//
//  Batch.h
//  interface/src/gpu
//
//  Created by Sam Gateau on 10/14/2014.
//  Copyright 2014 High Fidelity, Inc.
//
//  Distributed under the Apache License, Version 2.0.
//  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
//
#ifndef hifi_gpu_Batch_h
#define hifi_gpu_Batch_h

#include <assert.h>
#include "InterfaceConfig.h"

#include "Transform.h"

#include <vector>

#include "gpu/Stream.h"

#if defined(NSIGHT_FOUND)
    #include "nvToolsExt.h"
    class ProfileRange {
    public:
        ProfileRange(const char *name) {
            nvtxRangePush(name);
        }
        ~ProfileRange() {
            nvtxRangePop();
        }
    };

    #define PROFILE_RANGE(name) ProfileRange profileRangeThis(name);
#else
#define PROFILE_RANGE(name)
#endif

namespace gpu {

enum Primitive {
    POINTS = 0,
    LINES,
    LINE_STRIP,
    TRIANGLES,
    TRIANGLE_STRIP,
    QUADS,

    NUM_PRIMITIVES,
};

typedef ::Transform Transform;
typedef QSharedPointer< ::gpu::Transform > TransformPointer;
typedef std::vector< TransformPointer > Transforms;

class Batch {
public:
    typedef Stream::Slot Slot;

    Batch();
    Batch(const Batch& batch);
    ~Batch();

    void clear();

    // Drawcalls
    void draw(Primitive primitiveType, uint32 numVertices, uint32 startVertex = 0);
    void drawIndexed(Primitive primitiveType, uint32 nbIndices, uint32 startIndex = 0);
    void drawInstanced(uint32 nbInstances, Primitive primitiveType, uint32 nbVertices, uint32 startVertex = 0, uint32 startInstance = 0);
    void drawIndexedInstanced(uint32 nbInstances, Primitive primitiveType, uint32 nbIndices, uint32 startIndex = 0, uint32 startInstance = 0);

    // Input Stage
    // InputFormat
    // InputBuffers
    // IndexBuffer
    void setInputFormat(const Stream::FormatPointer& format);

    void setInputStream(Slot startChannel, const BufferStream& stream); // not a command, just unroll into a loop of setInputBuffer
    void setInputBuffer(Slot channel, const BufferPointer& buffer, Offset offset, Offset stride);

    void setIndexBuffer(Type type, const BufferPointer& buffer, Offset offset);

    // Transform Stage
    // Vertex position is transformed by ModelTransform from object space to world space
    // Then by the inverse of the ViewTransform from world space to eye space
    // finaly projected into the clip space by the projection transform
    // WARNING: ViewTransform transform from eye space to world space, its inverse is composed
    // with the ModelTransformu to create the equivalent of the glModelViewMatrix
    void setModelTransform(const TransformPointer& model);
    void setViewTransform(const TransformPointer& view);
    void setProjectionTransform(const TransformPointer& proj);


    // TODO: As long as we have gl calls explicitely issued from interface
    // code, we need to be able to record and batch these calls. THe long 
    // term strategy is to get rid of any GL calls in favor of the HIFI GPU API
    // For now, instead of calling the raw glCall, use the equivalent call on the batch so the call is beeing recorded
    // THe implementation of these functions is in GLBackend.cpp

    void _glEnable(GLenum cap);
    void _glDisable(GLenum cap);

    void _glEnableClientState(GLenum array);
    void _glDisableClientState(GLenum array);

    void _glCullFace(GLenum mode);
    void _glAlphaFunc(GLenum func, GLclampf ref);

    void _glDepthFunc(GLenum func);
    void _glDepthMask(GLboolean flag);
    void _glDepthRange(GLclampd zNear, GLclampd zFar);

    void _glBindBuffer(GLenum target, GLuint buffer);

    void _glBindTexture(GLenum target, GLuint texture);
    void _glActiveTexture(GLenum texture);

    void _glDrawBuffers(GLsizei n, const GLenum* bufs);

    void _glUseProgram(GLuint program);
    void _glUniform1f(GLint location, GLfloat v0);
    void _glUniformMatrix4fv(GLint location, GLsizei count, GLboolean transpose, const GLfloat* value);

    void _glMatrixMode(GLenum mode); 
    void _glPushMatrix();
    void _glPopMatrix();
    void _glMultMatrixf(const GLfloat *m);
    void _glLoadMatrixf(const GLfloat *m);
    void _glLoadIdentity(void);
    void _glRotatef(GLfloat angle, GLfloat x, GLfloat y, GLfloat z);
    void _glScalef(GLfloat x, GLfloat y, GLfloat z);
    void _glTranslatef(GLfloat x, GLfloat y, GLfloat z);

    void _glDrawArrays(GLenum mode, GLint first, GLsizei count);
    void _glDrawRangeElements(GLenum mode, GLuint start, GLuint end, GLsizei count, GLenum type, const void *indices);

    void _glColorPointer(GLint size, GLenum type, GLsizei stride, const void *pointer);
    void _glNormalPointer(GLenum type, GLsizei stride, const void *pointer);
    void _glTexCoordPointer(GLint size, GLenum type, GLsizei stride, const void *pointer);
    void _glVertexPointer(GLint size, GLenum type, GLsizei stride, const void *pointer);

    void _glVertexAttribPointer(GLuint index, GLint size, GLenum type, GLboolean normalized, GLsizei stride, const void *pointer);
    void _glEnableVertexAttribArray(GLint location);
    void _glDisableVertexAttribArray(GLint location);

    void _glColor4f(GLfloat red, GLfloat green, GLfloat blue, GLfloat alpha);

    void _glMaterialf(GLenum face, GLenum pname, GLfloat param);
    void _glMaterialfv(GLenum face, GLenum pname, const GLfloat *params);


    enum Command {
        COMMAND_draw = 0,
        COMMAND_drawIndexed,
        COMMAND_drawInstanced,
        COMMAND_drawIndexedInstanced,

