#include "CommandBufferGL.h"
#include "BufferGL.h"
#include "RenderPipelineGL.h"
#include "TextureGL.h"
#include "DepthStencilStateGL.h"
#include "ProgramGL.h"
#include "BlendStateGL.h"
#include "base/ccMacros.h"
#include "base/CCEventDispatcher.h"
#include "base/CCEventType.h"
#include "base/CCDirector.h"
#include "renderer/backend/opengl/UtilsGL.h"
#include <algorithm>

CC_BACKEND_BEGIN

namespace
{

    GLuint getHandler(TextureBackend *texture)
    {
        switch (texture->getTextureType())
        {
        case TextureType::TEXTURE_2D:
            return static_cast<Texture2DGL*>(texture)->getHandler();
        case TextureType::TEXTURE_CUBE:
            return static_cast<TextureCubeGL*>(texture)->getHandler();
        default:
            assert(false);
            return 0;
        }
    }

    void applyTexture(TextureBackend* texture, int slot)
    {
        switch (texture->getTextureType())
        {
        case TextureType::TEXTURE_2D:
            static_cast<Texture2DGL*>(texture)->apply(slot);
            break;
        case TextureType::TEXTURE_CUBE:
            static_cast<TextureCubeGL*>(texture)->apply(slot);
            break;
        default:
            assert(false);
            return ;
        }
    }
}

CommandBufferGL::CommandBufferGL()
{
    glGetIntegerv(GL_FRAMEBUFFER_BINDING, &_defaultFBO);

#if CC_ENABLE_CACHE_TEXTURE_DATA
    _backToForegroundListener = EventListenerCustom::create(EVENT_RENDERER_RECREATED, [this](EventCustom*){
       if(_generatedFBO)
           glGenFramebuffers(1, &_generatedFBO); //recreate framebuffer
    });
    Director::getInstance()->getEventDispatcher()->addEventListenerWithFixedPriority(_backToForegroundListener, -1);
#endif
}

CommandBufferGL::~CommandBufferGL()
{
    glDeleteFramebuffers(1, &_generatedFBO);
    cleanResources();

#if CC_ENABLE_CACHE_TEXTURE_DATA
    Director::getInstance()->getEventDispatcher()->removeEventListener(_backToForegroundListener);
#endif
}

void CommandBufferGL::beginFrame()
{
}

void CommandBufferGL::beginRenderPass(const RenderPassDescriptor& descirptor)
{
    applyRenderPassDescriptor(descirptor);
}

void CommandBufferGL::applyRenderPassDescriptor(const RenderPassDescriptor& descirptor)
{
    bool useColorAttachmentExternal = descirptor.needColorAttachment && descirptor.colorAttachmentsTexture[0];
    bool useDepthAttachmentExternal = descirptor.depthTestEnabled && descirptor.depthAttachmentTexture;
    bool useStencilAttachmentExternal = descirptor.stencilTestEnabled && descirptor.stencilAttachmentTexture;
    bool useGeneratedFBO = false;
    if (useColorAttachmentExternal || useDepthAttachmentExternal || useStencilAttachmentExternal)
    {
        if(_generatedFBO == 0)
        {
            glGenFramebuffers(1, &_generatedFBO);
        }
        _currentFBO = _generatedFBO;
        useGeneratedFBO = true;
    }
    else
    {
        _currentFBO = _defaultFBO;
    }
    glBindFramebuffer(GL_FRAMEBUFFER, _currentFBO);
    
    if (useDepthAttachmentExternal)
    {
        glFramebufferTexture2D(GL_FRAMEBUFFER,
                               GL_DEPTH_ATTACHMENT,
                               GL_TEXTURE_2D,
                               getHandler(descirptor.depthAttachmentTexture),
                               0);
        CHECK_GL_ERROR_DEBUG();

        _generatedFBOBindDepth = true;
    }
    else
    {
        if (_generatedFBOBindDepth && useGeneratedFBO)
        {
            glFramebufferTexture2D(GL_FRAMEBUFFER,
                                   GL_DEPTH_ATTACHMENT,
                                   GL_TEXTURE_2D,
                                   0,
                                   0);
            CHECK_GL_ERROR_DEBUG();

