/*     Copyright 2015-2018 Egor Yusov
 *  
 *  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 <memory>
#include <iomanip>

#include "PlatformDefinitions.h"
#include "NativeAppBase.hpp"
#include "StringTools.hpp"
#include "Timer.hpp"
#include "Errors.hpp"


#ifndef GLX_CONTEXT_MAJOR_VERSION_ARB
#    define GLX_CONTEXT_MAJOR_VERSION_ARB 0x2091
#endif

#ifndef GLX_CONTEXT_MINOR_VERSION_ARB
#    define GLX_CONTEXT_MINOR_VERSION_ARB 0x2092
#endif

#ifndef GLX_CONTEXT_FLAGS_ARB
#    define GLX_CONTEXT_FLAGS_ARB 0x2094
#endif

#ifndef GLX_CONTEXT_DEBUG_BIT_ARB
#    define GLX_CONTEXT_DEBUG_BIT_ARB 0x0001
#endif

typedef GLXContext (*glXCreateContextAttribsARBProc)(Display*, GLXFBConfig, GLXContext, int, const int*);

static constexpr uint16_t WindowWidth     = 1024;
static constexpr uint16_t WindowHeight    = 768;
static constexpr uint16_t MinWindowWidth  = 320;
static constexpr uint16_t MinWindowHeight = 240;

using namespace Diligent;

namespace
{

static constexpr int None = 0;

class WindowTitleHelper
{
public:
    WindowTitleHelper(std::string _Title) :
        Title{std::move(_Title)}
    {}

    std::string GetTitleWithFPS(double ElapsedTime)
    {
        double filterScale = 0.2;
        FilteredFrameTime  = FilteredFrameTime * (1.0 - filterScale) + filterScale * ElapsedTime;
        std::stringstream TitleWithFpsSS;
        TitleWithFpsSS << Title;
        TitleWithFpsSS << " - " << std::fixed << std::setprecision(1) << FilteredFrameTime * 1000;
        TitleWithFpsSS << " ms (" << 1.0 / FilteredFrameTime << " fps)";
        return TitleWithFpsSS.str();
    }

private:
    const std::string Title;
    double            FilteredFrameTime = 0.0;
};

} // namespace

#if VULKAN_SUPPORTED

// https://code.woboq.org/qt5/include/xcb/xcb_icccm.h.html
enum XCB_SIZE_HINT
{
    XCB_SIZE_HINT_US_POSITION   = 1 << 0,
    XCB_SIZE_HINT_US_SIZE       = 1 << 1,
    XCB_SIZE_HINT_P_POSITION    = 1 << 2,
    XCB_SIZE_HINT_P_SIZE        = 1 << 3,
    XCB_SIZE_HINT_P_MIN_SIZE    = 1 << 4,
    XCB_SIZE_HINT_P_MAX_SIZE    = 1 << 5,
    XCB_SIZE_HINT_P_RESIZE_INC  = 1 << 6,
    XCB_SIZE_HINT_P_ASPECT      = 1 << 7,
    XCB_SIZE_HINT_BASE_SIZE     = 1 << 8,
    XCB_SIZE_HINT_P_WIN_GRAVITY = 1 << 9
};

struct xcb_size_hints_t
{
    uint32_t flags;                          /** User specified flags */
    int32_t  x, y;                           /** User-specified position */
    int32_t  width, height;                  /** User-specified size */
    int32_t  min_width, min_height;          /** Program-specified minimum size */
    int32_t  max_width, max_height;          /** Program-specified maximum size */
    int32_t  width_inc, height_inc;          /** Program-specified resize increments */
    int32_t  min_aspect_num, min_aspect_den; /** Program-specified minimum aspect ratios */
    int32_t  max_aspect_num, max_aspect_den; /** Program-specified maximum aspect ratios */
    int32_t  base_width, base_height;        /** Program-specified base size */
    uint32_t win_gravity;                    /** Program-specified window gravity */
};

struct XCBInfo
{
    xcb_connection_t*        connection            = nullptr;
    uint32_t                 window                = 0;
    uint16_t                 width                 = 0;
    uint16_t                 height                = 0;
    xcb_intern_atom_reply_t* atom_wm_delete_window = nullptr;
};

