// This file is part of Desktop App Toolkit,
// a set of libraries for developing nice desktop applications.
//
// For license and copyright information please follow this link:
// https://github.com/desktop-app/legal/blob/master/LEGAL
//
#include "ui/platform/linux/ui_utility_linux.h"

#include "base/platform/base_platform_info.h"
#include "base/platform/linux/base_linux_glibmm_helper.h"
#include "base/platform/linux/base_linux_xdp_utilities.h"
#include "ui/platform/linux/ui_linux_wayland_integration.h"
#include "base/const_string.h"

#ifndef DESKTOP_APP_DISABLE_X11_INTEGRATION
#include "base/platform/linux/base_linux_xcb_utilities.h"
#include "base/platform/linux/base_linux_xsettings.h"
#endif // !DESKTOP_APP_DISABLE_X11_INTEGRATION

#include <QtCore/QPoint>
#include <QtGui/QWindow>
#include <QtWidgets/QApplication>

namespace Ui {
namespace Platform {
namespace {

constexpr auto kXCBFrameExtentsAtomName = "_GTK_FRAME_EXTENTS"_cs;

#ifndef DESKTOP_APP_DISABLE_X11_INTEGRATION
std::optional<bool> XCBWindowMapped(xcb_window_t window) {
	const auto connection = base::Platform::XCB::GetConnectionFromQt();
	if (!connection) {
		return std::nullopt;
	}

	const auto cookie = xcb_get_window_attributes(connection, window);
	const auto reply = base::Platform::XCB::MakeReplyPointer(
		xcb_get_window_attributes_reply(
			connection,
			cookie,
			nullptr));

	if (!reply) {
		return std::nullopt;
	}

	return reply->map_state == XCB_MAP_STATE_VIEWABLE;
}

std::optional<bool> XCBWindowHidden(xcb_window_t window) {
	const auto connection = base::Platform::XCB::GetConnectionFromQt();
	if (!connection) {
		return std::nullopt;
	}

	const auto stateAtom = base::Platform::XCB::GetAtom(
		connection,
		"_NET_WM_STATE");

	const auto stateHiddenAtom = base::Platform::XCB::GetAtom(
		connection,
		"_NET_WM_STATE_HIDDEN");

	if (!stateAtom.has_value() || !stateHiddenAtom.has_value()) {
		return std::nullopt;
	}

	const auto cookie = xcb_get_property(
		connection,
		false,
		window,
		*stateAtom,
		XCB_ATOM_ATOM,
		0,
		1024);

	const auto reply = base::Platform::XCB::MakeReplyPointer(
		xcb_get_property_reply(
			connection,
			cookie,
			nullptr));

	if (!reply) {
		return std::nullopt;
	}

	if (reply->type != XCB_ATOM_ATOM || reply->format != 32) {
		return std::nullopt;
	}

	const auto atomsStart = reinterpret_cast<xcb_atom_t*>(
		xcb_get_property_value(reply.get()));

	const auto states = std::vector<xcb_atom_t>(
		atomsStart,
		atomsStart + reply->length);

	return ranges::contains(states, *stateHiddenAtom);
}

QRect XCBWindowGeometry(xcb_window_t window) {
	const auto connection = base::Platform::XCB::GetConnectionFromQt();
	if (!connection) {
		return {};
	}

	const auto cookie = xcb_get_geometry(connection, window);
	const auto reply = base::Platform::XCB::MakeReplyPointer(
		xcb_get_geometry_reply(
			connection,
			cookie,
			nullptr));

	if (!reply) {
		return {};
	}

	return QRect(reply->x, reply->y, reply->width, reply->height);
}

std::optional<uint> XCBCurrentWorkspace() {
	const auto connection = base::Platform::XCB::GetConnectionFromQt();
	if (!connection) {
		return std::nullopt;
	}

	const auto root = base::Platform::XCB::GetRootWindow(connection);
	if (!root.has_value()) {
		return std::nullopt;
	}

	const auto currentDesktopAtom = base::Platform::XCB::GetAtom(
		connection,
		"_NET_CURRENT_DESKTOP");

	if (!currentDesktopAtom.has_value()) {
		return std::nullopt;
	}

	const auto cookie = xcb_get_property(
		connection,
		false,
		*root,
		*currentDesktopAtom,
		XCB_ATOM_CARDINAL,
		0,
		1024);

	const auto reply = base::Platform::XCB::MakeReplyPointer(
		xcb_get_property_reply(
			connection,
			cookie,
			nullptr));

	if (!reply) {
		return std::nullopt;
	}

	return (reply->type == XCB_ATOM_CARDINAL)
		? std::make_optional(
			*reinterpret_cast<ulong*>(xcb_get_property_value(reply.get())))
		: std::nullopt;
}

