#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cassert>

#include "../rwbase.h"
#include "../rwerror.h"
#include "../rwplg.h"
#include "../rwrender.h"
#include "../rwengine.h"
#include "../rwpipeline.h"
#include "../rwobjects.h"
#include "../rwanim.h"
#include "../rwplugins.h"
#ifdef RW_OPENGL
#include <GL/glew.h>
#endif
#include "rwgl3.h"
#include "rwgl3shader.h"
#include "rwgl3plg.h"

#include "rwgl3impl.h"

namespace rw {
namespace gl3 {

#ifdef RW_OPENGL

#define U(i) currentShader->uniformLocations[i]

static Shader *envShader;
static int32 u_texMatrix;
static int32 u_coefficient;

static void*
matfxOpen(void *o, int32, int32)
{
	u_texMatrix = registerUniform("u_texMatrix");
	u_coefficient = registerUniform("u_coefficient");
#include "shaders/matfx_gl3.inc"
	matFXGlobals.pipelines[PLATFORM_GL3] = makeMatFXPipeline();
	envShader = Shader::fromStrings(matfx_env_vert_src, matfx_env_frag_src);
	return o;
}

static void*
matfxClose(void *o, int32, int32)
{
	return o;
}

void
initMatFX(void)
{
	Driver::registerPlugin(PLATFORM_GL3, 0, ID_MATFX,
	                       matfxOpen, matfxClose);
}


void
matfxDefaultRender(InstanceDataHeader *header, InstanceData *inst)
{
	Material *m;
	RGBAf col;
	GLfloat surfProps[4];
	m = inst->material;

	simpleShader->use();

	convColor(&col, &m->color);
	glUniform4fv(U(u_matColor), 1, (GLfloat*)&col);

	surfProps[0] = m->surfaceProps.ambient;
	surfProps[1] = m->surfaceProps.specular;
	surfProps[2] = m->surfaceProps.diffuse;
	surfProps[3] = 0.0f;
	glUniform4fv(U(u_surfaceProps), 1, surfProps);

	setTexture(0, m->texture);

	rw::SetRenderState(VERTEXALPHA, inst->vertexAlpha || m->color.alpha != 0xFF);

	flushCache();
	glDrawElements(header->primType, inst->numIndex,
	               GL_UNSIGNED_SHORT, (void*)(uintptr)inst->offset);
}

void
calcEnvTexMatrix(Frame *f, float32 *mat)
{
	Matrix cam;
	if(f){
		// PS2 style - could be simplified by the shader
		cam = *((Camera*)engine->currentCamera)->getFrame()->getLTM();
		cam.pos = { 0.0, 0.0, 0.0 };
		cam.right.x = -cam.right.x;
		cam.right.y = -cam.right.y;
		cam.right.z = -cam.right.z;

		Matrix inv;
		Matrix::invert(&inv, f->getLTM());
		inv.pos = { -1.0, -1.0, -1.0 };
		inv.right.x *= -0.5f;
		inv.right.y *= -0.5f;
		inv.right.z *= -0.5f;
		inv.up.x *= -0.5f;
		inv.up.y *= -0.5f;
		inv.up.z *= -0.5f;
		inv.at.x *= -0.5f;
		inv.at.y *= -0.5f;
		inv.at.z *= -0.5f;
		inv.pos.x *= -0.5f;
		inv.pos.y *= -0.5f;
		inv.pos.z *= -0.5f;

		Matrix m;
		Matrix::mult(&m, &cam, &inv);

		memcpy(mat, &m, 64);
		mat[3] = mat[7] = mat[11] = 0.0f;
		mat[15] = 1.0f;

	}else{
		// D3D - TODO: find out what PS2 does
		mat[0]  = 0.5f;
		mat[1]  = 0.0f;
		mat[2]  = 0.0f;
		mat[3]  = 0.0f;

		mat[4]  = 0.0f;
		mat[5]  = -0.5f;
		mat[6]  = 0.0f;
		mat[7]  = 0.0f;

		mat[8]  = 0.0f;
		mat[9]  = 0.0f;
		mat[10] = 1.0f;
		mat[11] = 0.0f;

		mat[12] = 0.5f;
		mat[13] = 0.5f;
		mat[14] = 0.0f;
		mat[15] = 0.0f;
	}
}

void
matfxEnvRender(InstanceDataHeader *header, InstanceData *inst)
{
	Material *m;
	RGBAf col;
	GLfloat surfProps[4];
	float32 texMat[16];
	m = inst->material;

	matfxDefaultRender(header, inst);

	MatFX *fx = MatFX::get(m);
	int32 idx = fx->getEffectIndex(MatFX::ENVMAP);
	MatFX::Env *env = &fx->fx[idx].env;

	envShader->use();

	convColor(&col, &m->color);
	glUniform4fv(U(u_matColor), 1, (GLfloat*)&col);

	surfProps[0] = m->surfaceProps.ambient;
	surfProps[1] = m->surfaceProps.specular;
	surfProps[2] = m->surfaceProps.diffuse;
	surfProps[3] = 0.0f;
	glUniform4fv(U(u_surfaceProps), 1, surfProps);

	glUniform1fv(U(u_coefficient), 1, &env->coefficient);

	calcEnvTexMatrix(env->frame, texMat);
	glUniformMatrix4fv(U(u_texMatrix), 1, GL_FALSE, texMat);

	setTexture(0, env->tex);

	rw::SetRenderState(VERTEXALPHA, 1);
	rw::SetRenderState(SRCBLEND, BLENDONE);
	rw::SetRenderState(DESTBLEND, BLENDONE);

	flushCache();
	glDrawElements(header->primType, inst->numIndex,
	               GL_UNSIGNED_SHORT, (void*)(uintptr)inst->offset);

	rw::SetRenderState(SRCBLEND, BLENDSRCALPHA);
	rw::SetRenderState(DESTBLEND, BLENDINVSRCALPHA);
}

void
matfxRenderCB(Atomic *atomic, InstanceDataHeader *header)
{
	setWorldMatrix(atomic->getFrame()->getLTM());
	lightingCB();

	glBindBuffer(GL_ARRAY_BUFFER, header->vbo);
	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, header->ibo);
	setAttribPointers(header->attribDesc, header->numAttribs);

	InstanceData *inst = header->inst;
	int32 n = header->numMeshes;

//	rw::SetRenderState(ALPHATESTFUNC, 1);
//	rw::SetRenderState(ALPHATESTREF, 50);

	int32 fx;
	while(n--){
		fx = MatFX::getEffects(inst->material);
		switch(fx){
		case MatFX::ENVMAP:
			matfxEnvRender(header, inst);
			break;
		default:
			matfxDefaultRender(header, inst);
		}
		inst++;
	}
	disableAttribPointers(header->attribDesc, header->numAttribs);
}

ObjPipeline*
makeMatFXPipeline(void)
{
	ObjPipeline *pipe = new ObjPipeline(PLATFORM_GL3);
	pipe->instanceCB = defaultInstanceCB;
	pipe->uninstanceCB = defaultUninstanceCB;
	pipe->renderCB = matfxRenderCB;
	pipe->pluginID = ID_MATFX;
	pipe->pluginData = 0;
	return pipe;
}

#else

void initMatFX(void) { }

#endif

}
}