            _generatedFBOBindDepth = false;
        }
    }
        
    if (useStencilAttachmentExternal)
    {
        glFramebufferTexture2D(GL_FRAMEBUFFER,
                               GL_STENCIL_ATTACHMENT,
                               GL_TEXTURE_2D,
                               getHandler(descirptor.depthAttachmentTexture),
                               0);
        CHECK_GL_ERROR_DEBUG();

        _generatedFBOBindStencil = true;
    }
    else
    {
        if (_generatedFBOBindStencil && useGeneratedFBO)
        {
            glFramebufferTexture2D(GL_FRAMEBUFFER,
                                   GL_STENCIL_ATTACHMENT,
                                   GL_TEXTURE_2D,
                                   0,
                                   0);
            CHECK_GL_ERROR_DEBUG();

            _generatedFBOBindStencil = false;
        }
    }
    
    if (descirptor.needColorAttachment)
    {
        int i = 0;
        for (const auto& texture : descirptor.colorAttachmentsTexture)
        {
            if (texture)
            {
                // TODO: support texture cube
                glFramebufferTexture2D(GL_FRAMEBUFFER,
                                       GL_COLOR_ATTACHMENT0 + i,
                                       GL_TEXTURE_2D,
                                       getHandler(texture),
                                       0);
            }
            CHECK_GL_ERROR_DEBUG();
            ++i;
        }

        if (useGeneratedFBO)
            _generatedFBOBindColor = true;
    }
    else
    {
        if (_generatedFBOBindColor && useGeneratedFBO)
        {
           // FIXME: Now only support attaching to attachment 0.
           glFramebufferTexture2D(GL_FRAMEBUFFER,
                                  GL_COLOR_ATTACHMENT0,
                                  GL_TEXTURE_2D,
                                  0,
                                  0);

            _generatedFBOBindColor = false;
        }

        // If not draw buffer is needed, should invoke this line explicitly, or it will cause
        // GL_FRAMEBUFFER_INCOMPLETE_DRAW_BUFFER and GL_FRAMEBUFFER_INCOMPLETE_READ_BUFFER error.
        // https://stackoverflow.com/questions/28313782/porting-opengl-es-framebuffer-to-opengl
#if CC_TARGET_PLATFORM == CC_PLATFORM_WIN32 || CC_TARGET_PLATFORM == CC_PLATFORM_LINUX
        glDrawBuffer(GL_NONE);
        glReadBuffer(GL_NONE);
#endif
    }
    CHECK_GL_ERROR_DEBUG();
    
    // set clear color, depth and stencil
    GLbitfield mask = 0;
    if (descirptor.needClearColor)
    {
        mask |= GL_COLOR_BUFFER_BIT;
        const auto& clearColor = descirptor.clearColorValue;
        glClearColor(clearColor[0], clearColor[1], clearColor[2], clearColor[3]);
    }
    
    CHECK_GL_ERROR_DEBUG();
    
    GLboolean oldDepthWrite = GL_FALSE;
    GLboolean oldDepthTest = GL_FALSE;
    GLfloat oldDepthClearValue = 0.f;
    GLint oldDepthFunc = GL_LESS;
    if (descirptor.needClearDepth)
    {
        glGetBooleanv(GL_DEPTH_WRITEMASK, &oldDepthWrite);
        glGetBooleanv(GL_DEPTH_TEST, &oldDepthTest);
        glGetFloatv(GL_DEPTH_CLEAR_VALUE, &oldDepthClearValue);
        glGetIntegerv(GL_DEPTH_FUNC, &oldDepthFunc);
        
        mask |= GL_DEPTH_BUFFER_BIT;
        glClearDepth(descirptor.clearDepthValue);
        glEnable(GL_DEPTH_TEST);
        glDepthMask(GL_TRUE);
        glDepthFunc(GL_ALWAYS);
    }
    
    CHECK_GL_ERROR_DEBUG();
    
    if (descirptor.needClearStencil)
    {
        mask |= GL_STENCIL_BUFFER_BIT;
        glClearStencil(descirptor.clearStencilValue);
    }

    if(mask) glClear(mask);
    
    CHECK_GL_ERROR_DEBUG();
    
    // restore depth test
    if (descirptor.needClearDepth)
    {
        if (!oldDepthTest)
            glDisable(GL_DEPTH_TEST);
        
        glDepthMask(oldDepthWrite);
        glDepthFunc(oldDepthFunc);
        glClearDepth(oldDepthClearValue);
    }
    