        COMMAND_setInputFormat,
        COMMAND_setInputBuffer,
        COMMAND_setIndexBuffer,

        COMMAND_setModelTransform,
        COMMAND_setViewTransform,
        COMMAND_setProjectionTransform,

        // TODO: As long as we have gl calls explicitely issued from interface
        // code, we need to be able to record and batch these calls. THe long 
        // term strategy is to get rid of any GL calls in favor of the HIFI GPU API
        COMMAND_glEnable,
        COMMAND_glDisable,

        COMMAND_glEnableClientState,
        COMMAND_glDisableClientState,

        COMMAND_glCullFace,
        COMMAND_glAlphaFunc,

        COMMAND_glDepthFunc,
        COMMAND_glDepthMask,
        COMMAND_glDepthRange,

        COMMAND_glBindBuffer,

        COMMAND_glBindTexture,
        COMMAND_glActiveTexture,

        COMMAND_glDrawBuffers,

        COMMAND_glUseProgram,
        COMMAND_glUniform1f,
        COMMAND_glUniformMatrix4fv,

        COMMAND_glMatrixMode,
        COMMAND_glPushMatrix,
        COMMAND_glPopMatrix,
        COMMAND_glMultMatrixf,
        COMMAND_glLoadMatrixf,
        COMMAND_glLoadIdentity,
        COMMAND_glRotatef,
        COMMAND_glScalef,
        COMMAND_glTranslatef,

        COMMAND_glDrawArrays,
        COMMAND_glDrawRangeElements,

        COMMAND_glColorPointer,
        COMMAND_glNormalPointer,
        COMMAND_glTexCoordPointer,
        COMMAND_glVertexPointer,

        COMMAND_glVertexAttribPointer,
        COMMAND_glEnableVertexAttribArray,
        COMMAND_glDisableVertexAttribArray,

        COMMAND_glColor4f,

        COMMAND_glMaterialf,
        COMMAND_glMaterialfv,

        NUM_COMMANDS,
    };
    typedef std::vector<Command> Commands;
    typedef std::vector<uint32> CommandOffsets;

    const Commands& getCommands() const { return _commands; }
    const CommandOffsets& getCommandOffsets() const { return _commandOffsets; }

    class Param {
    public:
        union {
            int32 _int;
            uint32 _uint;
            float   _float;
            char _chars[4];
            double _double;
        };
        Param(int32 val) : _int(val) {}
        Param(uint32 val) : _uint(val) {}
        Param(float val) : _float(val) {}
        Param(double val) : _double(val) {}
    };
    typedef std::vector<Param> Params;

    const Params& getParams() const { return _params; }

    class ResourceCache {
    public:
        union {
            Resource* _resource;
            const void* _pointer;
        };
        ResourceCache(Resource* res) : _resource(res) {}
        ResourceCache(const void* pointer) : _pointer(pointer) {}
    };
    typedef std::vector<ResourceCache> Resources;

    template <typename T>
    class Cache {
    public:
        typedef QSharedPointer<T> Pointer;
        Pointer _pointer;
        Cache<T>(const Pointer& pointer) : _pointer(pointer) {}

        class Vector {
        public:
            std::vector< Cache<T> > _pointers;

            uint32 cache(const Pointer& pointer) {
                uint32 offset = _pointers.size();
                _pointers.push_back(Cache<T>(pointer));
                return offset;
            }

            Pointer get(uint32 offset) {
                if (offset >= _pointers.size()) {
                    return Pointer();
                }
                return (_pointers.data() + offset)->_pointer;
            }

            void clear() {
                _pointers.clear();
            }
        };
    };
    
    typedef Cache<Buffer>::Vector BufferCaches;
    typedef Cache<Stream::Format>::Vector StreamFormatCaches;
    typedef Cache<Transform>::Vector TransformCaches;

    typedef unsigned char Byte;
    typedef std::vector<Byte> Bytes;

    uint32 cacheResource(Resource* res);
    uint32 cacheResource(const void* pointer);
    ResourceCache* editResource(uint32 offset) {
        if (offset >= _resources.size()) {
            return 0;
        }
        return (_resources.data() + offset);
    }

    template <typename T>
    T* editResourcePointer(uint32 offset) {
        if (offset >= _resources.size()) {
            return 0;
        }
        return reinterpret_cast<T*>((_resources.data() + offset)->_pointer);
    }

    uint32 cacheData(uint32 size, const void* data);
    Byte* editData(uint32 offset) {
        if (offset >= _data.size()) {
            return 0;
        }
        return (_data.data() + offset);
    }

    Commands _commands;
    CommandOffsets _commandOffsets;
    Params _params;
    Resources _resources;
    Bytes _data;

    BufferCaches _buffers;
    StreamFormatCaches _streamFormats;
    TransformCaches _transforms;

protected:
};

};

#endif