std::optional<uint> XCBWindowWorkspace(xcb_window_t window) {
	const auto connection = base::Platform::XCB::GetConnectionFromQt();
	if (!connection) {
		return std::nullopt;
	}

	const auto desktopAtom = base::Platform::XCB::GetAtom(
		connection,
		"_NET_WM_DESKTOP");

	if (!desktopAtom.has_value()) {
		return std::nullopt;
	}

	const auto cookie = xcb_get_property(
		connection,
		false,
		window,
		*desktopAtom,
		XCB_ATOM_CARDINAL,
		0,
		1024);

	const auto reply = base::Platform::XCB::MakeReplyPointer(
		xcb_get_property_reply(
			connection,
			cookie,
			nullptr));

	if (!reply) {
		return std::nullopt;
	}

	return (reply->type == XCB_ATOM_CARDINAL)
		? std::make_optional(
			*reinterpret_cast<ulong*>(xcb_get_property_value(reply.get())))
		: std::nullopt;
}

std::optional<bool> XCBIsOverlapped(
		not_null<QWidget*> widget,
		const QRect &rect) {
	const auto window = widget->winId();
	Expects(window != XCB_WINDOW_NONE);

	const auto connection = base::Platform::XCB::GetConnectionFromQt();
	if (!connection) {
		return std::nullopt;
	}

	const auto root = base::Platform::XCB::GetRootWindow(connection);
	if (!root.has_value()) {
		return std::nullopt;
	}

	const auto windowWorkspace = XCBWindowWorkspace(window);
	const auto currentWorkspace = XCBCurrentWorkspace();
	if (windowWorkspace.has_value()
		&& currentWorkspace.has_value()
		&& *windowWorkspace != *currentWorkspace
		&& *windowWorkspace != 0xFFFFFFFF) {
		return true;
	}

	const auto windowGeometry = XCBWindowGeometry(window);
	if (windowGeometry.isNull()) {
		return std::nullopt;
	}

	const auto mappedRect = QRect(
		rect.topLeft()
			* widget->windowHandle()->devicePixelRatio()
			+ windowGeometry.topLeft(),
		rect.size() * widget->windowHandle()->devicePixelRatio());

	const auto cookie = xcb_query_tree(connection, *root);
	const auto reply = base::Platform::XCB::MakeReplyPointer(
		xcb_query_tree_reply(connection, cookie, nullptr));

	if (!reply) {
		return std::nullopt;
	}

	const auto tree = xcb_query_tree_children(reply.get());
	auto aboveTheWindow = false;

	for (auto i = 0, l = xcb_query_tree_children_length(reply.get()); i < l; ++i) {
		if (window == tree[i]) {
			aboveTheWindow = true;
			continue;
		}

		if (!aboveTheWindow) {
			continue;
		}

		const auto geometry = XCBWindowGeometry(tree[i]);
		if (!mappedRect.intersects(geometry)) {
			continue;
		}

		const auto workspace = XCBWindowWorkspace(tree[i]);
		if (workspace.has_value()
			&& windowWorkspace.has_value()
			&& *workspace != *windowWorkspace
			&& *workspace != 0xFFFFFFFF) {
			continue;
		}

		const auto mapped = XCBWindowMapped(tree[i]);
		if (mapped.has_value() && !*mapped) {
			continue;
		}

		const auto hidden = XCBWindowHidden(tree[i]);
		if (hidden.has_value() && *hidden) {
			continue;
		}

		return true;
	}

	return false;
}

void SetXCBFrameExtents(not_null<QWidget*> widget, const QMargins &extents) {
	const auto connection = base::Platform::XCB::GetConnectionFromQt();
	if (!connection) {
		return;
	}

	const auto frameExtentsAtom = base::Platform::XCB::GetAtom(
		connection,
		kXCBFrameExtentsAtomName.utf16());

	if (!frameExtentsAtom.has_value()) {
		return;
	}

	const auto nativeExtents = extents
		* widget->windowHandle()->devicePixelRatio();

	const auto extentsVector = std::vector<uint>{
		uint(nativeExtents.left()),
		uint(nativeExtents.right()),
		uint(nativeExtents.top()),
		uint(nativeExtents.bottom()),
	};

	xcb_change_property(
		connection,
		XCB_PROP_MODE_REPLACE,
		widget->winId(),
		*frameExtentsAtom,
		XCB_ATOM_CARDINAL,
		32,
		extentsVector.size(),
		extentsVector.data());
}

void UnsetXCBFrameExtents(not_null<QWidget*> widget) {
	const auto connection = base::Platform::XCB::GetConnectionFromQt();
	if (!connection) {
		return;
	}

	const auto frameExtentsAtom = base::Platform::XCB::GetAtom(
		connection,
		kXCBFrameExtentsAtomName.utf16());

