/*
This Source Code Form is subject to the
terms of the Mozilla Public License, v.
2.0. If a copy of the MPL was not
distributed with this file, You can
obtain one at
http://mozilla.org/MPL/2.0/.
*/

#pragma once

#include <stack>
#include <vector>

// encapsulation of the fixed pipeline opengl matrix stack
class opengl_matrices {

// types:
class opengl_stack {

public:
// constructors:
    opengl_stack() { m_stack.emplace(1.f); }

// methods:
    glm::mat4 const &
        data() const {
            return m_stack.top(); }
    void
        push_matrix() {
            m_stack.emplace( m_stack.top() ); }
    void
        pop_matrix( bool const Upload = true ) {
            if( m_stack.size() > 1 ) {
                m_stack.pop();
                if( Upload ) { upload(); } } }
    void
        load_identity( bool const Upload = true ) {
            m_stack.top() = glm::mat4( 1.f );
            if( Upload ) { upload(); } }
    void
        load_matrix( glm::mat4 const &Matrix, bool const Upload = true ) {
            m_stack.top() = Matrix;
            if( Upload ) { upload(); } }
    void
        rotate( float const Angle, glm::vec3 const &Axis, bool const Upload = true ) {
            m_stack.top() = glm::rotate( m_stack.top(), Angle, Axis );
            if( Upload ) { upload(); } }
    void
        translate( glm::vec3 const &Translation, bool const Upload = true ) {
            m_stack.top() = glm::translate( m_stack.top(), Translation );
            if( Upload ) { upload(); } }
    void
        scale( glm::vec3 const &Scale, bool const Upload = true ) {
            m_stack.top() = glm::scale( m_stack.top(), Scale );
            if( Upload ) { upload(); } }
    void
        multiply( glm::mat4 const &Matrix, bool const Upload = true ) {
            m_stack.top() *= Matrix;
            if( Upload ) { upload(); } }
    void
        ortho( float const Left, float const Right, float const Bottom, float const Top, float const Znear, float const Zfar, bool const Upload = true ) {
            m_stack.top() *= glm::ortho( Left, Right, Bottom, Top, Znear, Zfar );
            if( Upload ) { upload(); } }
    void
        perspective( float const Fovy, float const Aspect, float const Znear, float const Zfar, bool const Upload = true ) {
            m_stack.top() *= glm::perspective( Fovy, Aspect, Znear, Zfar );
            if( Upload ) { upload(); } }
    void
        look_at( glm::vec3 const &Eye, glm::vec3 const &Center, glm::vec3 const &Up, bool const Upload = true ) {
            m_stack.top() *= glm::lookAt( Eye, Center, Up );
            if( Upload ) { upload(); } }

private:
// types:
    typedef std::stack<glm::mat4> mat4_stack;

// methods:
    void
        upload() { ::glLoadMatrixf( glm::value_ptr( m_stack.top() ) ); }

// members:
    mat4_stack m_stack;
};

enum stack_mode { gl_modelview = 0, gl_projection = 1, gl_texture = 2 };
typedef std::vector<opengl_stack> openglstack_array;

public:
// constructors:
    opengl_matrices() {
        m_stacks.emplace_back(); // modelview
        m_stacks.emplace_back(); // projection
        m_stacks.emplace_back(); // texture
    }

