/** 
 * @file llglslshader.h
 * @brief GLSL shader wrappers
 *
 * $LicenseInfo:firstyear=2001&license=viewerlgpl$
 * Second Life Viewer Source Code
 * Copyright (C) 2010, Linden Research, Inc.
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation;
 * version 2.1 of the License only.
 * 
 * This library 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
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 * 
 * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
 * $/LicenseInfo$
 */

#ifndef LL_LLGLSLSHADER_H
#define LL_LLGLSLSHADER_H

#include "llgl.h"
#include "llrender.h"
#include "llstaticstringtable.h"
#include <boost/unordered/unordered_map.hpp>

class LLShaderFeatures
{
public:
	bool atmosphericHelpers;
	bool calculatesLighting;
	bool calculatesAtmospherics;
	bool hasLighting; // implies no transport (it's possible to have neither though)
	bool isAlphaLighting; // indicates lighting shaders need not be linked in (lighting performed directly in alpha shader to match deferred lighting functions)
	bool isShiny;
	bool isFullbright; // implies no lighting
	bool isSpecular;
	bool hasWaterFog; // implies no gamma
	bool hasTransport; // implies no lighting (it's possible to have neither though)
	bool hasSkinning;	
	bool hasObjectSkinning;
	bool hasAtmospherics;
	bool hasGamma;
    bool hasShadows;
    bool hasAmbientOcclusion;
	bool hasSrgb;
    bool encodesNormal;
    bool isDeferred;
	S32 mIndexedTextureChannels;
	bool disableTextureIndex;
	bool hasAlphaMask;
	bool attachNothing;

	// char numLights;
	
	LLShaderFeatures();
};

// ============= Structure for caching shader uniforms ===============
class LLGLSLShader;

class LLShaderUniforms
{
public:

    template<typename T>
    struct UniformSetting
    {
        S32 mUniform;
        T mValue;
    };

    typedef UniformSetting<S32> IntSetting;
    typedef UniformSetting<F32> FloatSetting;
    typedef UniformSetting<LLVector4> VectorSetting;
    typedef UniformSetting<LLVector3> Vector3Setting;

    void clear()
    {
        mIntegers.resize(0);
        mFloats.resize(0);
        mVectors.resize(0);
        mVector3s.resize(0);
    }

    void uniform1i(S32 index, S32 value)
    {
        mIntegers.push_back({ index, value });
    }

    void uniform1f(S32 index, F32 value)
    {
        mFloats.push_back({ index, value });
    }

    void uniform4fv(S32 index, const LLVector4& value)
    {
        mVectors.push_back({ index, value });
    }
    
    void uniform4fv(S32 index, const F32* value)
    {
        mVectors.push_back({ index, LLVector4(value) });
    }

    void uniform3fv(S32 index, const LLVector3& value)
    {
        mVector3s.push_back({ index, value });
    }

    void apply(LLGLSLShader* shader);
   

    std::vector<IntSetting> mIntegers;
    std::vector<FloatSetting> mFloats;
    std::vector<VectorSetting> mVectors;
    std::vector<Vector3Setting> mVector3s;
};
class LLGLSLShader
{
public:

    // enum primarily used to control application sky settings uniforms
	typedef enum 
	{
		SG_DEFAULT = 0,  // not sky or water specific
		SG_SKY,  //
		SG_WATER,
        SG_ANY,
        SG_COUNT
	} eGroup;

	struct gl_uniform_data_t {
		std::string name;
		GLenum type = (GLenum)-1;
		GLint size = -1;
		U32 texunit_priority = UINT_MAX; // Lower gets earlier texunits indices.
	};
	
	static std::set<LLGLSLShader*> sInstances;
	static bool sProfileEnabled;

	LLGLSLShader();
	~LLGLSLShader() = default;

	static GLhandleARB sCurBoundShader;
	static LLGLSLShader* sCurBoundShaderPtr;
	static S32 sIndexedTextureChannels;

	static void initProfile();
	static void finishProfile(bool emit_report = true);

	static void startProfile();
	static void stopProfile(U32 count, U32 mode);

	void unload();
	void clearStats();
	void dumpStats();
	void placeProfileQuery();
	void readProfileQuery(U32 count, U32 mode);