    CHECK_GL_ERROR_DEBUG();
}

void CommandBufferGL::setRenderPipeline(RenderPipeline* renderPipeline)
{
    assert(renderPipeline != nullptr);
    if (renderPipeline == nullptr)
        return;
    
    RenderPipelineGL* rp = static_cast<RenderPipelineGL*>(renderPipeline);
    rp->retain();
    CC_SAFE_RELEASE(_renderPipeline);
    _renderPipeline = rp;
}

void CommandBufferGL::setViewport(int x, int y, unsigned int w, unsigned int h)
{
    glViewport(x, y, w, h);
    _viewPort.x = x;
    _viewPort.y = y;
    _viewPort.w = w;
    _viewPort.h = h;
}

void CommandBufferGL::setCullMode(CullMode mode)
{
    _cullMode = mode;
}

void CommandBufferGL::setWinding(Winding winding)
{
    glFrontFace(UtilsGL::toGLFrontFace(winding));
}

void CommandBufferGL::setIndexBuffer(Buffer* buffer)
{
    assert(buffer != nullptr);
    if (buffer == nullptr)
        return;
    
    buffer->retain();
    CC_SAFE_RELEASE(_indexBuffer);
    _indexBuffer = static_cast<BufferGL*>(buffer);
}

void CommandBufferGL::setVertexBuffer(unsigned int index, Buffer* buffer)
{
    assert(buffer != nullptr);
    if (buffer == nullptr)
        return;
    
    buffer->retain();
    
    if (index >= _vertexBuffers.size())
        _vertexBuffers.resize(index + 1);

    CC_SAFE_RELEASE(_vertexBuffers[index]);
    _vertexBuffers[index] = static_cast<BufferGL*>(buffer);
}

void CommandBufferGL::setProgramState(ProgramState* programState)
{
    CC_SAFE_RETAIN(programState);
    CC_SAFE_RELEASE(_programState);
    _programState = programState;
}

void CommandBufferGL::drawArrays(PrimitiveType primitiveType, unsigned int start,  unsigned int count)
{
    prepareDrawing();
    glDrawArrays(UtilsGL::toGLPrimitiveType(primitiveType), start, count);
    
    cleanResources();
}

void CommandBufferGL::drawElements(PrimitiveType primitiveType, IndexFormat indexType, unsigned int count, unsigned int offset)
{
    prepareDrawing();
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, _indexBuffer->getHandler());
    glDrawElements(UtilsGL::toGLPrimitiveType(primitiveType), count, UtilsGL::toGLIndexType(indexType), (GLvoid*)offset);
    CHECK_GL_ERROR_DEBUG();
    cleanResources();
}

void CommandBufferGL::endRenderPass()
{
}

void CommandBufferGL::endFrame()
{
}

void CommandBufferGL::setDepthStencilState(DepthStencilState* depthStencilState)	
{	
    if (depthStencilState)	
    {	
        _depthStencilStateGL = static_cast<DepthStencilStateGL*>(depthStencilState);	
    }	
    else	
    {	
        _depthStencilStateGL = nullptr;	
    }	
}

void CommandBufferGL::prepareDrawing() const
{   
    const auto& program = _renderPipeline->getProgram();
    glUseProgram(program->getHandler());
    
    bindVertexBuffer(program);
    setUniforms(program);

    // Set depth/stencil state.
    if (_depthStencilStateGL)
    {
        _depthStencilStateGL->apply(_stencilReferenceValueFront, _stencilReferenceValueBack);
    }
        
    else
        DepthStencilStateGL::reset();
    
    // Set blend state.
    if (_renderPipeline->getBlendState())
        _renderPipeline->getBlendState()->apply();
    else
        BlendStateGL::reset();
    
