/*
 * Copyright 2011, Blender Foundation.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 */

#include "kernel_compat_cpu.h"
#include "kernel_types.h"
#include "kernel_globals.h"
#include "kernel_object.h"

#include "osl_services.h"
#include "osl_shader.h"

#include "util_foreach.h"

#include <OSL/oslexec.h>

CCL_NAMESPACE_BEGIN

tls_ptr(OSLGlobals::ThreadData, OSLGlobals::thread_data);

/* Threads */

void OSLShader::thread_init(KernelGlobals *kg)
{
	OSL::pvt::ShadingSystemImpl *ssi = (OSL::pvt::ShadingSystemImpl *)kg->osl.ss;

	OSLGlobals::ThreadData *tdata = new OSLGlobals::ThreadData();

	memset(&tdata->globals, 0, sizeof(OSL::ShaderGlobals));
	tdata->thread_info = ssi->create_thread_info();

	tls_set(kg->osl.thread_data, tdata);

	((OSLRenderServices *)ssi->renderer())->thread_init(kg);
}

void OSLShader::thread_free(KernelGlobals *kg)
{
	OSL::pvt::ShadingSystemImpl *ssi = (OSL::pvt::ShadingSystemImpl *)kg->osl.ss;

	OSLGlobals::ThreadData *tdata = tls_get(OSLGlobals::ThreadData, kg->osl.thread_data);

	ssi->destroy_thread_info(tdata->thread_info);

	delete tdata;
}

/* Globals */

#define TO_VEC3(v) (*(OSL::Vec3 *)&(v))
#define TO_COLOR3(v) (*(OSL::Color3 *)&(v))
#define TO_FLOAT3(v) make_float3(v[0], v[1], v[2])

static void shaderdata_to_shaderglobals(KernelGlobals *kg, ShaderData *sd,
                                        int path_flag, OSL::ShaderGlobals *globals)
{
	/* copy from shader data to shader globals */
	globals->P = TO_VEC3(sd->P);
	globals->dPdx = TO_VEC3(sd->dP.dx);
	globals->dPdy = TO_VEC3(sd->dP.dy);
	globals->I = TO_VEC3(sd->I);
	globals->dIdx = TO_VEC3(sd->dI.dx);
	globals->dIdy = TO_VEC3(sd->dI.dy);
	globals->N = TO_VEC3(sd->N);
	globals->Ng = TO_VEC3(sd->Ng);
	globals->u = sd->u;
	globals->dudx = sd->du.dx;
	globals->dudy = sd->du.dy;
	globals->v = sd->v;
	globals->dvdx = sd->dv.dx;
	globals->dvdy = sd->dv.dy;
	globals->dPdu = TO_VEC3(sd->dPdu);
	globals->dPdv = TO_VEC3(sd->dPdv);
	globals->surfacearea = (sd->object == ~0) ? 1.0f : object_surface_area(kg, sd->object);

	/* booleans */
	globals->raytype = path_flag; /* todo: add our own ray types */
	globals->backfacing = (sd->flag & SD_BACKFACING);

	/* don't know yet if we need this */
	globals->flipHandedness = false;
	
	/* shader data to be used in services callbacks */
	globals->renderstate = sd; 

	/* hacky, we leave it to services to fetch actual object matrix */
	globals->shader2common = sd;
	globals->object2common = sd;

	/* must be set to NULL before execute */
	globals->Ci = NULL;
}

/* Surface */

static void flatten_surface_closure_tree(ShaderData *sd, bool no_glossy,
                                         const OSL::ClosureColor *closure, float3 weight = make_float3(1.0f, 1.0f, 1.0f))
{
	/* OSL gives us a closure tree, we flatten it into arrays per
	 * closure type, for evaluation, sampling, etc later on. */

	if (closure->type == OSL::ClosureColor::COMPONENT) {
		OSL::ClosureComponent *comp = (OSL::ClosureComponent *)closure;
		OSL::ClosurePrimitive *prim = (OSL::ClosurePrimitive *)comp->data();

		if (prim) {
			ShaderClosure sc;
			sc.prim = prim;
			sc.weight = weight;

			switch (prim->category()) {
				case ClosurePrimitive::BSDF: {
					if (sd->num_closure == MAX_CLOSURE)
						return;

					OSL::BSDFClosure *bsdf = (OSL::BSDFClosure *)prim;
					ustring scattering = bsdf->scattering();

					/* no caustics option */
					if (no_glossy && scattering == OSL::Labels::GLOSSY)
						return;

					/* sample weight */
					float albedo = bsdf->albedo(TO_VEC3(sd->I));
					float sample_weight = fabsf(average(weight)) * albedo;
					float sample_sum = sd->osl_closure.bsdf_sample_sum + sample_weight;

					sc.sample_weight = sample_weight;
					sc.type = CLOSURE_BSDF_ID;
					sd->osl_closure.bsdf_sample_sum = sample_sum;

