/*
  Simple DirectMedia Layer
  Copyright (C) 1997-2024 Sam Lantinga <slouken@libsdl.org>

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not
     claim that you wrote the original software. If you use this software
     in a product, an acknowledgment in the product documentation would be
     appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be
     misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.
*/
#include "../../SDL_internal.h"

#ifdef SDL_VIDEO_DRIVER_X11

#ifdef __CYGWIN__
#undef SDL_VIDEO_DRIVER_WINDOWS
#endif

#include <X11/cursorfont.h>
#include "SDL_x11video.h"
#include "SDL_x11mouse.h"
#include "SDL_x11xinput2.h"
#include "../../events/SDL_mouse_c.h"

/* FIXME: Find a better place to put this... */
static Cursor x11_empty_cursor = None;
static SDL_bool x11_cursor_visible = SDL_TRUE;

static Display *GetDisplay(void)
{
    return ((SDL_VideoData *)SDL_GetVideoDevice()->driverdata)->display;
}

static Cursor X11_CreateEmptyCursor()
{
    if (x11_empty_cursor == None) {
        Display *display = GetDisplay();
        char data[1];
        XColor color;
        Pixmap pixmap;

        SDL_zeroa(data);
        color.red = color.green = color.blue = 0;
        pixmap = X11_XCreateBitmapFromData(display, DefaultRootWindow(display),
                                           data, 1, 1);
        if (pixmap) {
            x11_empty_cursor = X11_XCreatePixmapCursor(display, pixmap, pixmap,
                                                       &color, &color, 0, 0);
            X11_XFreePixmap(display, pixmap);
        }
    }
    return x11_empty_cursor;
}

static void X11_DestroyEmptyCursor(void)
{
    if (x11_empty_cursor != None) {
        X11_XFreeCursor(GetDisplay(), x11_empty_cursor);
        x11_empty_cursor = None;
    }
}

static SDL_Cursor *X11_CreateDefaultCursor()
{
    SDL_Cursor *cursor;

    cursor = SDL_calloc(1, sizeof(*cursor));
    if (cursor) {
        /* None is used to indicate the default cursor */
        cursor->driverdata = (void *)(uintptr_t)None;
    } else {
        SDL_OutOfMemory();
    }

    return cursor;
}

#ifdef SDL_VIDEO_DRIVER_X11_XCURSOR
static Cursor X11_CreateXCursorCursor(SDL_Surface *surface, int hot_x, int hot_y)
{
    Display *display = GetDisplay();
    Cursor cursor = None;
    XcursorImage *image;

    image = X11_XcursorImageCreate(surface->w, surface->h);
    if (!image) {
        SDL_OutOfMemory();
        return None;
    }
    image->xhot = hot_x;
    image->yhot = hot_y;
    image->delay = 0;

    SDL_assert(surface->format->format == SDL_PIXELFORMAT_ARGB8888);
    SDL_assert(surface->pitch == surface->w * 4);
    SDL_memcpy(image->pixels, surface->pixels, (size_t)surface->h * surface->pitch);

    cursor = X11_XcursorImageLoadCursor(display, image);

    X11_XcursorImageDestroy(image);

    return cursor;
}
#endif /* SDL_VIDEO_DRIVER_X11_XCURSOR */

static Cursor X11_CreatePixmapCursor(SDL_Surface *surface, int hot_x, int hot_y)
{
    Display *display = GetDisplay();
    XColor fg, bg;
    Cursor cursor = None;
    Uint32 *ptr;
    Uint8 *data_bits, *mask_bits;
    Pixmap data_pixmap, mask_pixmap;
    int x, y;
    unsigned int rfg, gfg, bfg, rbg, gbg, bbg, fgBits, bgBits;
    size_t width_bytes = ((surface->w + 7) & ~((size_t)7)) / 8;

    data_bits = SDL_calloc(1, surface->h * width_bytes);
    if (!data_bits) {
        SDL_OutOfMemory();
        return None;
    }

    mask_bits = SDL_calloc(1, surface->h * width_bytes);
    if (!mask_bits) {
        SDL_free(data_bits);
        SDL_OutOfMemory();
        return None;
    }

