#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include "ri.h"
#include "types.h"
#include "matrix.h"
#include "linklist.h"
#include "vars.h"
#include "grid.h"
#include "graph_state.h"
#include "object.h"

void Grid_create(grid_t *pObj, uint32_t npu, uint32_t npv)
{
	uint32_t i, j, k, nu, nv;
	ri_var_t *pVar;

	nu = npu + 1;
	nv = npv + 1;

	pObj->nu = nu;
	pObj->nv = nv;
	pObj->npoints = nu*nv;

	VarListInit(&pObj->vars);

	pObj->pPointPos = (pixelpos_t*)malloc(nu*nv*sizeof(pixelpos_t));
	memset(pObj->pPointPos, 0, nu*nv*sizeof(pixelpos_t));

	pObj->pPointState = (point_state_t*)malloc(nu*nv*sizeof(point_state_t));
	memset(pObj->pPointState, 0, nu*nv*sizeof(point_state_t));

	k=0;
	for (i=0; i < nv; i++)
	{
		for (j=0; j < nu; j++)
		{
			pObj->pPointPos[k][0] = j;
			pObj->pPointPos[k][1] = i;
			k++;
		}
	}
	for (i=0; i < (nv-1)*nu; i += nu)
	{
		for (j=0; j < nu-1; j++)
		{
			pObj->pPointState[i+j].has_face = 1;
		}
	}
	for (i=0; i < pObj->npoints; i ++)
	{
		pObj->pPointState[i].visible = 1;
	}

}

void Grid_free(grid_t *pObj)
{
	if (pObj->pPointPos)
		free(pObj->pPointPos);

	if (pObj->pPointState)
		free(pObj->pPointState);

//	VarListDelByName(&pObj->vars, "P");
//	VarListPrint(&pObj->vars);
	VarListFree(&pObj->vars);

}

void Grid_CopyVarByName(grid_t *pObj, RtToken pDstName, RtToken pSrcName)
{
	ri_var_t *pSrc, *pDst;
	RtPointer pSrcData, pDstData;

	pSrc = VarListFindByName(&pObj->vars, pSrcName);
	pDst = VarListFindByName(&pObj->vars, pDstName);

	if (pDst)
	{
		if (pSrc->etype != pDst->etype)
		{
			fprintf(stderr, "Grid_CopyVar(): Variables are not of same type!\n");
			return;
		}

		if (pSrc->nvalues != pDst->nvalues)
		{
			fprintf(stderr, "Grid_CopyVar(): Variables are not of same size!\n");
			return;
		}
	}
	else
	{
		pDst = VarListDeclare(&pObj->vars, pDstName, pSrc->cls, pSrc->type);
		VarAlloc(pDst, pSrc->nvalues);
	}

	pSrcData = VarGet(pSrc);
	pDstData = VarGet(pDst);

	memcpy(pDstData, pSrcData, pSrc->value_size*pSrc->nvalues);

}

void Grid_InitUV(grid_t *pObj)
{
	uint32_t i, j, k, nu, nv;
	RtFloat *pU, *pV, u, v, du, dv;
	ri_var_t *pVar;

	nu = pObj->nu;
	nv = pObj->nv;
	du = (RtFloat)1/(nu-1);
	dv = (RtFloat)1/(nv-1);

	pVar = VarListDeclare(&pObj->vars, "u", "varying", "float");
	pU = (RtFloat*)VarAlloc(pVar, nu*nv);

	pVar = VarListDeclare(&pObj->vars, "v", "varying", "float");
	pV = (RtFloat*)VarAlloc(pVar, nu*nv);

	pVar = VarListDeclare(&pObj->vars, "du", "uniform", "float");
	VarSet(pVar, (RtPointer)&du, 1);

	pVar = VarListDeclare(&pObj->vars, "dv", "uniform", "float");
	VarSet(pVar, (RtPointer)&dv, 1);

	// Init uv-coords
	k = 0;
	v = 0;
	for (i=0; i < nv; i++)
	{
		u = 0;
		for (j=0; j < nu; j++)
		{
			pU[k] = u;
			pV[k] = v;
			u += du;
			k++;
		}
		v += dv;
	}

