#ifndef STIM_OBJ_H
#define STIM_OBJ_H

#include <vector>
#include <sstream>
#include <fstream>
#include <stdlib.h>
#include <stim/parser/parser.h>
#include <stim/math/mathvec.h>

#include <ANN/ANN.h>

namespace stim{

/** This class provides an interface for loading, saving, and working with Wavefront OBJ files.
 *  The class structure uses similar terminology to the OBJ file structure, so one familiar with it
 *  should be able to work well with this class.
 *
 *  This class currently provides the ability to load explicitly defined geometric objects, including point lists,
 *  lines, and faces with positions, texture coordinates, and normals. This data is stored in a protected series
 *  of lists that are accessible to classes that extend this one.
 *
 *  Multiple helper classes are used to facilitate loading, storing, and saving geometry. These are protected
 *  and therefore only designed to be used within the confines of the class. These helper classes include:
 *
 *  vertex class - contains methods for loading, saving, and storing 1, 2, 3, and 4 component vectors
 *  triplet class - contains methods for loading, saving, and storing indexed vertices used for geometric objects
 *  geometry class - contains a list of triplets used to define a geometric structure, such as a face or line
 */

enum obj_type { OBJ_NONE, OBJ_LINE, OBJ_FACE, OBJ_POINTS };

template <typename T>
class obj{

protected:

	enum token_type { OBJ_INVALID, OBJ_V, OBJ_VT, OBJ_VN, OBJ_P, OBJ_L, OBJ_F };

	struct vertex : public stim::vec<T>{

		using vec<T>::push_back;
		using vec<T>::size;
		using vec<T>::at;

		//basic constructors (call the stim::vector constructors)
		vertex(){}
		vertex(T x, T y) : stim::vec<T>(x, y){}
		vertex(T x, T y, T z) : stim::vec<T>(x, y, z){}
		vertex(T x, T y, T z, T w) : stim::vec<T>(x, y, z, w){}

		//constructor creates a vertex from a line string
		vertex(std::string line){

			//create a temporary vector used to store string tokens
			std::vector<std::string> tokens = stim::parser::split(line, ' ');

			//create temporary storage for casting the token values
			T val;

			//for each token (skipping the first)
			for(unsigned int i =  1; i < tokens.size(); i++){
				std::stringstream ss(tokens[i]);				//create a stringstream object for casting
				ss>>val;										//cast the token to the correct numerical value
				push_back(val);									//push the coordinate into the vertex
			}
		}

		//output the vertex as a string
		std::string str(){

			std::stringstream ss;
			
			for(int i = 0; i < size(); i++){
				if(i > 0)
					ss<<' ';

				ss<<at(i);
			}

			return ss.str();	//return the vertex string
		}


	};	//end vertex

	//triplet used to specify geometric vertices consisting of a position vertex, texture vertex, and normal
	struct triplet : public std::vector<unsigned int>{
		
		//create a triplet given a parameter list (OBJ indices start at 1, so 0 can be used to indicate no value)
		triplet(unsigned int v, unsigned int vt = 0, unsigned int vn = 0){
			push_back(v);
			if(vn != 0){
				push_back(vt);
				push_back(vn);
			}
			else if(vt != 0)
				push_back(vt);
		}

		//build a triplet from a string
		triplet(std::string s){

			//create a temporary vector used to store string tokens
			std::vector<std::string> tokens = stim::parser::split(s, '\\');

			//std::cout<<"processing triplet: "<<s<<std::endl;
			if(tokens.size() >= 1)
				push_back( atoi( tokens[0].c_str() ) );

			if(tokens.size() >= 2){
				if(tokens[1].length())
					push_back( atoi( tokens[1].c_str() ) );
				else
					push_back(0);
			}

			if(tokens.size() == 3)
				push_back( atoi( tokens[2].c_str() ) );