    /* Code below assumes ARGB pixel format */
    SDL_assert(surface->format->format == SDL_PIXELFORMAT_ARGB8888);

    rfg = gfg = bfg = rbg = gbg = bbg = fgBits = bgBits = 0;
    for (y = 0; y < surface->h; ++y) {
        ptr = (Uint32 *)((Uint8 *)surface->pixels + y * surface->pitch);
        for (x = 0; x < surface->w; ++x) {
            int alpha = (*ptr >> 24) & 0xff;
            int red = (*ptr >> 16) & 0xff;
            int green = (*ptr >> 8) & 0xff;
            int blue = (*ptr >> 0) & 0xff;
            if (alpha > 25) {
                mask_bits[y * width_bytes + x / 8] |= (0x01 << (x % 8));

                if ((red + green + blue) > 0x40) {
                    fgBits++;
                    rfg += red;
                    gfg += green;
                    bfg += blue;
                    data_bits[y * width_bytes + x / 8] |= (0x01 << (x % 8));
                } else {
                    bgBits++;
                    rbg += red;
                    gbg += green;
                    bbg += blue;
                }
            }
            ++ptr;
        }
    }

    if (fgBits) {
        fg.red = rfg * 257 / fgBits;
        fg.green = gfg * 257 / fgBits;
        fg.blue = bfg * 257 / fgBits;
    } else {
        fg.red = fg.green = fg.blue = 0;
    }

    if (bgBits) {
        bg.red = rbg * 257 / bgBits;
        bg.green = gbg * 257 / bgBits;
        bg.blue = bbg * 257 / bgBits;
    } else {
        bg.red = bg.green = bg.blue = 0;
    }

    data_pixmap = X11_XCreateBitmapFromData(display, DefaultRootWindow(display),
                                            (char *)data_bits,
                                            surface->w, surface->h);
    mask_pixmap = X11_XCreateBitmapFromData(display, DefaultRootWindow(display),
                                            (char *)mask_bits,
                                            surface->w, surface->h);
    cursor = X11_XCreatePixmapCursor(display, data_pixmap, mask_pixmap,
                                     &fg, &bg, hot_x, hot_y);
    X11_XFreePixmap(display, data_pixmap);
    X11_XFreePixmap(display, mask_pixmap);
    SDL_free(data_bits);
    SDL_free(mask_bits);

    return cursor;
}

static SDL_Cursor *X11_CreateCursor(SDL_Surface *surface, int hot_x, int hot_y)
{
    SDL_Cursor *cursor;

    cursor = SDL_calloc(1, sizeof(*cursor));
    if (cursor) {
        Cursor x11_cursor = None;

#ifdef SDL_VIDEO_DRIVER_X11_XCURSOR
        if (SDL_X11_HAVE_XCURSOR) {
            x11_cursor = X11_CreateXCursorCursor(surface, hot_x, hot_y);
        }
#endif
        if (x11_cursor == None) {
            x11_cursor = X11_CreatePixmapCursor(surface, hot_x, hot_y);
        }
        cursor->driverdata = (void *)(uintptr_t)x11_cursor;
    } else {
        SDL_OutOfMemory();
    }

    return cursor;
}

static unsigned int GetLegacySystemCursorShape(SDL_SystemCursor id)
{
    switch (id) {
        /* X Font Cursors reference: */
        /*   http://tronche.com/gui/x/xlib/appendix/b/ */
        case SDL_SYSTEM_CURSOR_ARROW: return XC_left_ptr;
        case SDL_SYSTEM_CURSOR_IBEAM: return XC_xterm;
        case SDL_SYSTEM_CURSOR_WAIT: return XC_watch;
        case SDL_SYSTEM_CURSOR_CROSSHAIR: return XC_tcross;
        case SDL_SYSTEM_CURSOR_WAITARROW: return XC_watch;
        case SDL_SYSTEM_CURSOR_SIZENWSE: return XC_top_left_corner;
        case SDL_SYSTEM_CURSOR_SIZENESW: return XC_top_right_corner;
        case SDL_SYSTEM_CURSOR_SIZEWE: return XC_sb_h_double_arrow;
        case SDL_SYSTEM_CURSOR_SIZENS: return XC_sb_v_double_arrow;
        case SDL_SYSTEM_CURSOR_SIZEALL: return XC_fleur;
        case SDL_SYSTEM_CURSOR_NO: return XC_pirate;
        case SDL_SYSTEM_CURSOR_HAND: return XC_hand2;
        case SDL_NUM_SYSTEM_CURSORS: break;  /* so the compiler might notice if an enum value is missing here. */
    }

    SDL_assert(0);
    return 0;
}

static SDL_Cursor *X11_CreateSystemCursor(SDL_SystemCursor id)
{
    SDL_Cursor *cursor = NULL;
    Display *dpy = GetDisplay();
    Cursor x11_cursor = None;