	BOOL createShader(std::vector<LLStaticHashedString> * attributes,
						std::vector<LLStaticHashedString> * uniforms,
						U32 varying_count = 0,
						const char** varyings = NULL);
    BOOL attachFragmentObject(std::string_view object);
    BOOL attachVertexObject(std::string_view object);
	void attachObject(GLhandleARB object);
	void attachObjects(GLhandleARB* objects = NULL, S32 count = 0);
	BOOL mapAttributes(const std::vector<LLStaticHashedString> * attributes);
	BOOL mapUniforms(const std::vector<LLStaticHashedString> *);
	void mapUniform(const gl_uniform_data_t& gl_uniform, const std::vector<LLStaticHashedString> *);
	void uniform1i(U32 index, GLint i);
	void uniform1f(U32 index, GLfloat v);
	void uniform2f(U32 index, GLfloat x, GLfloat y);
	void uniform3f(U32 index, GLfloat x, GLfloat y, GLfloat z);
	void uniform4f(U32 index, GLfloat x, GLfloat y, GLfloat z, GLfloat w);
	void uniform1iv(U32 index, U32 count, const GLint* i);
	void uniform1fv(U32 index, U32 count, const GLfloat* v);
	void uniform2fv(U32 index, U32 count, const GLfloat* v);
	void uniform3fv(U32 index, U32 count, const GLfloat* v);
	void uniform4fv(U32 index, U32 count, const GLfloat* v);
	void uniform2i(const LLStaticHashedString& uniform, GLint i, GLint j);
	void uniformMatrix2fv(U32 index, U32 count, GLboolean transpose, const GLfloat *v);
	void uniformMatrix3fv(U32 index, U32 count, GLboolean transpose, const GLfloat *v);
	void uniformMatrix3x4fv(U32 index, U32 count, GLboolean transpose, const GLfloat *v);
	void uniformMatrix4fv(U32 index, U32 count, GLboolean transpose, const GLfloat *v);
	void uniform1i(const LLStaticHashedString& uniform, GLint i);
	void uniform1f(const LLStaticHashedString& uniform, GLfloat v);
	void uniform2f(const LLStaticHashedString& uniform, GLfloat x, GLfloat y);
	void uniform3f(const LLStaticHashedString& uniform, GLfloat x, GLfloat y, GLfloat z);
	void uniform1fv(const LLStaticHashedString& uniform, U32 count, const GLfloat* v);
	void uniform2fv(const LLStaticHashedString& uniform, U32 count, const GLfloat* v);
	void uniform3fv(const LLStaticHashedString& uniform, U32 count, const GLfloat* v);
	void uniform4fv(const LLStaticHashedString& uniform, U32 count, const GLfloat* v);
	void uniformMatrix4fv(const LLStaticHashedString& uniform, U32 count, GLboolean transpose, const GLfloat *v);

	void setMinimumAlpha(F32 minimum);

	void vertexAttrib4f(U32 index, GLfloat x, GLfloat y, GLfloat z, GLfloat w);
	void vertexAttrib4fv(U32 index, GLfloat* v);
	
	//GLint getUniformLocation(const std::string& uniform);
	GLint getUniformLocation(const LLStaticHashedString& uniform);	
	GLint getUniformLocation(U32 index);

	GLint getAttribLocation(U32 attrib);
	GLint mapUniformTextureChannel(GLint location, GLenum type);
	
    void clearPermutations();
	void addPremutations(std::map<std::string, std::string>& map)
	{
		mDefines.insert(map.begin(), map.end());
	}
	void addPermutation(std::string name, std::string value);
    void removePermutations(std::map<std::string, std::string>& map)
    {
		for (const auto& entry : map)
        {
            mDefines.erase(entry.first);
        }
    }
	void removePermutation(std::string name);
	
	//enable/disable texture channel for specified uniform
	//if given texture uniform is active in the shader, 
	//the corresponding channel will be active upon return
	//returns channel texture is enabled in from [0-MAX)
	S32 enableTexture(S32 uniform, LLTexUnit::eTextureType mode = LLTexUnit::TT_TEXTURE, LLTexUnit::eTextureColorSpace space = LLTexUnit::TCS_LINEAR);
    S32 disableTexture(S32 uniform, LLTexUnit::eTextureType mode = LLTexUnit::TT_TEXTURE, LLTexUnit::eTextureColorSpace space = LLTexUnit::TCS_LINEAR);
	
