#include <boost/lexical_cast.hpp>
#include "Is.h"
#include "Renderer.h"
#include "Camera.h"
#include "Light.h"
#include "PointLight.h"
#include "SpotLight.h"
#include "LightData.h"
#include "App.h"
#include "Scene.h"
#include "LightData.h"
#include "Collision.h"
#include "Vao.h"
#include "Sm.h"
#include "Smo.h"


//======================================================================================================================
// Constructor                                                                                                         =
//======================================================================================================================
Is::Is(Renderer& r_, Object* parent):
	RenderingPass(r_, parent),
	sm(new Sm(r_, this)),
	smo(new Smo(r_, this))
{}


//======================================================================================================================
// calcViewVectors                                                                                                     =
//======================================================================================================================
void Is::calcViewVectors()
{
	Vec3 viewVectors[4];

	const Camera& cam = r.getCamera();

	const uint& w = r.getWidth();
	const uint& h = r.getHeight();

	// From right up and CC wise to right down, Just like we render the quad
	uint pixels[4][2]={{w, h}, {0, h}, {0, 0}, {w, 0}};
	uint viewport[4]={0, 0, w, h};

	for(int i=0; i<4; i++)
	{
		/*
		Original Code:
		Renderer::unProject(pixels[i][0], pixels[i][1], 10, cam.getViewMatrix(), cam.getProjectionMatrix(), viewport,
		                    viewVectors[i].x, viewVectors[i].y, viewVectors[i].z);
		viewVectors[i] = cam.getViewMatrix() * viewVectors[i];
		The original code is the above 3 lines. The optimized follows:
		*/

		Vec3 vec;
		vec.x = (2.0 * (pixels[i][0] - viewport[0])) / viewport[2] - 1.0;
		vec.y = (2.0 * (pixels[i][1] - viewport[1])) / viewport[3] - 1.0;
		vec.z = 1.0;

		viewVectors[i] = vec.getTransformed(cam.getInvProjectionMatrix());
		// end of optimized code
	}

	viewVectorsVbo->write(viewVectors, sizeof(viewVectors));
}


//======================================================================================================================
// calcPlanes                                                                                                          =
//======================================================================================================================
void Is::calcPlanes()
{
	const Camera& cam = r.getCamera();

	planes.x = cam.getZFar() / (cam.getZNear() - cam.getZFar());
	planes.y = (cam.getZFar() * cam.getZNear()) / (cam.getZNear() -cam.getZFar());
}


//======================================================================================================================
// initFbo                                                                                                             =
//======================================================================================================================
void Is::initFbo()
{
	try
	{
		// create FBO
		fbo.create();
		fbo.bind();

		// init the stencil render buffer
		glGenRenderbuffers(1, &stencilRb);
		glBindRenderbuffer(GL_RENDERBUFFER, stencilRb);
		glRenderbufferStorage(GL_RENDERBUFFER, GL_STENCIL_INDEX, r.getWidth(), r.getHeight());
		glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_STENCIL_ATTACHMENT, GL_RENDERBUFFER, stencilRb);

		// inform in what buffers we draw
		fbo.setNumOfColorAttachements(1);

		// create the FAI
		fai.createEmpty2D(r.getWidth(), r.getHeight(), GL_RGB, GL_RGB, GL_FLOAT);

		// attach
		glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, fai.getGlId(), 0);
		//glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_TEXTURE_2D, r.ms.depthFai.getGlId(), 0);

		// test if success
		fbo.checkIfGood();

		// unbind
		fbo.unbind();
	}
	catch(std::exception& e)
	{
		throw EXCEPTION("Cannot create deferred shading illumination stage FBO: " + e.what());
	}
}


//======================================================================================================================
// init                                                                                                                =
//======================================================================================================================
void Is::init(const RendererInitializer& initializer)
{
	// init passes
	smo->init(initializer);
	sm->init(initializer);

	// load the shaders
	ambientPassSProg.loadRsrc("shaders/IsAp.glsl");

	// point light
	pointLightSProg.loadRsrc(ShaderProg::createSrcCodeToCache("shaders/IsLpGeneric.glsl", "#define POINT_LIGHT_ENABLED\n",
	                                                          "Point").c_str());

	// spot light no shadow
	spotLightNoShadowSProg.loadRsrc(ShaderProg::createSrcCodeToCache("shaders/IsLpGeneric.glsl",
	                                                                 "#define SPOT_LIGHT_ENABLED\n",
	                                                                 "SpotNoShadow").c_str());