		}

		//output the geometry as a string
		std::string str(){

			std::stringstream ss;

			ss<<at(0);	//the vertex is always the first value

			if(size() == 3){
				if(at(1) == 0)
					ss<<"\\\\"<<at(2);
				else
					ss<<'\\'<<at(1)<<'\\'<<at(2);
			}
			else if(size() == 2)
				ss<<"\\"<<at(1);

			return ss.str();
		}

	};	//end triplet

	//geometry used to specify a geometric structure consisting of several triplets
	struct geometry : public std::vector<triplet>{

		using std::vector<triplet>::size;
		using std::vector<triplet>::at;
		using std::vector<triplet>::push_back;

		geometry(){}

		//constructs a geometry object from a line read from an OBJ file
		geometry(std::string line){

			//create a temporary vector used to store string tokens
			std::vector<std::string> tokens = stim::parser::split(line, ' ');

			//for each triplet in the line
			for(unsigned int i = 1; i < tokens.size(); i++){
				//construct the triplet and push it to the geometry
				push_back( triplet(tokens[i]) );
			}

		}

		std::string str(){

			std::stringstream ss;

			for(unsigned int i = 0; i < size(); i++){

				if(i != 0)
					ss<<' ';

				ss<<at(i).str();
			}

			return ss.str();
		}
	};

	std::vector<vertex> V;		//vertex spatial position
	std::vector<vertex> VN;
	std::vector<vertex> VT;

	//structure lists
	std::vector<geometry> L;	//list of lines
	std::vector<geometry> P;	//list of points structures
	std::vector<geometry> F;	//list of faces

	//information for the current geometric object
	geometry current_geo;
	vertex current_vt;
	vertex current_vn;

		//flags for the current geometric object
		obj_type current_type;
		bool geo_flag_vt;
		bool geo_flag_vn;
		bool vert_flag_vt;
		bool vert_flag_vn;

	void update_vt(vertex vt){
		current_vt = vt;

		//the geometry vertex texture flag can only be set for the first vertex
		if(current_geo.size() == 0)
			geo_flag_vt = true;

		vert_flag_vt = true;
	}

	void update_vn(vertex vn){
		current_vn = vn;

		//the geometry normal flag can only be set for the first vertex
		if(current_geo.size() == 0)
			geo_flag_vn = true;

		vert_flag_vn = true;
	}

	//create a triple and add it to the current geometry
	void update_v(vertex vv){

		unsigned int v;
		unsigned int vt = 0;
		unsigned int vn = 0;

		//if the current geometry is using a texture coordinate, add the current texture coordinate to the geometry
		if(geo_flag_vt){
			if(vert_flag_vt)				//don't add it more than once
				VT.push_back(current_vt);
			vt = VT.size();
		}

		//if the current geometry is using a normal, add the current texture coordinate to the geometry
		if(geo_flag_vn){
			if(vert_flag_vn)				//don't add it more than once
				VN.push_back(current_vn);
			vn = VN.size();
		}

		//add the current vertex position to the geometry
		V.push_back(vv);
		v = V.size();

		//create a triplet and add it to the current geometry
		current_geo.push_back(triplet(v, vt, vn));

		//clear the vertex flags
		vert_flag_vt = false;
		vert_flag_vn = false;
	}

	void init(){
		//clear all lists
		V.clear();
		VT.clear();
		VN.clear();
		P.clear();
		L.clear();
		F.clear();

		//initialize all of the flags
		current_type = OBJ_NONE;
		geo_flag_vt = false;
		geo_flag_vn = false;
		vert_flag_vt = false;
		vert_flag_vn = false;
	}

	//gets the type of token representing the entry in the OBJ file
	token_type get_token(std::string s){

		//if the line contains a vertex
		if(s[0] == 'v'){
			if(s[1] == ' ') return OBJ_V;
			if(s[1] == 't') return OBJ_VT;
			if(s[1] == 'n') return OBJ_VN;
		}

		if(s[0] == 'l' && s[1] == ' ') return OBJ_L;
		if(s[0] == 'p' && s[1] == ' ') return OBJ_P;
		if(s[0] == 'f' && s[1] == ' ') return OBJ_F;

		return OBJ_INVALID;
	}

public:
	/// Constructor loads a Wavefront OBJ file
	obj(std::string filename){
		load(filename);
	}