#ifdef SDL_VIDEO_DRIVER_X11_XCURSOR
    if (SDL_X11_HAVE_XCURSOR) {
        x11_cursor = X11_XcursorLibraryLoadCursor(dpy, SDL_GetCSSCursorName(id, NULL));
    }
#endif

    if (x11_cursor == None) {
        x11_cursor = X11_XCreateFontCursor(dpy, GetLegacySystemCursorShape(id));
    }

    if (x11_cursor != None) {
        cursor = SDL_calloc(1, sizeof(*cursor));
        if (!cursor) {
            SDL_OutOfMemory();
        } else {
            cursor->driverdata = (void *)(uintptr_t)x11_cursor;
        }
    }

    return cursor;
}

static void X11_FreeCursor(SDL_Cursor *cursor)
{
    Cursor x11_cursor = (Cursor)cursor->driverdata;

    if (x11_cursor != None) {
        X11_XFreeCursor(GetDisplay(), x11_cursor);
    }
    SDL_free(cursor);
}

static int X11_ShowCursor(SDL_Cursor *cursor)
{
    Cursor x11_cursor = 0;

    if (cursor) {
        x11_cursor = (Cursor)cursor->driverdata;
    } else {
        x11_cursor = X11_CreateEmptyCursor();
    }

    /* FIXME: Is there a better way than this? */
    {
        SDL_VideoDevice *video = SDL_GetVideoDevice();
        Display *display = GetDisplay();
        SDL_Window *window;

        x11_cursor_visible = !!cursor;

        for (window = video->windows; window; window = window->next) {
            SDL_WindowData *data = (SDL_WindowData *)window->driverdata;
            if (data) {
                if (x11_cursor != None) {
                    X11_XDefineCursor(display, data->xwindow, x11_cursor);
                } else {
                    X11_XUndefineCursor(display, data->xwindow);
                }
            }
        }
        X11_XFlush(display);
    }
    return 0;
}

static void WarpMouseInternal(Window xwindow, const int x, const int y)
{
    SDL_VideoData *videodata = (SDL_VideoData *)SDL_GetVideoDevice()->driverdata;
    Display *display = videodata->display;
#ifdef SDL_VIDEO_DRIVER_X11_XINPUT2
    int deviceid = 0;
#endif
    SDL_bool warp_hack = SDL_FALSE;

    /* XWayland will only warp the cursor if it is hidden, so this workaround is required. */
    if (videodata->is_xwayland && x11_cursor_visible) {
        warp_hack = SDL_TRUE;
    }

    if (warp_hack) {
        X11_ShowCursor(NULL);
    }
#ifdef SDL_VIDEO_DRIVER_X11_XINPUT2
    if (X11_Xinput2IsInitialized()) {
        /* It seems XIWarpPointer() doesn't work correctly on multi-head setups:
         * https://developer.blender.org/rB165caafb99c6846e53d11c4e966990aaffc06cea
         */
        if (ScreenCount(display) == 1) {
            X11_XIGetClientPointer(display, None, &deviceid);
        }
    }
    if (deviceid != 0) {
        SDL_assert(SDL_X11_HAVE_XINPUT2);
        X11_XIWarpPointer(display, deviceid, None, xwindow, 0.0, 0.0, 0, 0, (double)x, (double)y);
    } else
#endif
    {
        X11_XWarpPointer(display, None, xwindow, 0, 0, 0, 0, x, y);
    }

    if (warp_hack) {
        X11_ShowCursor(SDL_GetCursor());
    }
    X11_XSync(display, False);
    videodata->global_mouse_changed = SDL_TRUE;
}

static void X11_WarpMouse(SDL_Window *window, int x, int y)
{
    SDL_WindowData *data = (SDL_WindowData *)window->driverdata;

#ifdef SDL_VIDEO_DRIVER_X11_XFIXES
    /* If we have no barrier, we need to warp */
    if (data->pointer_barrier_active == SDL_FALSE) {
        WarpMouseInternal(data->xwindow, x, y);
    }
#else
    WarpMouseInternal(data->xwindow, x, y);
#endif
}

static int X11_WarpMouseGlobal(int x, int y)
{
    WarpMouseInternal(DefaultRootWindow(GetDisplay()), x, y);
    return 0;
}

static int X11_SetRelativeMouseMode(SDL_bool enabled)
{
    return X11_Xinput2IsInitialized() ? 0 : SDL_Unsupported();
}

static int X11_CaptureMouse(SDL_Window *window)
{
    Display *display = GetDisplay();
    SDL_Window *mouse_focus = SDL_GetMouseFocus();

    if (window) {
        SDL_WindowData *data = (SDL_WindowData *)window->driverdata;
        const unsigned int mask = ButtonPressMask | ButtonReleaseMask | PointerMotionMask | FocusChangeMask;
        Window confined = (data->mouse_grabbed ? data->xwindow : None);
        const int rc = X11_XGrabPointer(display, data->xwindow, False,
                                        mask, GrabModeAsync, GrabModeAsync,
                                        confined, None, CurrentTime);
        if (rc != GrabSuccess) {
            return SDL_SetError("X server refused mouse capture");
        }
    } else if (mouse_focus) {
        SDL_UpdateWindowGrab(mouse_focus);
    } else {
        X11_XUngrabPointer(display, CurrentTime);
    }

