/*     Copyright 2019 Diligent Graphics LLC
 *  
 *  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
 * 
 *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 *  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 *  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF ANY PROPRIETARY RIGHTS.
 *
 *  In no event and under no legal theory, whether in tort (including negligence), 
 *  contract, or otherwise, unless required by applicable law (such as deliberate 
 *  and grossly negligent acts) or agreed to in writing, shall any Contributor be
 *  liable for any damages, including any direct, indirect, special, incidental, 
 *  or consequential damages of any character arising as a result of this License or 
 *  out of the use or inability to use the software (including but not limited to damages 
 *  for loss of goodwill, work stoppage, computer failure or malfunction, or any and 
 *  all other commercial damages or losses), even if such Contributor has been advised 
 *  of the possibility of such damages.
 */

#include "pch.h"

#include "GLContextWindows.h"
#include "DeviceCaps.h"
#include "GLTypeConversions.h"
#include "GraphicsAccessories.h"

namespace Diligent
{

void APIENTRY openglCallbackFunction(GLenum        source,
                                     GLenum        type,
                                     GLuint        id,
                                     GLenum        severity,
                                     GLsizei       length,
                                     const GLchar* message,
                                     const void*   userParam)
{
    // Note: disabling flood of notifications through glDebugMessageControl() has no effect,
    // so we have to filter them out here
    if (id == 131185 || // Buffer detailed info: Buffer object <X> (bound to GL_XXXX ... , usage hint is GL_DYNAMIC_DRAW)
                        // will use VIDEO memory as the source for buffer object operations.
        id == 131186    // Buffer object <X> (bound to GL_XXXX, usage hint is GL_DYNAMIC_DRAW) is being copied/moved from VIDEO memory to HOST memory.
    )
        return;

    std::stringstream MessageSS;

    MessageSS << "OpenGL debug message " << id << " (";
    switch (source)
    {
        // clang-format off
        case GL_DEBUG_SOURCE_API:             MessageSS << "Source: API.";             break;
        case GL_DEBUG_SOURCE_WINDOW_SYSTEM:   MessageSS << "Source: Window System.";   break;
        case GL_DEBUG_SOURCE_SHADER_COMPILER: MessageSS << "Source: Shader Compiler."; break;
        case GL_DEBUG_SOURCE_THIRD_PARTY:     MessageSS << "Source: Third Party.";     break;
        case GL_DEBUG_SOURCE_APPLICATION:     MessageSS << "Source: Application.";     break;
        case GL_DEBUG_SOURCE_OTHER:           MessageSS << "Source: Other.";           break;
        default:                              MessageSS << "Source: Unknown (" << source << ").";
            // clang-format on
    }

    switch (type)
    {
        // clang-format off
        case GL_DEBUG_TYPE_ERROR:               MessageSS << " Type: ERROR.";                break;
        case GL_DEBUG_TYPE_DEPRECATED_BEHAVIOR: MessageSS << " Type: Deprecated Behaviour."; break;
        case GL_DEBUG_TYPE_UNDEFINED_BEHAVIOR:  MessageSS << " Type: UNDEFINED BEHAVIOUR.";  break; 
        case GL_DEBUG_TYPE_PORTABILITY:         MessageSS << " Type: Portability.";          break;
        case GL_DEBUG_TYPE_PERFORMANCE:         MessageSS << " Type: PERFORMANCE.";          break;
        case GL_DEBUG_TYPE_MARKER:              MessageSS << " Type: Marker.";               break;
        case GL_DEBUG_TYPE_PUSH_GROUP:          MessageSS << " Type: Push Group.";           break;
        case GL_DEBUG_TYPE_POP_GROUP:           MessageSS << " Type: Pop Group.";            break;
        case GL_DEBUG_TYPE_OTHER:               MessageSS << " Type: Other.";                break;
        default:                                MessageSS << " Type: Unknown (" << type << ").";
            // clang-format on
    }

    switch (severity)
    {
        // clang-format off
        case GL_DEBUG_SEVERITY_HIGH:         MessageSS << " Severity: HIGH";         break;
        case GL_DEBUG_SEVERITY_MEDIUM:       MessageSS << " Severity: Medium";       break;
        case GL_DEBUG_SEVERITY_LOW:          MessageSS << " Severity: Low";          break;
        case GL_DEBUG_SEVERITY_NOTIFICATION: MessageSS << " Severity: Notification"; break;
        default:                             MessageSS << " Severity: Unknown (" << severity << ")"; break;
            // clang-format on
    }

    MessageSS << "): " << message;

    LOG_INFO_MESSAGE(MessageSS.str().c_str());
}

GLContext::GLContext(const EngineGLCreateInfo& InitAttribs, DeviceCaps& deviceCaps, const SwapChainDesc* pSCDesc) :
    m_Context{0},
    m_WindowHandleToDeviceContext{0}
{
    Int32 MajorVersion = 0, MinorVersion = 0;
    if (InitAttribs.pNativeWndHandle != nullptr)
    {
        HWND hWnd = reinterpret_cast<HWND>(InitAttribs.pNativeWndHandle);