XCBInfo InitXCBConnectionAndWindow(const std::string& Title)
{
    XCBInfo info;

    int scr         = 0;
    info.connection = xcb_connect(nullptr, &scr);
    if (info.connection == nullptr || xcb_connection_has_error(info.connection))
    {
        std::cerr << "Unable to make an XCB connection\n";
        exit(-1);
    }

    const xcb_setup_t*    setup = xcb_get_setup(info.connection);
    xcb_screen_iterator_t iter  = xcb_setup_roots_iterator(setup);
    while (scr-- > 0)
        xcb_screen_next(&iter);

    auto screen = iter.data;

    info.width  = WindowWidth;
    info.height = WindowHeight;

    uint32_t value_mask, value_list[32];

    info.window = xcb_generate_id(info.connection);

    value_mask    = XCB_CW_BACK_PIXEL | XCB_CW_EVENT_MASK;
    value_list[0] = screen->black_pixel;
    value_list[1] =
        XCB_EVENT_MASK_KEY_RELEASE |
        XCB_EVENT_MASK_KEY_PRESS |
        XCB_EVENT_MASK_EXPOSURE |
        XCB_EVENT_MASK_STRUCTURE_NOTIFY |
        XCB_EVENT_MASK_POINTER_MOTION |
        XCB_EVENT_MASK_BUTTON_PRESS |
        XCB_EVENT_MASK_BUTTON_RELEASE;

    xcb_create_window(info.connection, XCB_COPY_FROM_PARENT, info.window, screen->root, 0, 0, info.width, info.height, 0,
                      XCB_WINDOW_CLASS_INPUT_OUTPUT, screen->root_visual, value_mask, value_list);

    // Magic code that will send notification when window is destroyed
    xcb_intern_atom_cookie_t cookie = xcb_intern_atom(info.connection, 1, 12, "WM_PROTOCOLS");
    xcb_intern_atom_reply_t* reply  = xcb_intern_atom_reply(info.connection, cookie, 0);

    xcb_intern_atom_cookie_t cookie2 = xcb_intern_atom(info.connection, 0, 16, "WM_DELETE_WINDOW");
    info.atom_wm_delete_window       = xcb_intern_atom_reply(info.connection, cookie2, 0);

    xcb_change_property(info.connection, XCB_PROP_MODE_REPLACE, info.window, (*reply).atom, 4, 32, 1,
                        &(*info.atom_wm_delete_window).atom);
    free(reply);

    xcb_change_property(info.connection, XCB_PROP_MODE_REPLACE, info.window, XCB_ATOM_WM_NAME, XCB_ATOM_STRING,
                        8, Title.length(), Title.c_str());

    // https://stackoverflow.com/a/27771295
    xcb_size_hints_t hints = {};
    hints.flags            = XCB_SIZE_HINT_P_MIN_SIZE;
    hints.min_width        = MinWindowWidth;
    hints.min_height       = MinWindowHeight;
    xcb_change_property(info.connection, XCB_PROP_MODE_REPLACE, info.window, XCB_ATOM_WM_NORMAL_HINTS, XCB_ATOM_WM_SIZE_HINTS,
                        32, sizeof(xcb_size_hints_t), &hints);

    xcb_map_window(info.connection, info.window);

    // Force the x/y coordinates to 100,100 results are identical in consecutive
    // runs
    const uint32_t coords[] = {100, 100};
    xcb_configure_window(info.connection, info.window, XCB_CONFIG_WINDOW_X | XCB_CONFIG_WINDOW_Y, coords);
    xcb_flush(info.connection);

    xcb_generic_event_t* e;
    while ((e = xcb_wait_for_event(info.connection)))
    {
        if ((e->response_type & ~0x80) == XCB_EXPOSE) break;
    }
    return info;
}

void DestroyXCBConnectionAndWindow(XCBInfo& info)
{
    xcb_destroy_window(info.connection, info.window);
    xcb_disconnect(info.connection);
}

int xcb_main()
{
    std::unique_ptr<NativeAppBase> TheApp(CreateApplication());

    std::string Title   = TheApp->GetAppTitle();
    auto        xcbInfo = InitXCBConnectionAndWindow(Title);
    if (!TheApp->InitVulkan(xcbInfo.connection, xcbInfo.window))
        return -1;

    xcb_flush(xcbInfo.connection);

    Timer timer;
    auto  PrevTime = timer.GetElapsedTime();
    Title          = TheApp->GetAppTitle();
    WindowTitleHelper TitleHelper(Title);

    while (true)
    {
        xcb_generic_event_t* event = nullptr;

        bool Quit = false;
        while ((event = xcb_poll_for_event(xcbInfo.connection)) != nullptr)
        {
            TheApp->HandleXCBEvent(event);
            switch (event->response_type & 0x7f)
            {
                case XCB_CLIENT_MESSAGE:
                    if ((*(xcb_client_message_event_t*)event).data.data32[0] ==
                        (*xcbInfo.atom_wm_delete_window).atom)
                    {
                        Quit = true;
                    }
                    break;