	// spot light w/t shadow
	std::string pps = std::string("\n#define SPOT_LIGHT_ENABLED\n#define SHADOW_ENABLED\n") +
	                              "#define SHADOWMAP_SIZE " + boost::lexical_cast<std::string>(sm->getResolution()) + "\n";
	std::string prefix = "SpotShadowSmSize" + boost::lexical_cast<std::string>(sm->getResolution());
	if(sm->isPcfEnabled())
	{
		pps += "#define PCF_ENABLED\n";
		prefix += "Pcf";
	}
	spotLightShadowSProg.loadRsrc(ShaderProg::createSrcCodeToCache("shaders/IsLpGeneric.glsl", pps.c_str(),
	                                                               prefix.c_str()).c_str());

	// init the rest
	initFbo();

	// The VBOs and VAOs
	float quadVertCoords[][2] = {{1.0, 1.0}, {0.0, 1.0}, {0.0, 0.0}, {1.0, 0.0}};
	quadPositionsVbo = new Vbo(GL_ARRAY_BUFFER, sizeof(quadVertCoords), quadVertCoords, GL_STATIC_DRAW, this);

	ushort quadVertIndeces[2][3] = {{0, 1, 3}, {1, 2, 3}};
	quadVertIndecesVbo = new Vbo(GL_ELEMENT_ARRAY_BUFFER, sizeof(quadVertIndeces), quadVertIndeces, GL_STATIC_DRAW, this);

	viewVectorsVbo = new Vbo(GL_ARRAY_BUFFER, 4 * sizeof(Vec3), NULL, GL_DYNAMIC_DRAW, this);

	vao = new Vao(this);
	vao->attachArrayBufferVbo(*quadPositionsVbo, 0, 2, GL_FLOAT, false, 0, NULL);
	vao->attachArrayBufferVbo(*viewVectorsVbo, 1, 3, GL_FLOAT, false, 0, NULL);
	vao->attachElementArrayBufferVbo(*quadVertIndecesVbo);
}


//======================================================================================================================
// drawLightPassQuad                                                                                                   =
//======================================================================================================================
void Is::drawLightPassQuad() const
{
	vao->bind();
	glDrawElements(GL_TRIANGLES, 2 * 3, GL_UNSIGNED_SHORT, 0);
	vao->unbind();
}


//======================================================================================================================
// ambientPass                                                                                                         =
//======================================================================================================================
void Is::ambientPass(const Vec3& color)
{
	glDisable(GL_BLEND);

	// set the shader
	ambientPassSProg->bind();

	// set the uniforms
	ambientPassSProg->findUniVar("ambientCol")->setVec3(&color);
	ambientPassSProg->findUniVar("sceneColMap")->setTexture(r.getMs().diffuseFai, 0);

	// Draw quad
	r.drawQuad();
}


//======================================================================================================================
// pointLightPass                                                                                                      =
//======================================================================================================================
void Is::pointLightPass(const PointLight& light)
{
	const Camera& cam = r.getCamera();

	// frustum test
	Sphere sphere(light.getWorldTransform().origin, light.getRadius());
	if(!cam.insideFrustum(sphere))
	{
		return;
	}

	// stencil optimization
	smo->run(light);

	// shader prog
	const ShaderProg& shader = *pointLightSProg; // ensure the const-ness
	shader.bind();

	shader.findUniVar("msNormalFai")->setTexture(r.getMs().normalFai, 0);
	shader.findUniVar("msDiffuseFai")->setTexture(r.getMs().diffuseFai, 1);
	shader.findUniVar("msSpecularFai")->setTexture(r.getMs().specularFai, 2);
	shader.findUniVar("msDepthFai")->setTexture(r.getMs().depthFai, 3);
	shader.findUniVar("planes")->setVec2(&planes);
	Vec3 lightPosEyeSpace = light.getWorldTransform().origin.getTransformed(cam.getViewMatrix());
	shader.findUniVar("lightPos")->setVec3(&lightPosEyeSpace);
	shader.findUniVar("lightRadius")->setFloat(light.getRadius());
	shader.findUniVar("lightDiffuseCol")->setVec3(&light.lightData->getDiffuseCol());
	shader.findUniVar("lightSpecularCol")->setVec3(&light.lightData->getSpecularCol());

