/*
 * Copyright (C) 2017  Christopher J. Howard
 *
 * This file is part of Antkeeper Source Code.
 *
 * Antkeeper Source Code 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 3 of the License, or
 * (at your option) any later version.
 *
 * Antkeeper Source Code 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 Antkeeper Source Code.  If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef RENDER_PASSES_HPP
#define RENDER_PASSES_HPP

#include <emergent/emergent.hpp>
using namespace Emergent;

#include "material-loader.hpp"
#include "model-loader.hpp"
#include <cstdint>

/**
 * Clears framebuffers
 */
class ClearRenderPass: public RenderPass
{
public:
	ClearRenderPass();
	virtual bool load(const RenderContext* renderContext);
	virtual void unload();
	virtual void render(RenderContext* renderContext);
	
	void setClear(bool color, bool depth, bool stencil);
	void setClearColor(const Vector4& color);
	void setClearDepth(float depth);
	void setClearStencil(int index);
	
private:
	bool clearColor;
	bool clearDepth;
	bool clearStencil;
	Vector4 color;
	float depth;
	int index;
};

/**
 * Blurs a texture
 */
class BlurRenderPass: public RenderPass
{
public:
	BlurRenderPass();
	virtual bool load(const RenderContext* renderContext);
	virtual void unload();
	virtual void render(RenderContext* renderContext);
	
	inline void setGammaCorrect(bool gammaCorrect) { this->gammaCorrect = gammaCorrect; }
	
	/**
	 * Sets the texture to blur.
	 */
	inline void setTexture(const Texture2D* texture) { textureParam.setValue(texture); }
	
	/**
	 * Sets the direction of the blur.
	 */
	inline void setDirection(const Vector2& direction) { directionParam.setValue(direction); }
	
private:
	bool gammaCorrect;
	
	Shader shader;
	std::uint32_t permutation;
	ShaderTexture2D textureParam;
	ShaderVector2 resolutionParam;
	ShaderVector2 directionParam;
	
	int quadVertexCount;
	int quadIndexCount;
	GLuint quadVAO;
	GLuint quadVBO;
	GLuint quadIBO;
};

/**
 * Renders the distance from the view frustum's near clipping plane to scene geometry. The render target should have a depth only framebuffer.
 */
class ShadowMapRenderPass: public RenderPass
{
public:
	ShadowMapRenderPass();
	
	virtual bool load(const RenderContext* renderContext);
	virtual void unload();
	virtual void render(RenderContext* renderContext);
	
	inline void setViewCamera(const Camera* camera) { this->viewCamera = camera; }
	inline void setLightCamera(Camera* camera) { this->lightCamera = camera; }
	
	inline const SplitViewFrustum& getSplitViewFrustum() const { return *splitViewFrustum; }
	inline const Matrix4& getCropMatrix(std::size_t index) const { return cropMatrices[index]; }
	inline const Matrix4& getTileMatrix(std::size_t index) const { return tileMatrices[index]; }
	
private:
	class RenderOpCompare
	{
	public:
		// Sort render opations
		bool operator()(const RenderOperation& opA, const RenderOperation& opB) const;
	};
	
	Shader shader;
	std::uint32_t unskinnedPermutation;
	std::uint32_t skinnedPermutation;
	ShaderMatrix4 modelViewProjectionParam;
	ShaderMatrix4* matrixPaletteParam; // data not used, just getConnectedInput() then pass pose matrix palette pointer directly
	
	int maxBoneCount;
	int shadowMapResolution;
	int croppedShadowMapResolution;
	Vector4* croppedShadowMapViewports;
	Matrix4* cropMatrices;
	Matrix4* tileMatrices;
	const Camera* viewCamera;
	Camera* lightCamera;
	SplitViewFrustum* splitViewFrustum;
};

/**
 * Renders scene geometry.
 */
class LightingRenderPass: public RenderPass
{
public:
	LightingRenderPass();
	
	virtual bool load(const RenderContext* renderContext);
	virtual void unload();
	virtual void render(RenderContext* renderContext);
	
	inline void setShadowMap(const Texture2D* shadowMap) { this->shadowMap = shadowMap; }
	inline void setShadowCamera(const Camera* camera) { this->shadowCamera = camera; }
	inline void setShadowMapPass(const ShadowMapRenderPass* shadowMapPass) { this->shadowMapPass = shadowMapPass; }
	inline void setDiffuseCubemap(const TextureCube* cubemap) { this->diffuseCubemap = cubemap; }
	inline void setSpecularCubemap(const TextureCube* cubemap) { this->specularCubemap = cubemap; }
	
private:
	class RenderOpCompare
	{
	public:
		// Sort render opations
		bool operator()(const RenderOperation& opA, const RenderOperation& opB) const;
	};
	
	struct ParameterSet
	{
		ShaderMatrix4* matrixPalette;
		ShaderMatrix4 modelMatrix;
		ShaderMatrix4 modelViewMatrix;
		ShaderMatrix4 modelViewProjectionMatrix;
		ShaderMatrix3 normalModelViewMatrix;
		ShaderMatrix3 normalModelMatrix;
		ShaderMatrix4* lightViewProjectionMatrices;
		ShaderVector4 splitDistances;
		ShaderTexture2D shadowMap;
		ShaderVector3 cameraPosition;
		
