 
	glm::dvec3 interpolated;
	glm::dvec3 current;
	glm::dvec3 next;
	glm::vec4 tmp(1);
	glm::vec4 test_col(0, 0, 1, 1);
	if (bounds.size() > 1){
		for (int i = 0; i < bounds.size(); i++){
			int k = (i + 1 > bounds.size() - 1) ? 0 : i + 1;

			current = bounds[i];
			next = bounds[k];
			if (H[i] == false){ // If point is non-interceptive, project it. 
				insertPoint(_varray2, orthogonalProjection(current), tmp);
			}
			if (H[i] == true && H[i + 1] == false){ // current point is interceptive, next is not
				// find outer most point for interpolation
				mid = bisection(current, next, tolerance);
				for (int j = 1; j <= _isteps; j++){
					float t = (static_cast<float>(j) / _isteps);
					interpolated = interpolate(current, mid, t);
					_interceptVector = (j < _isteps) ? checkForIntercept(interpolated) : orthogonalProjection(interpolated);
					insertPoint(_varray2, _interceptVector, col_sq);
				}
			}
			if (H[i] == false && H[i + 1] == true){ // current point is non-interceptive, next is
				mid = bisection(next, current, tolerance);
				for (int j = 1; j <= _isteps; j++){
					float t = (static_cast<float>(j) / _isteps);
					interpolated = interpolate(mid, next, t);
					_interceptVector = (j > 1) ? checkForIntercept(interpolated) : orthogonalProjection(interpolated);
					insertPoint(_varray2, _interceptVector, col_sq);
				}
			}
			if (H[i] == true && H[i + 1] == true){ // both points intercept
				for (int j = 0; j <= _isteps; j++){
					float t = (static_cast<float>(j) / _isteps);
					interpolated = interpolate(current, next, t);
					_interceptVector = checkForIntercept(interpolated);
					insertPoint(_varray2, _interceptVector, col_sq);
				}
			}
		}
	 }
	if (_nrInserted == 0){
		_rebuild = false;
	} 
	else {
		_rebuild = true;
		//update size etc;
		_vtotal[1] = _nrInserted;
		_isize[1]  = _nrInserted;
		_vsize[1]  = static_cast<unsigned int>(_varray2.size());
		_iarray1[1] = new int[_isize[1]];
		for (unsigned int i = 0; i < _isize[1]; i++)
			_iarray1[1][i] = i;
	}
 
}

void RenderableFov::updateData() {
	glBindBuffer(GL_ARRAY_BUFFER, _vboID[0]);
	glBufferSubData(GL_ARRAY_BUFFER, 0, _vsize[0] * sizeof(GLfloat), &_varray1[0]);

	if (!_rebuild){
		glBindBuffer(GL_ARRAY_BUFFER, _vboID[1]);
		glBufferSubData(GL_ARRAY_BUFFER, 0, _vsize[1] * sizeof(GLfloat), &_varray2[0]);
	}else{
		glBindVertexArray(_vaoID[1]);
		glBindBuffer(GL_ARRAY_BUFFER, _vboID[1]);
		glBufferData(GL_ARRAY_BUFFER, _vsize[1] * sizeof(GLfloat), NULL, GL_STATIC_DRAW); // orphaning the buffer, sending NULL data.
		glBufferSubData(GL_ARRAY_BUFFER, 0, _vsize[1] * sizeof(GLfloat), &_varray2[0]);

		GLsizei st = sizeof(GLfloat) * _stride[0];

		glEnableVertexAttribArray(0);
		glEnableVertexAttribArray(1);
		glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, st, (void*)0);
		glVertexAttribPointer(1, 4, GL_FLOAT, GL_FALSE, st, (void*)(4 * sizeof(GLfloat)));

		glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, _iboID[1]);
		glBufferData(GL_ELEMENT_ARRAY_BUFFER, _isize[1] * sizeof(int), _iarray1[1], GL_STATIC_DRAW);
		glBindVertexArray(0);
	}
}
void RenderableFov::computeColors() {
	double t2 = openspace::ImageSequencer2::ref().getNextCaptureTime();
	double diff = (t2 - _time);
	float t = 0.0;
	if (diff <= 7.0)
        t = static_cast<float>(1.0 - (diff / 7.0));