}

void Grid_assign_derivs(grid_t *pObj)
{
	uint32_t i, j, k, nu, nv;
	RtPoint *pPoint, *pDPDU, *pDPDV, dpd2;
	RtFloat du, dv, ik;
	ri_var_t *pVar;

	nu = pObj->nu;
	nv = pObj->nv;

	pPoint = (RtPoint*)VarGetByName(&pObj->vars, "P");
	du = *((RtFloat*)VarGetByName(&pObj->vars, "du"));
	dv = *((RtFloat*)VarGetByName(&pObj->vars, "dv"));

	pDPDU = (RtPoint*)VarGetByName(&pObj->vars, "dpdu");
	if (!pDPDU)
		pDPDU = (RtPoint*)VarAlloc(VarListDeclare(&pObj->vars, "dpdu", "varying", "point"), pObj->npoints);

	pDPDV = (RtPoint*)VarGetByName(&pObj->vars, "dpdv");
	if (!pDPDV)
		pDPDV = (RtPoint*)VarAlloc(VarListDeclare(&pObj->vars, "dpdv", "varying", "point"), pObj->npoints);

	for (i=0; i < pObj->npoints; i += nu)
	{
		for (j=0; j < nu-1; j++)
		{
			ik =  (RtFloat)1/du;
			for (k=0; k < 3; k++)
			{
				pDPDU[i+j][k] = ik*(pPoint[i+j+1][k] - pPoint[i+j][k]);
			}
		}
		for (k=0; k < 3; k++)
		{
			pDPDU[i+j][k] = 2*pDPDU[i+j-1][k] - pDPDU[i+j-2][k];
		}

	}
	for (i=0; i < nu; i++)
	{
		for (j=0; j < (nv-1)*nu; j += nu)
		{
			ik =  (RtFloat)1/dv;
			for (k=0; k < 3; k++)
			{
				pDPDV[i+j][k] = ik*(pPoint[i+j+nu][k] - pPoint[i+j][k]);
			}
		}
		for (k=0; k < 3; k++)
		{
			pDPDV[i+j][k] = 2*pDPDV[i+j-nu][k] - pDPDV[i+j-2*nu][k];
		}
	}

}

void Grid_calc_normal(grid_t *pObj, RtToken name)
{
	uint32_t i;
	RtFloat *a, *b;
	RtPoint *pPoint, *pDPDU, *pDPDV, *pN;

	pDPDU = (RtPoint*)VarGetByName(&pObj->vars, "dpdu");
	pDPDV = (RtPoint*)VarGetByName(&pObj->vars, "dpdv");
	pN = (RtPoint*)VarGetByName(&pObj->vars, name);
	if (!pN)
		pN = (RtPoint*)VarAlloc(VarListDeclare(&pObj->vars, name, "varying", "point"), pObj->npoints);

	for (i=0; i < pObj->npoints; i++)
	{
		a = pDPDU[i];
		b = pDPDV[i];
		pN[i][0] = a[1]*b[2] - a[2]*b[1];
		pN[i][1] = a[2]*b[0] - a[0]*b[2];
		pN[i][2] = a[0]*b[1] - a[1]*b[0];
	}
}

void Grid_displace(grid_t *pObj)
{
	uint32_t i, j, k;
	RtPoint *pP, *pDPDU, *pDPDV, *pN;
	RtColor *pCs, *pCi;
	RtFloat *pU, *pV, fd, kn, kd;

	pP = (RtPoint*)VarGetByName(&pObj->vars, "P");
	pU = (RtFloat*)VarGetByName(&pObj->vars, "u");
	pV = (RtFloat*)VarGetByName(&pObj->vars, "v");
	pDPDU = (RtPoint*)VarGetByName(&pObj->vars, "dpdu");
	pDPDV = (RtPoint*)VarGetByName(&pObj->vars, "dpdv");
	pN = (RtPoint*)VarGetByName(&pObj->vars, "Ng");

	kd = 0.00;
	for (i=0; i < pObj->npoints; i++)
	{

		if (!pObj->pPointState[i].visible)
			continue;

		kn = (RtFloat)1/Norm((RtFloat*)pN[i], 3);

		fd = cos(10*3.141592654*pV[i]);
		pP[i][0] += kd*fd*pN[i][0]*kn;
		pP[i][1] += kd*fd*pN[i][1]*kn;
		pP[i][2] += kd*fd*pN[i][2]*kn;
	}
	Grid_assign_derivs(pObj);
	Grid_calc_normal(pObj, "Ng");

}

void Normalize(RtPoint N, RtPoint Nn)
{
	RtFloat k;
	
	k = (RtFloat)1/Norm((RtFloat*)N, 3);

	Nn[0] = N[0]*k;
	Nn[1] = N[1]*k;
	Nn[2] = N[2]*k;
	
}

void Negate(RtPoint N, RtPoint Ni)
{

	Ni[0] = -N[0];
	Ni[1] = -N[1];
	Ni[2] = -N[2];
	