    // Set cull mode.
    if (CullMode::NONE == _cullMode)
    {
        glDisable(GL_CULL_FACE);
    }
    else
    {
        glEnable(GL_CULL_FACE);
        glCullFace(UtilsGL::toGLCullMode(_cullMode));
    }
}

void CommandBufferGL::bindVertexBuffer(ProgramGL *program) const
{
    // Bind vertex buffers and set the attributes.
    int i = 0;
    const auto& attributeInfos = program->getAttributeInfos();
    const auto& vertexLayouts = getVertexLayouts();
    for (const auto& vertexBuffer : _vertexBuffers)
    {
        if (! vertexBuffer)
            continue;
        if (i >= attributeInfos.size())
            break;
        
        glBindBuffer(GL_ARRAY_BUFFER, vertexBuffer->getHandler());

        const auto& attributeInfo = attributeInfos[i];
        const auto &layouts = vertexLayouts->at(i);
        for (const auto& attribute : attributeInfo)
        {
            const auto &layoutInfo = layouts.getAttributes().at(attribute.name);
            glEnableVertexAttribArray(attribute.location);
            glVertexAttribPointer(attribute.location,
                UtilsGL::getGLAttributeSize(layoutInfo.format),
                UtilsGL::toGLAttributeType(layoutInfo.format),
                layoutInfo.needToBeNormallized,
                layouts.getStride(),
                (GLvoid*)layoutInfo.offset);
        }
        
        ++i;
    }
}

void CommandBufferGL::setUniforms(ProgramGL* program) const
{
    if (_programState)
    {
        auto& callbacks = _programState->getCallbackUniforms();
        auto& uniformInfos = _programState->getVertexUniformInfos();

        for (auto &cb : callbacks)
        {
            cb.second(_programState, cb.first);
        }

        int i = 0;
        for(auto& iter : uniformInfos)
        {
            auto& uniformInfo = iter.uniformInfo;
            if(uniformInfo.bufferSize <= 0)
                continue;

            int elementCount = uniformInfo.count;
            if (uniformInfo.isArray)
            {
                CCASSERT(uniformInfo.count * uniformInfo.bufferSize >= iter.data.size(), "uniform data size mismatch!");
                //iter.data.reserve(uniformInfo.count * uniformInfo.bufferSize);
                elementCount = std::min(elementCount, (int)(iter.data.size() / uniformInfo.bufferSize));
            }

            setUniform(uniformInfo.isArray,
                uniformInfo.location,
                elementCount,
                uniformInfo.type,
                (void*)iter.data.data());
        }
        
        const auto& textureInfo = _programState->getVertexTextureInfos();
        for(const auto& iter : textureInfo)
        {
            const auto& textures = iter.second.textures;
            const auto& slot = iter.second.slot;
            auto location = iter.first;
#if CC_ENABLE_CACHE_TEXTURE_DATA
            location = iter.second.location;
#endif
            int i = 0;
            for (const auto& texture: textures)
            {
                applyTexture(texture, slot[i]);
                ++i;
            }
            
            auto arrayCount = slot.size();
            if (arrayCount > 1)
                glUniform1iv(location, (uint32_t)arrayCount, (GLint*)slot.data());
            else
                glUniform1i(location, slot[0]);
        }
    }
}

