#include <stdio.h>
#include <stdlib.h>
#include <vector>
#include <memory>
#include <map>
#include <functional>
#include <list>
extern "C" {
	#include <lua.h>
	#include <lauxlib.h>
	#include <lualib.h>
}
#include <btBulletDynamicsCommon.h>
#include <btBulletCollisionCommon.h>
#include <BulletCollision/Gimpact/btGImpactShape.h>
#include "bphysmodel.hpp"
#include <shared/lua_api/common.hpp>
#include <shared/util/tinyobj.hpp>

#include <shared/lua_api/phys/bcollider.hpp>
#include <shared/lua_api/phys/bphysgeneric.hpp>

extern btDiscreteDynamicsWorld* World;
extern std::list<btRigidBody*> Objects;

//btRigidBody* load_obj(tinyobj_attrib_t attrib, tinyobj_shape_t *shapes, size_t num){
	//btTriangleMesh *trimesh = new btTriangleMesh();
//}

static void get_file_data(void* ctx, const char* filename, int is_mtl, const char *obj_filename, char **data, size_t *len){
	FILE *objfile = fopen(filename,"rb");
	fseek(objfile,0,SEEK_END);
	*len = (size_t)ftell(objfile);
	//printf("model data is %d long\n",(int)data_len);
	fseek(objfile,0,SEEK_SET);
	*data = (char*)malloc(sizeof(char) * *len);
	fread(*data , sizeof(char), *len, objfile);
	fclose(objfile);
}

//TODO: This will break in the future, see github.com/syoyo/tinyobjloader-c/issues/16
//"physicfile",mass[,position][,lookat] :: ud_rigidbody
void makebphysmodel(lua_State *L){
	//printf("making bphysmodel\n");
	int nargs = lua_gettop(L);
	double lx,ly,lz;
	double x,y,z;
	if(nargs > 3){
		//"physicsfile",{position},{lookat}
		popvector3d(L,&lx,&ly,&lz);
	}
	if(nargs > 2){
		//"physicsfile",{position}
		popvector3d(L,&x,&y,&z);
	}
	//printf("got arguments for bphysmodel\n");
	//"physicsfile"

	double mass = lua_tonumber(L,-1);
	const char *ppath = lua_tostring(L,-2);
	lua_pop(L,2);
	
	tinyobj_attrib_t attrib;
	tinyobj_shape_t *shapes = NULL;
	size_t meshcount;
	tinyobj_material_t *materials = NULL;
	size_t num_materials;

	size_t data_len = 0;
	FILE *objfile = fopen(ppath,"rb");
	fseek(objfile,0,SEEK_END);
	data_len = ftell(objfile);
	//printf("model data is %d long\n",(int)data_len);
	fseek(objfile,0,SEEK_SET);
	char *objdata = (char*)malloc(sizeof(char)*data_len);
	fread(objdata, sizeof(char), data_len, objfile);
	fclose(objfile);
	//printf("About to tinyobj_parse_obj\n");
	int err = tinyobj_parse_obj(
		&attrib, &shapes,
		&meshcount, &materials,
		&num_materials, ppath,
		get_file_data, (void*)NULL,
		TINYOBJ_FLAG_TRIANGULATE
	);
	//printf("Finished parsing tinyobj\n");
	if(err != TINYOBJ_SUCCESS){
		printf("Tinyobj failed to load model:%s\n",ppath);
	}
	//for(size_t s = 0; s < meshcount; s++){
		//btRigidBody *rb = load_obj(attrib,shapes,s);
	//}
	//u32 meshcount = pmesh->getMeshBufferCount();
	//__mingw_printf("attrib.num_vertices: %u\n",attrib.num_vertices);
	//__mingw_printf("attrib.num_faces: %u\n",attrib.num_faces);
	btTriangleMesh* trimesh = new btTriangleMesh();
	btVector3 vertexes[attrib.num_vertices];
	for(size_t i = 0; i < attrib.num_vertices; i++){ //0 - x, so num_vertices - 1
		float *vs =  attrib.vertices + (3*i);//3 floats per vertex 
		//For some reason irrlicht and bullet disagree with which direction +x is,
		//negate the x in the physics engine so the graphical stuff lines up
		//with the physics stuff
		float v1 = -vs[0];
		float v2 = vs[1];
		float v3 = vs[2];
		vertexes[i] = btVector3(v1,v2,v3);
		//printf("Adding vertex %lld at (%f,%f,%f)\n",i,v1,v2,v3);
	}
	//printf("Finished finding or adding vertexes\n");
	for(size_t i = 0; i < attrib.num_faces - 1; i+= 3){ //0 - y to num_faces - 1
		tinyobj_vertex_index_t i1,i2,i3;
		i1 = attrib.faces[i];
		i2 = attrib.faces[i+1];
		i3 = attrib.faces[i+2];
		btVector3 v1,v2,v3;
		v1 = vertexes[i1.v_idx];
		v2 = vertexes[i2.v_idx];
		v3 = vertexes[i3.v_idx];
		trimesh->addTriangle(vertexes[i1.v_idx],vertexes[i2.v_idx],vertexes[i3.v_idx],false);//Some triangles are "the wrong way round",
		//printf("Adding triangle:(%d,%d,%d)\n",i1.v_idx,i2.v_idx,i3.v_idx);
		trimesh->addTriangle(vertexes[i3.v_idx],vertexes[i2.v_idx],vertexes[i1.v_idx],true);//double-side all triangles
	}
	//printf("Finished adding triangle indicies\n");
	//printf("Done building trimesh\n");
	//btConvexTriangleMeshShape *shape = new btConvexTriangleMeshShape(trimesh);
	btGImpactShapeInterface *shape = new btGImpactMeshShape(trimesh);
	shape->updateBound();
	//btCollisionShape *shape = new btBvhTriangleMeshShape(trimesh,true);
	btTransform tr;
	tr.setIdentity();
	tr.setOrigin(btVector3(x,y,z));
	//printf("Created default motion shape\n");
	btDefaultMotionState *ms = new btDefaultMotionState(tr);
	btVector3 li;
	shape->calculateLocalInertia(mass, li);
	btRigidBody *rb = new btRigidBody(mass,ms,shape,li);
	World->addRigidBody(rb);
	Objects.push_back(rb);
	//printf("Rigid body finished\n");
	lua_pushlightuserdata(L,rb);//ud_rigidbody
}