}

RtFloat* Diffuse(linkedlist_t *pLightList, RtPoint N, RtPoint P)
{
	static RtFloat result[3];
	RtPoint L, Ln, Nn;
	linkedlist_t *pLights;
	object_t *pLight;
	RtFloat k, kn;

	pLights = LinkedList_find_first(pLightList);

	memset(result, 0, sizeof(RtColor));
	Normalize(N, Nn);

	while(pLights)
	{
		pLight = (object_t*)LinkedList_get(pLights);
		L[0] = (*pLight->pXform)[0][3] - P[0];
		L[1] = (*pLight->pXform)[1][3] - P[1];
		L[2] = (*pLight->pXform)[2][3] - P[2];
		Normalize(L, Ln);
		k = MAX(ScalarProduct(Ln, Nn, 3), 0);

		result[0] += pLight->pAttr->cs[0] * k;
		result[1] += pLight->pAttr->cs[1] * k;
		result[2] += pLight->pAttr->cs[2] * k;

		pLights = pLights->pNext;
	}

	return result;
	
}

RtFloat* Specular(linkedlist_t *pLightList, RtPoint N, RtPoint P, RtPoint I, RtFloat roughness)
{
	static RtFloat result[3];
	RtPoint L, H, Hn, Ln, Nn, In, Ini;
	linkedlist_t *pLights;
	object_t *pLight;
	RtFloat k, kn;

	pLights = LinkedList_find_first(pLightList);

	memset(result, 0, sizeof(RtColor));
	Normalize(N, Nn);
	Normalize(I, In);
	Negate(In, Ini);

	while(pLights)
	{
		pLight = (object_t*)LinkedList_get(pLights);
		L[0] = (*pLight->pXform)[0][3] - P[0];
		L[1] = (*pLight->pXform)[1][3] - P[1];
		L[2] = (*pLight->pXform)[2][3] - P[2];
		Normalize(L, Ln);
		H[0] = Ini[0] + Ln[0];
		H[1] = Ini[1] + Ln[1];
		H[2] = Ini[2] + Ln[2];
		Normalize(H, Hn);

		k = pow(MAX(ScalarProduct(Nn, Hn, 3), 0), (RtFloat)1/roughness);

		result[0] += pLight->pAttr->cs[0] * k;
		result[1] += pLight->pAttr->cs[1] * k;
		result[2] += pLight->pAttr->cs[2] * k;

		pLights = pLights->pNext;
	}

	return result;
	
}

void Grid_shade(grid_t *pObj, RtMatrix *pXform, linkedlist_t *pLights)
{
	uint32_t i, j, k;
	RtPoint *pP, *pDPDU, *pDPDV, *pN, *pI;
	RtColor *pCs, *pCi;
	RtFloat *pU, *pV, fd, kn, vt, p[4], d[4], *pCl_diff, *pCl_spec;
	RtFloat kd, ks;

	pP = (RtPoint*)VarGetByName(&pObj->vars, "P");
	pU = (RtFloat*)VarGetByName(&pObj->vars, "u");
	pV = (RtFloat*)VarGetByName(&pObj->vars, "v");
	pCs = (RtColor*)VarGetByName(&pObj->vars, "Cs");
	pDPDU = (RtPoint*)VarGetByName(&pObj->vars, "dpdu");
	pDPDV = (RtPoint*)VarGetByName(&pObj->vars, "dpdv");
	pN = (RtPoint*)VarGetByName(&pObj->vars, "Ng");
	pI = (RtPoint*)VarGetByName(&pObj->vars, "I");

	pCi = (RtColor*)VarAlloc(VarListDeclare(&pObj->vars, "Ci", "varying", "color"), pObj->npoints);
	p[3] = (RtFloat)1.0;

	kd = 1;
	ks = 0.4;

	for (i=0; i < pObj->npoints; i++)
	{

		if (!pObj->pPointState[i].visible)
			continue;

		pCl_diff = Diffuse(pLights, pN[i], pP[i]);
		pCl_spec = Specular(pLights, pN[i], pP[i], pI[i], 0.01);

		fd = (RtFloat)rand()/RAND_MAX;
		pCi[i][0] = (*pCs)[0]*(kd*pCl_diff[0]) + ks*pCl_spec[0];
		pCi[i][1] = (*pCs)[1]*(kd*pCl_diff[1]) + ks*pCl_spec[1];
		pCi[i][2] = (*pCs)[2]*(kd*pCl_diff[2]) + ks*pCl_spec[2];
	}

}

void Grid_shadeConstant(grid_t *pObj)
{
	uint32_t i;
	RtColor *pCs, *pCi;

	pCs = (RtColor*)VarGetByName(&pObj->vars, "Cs");
	pCi = (RtColor*)VarAlloc(VarListDeclare(&pObj->vars, "Ci", "varying", "color"), pObj->npoints);

	for (i=0; i < pObj->npoints; i++)
	{

		if (!pObj->pPointState[i].visible)
			continue;


		pCi[i][0] = (*pCs)[0];
		pCi[i][1] = (*pCs)[1];
		pCi[i][2] = (*pCs)[2];
	}

}