/*
 * Copyright (C) 2017 Damir Porobic <https://github.com/damirporobic>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 */

/*
 * blendCursorImage() and getNativeCursorPosition() functions have been taken
 * from KDE Spectacle X11ImageGrabber and slightly modified to fit this
 * implementation.
 */

#include "X11Wrapper.h"

#include <X11/Xlib.h>

bool X11Wrapper::isCompositorActive() const
{
	auto display = QX11Info::display();
	auto prop_atom = XInternAtom(display, "_NET_WM_CM_S0", false);
	return XGetSelectionOwner(display, prop_atom) != None;
}

QRect X11Wrapper::getFullScreenRect() const
{
	return getWindowRect(QX11Info::appRootWindow());
}

QRect X11Wrapper::getActiveWindowRect() const
{
	auto windowId = getActiveWindowId();
	return getWindowRect(windowId);
}

QRect X11Wrapper::getWindowRect(xcb_window_t windowId) const
{
	// In case of window id 0 return empty rect
	if (windowId == 0) {
		return {};
	}

	auto connection = QX11Info::connection();
	auto geomCookie = xcb_get_geometry_unchecked(connection, windowId);
	ScopedCPointer<xcb_get_geometry_reply_t> geomReply(xcb_get_geometry_reply(connection, geomCookie, nullptr));

	return { geomReply->x, geomReply->y, geomReply->width, geomReply->height };
}

xcb_window_t X11Wrapper::getActiveWindowId() const
{
	xcb_query_tree_cookie_t treeCookie;
	auto connection = QX11Info::connection();
	ScopedCPointer<xcb_get_input_focus_reply_t> focusReply(xcb_get_input_focus_reply(connection, xcb_get_input_focus(connection), nullptr));

	// Get ID of focused window, however, this must not always be the top level
	// window so we loop through parents and search for the top level window.
	auto windowId = focusReply->focus;
	while (true) {
		treeCookie = xcb_query_tree_unchecked(connection, windowId);
		ScopedCPointer<xcb_query_tree_reply_t> treeReply(xcb_query_tree_reply(connection, treeCookie, nullptr));
		if (!treeReply) {
			return 0;
		}
		// If the root window it is equal to the parent or the window ID itself
		// the this must be the top level window.
		if (windowId == treeReply->root || treeReply->parent == treeReply->root) {
			return windowId;
		} else {
			windowId = treeReply->parent;
		}
	}
}

QPoint X11Wrapper::getNativeCursorPosition() const
{
	// QCursor::pos() is not used because it requires additional calculations.
	// Its value is the offset to the origin of the current screen is in
	// device-independent pixels while the origin itself uses native pixels.

	auto xcbConn = QX11Info::connection();
	auto pointerCookie = xcb_query_pointer_unchecked(xcbConn, QX11Info::appRootWindow());
	ScopedCPointer<xcb_query_pointer_reply_t> pointerReply(xcb_query_pointer_reply(xcbConn, pointerCookie, nullptr));

	return { pointerReply->root_x, pointerReply->root_y };
}

ImageWithPosition X11Wrapper::getCursorWithPosition() const
{
	auto cursorPosition = getNativeCursorPosition();

	// now we can get the image and start processing
	auto xcbConn = QX11Info::connection();

	auto cursorCookie = xcb_xfixes_get_cursor_image_unchecked(xcbConn);
	ScopedCPointer<xcb_xfixes_get_cursor_image_reply_t> cursorReply(xcb_xfixes_get_cursor_image_reply(xcbConn, cursorCookie, nullptr));
	if (cursorReply.isNull()) {
		return ImageWithPosition();
	}

	auto pixelData = xcb_xfixes_get_cursor_image_cursor_image(cursorReply.data());
	if (!pixelData) {
		return ImageWithPosition();
	}

	// process the image into a QImage
	auto cursorImage = QImage((quint8 *) pixelData,
	                          cursorReply->width,
	                          cursorReply->height,
	                          QImage::Format_ARGB32_Premultiplied);

	// a small fix for the cursor position for fancier cursor
	cursorPosition -= QPoint(cursorReply->xhot, cursorReply->yhot);

	return { cursorImage, cursorPosition };
}