	// bindTexture returns the texture unit we've bound the texture to.
	// You can reuse the return value to unbind a texture when required.
	S32 bindTexture(const std::string& uniform, LLTexture *texture, LLTexUnit::eTextureType mode = LLTexUnit::TT_TEXTURE, LLTexUnit::eTextureColorSpace space = LLTexUnit::TCS_LINEAR);
	S32 bindTexture(S32 uniform, LLTexture *texture, LLTexUnit::eTextureType mode = LLTexUnit::TT_TEXTURE, LLTexUnit::eTextureColorSpace space = LLTexUnit::TCS_LINEAR);
	S32 unbindTexture(const std::string& uniform, LLTexUnit::eTextureType mode = LLTexUnit::TT_TEXTURE);
	S32 unbindTexture(S32 uniform, LLTexUnit::eTextureType mode = LLTexUnit::TT_TEXTURE);
	
    BOOL link(BOOL suppress_errors = FALSE);
	void bind();
    //helper to conditionally bind mRiggedVariant instead of this
    void bind(bool rigged);
	void unbind();

	// Unbinds any previously bound shader by explicitly binding no shader.
	static void bindNoShader(void);

	U32 mMatHash[LLRender::NUM_MATRIX_MODES];
	U32 mLightHash;

	GLhandleARB mProgramObject;
#if LL_RELEASE_WITH_DEBUG_INFO
	struct attr_name
	{
		GLint loc;
		const char *name;
		void operator = (GLint _loc) { loc = _loc; }
		operator GLint () { return loc; }
	};
	std::vector<attr_name> mAttribute; //lookup table of attribute enum to attribute channel
#else
	std::vector<GLint> mAttribute; //lookup table of attribute enum to attribute channel
#endif
	U32 mAttributeMask;  //mask of which reserved attributes are set (lines up with LLVertexBuffer::getTypeMask())
	std::vector<GLint> mUniform;   //lookup table of uniform enum to uniform location
	LLStaticStringTable<GLint> mUniformMap; //lookup map of uniform name to uniform location
    typedef boost::unordered_flat_map<GLint, std::string> uniform_name_map_t;
    typedef boost::unordered_flat_map<GLint, LLVector4> uniform_value_map_t;
    uniform_name_map_t mUniformNameMap; //lookup map of uniform location to uniform name
	uniform_value_map_t mValue; //lookup map of uniform location to last known value
	std::vector<GLint> mTexture;
	S32 mTotalUniformSize;
	S32 mActiveTextureChannels;
	S32 mShaderLevel;
	S32 mShaderGroup; // see LLGLSLShader::eGroup
	BOOL mUniformsDirty;
	LLShaderFeatures mFeatures;
	std::vector< std::pair< std::string, GLenum > > mShaderFiles;
	std::string mName;
    typedef boost::unordered_map<std::string, std::string> defines_map_t;
	defines_map_t mDefines;

	//statistcis for profiling shader performance
	U32 mTimerQuery;
	U32 mSamplesQuery;
	U64 mTimeElapsed;
	static U64 sTotalTimeElapsed;
	U32 mTrianglesDrawn;
	static U32 sTotalTrianglesDrawn;
	U64 mSamplesDrawn;
	static U64 sTotalSamplesDrawn;
	U32 mDrawCalls;
	static U32 sTotalDrawCalls;

	bool mTextureStateFetched;
	std::vector<U32> mTextureMagFilter;
	std::vector<U32> mTextureMinFilter;

    // this pointer should be set to whichever shader represents this shader's rigged variant
    LLGLSLShader* mRiggedVariant = nullptr;

private:
	void unloadInternal();
};

//UI shader (declared here so llui_libtest will link properly)
extern LLGLSLShader			gUIProgram;
//output vec4(color.rgb,color.a*tex0[tc0].a)
extern LLGLSLShader			gSolidColorProgram;
//Alpha mask shader (declared here so llappearance can access properly)
extern LLGLSLShader			gAlphaMaskProgram;


#endif