	if (!frameExtentsAtom.has_value()) {
		return;
	}

	xcb_delete_property(
		connection,
		widget->winId(),
		*frameExtentsAtom);
}

void ShowXCBWindowMenu(not_null<QWidget*> widget, const QPoint &point) {
	const auto connection = base::Platform::XCB::GetConnectionFromQt();
	if (!connection) {
		return;
	}

	const auto root = base::Platform::XCB::GetRootWindow(connection);
	if (!root.has_value()) {
		return;
	}

	const auto showWindowMenuAtom = base::Platform::XCB::GetAtom(
		connection,
		"_GTK_SHOW_WINDOW_MENU");

	if (!showWindowMenuAtom.has_value()) {
		return;
	}

	const auto windowGeometry = XCBWindowGeometry(widget->winId());
	if (windowGeometry.isNull()) {
		return;
	}

	const auto globalPos = point
		* widget->windowHandle()->devicePixelRatio()
		+ windowGeometry.topLeft();

	xcb_client_message_event_t xev;
	xev.response_type = XCB_CLIENT_MESSAGE;
	xev.type = *showWindowMenuAtom;
	xev.sequence = 0;
	xev.window = widget->winId();
	xev.format = 32;
	xev.data.data32[0] = 0;
	xev.data.data32[1] = globalPos.x();
	xev.data.data32[2] = globalPos.y();
	xev.data.data32[3] = 0;
	xev.data.data32[4] = 0;

	xcb_ungrab_pointer(connection, XCB_CURRENT_TIME);
	xcb_send_event(
		connection,
		false,
		*root,
		XCB_EVENT_MASK_SUBSTRUCTURE_REDIRECT
			| XCB_EVENT_MASK_SUBSTRUCTURE_NOTIFY,
		reinterpret_cast<const char*>(&xev));
}
#endif // !DESKTOP_APP_DISABLE_X11_INTEGRATION

TitleControls::Control GtkKeywordToTitleControl(const QString &keyword) {
	if (keyword == qstr("minimize")) {
		return TitleControls::Control::Minimize;
	} else if (keyword == qstr("maximize")) {
		return TitleControls::Control::Maximize;
	} else if (keyword == qstr("close")) {
		return TitleControls::Control::Close;
	}

	return TitleControls::Control::Unknown;
}

TitleControls::Layout GtkKeywordsToTitleControlsLayout(const QString &keywords) {
	const auto splitted = keywords.split(':');

	std::vector<TitleControls::Control> controlsLeft;
	ranges::transform(
		splitted[0].split(','),
		ranges::back_inserter(controlsLeft),
		GtkKeywordToTitleControl);

	std::vector<TitleControls::Control> controlsRight;
	if (splitted.size() > 1) {
		ranges::transform(
			splitted[1].split(','),
			ranges::back_inserter(controlsRight),
			GtkKeywordToTitleControl);
	}

	return TitleControls::Layout{
		.left = controlsLeft,
		.right = controlsRight
	};
}

} // namespace

bool IsApplicationActive() {
	return QApplication::activeWindow() != nullptr;
}

bool TranslucentWindowsSupported() {
	if (::Platform::IsWayland()) {
		return true;
	}

#ifndef DESKTOP_APP_DISABLE_X11_INTEGRATION
	if (::Platform::IsX11()) {
		const auto connection = base::Platform::XCB::GetConnectionFromQt();
		if (!connection) {
			return false;
		}

		const auto atom = base::Platform::XCB::GetAtom(
			connection,
			"_NET_WM_CM_S0");

		if (!atom) {
			return false;
		}

		const auto cookie = xcb_get_selection_owner(connection, *atom);

		const auto result = base::Platform::XCB::MakeReplyPointer(
			xcb_get_selection_owner_reply(
				connection,
				cookie,
				nullptr));

		if (!result) {
			return false;
		}

		return result->owner;
	}
#endif // !DESKTOP_APP_DISABLE_X11_INTEGRATION

	return false;
}

void IgnoreAllActivation(not_null<QWidget*> widget) {
}

void ClearTransientParent(not_null<QWidget*> widget) {
#ifndef DESKTOP_APP_DISABLE_X11_INTEGRATION
	if (::Platform::IsX11()) {
		xcb_delete_property(
			base::Platform::XCB::GetConnectionFromQt(),
			widget->winId(),
			XCB_ATOM_WM_TRANSIENT_FOR);
	}
#endif // !DESKTOP_APP_DISABLE_X11_INTEGRATION
}

std::optional<bool> IsOverlapped(
		not_null<QWidget*> widget,
		const QRect &rect) {
#ifndef DESKTOP_APP_DISABLE_X11_INTEGRATION
	if (::Platform::IsX11()) {
		return XCBIsOverlapped(widget, rect);
	}
#endif // !DESKTOP_APP_DISABLE_X11_INTEGRATION

	return std::nullopt;
}

bool WindowExtentsSupported() {
	if (const auto integration = WaylandIntegration::Instance()) {
		return integration->windowExtentsSupported();
	}

