/************************************************************************************

Filename    :   Platform_Linux.cpp
Content     :   Linux (X11) implementation of Platform app infrastructure
Created     :   September 6, 2012
Authors     :   Andrew Reisse

Copyright   :   Copyright 2012 Oculus VR, Inc. All Rights reserved.

Use of this software is subject to the terms of the Oculus LLC license
agreement provided at the time of installation or download, or which
otherwise accompanies this software in either electronic or hard copy form.

************************************************************************************/

#include "Kernel/OVR_System.h"
#include "Kernel/OVR_Array.h"
#include "Kernel/OVR_String.h"
#include "Kernel/OVR_Timer.h"

#include "Linux_Platform.h"
#include "Linux_Gamepad.h"

// Renderers
#include "../Render/Render_GL_Device.h"

#include <X11/extensions/Xrandr.h>


namespace OVR { namespace Platform { namespace Linux {

static const char *AtomNames[] = {"WM_PROTOCOLS", "WM_DELETE_WINDOW"};

PlatformCore::PlatformCore(Application* app)
    : Platform::PlatformCore(app), Disp(NULL), Win(0), Vis(NULL), Quit(0), MMode(Mouse_Normal)
{
    pGamepadManager = *new Linux::GamepadManager();
}
PlatformCore::~PlatformCore()
{
    XFreeCursor(Disp, InvisibleCursor);

    if (Disp)
        XCloseDisplay(Disp);
}

// Setup an X11 window in windowed mode.
bool PlatformCore::SetupWindow(int w, int h)
{

    if (!Disp)
    {
        XInitThreads();

        Disp = XOpenDisplay(NULL);
        if (!Disp)
        {
            OVR_DEBUG_LOG(("XOpenDisplay failed."));
            return false;
        }

        XInternAtoms(Disp, const_cast<char**>(AtomNames), NumAtoms, false, Atoms);
    }

    XSetWindowAttributes winattr;
    unsigned attrmask = CWEventMask | CWBorderPixel;

    winattr.event_mask = ButtonPressMask|ButtonReleaseMask|KeyPressMask|KeyReleaseMask|ButtonMotionMask|PointerMotionMask|
        /*PointerMotionHintMask|*/StructureNotifyMask;//|ExposureMask;
    winattr.border_pixel = 0;

    int screenNumber = DefaultScreen(Disp);

    if (!Vis)
    {
        int attr[16];
        int nattr = 2;

        attr[0] = GLX_RGBA;
        attr[1] = GLX_DOUBLEBUFFER;
        attr[nattr++] = GLX_DEPTH_SIZE;
        attr[nattr++] = 24;
        attr[nattr] = 0;

        Vis = glXChooseVisual(Disp, screenNumber, attr);

        if (!Vis)
        {
            OVR_DEBUG_LOG(("glXChooseVisual failed."));
            return false;
        }
    }

    Window rootWindow = XRootWindow(Disp, Vis->screen);

    winattr.colormap = XCreateColormap(Disp, rootWindow, Vis->visual, AllocNone);
    attrmask |= CWColormap;


    Win = XCreateWindow(Disp, rootWindow, 0, 0, w, h, 0, Vis->depth,
                        InputOutput, Vis->visual, attrmask, &winattr);

    if (!Win)
    {
        OVR_DEBUG_LOG(("XCreateWindow failed."));
        return false;
    }


    XStoreName(Disp, Win, "OVR App");
    XSetWMProtocols(Disp, Win, &Atoms[WM_DELETE_WINDOW], 1);

    // Intialize empty cursor for show/hide.
    XColor black;
    static char noData[] = { 0,0,0,0,0,0,0,0 };
    black.red = black.green = black.blue = 0;

    Pixmap bitmapNoData = XCreateBitmapFromData(Disp, Win, noData, 8, 8);
    InvisibleCursor = XCreatePixmapCursor(Disp, bitmapNoData, bitmapNoData,
                                         &black, &black, 0, 0);
    XDefineCursor(Disp, Win, InvisibleCursor);