		ShaderTextureCube diffuseCubemap;
		ShaderTextureCube specularCubemap;
		
		ShaderInt directionalLightCount;
		ShaderVector3* directionalLightColors;
		ShaderVector3* directionalLightDirections;
		
		ShaderInt spotlightCount;
		ShaderVector3 spotlightColors;
		ShaderVector3 spotlightPositions;
		ShaderVector3 spotlightAttenuations;
		ShaderVector3 spotlightDirections;
		ShaderFloat spotlightCutoffs;
		ShaderFloat spotlightExponents;
		
		ShaderTexture2D albedoOpacityMap;
		ShaderTexture2D metalnessRoughnessMap;
		ShaderTexture2D normalOcclusionMap;
		
		// Material shader parameters (uploaded by material directly)
		//ShaderTexture2D albedoOpacityMap;
		//ShaderTexture2D metalnessRoughnessMap;
		//ShaderTexture2D normalOcclusionMap;
	};
	
	//std::map<Shader* shader, ParameterSet> parameterSets;
	
	Shader shader;
	ParameterSet parameters;
	std::uint32_t unskinnedPermutation;
	std::uint32_t skinnedPermutation;
	
	int maxBoneCount;
	int maxDirectionalLightCount;
	int maxSpotlightCount;
	
	
	Matrix4 biasMatrix;
	const Texture2D* shadowMap;
	const TextureCube* diffuseCubemap;
	const TextureCube* specularCubemap;
	const Camera* shadowCamera;
	float time;
	const ShadowMapRenderPass* shadowMapPass;
};

/**
 * Renders bounding boxes, skeletons
 */
class DebugRenderPass: public RenderPass
{
public:
	DebugRenderPass();
	virtual bool load(const RenderContext* renderContext);
	virtual void unload();
	virtual void render(RenderContext* renderContext);
	
	//void setDrawBounds(bool enabled);
	//void setDrawSkeletons(bool enabled);
	//void setDrawCameras(bool enabled);
	//void setDrawLights(bool enabled);
	
private:
	Shader shader;
	std::uint32_t permutation;
	ShaderMatrix4 modelViewProjectionMatrixParam;
	
	int aabbVertexCount;
	int aabbIndexCount;
	GLuint aabbVAO;
	GLuint aabbVBO;
	GLuint aabbIBO;
};

/**
 * Renders the user interface
 */
class UIRenderPass: public RenderPass
{
public:
	UIRenderPass();
	virtual bool load(const RenderContext* renderContext);
	virtual void unload();
	virtual void render(RenderContext* renderContext);
	
private:
	Shader shader;
	std::uint32_t texturedPermutation;
	std::uint32_t untexturedPermutation;
	
	ShaderMatrix4 modelViewProjectionMatrixParam;
	ShaderTexture2D textureParam;
	ShaderVector2 textureOffsetParam;
	ShaderVector2 textureScaleParam;
};

/**
 * Renders a vignette
 */
/*
class VignetteRenderPass: public RenderPass
{
public:
	VignetteRenderPass();
	virtual bool load(const RenderContext* renderContext);
	virtual void unload();
	virtual void render(RenderContext* renderContext);
	
private:
	ShaderParameterSet parameterSet;
	const ShaderParameter* modelViewProjectionParam;
	const ShaderParameter* bayerTextureParam;
	
	ShaderLoader shaderLoader;
	Shader* shader;
	GLuint bayerTextureID;
};
*/

/**
 * Renders a skybox
 */
class SkyboxRenderPass: public RenderPass
{
public:
	SkyboxRenderPass();
	
	inline void setCubemap(TextureCube* cubemap) { this->cubemap = cubemap; }
	virtual bool load(const RenderContext* renderContext);
	virtual void unload();
	virtual void render(RenderContext* renderContext);
	
private:
	Shader shader;
	std::uint32_t permutation;
	ShaderMatrix4 matrixParam;
	ShaderTextureCube cubemapParam;
	TextureCube* cubemap;
	
	int quadVertexCount;
	int quadIndexCount;
	GLuint quadVAO;
	GLuint quadVBO;
	GLuint quadIBO;
};

#endif // RENDER_PASSES_HPP