//newbphysmodel("graphicfile","physicfile",mass[,position][,lookat]) :: ud_rigidbody
static int newbphysmodel(lua_State* L){
	//printf("Creating bphysmodel\n");
	int nargs = lua_gettop(L);
	double lx,ly,lz;
	double x,y,z;
	if(nargs > 4){
		//"graphicsfile","physicsfile",{position},{lookat}
		popvector3d(L,&lx,&ly,&lz);
	}else{
		lx = 1; ly = 1; lz = 1;
	}
	if(nargs > 3){
		//"graphicsfile","physicsfile",{position}
		popvector3d(L,&x,&y,&z);
	}else{
		x = 0; y = 0; z = 0;
	}
	//"graphicsfile","physicsfile"

	double mass = lua_tonumber(L,-1);
	const char *ppath = lua_tostring(L,-2);
	//const char *gpath = lua_tostring(L,-3);
	lua_pop(L,3);//

	lua_pushstring(L,ppath);//"phys_path"
	lua_pushnumber(L,mass);//"phys_path",double_mass
	pushvector3d(L,x,y,z);//"phys_path",double_mass,{position}
	pushvector3d(L,lx,ly,lz);//"phys_path",double_mass,{position},{lookat}
	//printf("Starting makeing bphysmodel\n");
	makebphysmodel(L);//ud_rigidbody
	//printf("Done making bphysmodel\n");
	btRigidBody *rb = (btRigidBody*)lua_touserdata(L,-1);
	//printf("bphysnode, createing the physics body\n");

	//Create the lua representation
	lua_newtable(L);//{}
	lua_pushlightuserdata(L,rb);//{},ud_rigidbody
	lua_setfield(L,-2,"collider");//{collider=ud_rigidbody}
	lua_pushstring(L,"rigidbody");//{collider=ud_rigidbody},"rigidbody"
	lua_setfield(L,-2,"type");//{rb}
	
	//printf("Added collider to lua rep.\n");

	//Add it to the global list of colliders
	lua_getglobal(L,"phys");//{rb},{phys}
	lua_getfield(L,-1,"colliders");//{rb},{phys},{phys.colliders}
	lua_pushlightuserdata(L,rb);//{rb},{phys},{phys.colliders},ud_collider
	lua_pushvalue(L,-4);//{rb},{phys},{phys.colliders},ud_collider,{rb}
	lua_settable(L,-3);//{rb},{phys},{phys.colliders}
	lua_pop(L,2);//{rb}

	//printf("Added collider to phys.colliders\n");

	//lua_pushlightuserdata(L,node);
	//lua_setfield(L,-2,"node");
	luaL_getmetatable(L,"phys.physmodel");
	lua_setmetatable(L,-2);
	//printf("finished creating the lua representation\n");

	return 1;
}

static const luaL_Reg bphysmodel_f[] = {
	{"newphysmodel",           newbphysmodel},
	{0,0},
};

static const luaL_Reg bphysmodel_m[] = {
	{0, 0},
};

int bphysmodel_register(lua_State* L){

	//device = d;

	//printf("bphysmodel registered\n");

	luaL_newmetatable(L, "phys.physmodel");//{m_physmodel}
	lua_newtable(L);//{m_physmodel},{}
	luaL_register(L,NULL,bcollider_m);
	luaL_register(L,NULL,bphysmodel_m);
	luaL_register(L,NULL,brigidbody_m);
	lua_setfield(L,-2,"__index");//{m_physmodel}
	lua_pop(L,1);//
	//luaL_register(L,NULL,igeneric_m); //Inherit all the things to do with scene nodes
	
	lua_getglobal(L,"phys");
	luaL_register(L,NULL,bphysmodel_f);
	lua_pop(L,1);

	return 0;
}