					/* scattering flags */
					if (scattering == OSL::Labels::DIFFUSE)
						sd->flag |= SD_BSDF | SD_BSDF_HAS_EVAL;
					else if (scattering == OSL::Labels::GLOSSY)
						sd->flag |= SD_BSDF | SD_BSDF_HAS_EVAL | SD_BSDF_GLOSSY;
					else
						sd->flag |= SD_BSDF;

					/* add */
					sd->closure[sd->num_closure++] = sc;
					break;
				}
				case ClosurePrimitive::Emissive: {
					if (sd->num_closure == MAX_CLOSURE)
						return;

					/* sample weight */
					float sample_weight = fabsf(average(weight));
					float sample_sum = sd->osl_closure.emissive_sample_sum + sample_weight;

					sc.sample_weight = sample_weight;
					sc.type = CLOSURE_EMISSION_ID;
					sd->osl_closure.emissive_sample_sum = sample_sum;

					/* flag */
					sd->flag |= SD_EMISSION;

					sd->closure[sd->num_closure++] = sc;
					break;
				}
				case ClosurePrimitive::Holdout:
					if (sd->num_closure == MAX_CLOSURE)
						return;

					sc.sample_weight = 0.0f;
					sc.type = CLOSURE_HOLDOUT_ID;
					sd->flag |= SD_HOLDOUT;
					sd->closure[sd->num_closure++] = sc;
					break;
				case ClosurePrimitive::BSSRDF:
				case ClosurePrimitive::Debug:
					break; /* not implemented */
				case ClosurePrimitive::Background:
				case ClosurePrimitive::Volume:
					break; /* not relevant */
			}
		}
	}
	else if (closure->type == OSL::ClosureColor::MUL) {
		OSL::ClosureMul *mul = (OSL::ClosureMul *)closure;
		flatten_surface_closure_tree(sd, no_glossy, mul->closure, TO_FLOAT3(mul->weight) * weight);
	}
	else if (closure->type == OSL::ClosureColor::ADD) {
		OSL::ClosureAdd *add = (OSL::ClosureAdd *)closure;
		flatten_surface_closure_tree(sd, no_glossy, add->closureA, weight);
		flatten_surface_closure_tree(sd, no_glossy, add->closureB, weight);
	}
}

void OSLShader::eval_surface(KernelGlobals *kg, ShaderData *sd, float randb, int path_flag)
{
	/* gather pointers */
	OSL::pvt::ShadingSystemImpl *ssi = (OSL::pvt::ShadingSystemImpl *)kg->osl.ss;
	OSLGlobals::ThreadData *tdata = tls_get(OSLGlobals::ThreadData, kg->osl.thread_data);
	OSL::ShaderGlobals *globals = &tdata->globals;
	OSL::pvt::ShadingContext *ctx = ssi->get_context(tdata->thread_info);

	/* setup shader globals from shader data */
	sd->osl_ctx = ctx;
	shaderdata_to_shaderglobals(kg, sd, path_flag, globals);

	/* execute shader for this point */
	int shader = sd->shader & SHADER_MASK;

	if (kg->osl.surface_state[shader])
		ctx->execute(OSL::pvt::ShadUseSurface, *(kg->osl.surface_state[shader]), *globals);

	/* flatten closure tree */
	sd->num_closure = 0;
	sd->randb_closure = randb;

	if (globals->Ci) {
		bool no_glossy = (path_flag & PATH_RAY_DIFFUSE) && kernel_data.integrator.no_caustics;
		flatten_surface_closure_tree(sd, no_glossy, globals->Ci);
	}
}

/* Background */

static float3 flatten_background_closure_tree(const OSL::ClosureColor *closure)
{
	/* OSL gives us a closure tree, if we are shading for background there
	 * is only one supported closure type at the moment, which has no evaluation
	 * functions, so we just sum the weights */

	if (closure->type == OSL::ClosureColor::COMPONENT) {
		OSL::ClosureComponent *comp = (OSL::ClosureComponent *)closure;
		OSL::ClosurePrimitive *prim = (OSL::ClosurePrimitive *)comp->data();

		if (prim && prim->category() == OSL::ClosurePrimitive::Background)
			return make_float3(1.0f, 1.0f, 1.0f);
	}
	else if (closure->type == OSL::ClosureColor::MUL) {
		OSL::ClosureMul *mul = (OSL::ClosureMul *)closure;

		return TO_FLOAT3(mul->weight) * flatten_background_closure_tree(mul->closure);
	}
	else if (closure->type == OSL::ClosureColor::ADD) {
		OSL::ClosureAdd *add = (OSL::ClosureAdd *)closure;

