/**
 Copyright 2013 BlackBerry Inc.
 Copyright (c) 2015-2017 Chukong Technologies
 Copyright (c) 2017-2018 Xiamen Yaji Software Co., Ltd.

 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at

 http://www.apache.org/licenses/LICENSE-2.0

 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.

 Original file from GamePlay3D: http://gameplay3d.org

 This file was modified to fit the cocos2d-x project
 */

#include "renderer/CCVertexAttribBinding.h"
#include "renderer/backend/Program.h"
#include "renderer/CCPass.h"
#include "base/CCConfiguration.h"
#include "3d/CCMeshVertexIndexData.h"
#include "3d/CC3DProgramInfo.h"

NS_CC_BEGIN


static GLuint __maxVertexAttribs = 0;
static std::vector<VertexAttribBinding*> __vertexAttribBindingCache;

VertexAttribBinding::VertexAttribBinding() :
    _handle(0), _meshIndexData(nullptr), _programState(nullptr), _attributes()
{
}

VertexAttribBinding::~VertexAttribBinding()
{
    // Delete from the vertex attribute binding cache.
    std::vector<VertexAttribBinding*>::iterator itr = std::find(__vertexAttribBindingCache.begin(), __vertexAttribBindingCache.end(), this);
    if (itr != __vertexAttribBindingCache.end())
    {
        __vertexAttribBindingCache.erase(itr);
    }

    CC_SAFE_RELEASE(_meshIndexData);
    CC_SAFE_RELEASE(_programState);
    _attributes.clear();

    if (_handle)
    {
        glDeleteVertexArrays(1, &_handle);
        _handle = 0;
    }
}

VertexAttribBinding* VertexAttribBinding::create(MeshIndexData* meshIndexData, Pass* pass)
{
    CCASSERT(meshIndexData && pass && pass->getProgramState(), "Invalid MeshIndexData and/or programState");

    // Search for an existing vertex attribute binding that can be used.
    VertexAttribBinding* b;
    for (size_t i = 0, count = __vertexAttribBindingCache.size(); i < count; ++i)
    {
        b = __vertexAttribBindingCache[i];
        CC_ASSERT(b);
        if (b->_meshIndexData == meshIndexData && b->_programState == pass->getProgramState())
        {
            // Found a match!
            return b;
        }
    }

    b = new (std::nothrow) VertexAttribBinding();
    if (b && b->init(meshIndexData, pass))
    {
        b->autorelease();
        __vertexAttribBindingCache.push_back(b);
    }

    return b;
}

bool VertexAttribBinding::init(MeshIndexData* meshIndexData, Pass* pass)
{

    CCASSERT(meshIndexData && pass && pass->getProgramState(), "Invalid arguments");

    auto programState = pass->getProgramState();

    _vertexLayout = pass->getVertexLayout();

    // One-time initialization.
    //TODO arnold
//    if (__maxVertexAttribs == 0)
//    {
//        GLint temp;
//        glGetIntegerv(GL_MAX_VERTEX_ATTRIBS, &temp);
//
//        __maxVertexAttribs = temp;
//        if (__maxVertexAttribs <= 0)
//        {
//            CCLOGERROR("The maximum number of vertex attributes supported by OpenGL on the current device is 0 or less.");
//            return false;
//        }
//    }

    _meshIndexData = meshIndexData;
    _meshIndexData->retain();
    _programState = programState;
    _programState->retain();

    auto meshVertexData = meshIndexData->getMeshVertexData();
    auto attributeCount = meshVertexData->getMeshVertexAttribCount();


    // Parse and set attributes
    parseAttributes();
    int offset = 0;
    for (auto k = 0; k < attributeCount; k++)
    {
        auto meshattribute = meshVertexData->getMeshVertexAttrib(k);
        setVertexAttribPointer(
                               shaderinfos::getAttributeName(meshattribute.vertexAttrib),
                               meshattribute.type,
                               GL_FALSE,
                               offset);
        offset += meshattribute.getAttribSizeBytes();
    }

    _vertexLayout->setLayout(offset, backend::VertexStepMode::VERTEX);

    CCASSERT(offset == meshVertexData->getSizePerVertex(), "vertex layout mismatch!");

    //// VAO hardware
    //if (Configuration::getInstance()->supportsShareableVAO())
    //{
    //    glGenVertexArrays(1, &_handle);
    //    glBindVertexArray(_handle);
    //    glBindBuffer(GL_ARRAY_BUFFER, meshVertexData->getVertexBuffer()->getVBO());

    //    enableVertexAttributes(_vertexAttribsFlags);

    //    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, meshIndexData->getIndexBuffer()->getVBO());

    //    for(auto &attribute : _attributes)
    //    {
    //        attribute.second.apply();
    //    }

    //    glBindVertexArray(0);
    //    glBindBuffer(GL_ARRAY_BUFFER, 0);
    //    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
    //}

    return true;
}

//void VertexAttribBinding::bind(backend::VertexLayout &layout)
//{
//
//    if (_handle)
//    {
//        // hardware
//        glBindVertexArray(_handle);
//    }
//    else
//    {
//        // software
//        auto meshVertexData = _meshIndexData->getMeshVertexData();
//        glBindBuffer(GL_ARRAY_BUFFER, meshVertexData->getVertexBuffer()->getVBO());
//        glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, _meshIndexData->getIndexBuffer()->getVBO());
//
//        // Software mode
//        enableVertexAttributes(_vertexAttribsFlags);
//        // set attributes
//        for(auto &attribute : _attributes)
//        {
//            attribute.second.apply();
//        }
//        
//    }
//    
//}

//void VertexAttribBinding::unbind()
//{
//    if (_handle)
//    {
//        // Hardware
//        glBindVertexArray(0);
//    }
//    else
//    {
//        // Software
//        glBindBuffer(GL_ARRAY_BUFFER, 0);
//        glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
//    }
//}

uint32_t VertexAttribBinding::getVertexAttribsFlags() const
{
    return _vertexAttribsFlags;
}

void VertexAttribBinding::parseAttributes()
{
    CCASSERT(_programState, "invalid glprogram");

    _attributes.clear();
    _vertexAttribsFlags = 0;

    auto program = _programState->getProgram();
    
    auto attributes = program->getActiveAttributes();

    for(auto &attrib: attributes)
    {
        _attributes[attrib.attributeName] = attrib;
    }
}

//void VertexAttribBinding::enableVertexAttributes(uint32_t flags) const
//{
//    auto tmpFlags = flags;
//    for (int i = 0; tmpFlags > 0; i++)
//    {
//        int flag = 1 << i;
//        if (flag & tmpFlags)
//            glEnableVertexAttribArray(i);
//        
//        tmpFlags &= ~flag;
//    }
//}

backend::AttributeBindInfo* VertexAttribBinding::getVertexAttribValue(const std::string& name)
{
    const auto itr = _attributes.find(name);
    if( itr != _attributes.end())
        return &itr->second;
    return nullptr;
}

void VertexAttribBinding::setVertexAttribPointer(const std::string &name, backend::VertexFormat type, GLboolean normalized, int offset)
{
    auto v = getVertexAttribValue(name);
    if(v) {
        //v->setPointer(size, type, normalized, stride, offset);
        CCLOG("bind attribute %s to location: %d, offset: %d", name.c_str(), v->location, offset);
        _vertexLayout->setAtrribute(name, v->location, type, offset, normalized);
        _vertexAttribsFlags |= 1 << v->location;
    }
    else
    {
        CCLOG("cocos2d: warning: Attribute not found: %s", name.c_str());
    }
}

NS_CC_END