#ifndef DESKTOP_APP_DISABLE_X11_INTEGRATION
	namespace XCB = base::Platform::XCB;
	if (::Platform::IsX11()
		&& XCB::IsSupportedByWM(
			XCB::GetConnectionFromQt(),
			kXCBFrameExtentsAtomName.utf16())) {
		return true;
	}
#endif // !DESKTOP_APP_DISABLE_X11_INTEGRATION

	return false;
}

void SetWindowExtents(not_null<QWidget*> widget, const QMargins &extents) {
	if (const auto integration = WaylandIntegration::Instance()) {
		integration->setWindowExtents(widget, extents);
	} else if (::Platform::IsX11()) {
#ifndef DESKTOP_APP_DISABLE_X11_INTEGRATION
		SetXCBFrameExtents(widget, extents);
#endif // !DESKTOP_APP_DISABLE_X11_INTEGRATION
	}
}

void UnsetWindowExtents(not_null<QWidget*> widget) {
	if (const auto integration = WaylandIntegration::Instance()) {
		integration->unsetWindowExtents(widget);
	} else if (::Platform::IsX11()) {
#ifndef DESKTOP_APP_DISABLE_X11_INTEGRATION
		UnsetXCBFrameExtents(widget);
#endif // !DESKTOP_APP_DISABLE_X11_INTEGRATION
	}
}

void ShowWindowMenu(not_null<QWidget*> widget, const QPoint &point) {
	if (const auto integration = WaylandIntegration::Instance()) {
		integration->showWindowMenu(widget, point);
	} else if (::Platform::IsX11()) {
#ifndef DESKTOP_APP_DISABLE_X11_INTEGRATION
		ShowXCBWindowMenu(widget, point);
#endif // !DESKTOP_APP_DISABLE_X11_INTEGRATION
	}
}

namespace internal {

TitleControls::Layout TitleControlsLayout() {
	[[maybe_unused]] static const auto Inited = [] {
#ifndef DESKTOP_APP_DISABLE_X11_INTEGRATION
		using base::Platform::XCB::XSettings;
		if (const auto xSettings = XSettings::Instance()) {
			xSettings->registerCallbackForProperty("Gtk/DecorationLayout", [](
					xcb_connection_t *,
					const QByteArray &,
					const QVariant &,
					void *) {
				NotifyTitleControlsLayoutChanged();
			}, nullptr);
		}
#endif // !DESKTOP_APP_DISABLE_X11_INTEGRATION

		using XDPSettingWatcher = base::Platform::XDP::SettingWatcher;
		static const XDPSettingWatcher settingWatcher(
			[=](
				const Glib::ustring &group,
				const Glib::ustring &key,
				const Glib::VariantBase &value) {
				if (group == "org.gnome.desktop.wm.preferences"
					&& key == "button-layout") {
					NotifyTitleControlsLayoutChanged();
				}
			});

		return true;
	}();

#ifndef DESKTOP_APP_DISABLE_X11_INTEGRATION
	const auto xSettingsResult = []() -> std::optional<TitleControls::Layout> {
		using base::Platform::XCB::XSettings;
		const auto xSettings = XSettings::Instance();
		if (!xSettings) {
			return std::nullopt;
		}

		const auto decorationLayout = xSettings->setting("Gtk/DecorationLayout");
		if (!decorationLayout.isValid()) {
			return std::nullopt;
		}

		return GtkKeywordsToTitleControlsLayout(decorationLayout.toString());
	}();

	if (xSettingsResult.has_value()) {
		return *xSettingsResult;
	}
#endif // !DESKTOP_APP_DISABLE_X11_INTEGRATION

	const auto portalResult = []() -> std::optional<TitleControls::Layout> {
		try {
			using namespace base::Platform::XDP;

			const auto decorationLayout = ReadSetting(
				"org.gnome.desktop.wm.preferences",
				"button-layout");

			if (!decorationLayout.has_value()) {
				return std::nullopt;
			}

			return GtkKeywordsToTitleControlsLayout(
				QString::fromStdString(
					base::Platform::GlibVariantCast<Glib::ustring>(
						*decorationLayout)));
		} catch (...) {
		}

		return std::nullopt;
	}();

	if (portalResult.has_value()) {
		return *portalResult;
	}

	return TitleControls::Layout{
		.right = {
			TitleControls::Control::Minimize,
			TitleControls::Control::Maximize,
			TitleControls::Control::Close,
		}
	};
}

} // namespace internal
} // namespace Platform
} // namespace Ui