		return flatten_background_closure_tree(add->closureA) +
		       flatten_background_closure_tree(add->closureB);
	}

	return make_float3(0.0f, 0.0f, 0.0f);
}

float3 OSLShader::eval_background(KernelGlobals *kg, ShaderData *sd, int path_flag)
{
	/* gather pointers */
	OSL::pvt::ShadingSystemImpl *ssi = (OSL::pvt::ShadingSystemImpl *)kg->osl.ss;
	OSLGlobals::ThreadData *tdata = tls_get(OSLGlobals::ThreadData, kg->osl.thread_data);
	OSL::ShaderGlobals *globals = &tdata->globals;
	OSL::pvt::ShadingContext *ctx = ssi->get_context(tdata->thread_info);

	/* setup shader globals from shader data */
	sd->osl_ctx = ctx;
	shaderdata_to_shaderglobals(kg, sd, path_flag, globals);

	/* execute shader for this point */
	if (kg->osl.background_state)
		ctx->execute(OSL::pvt::ShadUseSurface, *kg->osl.background_state, *globals);

	/* return background color immediately */
	if (globals->Ci)
		return flatten_background_closure_tree(globals->Ci);

	return make_float3(0.0f, 0.0f, 0.0f);
}

/* Volume */

static void flatten_volume_closure_tree(ShaderData *sd,
                                        const OSL::ClosureColor *closure, float3 weight = make_float3(1.0f, 1.0f, 1.0f))
{
	/* OSL gives us a closure tree, we flatten it into arrays per
	 * closure type, for evaluation, sampling, etc later on. */

	if (closure->type == OSL::ClosureColor::COMPONENT) {
		OSL::ClosureComponent *comp = (OSL::ClosureComponent *)closure;
		OSL::ClosurePrimitive *prim = (OSL::ClosurePrimitive *)comp->data();

		if (prim) {
			ShaderClosure sc;
			sc.prim = prim;
			sc.weight = weight;

			switch (prim->category()) {
				case ClosurePrimitive::Volume: {
					if (sd->num_closure == MAX_CLOSURE)
						return;

					/* sample weight */
					float sample_weight = fabsf(average(weight));
					float sample_sum = sd->osl_closure.volume_sample_sum + sample_weight;

					sc.sample_weight = sample_weight;
					sc.type = CLOSURE_VOLUME_ID;
					sd->osl_closure.volume_sample_sum = sample_sum;

					/* add */
					sd->closure[sd->num_closure++] = sc;
					break;
				}
				case ClosurePrimitive::Holdout:
				case ClosurePrimitive::Debug:
					break; /* not implemented */
				case ClosurePrimitive::Background:
				case ClosurePrimitive::BSDF:
				case ClosurePrimitive::Emissive:
				case ClosurePrimitive::BSSRDF:
					break; /* not relevant */
			}
		}
	}
	else if (closure->type == OSL::ClosureColor::MUL) {
		OSL::ClosureMul *mul = (OSL::ClosureMul *)closure;
		flatten_volume_closure_tree(sd, mul->closure, TO_FLOAT3(mul->weight) * weight);
	}
	else if (closure->type == OSL::ClosureColor::ADD) {
		OSL::ClosureAdd *add = (OSL::ClosureAdd *)closure;
		flatten_volume_closure_tree(sd, add->closureA, weight);
		flatten_volume_closure_tree(sd, add->closureB, weight);
	}
}

void OSLShader::eval_volume(KernelGlobals *kg, ShaderData *sd, float randb, int path_flag)
{
	/* gather pointers */
	OSL::pvt::ShadingSystemImpl *ssi = (OSL::pvt::ShadingSystemImpl *)kg->osl.ss;
	OSLGlobals::ThreadData *tdata = tls_get(OSLGlobals::ThreadData, kg->osl.thread_data);
	OSL::ShaderGlobals *globals = &tdata->globals;
	OSL::pvt::ShadingContext *ctx = ssi->get_context(tdata->thread_info);

	/* setup shader globals from shader data */
	sd->osl_ctx = ctx;
	shaderdata_to_shaderglobals(kg, sd, path_flag, globals);

	/* execute shader */
	int shader = sd->shader & SHADER_MASK;

	if (kg->osl.volume_state[shader])
		ctx->execute(OSL::pvt::ShadUseSurface, *(kg->osl.volume_state[shader]), *globals);