        // See http://www.opengl.org/wiki/Tutorial:_OpenGL_3.1_The_First_Triangle_(C%2B%2B/Win)
        //     http://www.opengl.org/wiki/Creating_an_OpenGL_Context_(WGL)
        PIXELFORMATDESCRIPTOR pfd;
        memset(&pfd, 0, sizeof(PIXELFORMATDESCRIPTOR));
        pfd.nSize      = sizeof(PIXELFORMATDESCRIPTOR);
        pfd.nVersion   = 1;
        pfd.dwFlags    = PFD_DOUBLEBUFFER | PFD_SUPPORT_OPENGL | PFD_DRAW_TO_WINDOW;
        pfd.iPixelType = PFD_TYPE_RGBA;
        if (pSCDesc != nullptr)
        {
            auto ColorFmt = pSCDesc->ColorBufferFormat;
            if (ColorFmt == TEX_FORMAT_RGBA8_UNORM || ColorFmt == TEX_FORMAT_RGBA8_UNORM_SRGB ||
                ColorFmt == TEX_FORMAT_BGRA8_UNORM || ColorFmt == TEX_FORMAT_BGRA8_UNORM_SRGB)
            {
                pfd.cColorBits = 32;
            }
            else
            {
                LOG_WARNING_MESSAGE("Unsupported color buffer format ", GetTextureFormatAttribs(ColorFmt).Name, ". "
                                                                                                                "OpenGL only supports 32-bit UNORM color buffer formats.");
                pfd.cColorBits = 32;
            }

            auto DepthFmt = pSCDesc->DepthBufferFormat;
            switch (DepthFmt)
            {
                case TEX_FORMAT_UNKNOWN:
                    pfd.cDepthBits   = 0;
                    pfd.cStencilBits = 0;
                    break;

                case TEX_FORMAT_D32_FLOAT_S8X24_UINT:
                    pfd.cDepthBits   = 32;
                    pfd.cStencilBits = 8;
                    break;

                case TEX_FORMAT_D32_FLOAT:
                    pfd.cDepthBits = 32;
                    break;

                case TEX_FORMAT_D24_UNORM_S8_UINT:
                    pfd.cDepthBits   = 24;
                    pfd.cStencilBits = 8;
                    break;

                case TEX_FORMAT_D16_UNORM:
                    pfd.cDepthBits = 16;
                    break;

                default:
                    LOG_ERROR_MESSAGE("Unsupported depth buffer format ", GetTextureFormatAttribs(DepthFmt).Name);
                    pfd.cDepthBits = 32;
            }
        }
        else
        {
            pfd.cColorBits = 32;
            pfd.cDepthBits = 32;
        }
        pfd.iLayerType = PFD_MAIN_PLANE;

        m_WindowHandleToDeviceContext = GetDC(hWnd);
        int nPixelFormat              = ChoosePixelFormat(m_WindowHandleToDeviceContext, &pfd);

        if (nPixelFormat == 0)
            LOG_ERROR_AND_THROW("Invalid Pixel Format");

        BOOL bResult = SetPixelFormat(m_WindowHandleToDeviceContext, nPixelFormat, &pfd);
        if (!bResult)
            LOG_ERROR_AND_THROW("Failed to set Pixel Format");

        // Create standard OpenGL (2.1) rendering context which will be used only temporarily,
        HGLRC tempContext = wglCreateContext(m_WindowHandleToDeviceContext);
        // and make it current
        wglMakeCurrent(m_WindowHandleToDeviceContext, tempContext);

        // Initialize GLEW
        GLenum err = glewInit();
        if (GLEW_OK != err)
            LOG_ERROR_AND_THROW("Failed to initialize GLEW");

        if (wglewIsSupported("WGL_ARB_create_context") == 1)
        {
            std::pair<int, int> gl_versions[] = {{4, 4}, {4, 3}, {4, 2}};
            for (size_t i = 0; i < _countof(gl_versions) && m_Context == NULL; ++i)
            {
                const auto& version = gl_versions[i];
                MajorVersion        = version.first;
                MinorVersion        = version.second;
                // Setup attributes for a new OpenGL rendering context
                int attribs[] =
                    {
                        WGL_CONTEXT_MAJOR_VERSION_ARB, MajorVersion,
                        WGL_CONTEXT_MINOR_VERSION_ARB, MinorVersion,
                        WGL_CONTEXT_FLAGS_ARB, WGL_CONTEXT_FORWARD_COMPATIBLE_BIT_ARB,
                        GL_CONTEXT_PROFILE_MASK, GL_CONTEXT_CORE_PROFILE_BIT,
                        0, 0 //
                    };

#ifdef _DEBUG
                attribs[5] |= WGL_CONTEXT_DEBUG_BIT_ARB;
#endif

                // Create new rendering context
                // In order to create new OpenGL rendering context we have to call function wglCreateContextAttribsARB(),
                // which is an OpenGL function and requires OpenGL to be active when it is called.
                // The only way is to create an old context, activate it, and while it is active create a new one.
                // Very inconsistent, but we have to live with it!
                m_Context = wglCreateContextAttribsARB(m_WindowHandleToDeviceContext, 0, attribs);
            }

            if (m_Context == NULL)
            {
                LOG_ERROR_AND_THROW("Failed to initialize OpenGL context.");
            }