	// render quad
	drawLightPassQuad();
}


//======================================================================================================================
// spotLightPass                                                                                                       =
//======================================================================================================================
void Is::spotLightPass(const SpotLight& light)
{
	const Camera& cam = r.getCamera();

	// frustum test
	if(!cam.insideFrustum(light.getCamera()))
	{
		return;
	}

	// shadow mapping
	if(light.castsShadow() && sm->isEnabled())
	{
		sm->run(light.getCamera());

		// restore the IS FBO
		fbo.bind();

		// and restore blending and depth test
		glEnable(GL_BLEND);
		glBlendFunc(GL_ONE, GL_ONE);
		glDisable(GL_DEPTH_TEST);
		Renderer::setViewport(0, 0, r.getWidth(), r.getHeight());
	}

	// stencil optimization
	smo->run(light);

	// set the texture
	light.lightData->getTexture().setRepeat(false);

	// shader prog
	const ShaderProg* shdr;

	if(light.castsShadow() && sm->isEnabled())
	{
		shdr = spotLightShadowSProg.get();
	}
	else
	{
		shdr = spotLightNoShadowSProg.get();
	}

	shdr->bind();

	// bind the FAIs
	shdr->findUniVar("msNormalFai")->setTexture(r.getMs().normalFai, 0);
	shdr->findUniVar("msDiffuseFai")->setTexture(r.getMs().diffuseFai, 1);
	shdr->findUniVar("msSpecularFai")->setTexture(r.getMs().specularFai, 2);
	shdr->findUniVar("msDepthFai")->setTexture(r.getMs().depthFai, 3);

	// the planes
	shdr->findUniVar("planes")->setVec2(&planes);

	// the light params
	Vec3 lightPosEyeSpace = light.getWorldTransform().origin.getTransformed(cam.getViewMatrix());
	shdr->findUniVar("lightPos")->setVec3(&lightPosEyeSpace);
	shdr->findUniVar("lightRadius")->setFloat(light.getDistance());
	shdr->findUniVar("lightDiffuseCol")->setVec3(&light.lightData->getDiffuseCol());
	shdr->findUniVar("lightSpecularCol")->setVec3(&light.lightData->getSpecularCol());
	shdr->findUniVar("lightTex")->setTexture(light.lightData->getTexture(), 4);

	// set texture matrix for texture & shadowmap projection
	// Bias * P_light * V_light * inv(V_cam)
	static Mat4 biasMat4(0.5, 0.0, 0.0, 0.5, 0.0, 0.5, 0.0, 0.5, 0.0, 0.0, 0.5, 0.5, 0.0, 0.0, 0.0, 1.0);
	Mat4 texProjectionMat;
	texProjectionMat = biasMat4 * light.getCamera().getProjectionMatrix() *
	                   Mat4::combineTransformations(light.getCamera().getViewMatrix(), Mat4(cam.getWorldTransform()));
	shdr->findUniVar("texProjectionMat")->setMat4(&texProjectionMat);

	// the shadowmap
	if(light.castsShadow() && sm->isEnabled())
	{
		shdr->findUniVar("shadowMap")->setTexture(sm->shadowMap, 5);
	}

	// render quad
	drawLightPassQuad();
}


//======================================================================================================================
// run                                                                                                                 =
//======================================================================================================================
void Is::run()
{
	// FBO
	fbo.bind();

	// OGL stuff
	Renderer::setViewport(0, 0, r.getWidth(), r.getHeight());

	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();

	glDisable(GL_DEPTH_TEST);

	// ambient pass
	ambientPass(app->getScene().getAmbientCol());

	// light passes
	glEnable(GL_BLEND);
	glBlendFunc(GL_ONE, GL_ONE);
	glEnable(GL_STENCIL_TEST);

	calcViewVectors();
	calcPlanes();

	// for all lights
	for(uint i=0; i<app->getScene().lights.size(); i++)
	{
		const Light& light = *app->getScene().lights[i];
		switch(light.getType())
		{
			case Light::LT_POINT:
			{
				const PointLight& pointl = static_cast<const PointLight&>(light);
				pointLightPass(pointl);
				break;
			}

			case Light::LT_SPOT:
			{
				const SpotLight& projl = static_cast<const SpotLight&>(light);
				spotLightPass(projl);
				break;
			}

			default:
				RASSERT_THROW_EXCEPTION("WTF?");
		}
	}

	glDisable(GL_STENCIL_TEST);

	// FBO
	fbo.unbind();
}