    Width = w;
    Height = h;

    return true;
}

void PlatformCore::SetMouseMode(MouseMode mm)
{
    if (mm == MMode)
        return;

    if (Win)
    {
        if (mm == Mouse_Relative)
        {
            XWarpPointer(Disp, Win, Win, 0,0,Width,Height, Width/2, Height/2);
        }
        else
        {
            //if (MMode == Mouse_Relative)
            //  ShowCursor(TRUE);
        }
    }
    MMode = mm;
}

void PlatformCore::GetWindowSize(int* w, int* h) const
{
    *w = Width;
    *h = Height;
}

void PlatformCore::SetWindowTitle(const char* title)
{
    XStoreName(Disp, Win, title);
}

void PlatformCore::ShowWindow(bool show)
{
    if (show)
        XRaiseWindow(Disp, Win);
    else
        XIconifyWindow(Disp, Win, 0);
}

void PlatformCore::DestroyWindow()
{
    if (Win)
        XDestroyWindow(Disp, Win);
    Win = 0;
}


static int KeyMap[][2] =
{
    { XK_BackSpace,      Key_Backspace },
    { XK_Tab,       Key_Tab },
    { XK_Clear,     Key_Clear },
    { XK_Return,    Key_Return },
    { XK_Shift_L,     Key_Shift },
    { XK_Control_L,   Key_Control },
    { XK_Alt_L,      Key_Alt },
    { XK_Shift_R,     Key_Shift },
    { XK_Control_R,   Key_Control },
    { XK_Alt_R,      Key_Alt },
    { XK_Pause,     Key_Pause },
    { XK_Caps_Lock,   Key_CapsLock },
    { XK_Escape,    Key_Escape },
    { XK_space,     Key_Space },
    { XK_Page_Up,     Key_PageUp },
    { XK_Page_Down,      Key_PageDown },
    { XK_Prior,     Key_PageUp },
    { XK_Next,      Key_PageDown },
    { XK_End,       Key_End },
    { XK_Home,      Key_Home },
    { XK_Left,      Key_Left },
    { XK_Up,        Key_Up },
    { XK_Right,     Key_Right },
    { XK_Down,      Key_Down },
    { XK_Insert,    Key_Insert },
    { XK_Delete,    Key_Delete },
    { XK_Help,      Key_Help },
    { XK_Num_Lock,   Key_NumLock },
    { XK_Scroll_Lock,    Key_ScrollLock },
};


static KeyCode MapXKToKeyCode(unsigned vk)
{
    unsigned key = Key_None;

    if ((vk >= 'a') && (vk <= 'z'))
    {
        key = vk - 'a' + Key_A;
    }
    else if ((vk >= ' ') && (vk <= '~'))
    {
        key = vk;
    }
    else if ((vk >= XK_KP_0) && (vk <= XK_KP_9))
    {
        key = vk - XK_KP_0 + Key_KP_0;
    }
    else if ((vk >= XK_F1) && (vk <= XK_F15))
    {
        key = vk - XK_F1 + Key_F1;
    }
    else
    {
        for (unsigned i = 0; i< (sizeof(KeyMap) / sizeof(KeyMap[1])); i++)
        {
            if (vk == KeyMap[i][0])
            {
                key = KeyMap[i][1];
                break;
            }
        }
    }

    return (KeyCode)key;
}

static int MapModifiers(int xmod)
{
    int mod = 0;
    if (xmod & ShiftMask)
        mod |= Mod_Shift;
    if (xmod & ControlMask)
        mod |= Mod_Control;
    if (xmod & Mod1Mask)
        mod |= Mod_Alt;
    if (xmod & Mod4Mask)
        mod |= Mod_Meta;
    return mod;
}

void PlatformCore::processEvent(XEvent& event)
{
    switch (event.xany.type)
    {
    case ConfigureNotify:
        if (event.xconfigure.width != Width || event.xconfigure.height != Height)
        {
            Width = event.xconfigure.width;
            Height = event.xconfigure.height;
            pApp->OnResize(Width, Height);

            if (pRender)
                pRender->SetWindowSize(Width, Height);
        }
        break;

    case KeyPress:
    case KeyRelease:
        {
            char chars[8] = {0};
            KeySym xk;
            XComposeStatus comp;
            XLookupString(&event.xkey, chars, sizeof(chars), &xk, &comp);
            if (xk != XK_VoidSymbol)
                pApp->OnKey(MapXKToKeyCode((unsigned)xk), chars[0], event.xany.type == KeyPress, MapModifiers(event.xkey.state));
            if (xk == XK_Escape && MMode == Mouse_Relative)
            {
                //ungrab
                MMode = Mouse_RelativeEscaped;
                showCursor(true);
            }
        }
        break;

    case MotionNotify:
        if (MMode == Mouse_Relative)
        {
            int dx = event.xmotion.x - Width/2;
            int dy = event.xmotion.y - Height/2;