            // Delete tempContext
            wglMakeCurrent(NULL, NULL);
            wglDeleteContext(tempContext);
            // Make new context current
            wglMakeCurrent(m_WindowHandleToDeviceContext, m_Context);
            wglSwapIntervalEXT(0);
        }
        else
        { //It's not possible to make a GL 4.x context. Use the old style context (GL 2.1 and before)
            m_Context = tempContext;
        }

        if (glDebugMessageCallback)
        {
            glEnable(GL_DEBUG_OUTPUT_SYNCHRONOUS);
            glDebugMessageCallback(openglCallbackFunction, nullptr);
            GLuint unusedIds = 0;
            glDebugMessageControl(
                GL_DONT_CARE, // Source of debug messages to enable or disable
                GL_DONT_CARE, // Type of debug messages to enable or disable
                GL_DONT_CARE, // Severity of debug messages to enable or disable
                0,            // The length of the array ids
                &unusedIds,   // Array of unsigned integers contianing the ids of the messages to enable or disable
                GL_TRUE       // Flag determining whether the selected messages should be enabled or disabled
            );
            if (glGetError() != GL_NO_ERROR)
                LOG_ERROR_MESSAGE("Failed to enable debug messages");
        }
    }
    else
    {
        auto CurrentCtx = wglGetCurrentContext();
        if (CurrentCtx == 0)
        {
            LOG_ERROR_AND_THROW("No current GL context found! Provide non-null handle to a native Window to create a GL context");
        }

        // Initialize GLEW
        GLenum err = glewInit();
        if (GLEW_OK != err)
            LOG_ERROR_AND_THROW("Failed to initialize GLEW");
    }

    //Checking GL version
    const GLubyte* GLVersionString = glGetString(GL_VERSION);

    //Or better yet, use the GL3 way to get the version number
    glGetIntegerv(GL_MAJOR_VERSION, &MajorVersion);
    glGetIntegerv(GL_MINOR_VERSION, &MinorVersion);
    LOG_INFO_MESSAGE(InitAttribs.pNativeWndHandle != nullptr ? "Initialized OpenGL " : "Attached to OpenGL ", MajorVersion, '.', MinorVersion, " context (", GLVersionString, ')');

    // Under the standard filtering rules for cubemaps, filtering does not work across faces of the cubemap.
    // This results in a seam across the faces of a cubemap. This was a hardware limitation in the past, but
    // modern hardware is capable of interpolating across a cube face boundary.
    // GL_TEXTURE_CUBE_MAP_SEAMLESS is not defined in OpenGLES
    glEnable(GL_TEXTURE_CUBE_MAP_SEAMLESS);
    if (glGetError() != GL_NO_ERROR)
        LOG_ERROR_MESSAGE("Failed to enable seamless cubemap filtering");

    // When GL_FRAMEBUFFER_SRGB is enabled, and if the destination image is in the sRGB colorspace
    // then OpenGL will assume the shader's output is in the linear RGB colorspace. It will therefore
    // convert the output from linear RGB to sRGB.
    // Any writes to images that are not in the sRGB format should not be affected.
    // Thus this setting should be just set once and left that way
    glEnable(GL_FRAMEBUFFER_SRGB);
    if (glGetError() != GL_NO_ERROR)
        LOG_ERROR_MESSAGE("Failed to enable SRGB framebuffers");

    deviceCaps.DevType                                 = DeviceType::OpenGL;
    deviceCaps.MajorVersion                            = MajorVersion;
    deviceCaps.MinorVersion                            = MinorVersion;
    bool  IsGL43OrAbove                                = MajorVersion >= 5 || MajorVersion == 4 && MinorVersion >= 3;
    auto& TexCaps                                      = deviceCaps.TexCaps;
    TexCaps.bTexture2DMSSupported                      = IsGL43OrAbove;
    TexCaps.bTexture2DMSArraySupported                 = IsGL43OrAbove;
    TexCaps.bTextureViewSupported                      = IsGL43OrAbove;
    TexCaps.bCubemapArraysSupported                    = IsGL43OrAbove;
    deviceCaps.bMultithreadedResourceCreationSupported = False;
}

GLContext::~GLContext()
{
    // Do not destroy context if it was created by the app.
    if (m_Context)
    {
        wglMakeCurrent(m_WindowHandleToDeviceContext, 0);
        wglDeleteContext(m_Context);
    }
}

void GLContext::SwapBuffers()
{
    if (m_WindowHandleToDeviceContext)
        ::SwapBuffers(m_WindowHandleToDeviceContext);
    else
        LOG_ERROR("Swap buffer failed because window handle to device context is not initialized");
}

GLContext::NativeGLContextType GLContext::GetCurrentNativeGLContext()
{
    return wglGetCurrentContext();
}

} // namespace Diligent