	//functions for setting the texture coordinate for the next vertex
	void TexCoord(T x){ update_vt(vertex(x));}
	void TexCoord(T x, T y){ update_vt(vertex(x, y));}
	void TexCoord(T x, T y, T z){ update_vt(vertex(x, y, z));}
	void TexCoord(T x, T y, T z, T w){ update_vt(vertex(x, y, z, w));}

	//functions for setting the normal for the next vertex
	void Normal(T x){ update_vn(vertex(x));}
	void Normal(T x, T y){ update_vn(vertex(x, y));}
	void Normal(T x, T y, T z){ update_vn(vertex(x, y, z));}
	void Normal(T x, T y, T z, T w){ update_vn(vertex(x, y, z, w));}

	//functions for setting the next vertex position (note that this updates the current geometry)
	void Vertex(T x){ update_v(vertex(x));}
	void Vertex(T x, T y){ update_v(vertex(x, y));}
	void Vertex(T x, T y, T z){ update_v(vertex(x, y, z));}
	void Vertex(T x, T y, T z, T w){ update_v(vertex(x, y, z, w));}

	///This function starts drawing of a primitive object, such as a line, face, or point set

	/// @param t is the type of object to be drawn: OBJ_POINTS, OBJ_LINE, OBJ_FACE
	void Begin(obj_type t){
		current_type = t;
	}

	/// This function terminates drawing of a primitive object, such as a line, face, or point set
	void End(){

		//copy the current object to the appropriate list
		switch(current_type){

		case OBJ_NONE:
			std::cout<<"STIM::OBJ error, objEnd() called before objBegin()."<<std::endl;
			break;

		case OBJ_POINTS:
			P.push_back(current_geo);
			break;

		case OBJ_LINE:
			L.push_back(current_geo);
			break;

		case OBJ_FACE:
			F.push_back(current_geo);
		}

		//clear everything
		current_type = OBJ_NONE;
		current_geo.clear();
		vert_flag_vt = false;
		vert_flag_vn = false;
		geo_flag_vt = false;
		geo_flag_vn = false;
	}

	//output the OBJ structure as a string
	std::string str(){

		std::stringstream ss;

		unsigned int i;
		
		//output all of the vertices
		if(V.size()){
			ss<<"#vertex positions"<<std::endl;
			for(i = 0; i < V.size(); i++){
				ss<<"v "<<V[i].str()<<std::endl;
			}
		}

		//output all of the texture coordinates
		if(VT.size()){
			ss<<std::endl<<"#vertex texture coordinates"<<std::endl;
			for(i = 0; i < VT.size(); i++){
				ss<<"vt "<<VT[i].str()<<std::endl;
			}
		}

		//output all of the normals
		if(VN.size()){
			ss<<std::endl<<"#vertex normals"<<std::endl;
			for(i = 0; i < VN.size(); i++){
				ss<<"vn "<<VN[i].str()<<std::endl;
			}
		}

		//output all of the points
		if(P.size()){
			ss<<std::endl<<"#point structures"<<std::endl;
			for(i = 0; i < P.size(); i++){
				ss<<"p "<<P[i].str()<<std::endl;
			}
		}

		//output all of the lines
		if(L.size()){
			ss<<std::endl<<"#line structures"<<std::endl;
			for(i = 0; i < L.size(); i++){
				ss<<"l "<<L[i].str()<<std::endl;
			}
		}