                case XCB_KEY_RELEASE:
                {
                    const auto* keyEvent = reinterpret_cast<const xcb_key_release_event_t*>(event);
                    switch (keyEvent->detail)
                    {
#    define KEY_ESCAPE 0x9
                        case KEY_ESCAPE:
                            Quit = true;
                            break;
                    }
                }
                break;

                case XCB_DESTROY_NOTIFY:
                    Quit = true;
                    break;

                case XCB_CONFIGURE_NOTIFY:
                {
                    const auto* cfgEvent = reinterpret_cast<const xcb_configure_notify_event_t*>(event);
                    if ((cfgEvent->width != xcbInfo.width) || (cfgEvent->height != xcbInfo.height))
                    {
                        xcbInfo.width  = cfgEvent->width;
                        xcbInfo.height = cfgEvent->height;
                        if ((xcbInfo.width > 0) && (xcbInfo.height > 0))
                        {
                            TheApp->WindowResize(xcbInfo.width, xcbInfo.height);
                        }
                    }
                }
                break;

                default:
                    break;
            }
            free(event);
        }

        if (Quit)
            break;

        // Render the scene
        auto CurrTime    = timer.GetElapsedTime();
        auto ElapsedTime = CurrTime - PrevTime;
        PrevTime         = CurrTime;

        TheApp->Update(CurrTime, ElapsedTime);

        TheApp->Render();

        TheApp->Present();

        auto TitleWithFPS = TitleHelper.GetTitleWithFPS(ElapsedTime);
        xcb_change_property(xcbInfo.connection, XCB_PROP_MODE_REPLACE, xcbInfo.window, XCB_ATOM_WM_NAME, XCB_ATOM_STRING,
                            8, TitleWithFPS.length(), TitleWithFPS.c_str());
        xcb_flush(xcbInfo.connection);
    }

    TheApp.reset();
    DestroyXCBConnectionAndWindow(xcbInfo);

    return 0;
}

#endif


int x_main()
{
    std::unique_ptr<NativeAppBase> TheApp(CreateApplication());
    Display*                       display = XOpenDisplay(0);

    // clang-format off
    static int visual_attribs[] =
    {
        GLX_RENDER_TYPE,    GLX_RGBA_BIT,
        GLX_DRAWABLE_TYPE,  GLX_WINDOW_BIT,
        GLX_DOUBLEBUFFER,   true,

        // The largest available total RGBA color buffer size (sum of GLX_RED_SIZE, 
        // GLX_GREEN_SIZE, GLX_BLUE_SIZE, and GLX_ALPHA_SIZE) of at least the minimum
        // size specified for each color component is preferred.
        GLX_RED_SIZE,       8,
        GLX_GREEN_SIZE,     8,
        GLX_BLUE_SIZE,      8,
        GLX_ALPHA_SIZE,     8,

        // The largest available depth buffer of at least GLX_DEPTH_SIZE size is preferred
        GLX_DEPTH_SIZE,     24,

        GLX_SAMPLE_BUFFERS, 0,

        // Setting GLX_SAMPLES to 1 results in 2x MS backbuffer, which is 
        // against the spec that states:
        //     if GLX SAMPLE BUFFERS is zero, then GLX SAMPLES will also be zero
        // GLX_SAMPLES, 1,

        None
     };
    // clang-format on

    int          fbcount = 0;
    GLXFBConfig* fbc     = glXChooseFBConfig(display, DefaultScreen(display), visual_attribs, &fbcount);
    if (!fbc)
    {
        LOG_ERROR_MESSAGE("Failed to retrieve a framebuffer config");
        return -1;
    }

    XVisualInfo* vi = glXGetVisualFromFBConfig(display, fbc[0]);

    XSetWindowAttributes swa;
    swa.colormap     = XCreateColormap(display, RootWindow(display, vi->screen), vi->visual, AllocNone);
    swa.border_pixel = 0;
    swa.event_mask =
        StructureNotifyMask |
        ExposureMask |
        KeyPressMask |
        KeyReleaseMask |
        ButtonPressMask |
        ButtonReleaseMask |
        PointerMotionMask;

    Window win = XCreateWindow(display, RootWindow(display, vi->screen), 0, 0, WindowWidth, WindowHeight, 0, vi->depth, InputOutput, vi->visual, CWBorderPixel | CWColormap | CWEventMask, &swa);
    if (!win)
    {
        LOG_ERROR_MESSAGE("Failed to create window.");
        return -1;
    }

    {
        auto SizeHints        = XAllocSizeHints();
        SizeHints->flags      = PMinSize;
        SizeHints->min_width  = MinWindowWidth;
        SizeHints->min_height = MinWindowHeight;
        XSetWMNormalHints(display, win, SizeHints);
        XFree(SizeHints);
    }

