////////////////////////////////////////////////////////////////////////////////
// Copyright (c) 2011, Computer Graphics Group RWTH Aachen University         //
// All rights reserved.                                                       //
////////////////////////////////////////////////////////////////////////////////

#ifndef ACGL_OPENGL_OBJECTS_SHADERPROGRAM_HH
#define ACGL_OPENGL_OBJECTS_SHADERPROGRAM_HH

#include <ACGL/ACGL.hh>

#include <ACGL/Base/Macros.hh>
#include <ACGL/OpenGL/GL.hh>
#include <ACGL/OpenGL/Objects/Shader.hh>
#include <ACGL/OpenGL/Objects/Texture.hh>
#include <ACGL/Math/Math.hh>

#include <vector>
#include <tr1/memory>

namespace ACGL{
namespace OpenGL{

class ShaderProgram
{
    ACGL_NOT_COPYABLE(ShaderProgram)

    // ===================================================================================================== \/
    // ============================================================================================ TYPEDEFS \/
    // ===================================================================================================== \/
public:
    typedef std::vector< ConstSharedShader > ConstSharedShaderVec;

    // ========================================================================================================= \/
    // ============================================================================================ CONSTRUCTORS \/
    // ========================================================================================================= \/
public:
    ShaderProgram(void)
    :   mContext(0),
        mShaders()
    {
        mContext = glCreateProgram();
    }

    virtual ~ShaderProgram(void)
    {
        // "DeleteProgram will silently ignore the value zero." - GL Spec
        glDeleteProgram(mContext);
    }

    // ==================================================================================================== \/
    // ============================================================================================ GETTERS \/
    // ==================================================================================================== \/
public:
    inline       GLuint                getContext (void) const { return mContext; }
    inline const ConstSharedShaderVec& getShaders (void) const { return mShaders; }

    // ===================================================================================================== \/
    // ============================================================================================ WRAPPERS \/
    // ===================================================================================================== \/
public:
    inline GLint getUniformLocation      (const std::string& _nameInShader) const { return glGetUniformLocation (mContext, _nameInShader.c_str()); }
    inline GLint getAttributeLocation    (const std::string& _nameInShader) const { return glGetAttribLocation  (mContext, _nameInShader.c_str()); }
    inline GLint getFragmentDataLocation (const std::string& _nameInShader) const { return glGetFragDataLocation(mContext, _nameInShader.c_str()); }

    inline void use(void) const { glUseProgram(mContext); }

    inline void attachShader(const ConstSharedShader& _shader)
    {
        mShaders.push_back(_shader);
        glAttachShader(mContext, _shader->getContext());
    }

    bool link (void) const;

    inline void setUniform (GLint _location, GLint _v)   const { glUniform1i (_location, _v); }
    inline void setUniform (GLint _location, GLfloat _v) const { glUniform1f (_location, _v); }

    inline void setUniform (GLint _location, const glm::vec2& _v) const { glUniform2fv(_location, 1, glm::value_ptr(_v)); }
    inline void setUniform (GLint _location, const glm::vec3& _v) const { glUniform3fv(_location, 1, glm::value_ptr(_v)); }
    inline void setUniform (GLint _location, const glm::vec4& _v) const { glUniform4fv(_location, 1, glm::value_ptr(_v)); }

    inline void setUniform (GLint _location, const glm::mat2& _v, GLboolean _transpose = GL_FALSE) const { glUniformMatrix2fv(_location, 1, _transpose, glm::value_ptr(_v)); }
    inline void setUniform (GLint _location, const glm::mat3& _v, GLboolean _transpose = GL_FALSE) const { glUniformMatrix3fv(_location, 1, _transpose, glm::value_ptr(_v)); }
    inline void setUniform (GLint _location, const glm::mat4& _v, GLboolean _transpose = GL_FALSE) const { glUniformMatrix4fv(_location, 1, _transpose, glm::value_ptr(_v)); }

    inline void setTexture (GLint _location, const ConstSharedTexture& _texture, GLenum _unit = 0) const { glUniform1i(_location, _unit); _texture->bind(_unit); }

    // =================================================================================================== \/
    // ============================================================================== HIGH LEVEL FUNCTIONS \/
    // =================================================================================================== \/

    inline void setUniform (const std::string& _nameInShader, GLint _v)   const { glUniform1i (getUniformLocation(_nameInShader), _v); }
    inline void setUniform (const std::string& _nameInShader, GLfloat _v) const { glUniform1f (getUniformLocation(_nameInShader), _v); }

    inline void setUniform (const std::string& _nameInShader, const glm::vec2& _v) const { glUniform2fv(getUniformLocation(_nameInShader), 1, glm::value_ptr(_v)); }
    inline void setUniform (const std::string& _nameInShader, const glm::vec3& _v) const { glUniform3fv(getUniformLocation(_nameInShader), 1, glm::value_ptr(_v)); }
    inline void setUniform (const std::string& _nameInShader, const glm::vec4& _v) const { glUniform4fv(getUniformLocation(_nameInShader), 1, glm::value_ptr(_v)); }

    inline void setUniform (const std::string& _nameInShader, const glm::mat2& _v, GLboolean _transpose = GL_FALSE) const { glUniformMatrix2fv(getUniformLocation(_nameInShader), 1, _transpose, glm::value_ptr(_v)); }
    inline void setUniform (const std::string& _nameInShader, const glm::mat3& _v, GLboolean _transpose = GL_FALSE) const { glUniformMatrix3fv(getUniformLocation(_nameInShader), 1, _transpose, glm::value_ptr(_v)); }
    inline void setUniform (const std::string& _nameInShader, const glm::mat4& _v, GLboolean _transpose = GL_FALSE) const { glUniformMatrix4fv(getUniformLocation(_nameInShader), 1, _transpose, glm::value_ptr(_v)); }

    inline void setTexture (const std::string& _nameInShader, const ConstSharedTexture& _texture, GLenum _unit = 0) const { glUniform1i(getUniformLocation(_nameInShader), _unit); _texture->bind(_unit); }

    // =================================================================================================== \/
    // ============================================================================================ FIELDS \/
    // =================================================================================================== \/
protected:
    void bindAttributeLocations() const;
    void bindFragmentDataLocations() const;

    GLuint               mContext;
    ConstSharedShaderVec mShaders;
};

ACGL_SHARED_TYPEDEF(ShaderProgram)

} // OpenGL
} // ACGL

#endif // ACGL_OPENGL_OBJECTS_SHADERPROGRAM_HH