	if (diff < 0.0)
        t = 0.f;
	// i need to add an *.h file with colortables....
	c_project = glm::vec4(0.0, 1.0, 0.00,1);
	col_end   = glm::vec4(1.00, 0.29, 0.00, 1);
	blue      = glm::vec4(0, 0.5, 0.7, 1);
	col_gray  = glm::vec4(0.7);
	col_start = glm::vec4(1.00, 0.89, 0.00, 1);
	col_sq    = glm::vec4(1.00, 0.29, 0.00, 1);

	col_end.x = c_project.x*t + col_end.x*(1 - t);
	col_end.y = c_project.y*t + col_end.y*(1 - t);
	col_end.z = c_project.z*t + col_end.z*(1 - t);

	blue.x = c_project.x*t + blue.x*(1 - t);
	blue.y = c_project.y*t + blue.y*(1 - t);
	blue.z = c_project.z*t + blue.z*(1 - t);

	col_sq.x = c_project.x*t + col_sq.x*(1 - t);
	col_sq.y = c_project.y*t + col_sq.y*(1 - t);
	col_sq.z = c_project.z*t + col_sq.z*(1 - t);

	blue.w = 0.5;
	c_project.w = 0.5;
	col_end.w = 0.5;
}

void RenderableFov::render(const RenderData& data) {
	assert(_programObject);
	_programObject->activate();
	// fetch data
	glm::mat4 transform(1);

	glm::mat4 spacecraftRot = glm::mat4(1);
	for (int i = 0; i < 3; i++){
		for (int j = 0; j < 3; j++){
			spacecraftRot[i][j] = static_cast<float>(_stateMatrix[i][j]);
		}
	}
	bool drawFOV = false;
	
	// setup the data to the shader
	_programObject->setUniform("ViewProjection", data.camera.viewProjectionMatrix());
	_programObject->setUniform("ModelTransform", transform);
	setPscUniforms(_programObject, &data.camera, data.position);
	
	if (openspace::ImageSequencer2::ref().isReady()){
		drawFOV = ImageSequencer2::ref().instrumentActive(_instrumentID);
	}


	if (drawFOV){
		// update only when time progresses.
		if (_oldTime != _time){
			std::string shape, instrument;
			std::vector<glm::dvec3> bounds;
			glm::dvec3 boresight;

			// fetch data for specific instrument (shape, boresight, bounds etc)
			bool found = openspace::SpiceManager::ref().getFieldOfView(_instrumentID, shape, instrument, boresight, bounds);
			if (!found) {
                LERROR("Could not locate instrument");
                return;
            }
			const unsigned int size = 4 * sizeof(float);
			int indx = 0;

			_fovTarget = _potentialTargets[0]; //default
			for (int i = 0; i < _potentialTargets.size(); i++){
				bool success = openspace::SpiceManager::ref().targetWithinFieldOfView(
                    _instrumentID,
                    _potentialTargets[i],
					_spacecraft,
                    _method,
					_aberrationCorrection,
                    _time,
                    _withinFOV);
				if (success && _withinFOV){
					_fovTarget = _potentialTargets[i];
					break;
				}
			}

			computeColors();

			double targetEpoch;
			// for each FOV vector
			for (int i = 0; i <= bounds.size(); i++){
				int r = (i == bounds.size()) ? 0 : i;
				
				// compute surface intercept
				openspace::SpiceManager::ref().getSurfaceIntercept(_fovTarget, _spacecraft, _instrumentID,
																   _frame, _method, _aberrationCorrection,
																   _time, targetEpoch, bounds[r], ipoint, ivec, _interceptTag[r]);
				// if not found, use the orthogonal projected point
				if (!_interceptTag[r]) _projectionBounds[r] = orthogonalProjection(bounds[r]);