    XMapWindow(display, win);

    glXCreateContextAttribsARBProc glXCreateContextAttribsARB = nullptr;
    {
        // Create an oldstyle context first, to get the correct function pointer for glXCreateContextAttribsARB
        GLXContext ctx_old         = glXCreateContext(display, vi, 0, GL_TRUE);
        glXCreateContextAttribsARB = (glXCreateContextAttribsARBProc)glXGetProcAddress((const GLubyte*)"glXCreateContextAttribsARB");
        glXMakeCurrent(display, None, NULL);
        glXDestroyContext(display, ctx_old);
    }

    if (glXCreateContextAttribsARB == nullptr)
    {
        LOG_ERROR("glXCreateContextAttribsARB entry point not found. Aborting.");
        return -1;
    }

    int Flags = GLX_CONTEXT_FORWARD_COMPATIBLE_BIT_ARB;
#ifdef _DEBUG
    Flags |= GLX_CONTEXT_DEBUG_BIT_ARB;
#endif

    int major_version = 4;
    int minor_version = 3;

    static int context_attribs[] =
        {
            GLX_CONTEXT_MAJOR_VERSION_ARB, major_version,
            GLX_CONTEXT_MINOR_VERSION_ARB, minor_version,
            GLX_CONTEXT_FLAGS_ARB, Flags,
            None //
        };

    constexpr int True = 1;
    GLXContext    ctx  = glXCreateContextAttribsARB(display, fbc[0], NULL, True, context_attribs);
    if (!ctx)
    {
        LOG_ERROR("Failed to create GL context.");
        return -1;
    }
    XFree(fbc);


    glXMakeCurrent(display, win, ctx);
    if (!TheApp->OnGLContextCreated(display, win))
    {
        LOG_ERROR("Unable to initialize the application in OpenGL mode. Aborting");
        return -1;
    }
    std::string Title = TheApp->GetAppTitle();

    Timer             timer;
    auto              PrevTime = timer.GetElapsedTime();
    WindowTitleHelper TitleHelper(Title);

    while (true)
    {
        bool   EscPressed = false;
        XEvent xev;
        // Handle all events in the queue
        while (XCheckMaskEvent(display, 0xFFFFFFFF, &xev))
        {
            TheApp->HandleXEvent(&xev);
            switch (xev.type)
            {
                case KeyPress:
                {
                    KeySym keysym;
                    char   buffer[80];
                    int    num_char = XLookupString((XKeyEvent*)&xev, buffer, _countof(buffer), &keysym, 0);
                    EscPressed      = (keysym == XK_Escape);
                }

                case ConfigureNotify:
                {
                    XConfigureEvent& xce = reinterpret_cast<XConfigureEvent&>(xev);
                    if (xce.width != 0 && xce.height != 0)
                        TheApp->WindowResize(xce.width, xce.height);
                    break;
                }
            }
        }

        if (EscPressed)
            break;

        // Render the scene
        auto CurrTime    = timer.GetElapsedTime();
        auto ElapsedTime = CurrTime - PrevTime;
        PrevTime         = CurrTime;

        TheApp->Update(CurrTime, ElapsedTime);

        TheApp->Render();

        TheApp->Present();

        auto TitleWithFPS = TitleHelper.GetTitleWithFPS(ElapsedTime);
        XStoreName(display, win, TitleWithFPS.c_str());
    }

    TheApp.reset();

    ctx = glXGetCurrentContext();
    glXMakeCurrent(display, None, NULL);
    glXDestroyContext(display, ctx);
    XDestroyWindow(display, win);
    XCloseDisplay(display);

    return 0;
}

int main(int argc, char** argv)
{
    bool UseVulkan = false;

#if VULKAN_SUPPORTED
    UseVulkan = true;
    if (argc > 1)
    {
        const auto* Key = "-mode ";
        const auto* pos = strstr(argv[1], Key);
        if (pos != nullptr)
        {
            pos += strlen(Key);
            while (*pos != 0 && *pos == ' ') ++pos;
            if (strcasecmp(pos, "GL") == 0)
            {
                UseVulkan = false;
            }
            else if (strcasecmp(pos, "VK") == 0)
            {
                UseVulkan = true;
            }
            else
            {
                std::cerr << "Unknown device type. Only the following types are supported: GL, VK";
                return -1;
            }
        }
    }

    if (UseVulkan)
    {
        auto ret = xcb_main();
        if (ret >= 0)
        {
            return ret;
        }
        else
        {
            LOG_ERROR_MESSAGE("Failed to initialize the engine in Vulkan mode. Attempting to use OpenGL");
        }
    }
#endif

    return x_main();
}