    X11_XSync(display, False);

    return 0;
}

static Uint32 X11_GetGlobalMouseState(int *x, int *y)
{
    SDL_VideoData *videodata = (SDL_VideoData *)SDL_GetVideoDevice()->driverdata;
    Display *display = GetDisplay();
    const int num_screens = SDL_GetNumVideoDisplays();
    int i;

    /* !!! FIXME: should we XSync() here first? */

    if (!X11_Xinput2IsInitialized()) {
        videodata->global_mouse_changed = SDL_TRUE;
    }

    /* check if we have this cached since XInput last saw the mouse move. */
    /* !!! FIXME: can we just calculate this from XInput's events? */
    if (videodata->global_mouse_changed) {
        for (i = 0; i < num_screens; i++) {
            SDL_DisplayData *data = (SDL_DisplayData *)SDL_GetDisplayDriverData(i);
            if (data) {
                Window root, child;
                int rootx, rooty, winx, winy;
                unsigned int mask;
                if (X11_XQueryPointer(display, RootWindow(display, data->screen), &root, &child, &rootx, &rooty, &winx, &winy, &mask)) {
                    XWindowAttributes root_attrs;
                    Uint32 buttons = 0;
                    buttons |= (mask & Button1Mask) ? SDL_BUTTON_LMASK : 0;
                    buttons |= (mask & Button2Mask) ? SDL_BUTTON_MMASK : 0;
                    buttons |= (mask & Button3Mask) ? SDL_BUTTON_RMASK : 0;
                    /* Use the SDL state for the extended buttons - it's better than nothing */
                    buttons |= (SDL_GetMouseState(NULL, NULL) & (SDL_BUTTON_X1MASK | SDL_BUTTON_X2MASK));
                    /* SDL_DisplayData->x,y point to screen origin, and adding them to mouse coordinates relative to root window doesn't do the right thing
                     * (observed on dual monitor setup with primary display being the rightmost one - mouse was offset to the right).
                     *
                     * Adding root position to root-relative coordinates seems to be a better way to get absolute position. */
                    X11_XGetWindowAttributes(display, root, &root_attrs);
                    videodata->global_mouse_position.x = root_attrs.x + rootx;
                    videodata->global_mouse_position.y = root_attrs.y + rooty;
                    videodata->global_mouse_buttons = buttons;
                    videodata->global_mouse_changed = SDL_FALSE;
                    break;
                }
            }
        }
    }

    SDL_assert(!videodata->global_mouse_changed); /* The pointer wasn't on any X11 screen?! */

    *x = videodata->global_mouse_position.x;
    *y = videodata->global_mouse_position.y;
    return videodata->global_mouse_buttons;
}

void X11_InitMouse(_THIS)
{
    SDL_Mouse *mouse = SDL_GetMouse();

    mouse->CreateCursor = X11_CreateCursor;
    mouse->CreateSystemCursor = X11_CreateSystemCursor;
    mouse->ShowCursor = X11_ShowCursor;
    mouse->FreeCursor = X11_FreeCursor;
    mouse->WarpMouse = X11_WarpMouse;
    mouse->WarpMouseGlobal = X11_WarpMouseGlobal;
    mouse->SetRelativeMouseMode = X11_SetRelativeMouseMode;
    mouse->CaptureMouse = X11_CaptureMouse;
    mouse->GetGlobalMouseState = X11_GetGlobalMouseState;

    SDL_SetDefaultCursor(X11_CreateDefaultCursor());
}

void X11_QuitMouse(_THIS)
{
    SDL_VideoData *data = (SDL_VideoData *)_this->driverdata;
    SDL_XInput2DeviceInfo *i;
    SDL_XInput2DeviceInfo *next;

    for (i = data->mouse_device_info; i; i = next) {
        next = i->next;
        SDL_free(i);
    }
    data->mouse_device_info = NULL;

    X11_DestroyEmptyCursor();
}

#endif /* SDL_VIDEO_DRIVER_X11 */