            // do not remove this check, WarpPointer generates events too.
            if (dx == 0 && dy == 0)
                break;

            XWarpPointer(Disp, Win, Win, 0,0,Width,Height, Width/2, Height/2);
            pApp->OnMouseMove(dx, dy, Mod_MouseRelative|MapModifiers(event.xmotion.state));
        }
        else
        {
            pApp->OnMouseMove(event.xmotion.x, event.xmotion.y, MapModifiers(event.xmotion.state));
        }
        break;

    case MapNotify:
        if (MMode == Mouse_Relative)
        {
            XWarpPointer(Disp, Win, Win, 0,0,Width,Height, Width/2, Height/2);
            showCursor(false);
        }
        break;

    case ButtonPress:
        if (event.xbutton.button == 1)
        {
            //grab

            if (MMode == Mouse_RelativeEscaped)
            {
                XWarpPointer(Disp, Win, Win, 0,0,Width,Height, Width/2, Height/2);
                showCursor(false);
                MMode = Mouse_Relative;
            }
        }
        break;

    case FocusOut:
        if (MMode == Mouse_Relative)
        {
            MMode = Mouse_RelativeEscaped;
            showCursor(true);
        }
        break;

    case ClientMessage:
        if (event.xclient.message_type == Atoms[WM_PROTOCOLS] &&
            Atom(event.xclient.data.l[0]) == Atoms[WM_DELETE_WINDOW])
            pApp->OnQuitRequest();
        break;
    }
}

int PlatformCore::Run()
{
    while (!Quit)
    {
        if (XPending(Disp))
        {
            XEvent event;
            XNextEvent(Disp, &event);

            if (pApp && event.xany.window == Win)
                processEvent(event);
        }
        else
        {
            pApp->OnIdle();
        }
    }

    return ExitCode;
}

bool PlatformCore::determineScreenOffset(int screenId, int* screenOffsetX, int* screenOffsetY)
{
    bool result = false;
    if (screenId) {
        Display* display = XOpenDisplay(NULL);
        XRRScreenResources *screen = XRRGetScreenResources(display, DefaultRootWindow(display));
        XRROutputInfo * info = XRRGetOutputInfo (display, screen, screenId);
        if (info->crtc) {
            XRRCrtcInfo * crtc_info = XRRGetCrtcInfo (display, screen, info->crtc);
            *screenOffsetX = crtc_info->x;
            *screenOffsetY = crtc_info->y;
            XRRFreeCrtcInfo(crtc_info);
            result = true;
        }
        XRRFreeOutputInfo (info);
        XRRFreeScreenResources(screen);
    }

    return result;
}

void PlatformCore::showWindowDecorations(bool show)
{
    // Declaration of 'MOTIF_WM_HINTS' struct and flags can be found at:
    // https://people.gnome.org/~tthurman/docs/metacity/xprops_8h-source.html
    typedef struct WMHints
    {
        unsigned long   flags;
        unsigned long   functions;
        unsigned long   decorations;
        long            inputMode;
        unsigned long   status;
    } Hints;

    #define MWM_DECOR_ALL           (1L << 0)
    #define MWM_DECOR_BORDER        (1L << 1)
    #define MWM_DECOR_RESIZEH       (1L << 2)
    #define MWM_DECOR_TITLE         (1L << 3)
    #define MWM_DECOR_MENU          (1L << 4)
    #define MWM_DECOR_MINIMIZE      (1L << 5)
    #define MWM_DECOR_MAXIMIZE      (1L << 6)

    Atom property = XInternAtom(Disp, "_MOTIF_WM_HINTS", true);