	/* retrieve resulting closures */
	sd->osl_closure.volume_sample_sum = 0.0f;
	sd->osl_closure.num_volume = 0;
	sd->osl_closure.randb = randb;

	if (globals->Ci)
		flatten_volume_closure_tree(sd, globals->Ci);
}

/* Displacement */

void OSLShader::eval_displacement(KernelGlobals *kg, ShaderData *sd)
{
	/* gather pointers */
	OSL::pvt::ShadingSystemImpl *ssi = (OSL::pvt::ShadingSystemImpl *)kg->osl.ss;
	OSLGlobals::ThreadData *tdata = tls_get(OSLGlobals::ThreadData, kg->osl.thread_data);
	OSL::ShaderGlobals *globals = &tdata->globals;
	OSL::pvt::ShadingContext *ctx = ssi->get_context(tdata->thread_info);

	/* setup shader globals from shader data */
	sd->osl_ctx = ctx;
	shaderdata_to_shaderglobals(kg, sd, 0, globals);

	/* execute shader */
	int shader = sd->shader & SHADER_MASK;

	if (kg->osl.displacement_state[shader])
		ctx->execute(OSL::pvt::ShadUseSurface, *(kg->osl.displacement_state[shader]), *globals);

	/* get back position */
	sd->P = TO_FLOAT3(globals->P);
}

void OSLShader::release(KernelGlobals *kg, const ShaderData *sd)
{
	OSL::pvt::ShadingSystemImpl *ssi = (OSL::pvt::ShadingSystemImpl *)kg->osl.ss;
	OSLGlobals::ThreadData *tdata = tls_get(OSLGlobals::ThreadData, kg->osl.thread_data);

	ssi->release_context((OSL::pvt::ShadingContext *)sd->osl_ctx, tdata->thread_info);
}

/* BSDF Closure */

int OSLShader::bsdf_sample(const ShaderData *sd, const ShaderClosure *sc, float randu, float randv, float3& eval, float3& omega_in, differential3& domega_in, float& pdf)
{
	OSL::BSDFClosure *sample_bsdf = (OSL::BSDFClosure *)sc->prim;
	int label = LABEL_NONE;

	pdf = 0.0f;

	/* sample BSDF closure */
	ustring ulabel;

	ulabel = sample_bsdf->sample(TO_VEC3(sd->Ng),
	                             TO_VEC3(sd->I), TO_VEC3(sd->dI.dx), TO_VEC3(sd->dI.dy),
	                             randu, randv,
	                             TO_VEC3(omega_in), TO_VEC3(domega_in.dx), TO_VEC3(domega_in.dy),
	                             pdf, TO_COLOR3(eval));

	/* convert OSL label */
	if (ulabel == OSL::Labels::REFLECT)
		label = LABEL_REFLECT;
	else if (ulabel == OSL::Labels::TRANSMIT)
		label = LABEL_TRANSMIT;
	else
		return LABEL_NONE;  /* sampling failed */

	/* convert scattering to our bitflag label */
	ustring uscattering = sample_bsdf->scattering();

	if (uscattering == OSL::Labels::DIFFUSE)
		label |= LABEL_DIFFUSE;
	else if (uscattering == OSL::Labels::GLOSSY)
		label |= LABEL_GLOSSY;
	else if (uscattering == OSL::Labels::SINGULAR)
		label |= LABEL_SINGULAR;
	else
		label |= LABEL_TRANSPARENT;

	return label;
}

float3 OSLShader::bsdf_eval(const ShaderData *sd, const ShaderClosure *sc, const float3& omega_in, float& pdf)
{
	OSL::BSDFClosure *bsdf = (OSL::BSDFClosure *)sc->prim;
	OSL::Color3 bsdf_eval;

	if (dot(sd->Ng, omega_in) >= 0.0f)
		bsdf_eval = bsdf->eval_reflect(TO_VEC3(sd->I), TO_VEC3(omega_in), pdf);
	else
		bsdf_eval = bsdf->eval_transmit(TO_VEC3(sd->I), TO_VEC3(omega_in), pdf);
	
	return TO_FLOAT3(bsdf_eval);
}

/* Emissive Closure */

float3 OSLShader::emissive_eval(const ShaderData *sd, const ShaderClosure *sc)
{
	OSL::EmissiveClosure *emissive = (OSL::EmissiveClosure *)sc->prim;
	OSL::Color3 emissive_eval = emissive->eval(TO_VEC3(sd->Ng), TO_VEC3(sd->I));
	eval += TO_FLOAT3(emissive_eval);

	return eval;
}

/* Volume Closure */

float3 OSLShader::volume_eval_phase(const ShaderData *sd, const ShaderClosure *sc, const float3 omega_in, const float3 omega_out)
{
	OSL::VolumeClosure *volume = (OSL::VolumeClosure *)sc->prim;
	OSL::Color3 volume_eval = volume->eval_phase(TO_VEC3(omega_in), TO_VEC3(omega_out));
	return TO_FLOAT3(volume_eval) * sc->weight;
}

CCL_NAMESPACE_END