				// VBO1 : draw vectors representing outer points of FOV. 
				if (_interceptTag[r]){
					_interceptVector = PowerScaledCoordinate::CreatePowerScaledCoordinate(ivec[0], ivec[1], ivec[2]);
					_interceptVector[3] += 3;
					// INTERCEPTIONS
					memcpy(&_varray1[indx], glm::value_ptr(glm::vec4(0)), size);
					indx += 4;
					memcpy(&_varray1[indx], glm::value_ptr(col_start), size);
					indx += 4;
					memcpy(&_varray1[indx], glm::value_ptr(_interceptVector.vec4()), size);
					indx += 4;
					memcpy(&_varray1[indx], glm::value_ptr(col_end), size);
					indx += 4;
				}
				else if (_withinFOV){
					// FOV OUTSIDE OBJECT
					memcpy(&_varray1[indx], glm::value_ptr(glm::vec4(0)), size);
					indx += 4;
					memcpy(&_varray1[indx], glm::value_ptr(glm::vec4(0, 0, 1, 1)), size);
					indx += 4;
					memcpy(&_varray1[indx], glm::value_ptr(_projectionBounds[r].vec4()), size);
					indx += 4;
					memcpy(&_varray1[indx], glm::value_ptr(blue), size);
					indx += 4;
				}
				else{
					glm::vec4 corner(bounds[r][0], bounds[r][1], bounds[r][2], data.position[3] + 2);
					corner = spacecraftRot*corner;
					// "INFINITE" FOV
					memcpy(&_varray1[indx], glm::value_ptr(glm::vec4(0)), size);
					indx += 4;
					memcpy(&_varray1[indx], glm::value_ptr(col_gray), size);
					indx += 4;
					memcpy(&_varray1[indx], glm::value_ptr(corner), size);
					indx += 4;
					memcpy(&_varray1[indx], glm::value_ptr(glm::vec4(0)), size);
					indx += 4;
				}
			}

			_interceptTag[bounds.size()] = _interceptTag[0]; 


			if (!(_instrumentID == "NH_LORRI") && !(_instrumentID == "ROS_NAVCAM-A")) // image plane replaces fov square
				fovProjection(_interceptTag, bounds);
			
			updateData();
			glm::vec3 aim = (spacecraftRot * glm::vec4(boresight, 1)).xyz;
			psc position;
			double lt;
			SpiceManager::ref().getTargetPosition(_fovTarget,
												  _spacecraft,
												  _frame,
												  _aberrationCorrection,
												  _time,
												  position,
												  lt);
			pss length = position.length();
			if (length[0] < DBL_EPSILON) {
				drawFOV = false;
				return;
			}
			//if aimed 80 deg away from target, dont draw white square
			if (glm::dot(glm::normalize(aim), glm::normalize(position.vec3())) < 0.2){
				drawFOV = false;
			}

		}
		_oldTime = _time;

		if (!_drawSolid) _mode = GL_LINES;
		else _mode = GL_TRIANGLE_STRIP;

		glLineWidth(_lineWidth);
		glBindVertexArray(_vaoID[0]);
		glDrawArrays(_mode, 0, _vtotal[0]);
		glBindVertexArray(0);

		if (drawFOV){
			glLineWidth(2.f);
			glBindVertexArray(_vaoID[1]);
			glDrawArrays(GL_LINE_LOOP, 0, _vtotal[1]);
			glBindVertexArray(0);

			//trying to improve interpolation altorithm @mm 
			//glPointSize(5.f);
			//glBindVertexArray(_vaoID[1]);
			//glDrawArrays(GL_POINTS, 0, _vtotal[1]);
			//glBindVertexArray(0);
			//glPointSize(1.f);
		}
        glLineWidth(1.f);
	}
	_programObject->deactivate();
}

void RenderableFov::update(const UpdateData& data) {
	_time  = data.time;
	openspace::SpiceManager::ref().getPositionTransformMatrix(_instrumentID, _frame, data.time, _stateMatrix);
}

} // namespace openspace