    Hints hints;
    hints.flags = 2;    // We only want to specify decoration.

    if (show)
    {
        hints.decorations = MWM_DECOR_BORDER | MWM_DECOR_TITLE | MWM_DECOR_MENU | MWM_DECOR_MINIMIZE | MWM_DECOR_MAXIMIZE;
    }
    else
    {
        // Remove all window border items.
        hints.decorations = 0;
    }

    XChangeProperty(Disp,Win,property,property,32,PropModeReplace,(unsigned char *)&hints,5);
}

bool PlatformCore::SetFullscreen(const Render::RendererParams& rp, int fullscreen)
{
    if (rp.Fullscreen == Render::Display_Window && fullscreen == Render::Display_FakeFullscreen)
    {
        // Transitioning from windowed to fake fullscreen.
        int xOffset;
        int yOffset;

        if (!determineScreenOffset(rp.Display.CgDisplayId, &xOffset, &yOffset))
        {
            return false;
        }

        showWindowDecorations(false);

        XMoveWindow(Disp, Win, xOffset, yOffset);
        XMapRaised(Disp, Win);

        Platform::PlatformCore::SetFullscreen(rp, fullscreen);
        return true;
    }
    else if (rp.Fullscreen == Render::Display_FakeFullscreen && fullscreen == Render::Display_Window)
    {
        // Transitioning from fake fullscreen to windowed.
        showWindowDecorations(true);

        XMoveWindow(Disp, Win, 0, 0);
        XMapRaised(Disp, Win);

        Platform::PlatformCore::SetFullscreen(rp, fullscreen);
        return true;
    }
    else if (fullscreen == Render::Display_Fullscreen)
    {
        return false;
    }
}

RenderDevice* PlatformCore::SetupGraphics(const SetupGraphicsDeviceSet& setupGraphicsDesc,
                                          const char* type, const Render::RendererParams& rp)
{
    const SetupGraphicsDeviceSet* setupDesc = setupGraphicsDesc.PickSetupDevice(type);
    OVR_ASSERT(setupDesc);

    pRender = *setupDesc->pCreateDevice(rp, this);
    if (pRender)
        pRender->SetWindowSize(Width, Height);

    return pRender.GetPtr();
}

void PlatformCore::showCursor(bool show)
{
    if (show)
    {
        XUndefineCursor(Disp, Win);
    }
    else
    {
        XDefineCursor(Disp, Win, InvisibleCursor);
    }
}

}}

// GL
namespace Render { namespace GL { namespace Linux {

Render::RenderDevice* RenderDevice::CreateDevice(const RendererParams& rp, void* oswnd)
{
    Platform::Linux::PlatformCore* PC = (Platform::Linux::PlatformCore*)oswnd;

    GLXContext context = glXCreateContext(PC->Disp, PC->Vis, 0, GL_TRUE);

    if (!context)
        return NULL;

    if (!glXMakeCurrent(PC->Disp, PC->Win, context))
    {
        glXDestroyContext(PC->Disp, context);
        return NULL;
    }

    XMapRaised(PC->Disp, PC->Win);

    return new Render::GL::Linux::RenderDevice(rp, PC->Disp, PC->Win, context);
}

void RenderDevice::Present()
{
    glXSwapBuffers(Disp, Win);
}

void RenderDevice::Shutdown()
{
    if (Context)
    {
        glXMakeCurrent(Disp, 0, NULL);
        glXDestroyContext(Disp, Context);
        Context = NULL;
        Win = 0;
    }
}

}}}}


int main(int argc, char** argv)
{
    using namespace OVR;
    using namespace OVR::Platform;

    // CreateApplication must be the first call since it does OVR::System::Initialize.
    Application*       app = Application::CreateApplication();
    Linux::PlatformCore* platform = new Linux::PlatformCore(app);
    // The platform attached to an app will be deleted by DestroyApplication.
    app->SetPlatformCore(platform);

    int exitCode = app->OnStartup(argc, argv);
    if (!exitCode)
        exitCode = platform->Run();

    // No OVR functions involving memory are allowed after this.
    Application::DestroyApplication(app);
    app = 0;

    return exitCode;
}