#define DEF_TO_INT(pointer, index)     (*((GLint*)(pointer) + index))
#define DEF_TO_FLOAT(pointer, index)   (*((GLfloat*)(pointer) + index))
void CommandBufferGL::setUniform(bool isArray, GLuint location, unsigned int size, GLenum uniformType, void* data) const
{
    GLsizei count = size;
    switch (uniformType)
    {
        case GL_INT:
        case GL_BOOL:
        case GL_SAMPLER_2D:
        case GL_SAMPLER_CUBE:
            if (isArray)
                glUniform1iv(location, count, (GLint*)data);
            else
                glUniform1i(location, DEF_TO_INT(data, 0));
            break;
        case GL_INT_VEC2:
        case GL_BOOL_VEC2:
            if (isArray)
                glUniform2iv(location, count, (GLint*)data);
            else
                glUniform2i(location, DEF_TO_INT(data, 0), DEF_TO_INT(data, 1));
            break;
        case GL_INT_VEC3:
        case GL_BOOL_VEC3:
            if (isArray)
                glUniform3iv(location, count, (GLint*)data);
            else
                glUniform3i(location,
                            DEF_TO_INT(data, 0),
                            DEF_TO_INT(data, 1),
                            DEF_TO_INT(data, 2));
            break;
        case GL_INT_VEC4:
        case GL_BOOL_VEC4:
            if (isArray)
                glUniform4iv(location, count, (GLint*)data);
            else
                glUniform4i(location,
                            DEF_TO_INT(data, 0),
                            DEF_TO_INT(data, 1),
                            DEF_TO_INT(data, 2),
                            DEF_TO_INT(data, 4));
            break;
        case GL_FLOAT:
            if (isArray)
                glUniform1fv(location, count, (GLfloat*)data);
            else
                glUniform1f(location, DEF_TO_FLOAT(data, 0));
            break;
        case GL_FLOAT_VEC2:
            if (isArray)
                glUniform2fv(location, count, (GLfloat*)data);
            else
                glUniform2f(location, DEF_TO_FLOAT(data, 0), DEF_TO_FLOAT(data, 1));
            break;
        case GL_FLOAT_VEC3:
            if (isArray)
                glUniform3fv(location, count, (GLfloat*)data);
            else
                glUniform3f(location,
                            DEF_TO_FLOAT(data, 0),
                            DEF_TO_FLOAT(data, 1),
                            DEF_TO_FLOAT(data, 2));
            break;
        case GL_FLOAT_VEC4:
            if (isArray)
                glUniform4fv(location, count, (GLfloat*)data);
            else
                glUniform4f(location,
                            DEF_TO_FLOAT(data, 0),
                            DEF_TO_FLOAT(data, 1),
                            DEF_TO_FLOAT(data, 2),
                            DEF_TO_FLOAT(data, 3));
            break;
        case GL_FLOAT_MAT2:
            glUniformMatrix2fv(location, count, GL_FALSE, (GLfloat*)data);
            break;
        case GL_FLOAT_MAT3:
            glUniformMatrix3fv(location, count, GL_FALSE, (GLfloat*)data);
            break;
        case GL_FLOAT_MAT4:
            glUniformMatrix4fv(location, count, GL_FALSE, (GLfloat*)data);
            break;
        break;
        
        default:
            CCASSERT(false, "invalidate Uniform data type");
        break;
    }
}

void CommandBufferGL::cleanResources()
{
    CC_SAFE_RELEASE_NULL(_indexBuffer);
    CC_SAFE_RELEASE_NULL(_renderPipeline);
    CC_SAFE_RELEASE_NULL(_programState);
      
    for (const auto& vertexBuffer : _vertexBuffers)
        CC_SAFE_RELEASE(vertexBuffer);
    
    _vertexBuffers.clear();
}

void CommandBufferGL::setLineWidth(float lineWidth)
{
    if(lineWidth > 0.0f)
        glLineWidth(lineWidth);
    else
        glLineWidth(1.0f);
    
}


void CommandBufferGL::setScissorRect(bool isEnabled, float x, float y, float width, float height)
{
    if(isEnabled)
    {
        glEnable(GL_SCISSOR_TEST);
        glScissor(x, y, width, height);
    }
    else
    {
        glDisable(GL_SCISSOR_TEST);
    }
}

void CommandBufferGL::captureScreen(std::function<void(const unsigned char*, int, int)> callback)
{
    int bufferSize = _viewPort.w * _viewPort.h *4;
    std::shared_ptr<GLubyte> buffer(new GLubyte[bufferSize], [](GLubyte* p){ CC_SAFE_DELETE_ARRAY(p); });
    memset(buffer.get(), 0, bufferSize);
    if (!buffer)
    {
        callback(nullptr, 0, 0);
        return;
    }
    glPixelStorei(GL_PACK_ALIGNMENT, 1);
    glReadPixels(0, 0, _viewPort.w, _viewPort.h, GL_RGBA, GL_UNSIGNED_BYTE, buffer.get());

    std::shared_ptr<GLubyte> flippedBuffer(new GLubyte[bufferSize], [](GLubyte* p) { CC_SAFE_DELETE_ARRAY(p); });
    memset(flippedBuffer.get(), 0, bufferSize);
    if (!flippedBuffer)
    {
        callback(nullptr, 0, 0);
        return;
    }
    for (int row = 0; row < _viewPort.h; ++row)
    {
        memcpy(flippedBuffer.get() + (_viewPort.h - row - 1) * _viewPort.w * 4, buffer.get() + row * _viewPort.w * 4, _viewPort.w * 4);
    }

    callback(flippedBuffer.get(), _viewPort.w, _viewPort.h);
}

CC_BACKEND_END