		//output all of the lines
		if(F.size()){
			ss<<std::endl<<"#face structures"<<std::endl;
			for(i = 0; i < F.size(); i++){
				ss<<"f "<<F[i].str()<<std::endl;
			}
		}

		return ss.str();	//return the constructed string
	}

	obj(){
		init();		//private function that initializes everything
	}

	void clear(){
		init();
	}

	/// This function saves the current structure as a Wavefront OBJ file

	/// @param filename is the name of the file to be saved
	bool save(std::string filename){

		std::ofstream outfile(filename.c_str());

		if(!outfile){
			std::cout<<"STIM::OBJ error opening file for writing"<<std::endl;
			return false;
		}

		//output the OBJ data to the file
		outfile<<str();

		//close the file
		outfile.close();

		return true;
	}

	/// Load a Wavefront OBJ file (support for faces, lines, and point lists)

	/// @param filename is the name of the OBJ file to load
	bool load(std::string filename){

		//load the file
		std::ifstream infile(filename.c_str());

		//if the file is invalid, throw an error
		if(!infile){
			std::cout<<"STIM::OBJ Error loading file "<<filename<<std::endl;
			return false;
		}

		std::string line;
		getline(infile, line);		//get the first line
		while(infile){



			//get the token representing the first parameter
			token_type token = get_token(line);

			switch(token){

			case OBJ_INVALID:
				break;

			case OBJ_V:
				V.push_back(vertex(line));
				break;

			case OBJ_VT:
				VT.push_back(vertex(line));
				break;

			case OBJ_VN:
				VN.push_back(vertex(line));
				break;

			case OBJ_F:
				F.push_back(geometry(line));
				break;

			case OBJ_L:
				L.push_back(geometry(line));
				break;

			};

			//get the next line
			getline(infile, line);
		}



		//close the file
		infile.close();

		return true;

	}

	/// Return the number of position vertices in the OBJ model
	unsigned int numV(){
		return V.size();
	}

	/// Retrieve the vertex stored in index i

	/// @param i is the desired vertex index
	stim::vec<T> getV(unsigned int i){

		stim::vec<T> v = V[i];
		return v;
	}

	stim::vec<T> centroid(){

		//get the number of coordinates
		unsigned int N = V[0].size();

		//allocate space for the minimum and maximum coordinate points (bounding box corners)
		stim::vec<float> vmin, vmax;
		vmin.resize(N);
		vmax.resize(N);

		//find the minimum and maximum value for each coordinate
		unsigned int NV = V.size();
		for(unsigned int v = 0; v < NV; v++)
			for(unsigned int i = 0; i < N; i++){

				if(V[v][i] < vmin[i])
					vmin[i] = V[v][i];
				if(V[v][i] > vmax[i])
					vmax[i] = V[v][i];
			}

		//find the centroid using the min and max points
		stim::vec<T> c = vmin * 0.5 + vmax * 0.5;

		return c;
	}

	/// Returns the number of lines in the OBJ structure
	unsigned int numL(){
		return L.size();
	}

	/// Returns all points in the line corresponding to a given index

	/// @param i is the index of the desired line
	std::vector< stim::vec<T> > getL_V(unsigned int i){

		//get the number of points in the specified line
		unsigned int nP = L[i].size();

		//create a vector of points
		std::vector< stim::vec<T> > l;

		//set the size of the vector
		l.resize(nP);

		//copy the points from the point list to the stim vector
		unsigned int pi;
		for(unsigned int p = 0; p < nP; p++){

			//get the index of the geometry point
			pi = L[i][p][0] - 1;

			//get the coordinates of the current point
			stim::vec<T> newP = V[pi];

			//copy the point into the vector
			l[p] = newP;
		}

		return l;

	}

	/// Returns the vertex indices for the specified line
	/// @param i is the index of the line
	std::vector< unsigned int > getL_Vi(unsigned int i){

		unsigned int nP = L[i].size();

		std::vector< unsigned int > l;

		//set the size of the vector
		l.resize(nP);

		//copy the indices from the geometry structure to the array
		for(unsigned int p = 0; p < nP; p++){
			
			l[p] = L[i][p][0];

		}

		return l;

	}

};






};


#endif