// methods:
    bool &
        upload() {
            return m_upload; }
    void
        mode( GLuint const Mode ) {
            switch( Mode ) {
                case GL_MODELVIEW:  { m_mode = stack_mode::gl_modelview; break; }
                case GL_PROJECTION: { m_mode = stack_mode::gl_projection; break; }
                case GL_TEXTURE:    { m_mode = stack_mode::gl_texture; break; }
                default:            { break; } }
            if( m_upload ) {::glMatrixMode( Mode ); } }
    glm::mat4 const &
        data( GLuint const Mode = -1 ) const {
            switch( Mode ) {
                case GL_MODELVIEW:  { return m_stacks[ stack_mode::gl_modelview ].data(); }
                case GL_PROJECTION: { return m_stacks[ stack_mode::gl_projection ].data(); }
                case GL_TEXTURE:    { return m_stacks[ stack_mode::gl_texture ].data(); }
                default:            { return m_stacks[ m_mode ].data(); } } }
    float const *
        data_array( GLuint const Mode = -1 ) const {
            return glm::value_ptr( data( Mode ) ); }
    void
        push_matrix() { m_stacks[ m_mode ].push_matrix(); }
    void
        pop_matrix() { m_stacks[ m_mode ].pop_matrix( m_upload ); }
    void
        load_identity() { m_stacks[ m_mode ].load_identity( m_upload ); }
    void
        load_matrix( glm::mat4 const &Matrix ) { m_stacks[ m_mode ].load_matrix( Matrix, m_upload ); }
    template <typename Type_>
    void
        load_matrix( Type_ const *Matrix ) { load_matrix( glm::make_mat4( Matrix ) ); }
    template <typename Type_>
    void
        rotate( Type_ const Angle, Type_ const X, Type_ const Y, Type_ const Z ) {
            m_stacks[ m_mode ].rotate(
                static_cast<float>(glm::radians(Angle)),
                glm::vec3(
                    static_cast<float>( X ),
                    static_cast<float>( Y ),
                    static_cast<float>( Z ) ),
                m_upload ); }
    template <typename Type_>
    void
        translate( Type_ const X, Type_ const Y, Type_ const Z ) {
            m_stacks[ m_mode ].translate(
                glm::vec3(
                    static_cast<float>( X ),
                    static_cast<float>( Y ),
                    static_cast<float>( Z ) ),
                m_upload ); }
    template <typename Type_>
    void
        scale( Type_ const X, Type_ const Y, Type_ const Z ) {
            m_stacks[ m_mode ].scale(
                glm::vec3(
                    static_cast<float>( X ),
                    static_cast<float>( Y ),
                    static_cast<float>( Z ) ),
                m_upload ); }
    template <typename Type_>
    void
        multiply( Type_ const *Matrix ) {
            m_stacks[ m_mode ].multiply(
                glm::make_mat4( Matrix ),
                m_upload ); }
    template <typename Type_>
    void
        ortho( Type_ const Left, Type_ const Right, Type_ const Bottom, Type_ const Top, Type_ const Znear, Type_ const Zfar ) {
            m_stacks[ m_mode ].ortho(
                static_cast<float>( Left ),
                static_cast<float>( Right ),
                static_cast<float>( Bottom ),
                static_cast<float>( Top ),
                static_cast<float>( Znear ),
                static_cast<float>( Zfar ),
                m_upload ); }
    template <typename Type_>
    void
        perspective( Type_ const Fovy, Type_ const Aspect, Type_ const Znear, Type_ const Zfar ) {
            m_stacks[ m_mode ].perspective(
                static_cast<float>( glm::radians( Fovy ) ),
                static_cast<float>( Aspect ),
                static_cast<float>( Znear ),
                static_cast<float>( Zfar ),
                m_upload ); }
    template <typename Type_>
    void
        look_at( Type_ const Eyex, Type_ const Eyey, Type_ const Eyez, Type_ const Centerx, Type_ const Centery, Type_ const Centerz, Type_ const Upx, Type_ const Upy, Type_ const Upz ) {
            m_stacks[ m_mode ].look_at(
                glm::vec3(
                    static_cast<float>( Eyex ),
                    static_cast<float>( Eyey ),
                    static_cast<float>( Eyez ) ),
                glm::vec3(
                    static_cast<float>( Centerx ),
                    static_cast<float>( Centery ),
                    static_cast<float>( Centerz ) ),
                glm::vec3(
                    static_cast<float>( Upx ),
                    static_cast<float>( Upy ),
                    static_cast<float>( Upz ) ),
                m_upload ); }

private:
// members:
    stack_mode m_mode{ stack_mode::gl_projection };
    openglstack_array m_stacks;
    bool m_upload { true };
};

extern opengl_matrices OpenGLMatrices;

// NOTE: standard opengl calls re-definitions

#undef glMatrixMode
#undef glPushMatrix
#undef glPopMatrix
#undef glLoadIdentity
#undef glLoadMatrixf
#undef glLoadMatrixd
#undef glRotated
#undef glRotatef
#undef glTranslated
#undef glTranslatef
#undef glScaled
#undef glScalef
#undef glMultMatrixd
#undef glMultMatrixf
#undef glOrtho
#undef gluPerspective
#undef gluLookAt

#define glMatrixMode OpenGLMatrices.mode
#define glPushMatrix OpenGLMatrices.push_matrix
#define glPopMatrix OpenGLMatrices.pop_matrix
#define glLoadIdentity OpenGLMatrices.load_identity
#define glLoadMatrixf OpenGLMatrices.load_matrix
#define glLoadMatrixd OpenGLMatrices.load_matrix
#define glRotated OpenGLMatrices.rotate
#define glRotatef OpenGLMatrices.rotate
#define glTranslated OpenGLMatrices.translate
#define glTranslatef OpenGLMatrices.translate
#define glScaled OpenGLMatrices.scale
#define glScalef OpenGLMatrices.scale
#define glMultMatrixd OpenGLMatrices.multiply
#define glMultMatrixf OpenGLMatrices.multiply
#define glOrtho OpenGLMatrices.ortho
#define gluPerspective OpenGLMatrices.perspective
#define gluLookAt OpenGLMatrices.look_at

//---------------------------------------------------------------------------