// SPDX-License-Identifier: LGPL-2.1-or-later
#include "review_x11.h"
// This is a Unix library in a Winelib translation unit, not Windows XCB.
#pragma push_macro("_WIN32")
#undef _WIN32
#include <xcb/xcb.h>
#include <xcb/xcbext.h>
#pragma pop_macro("_WIN32")
#include <poll.h>
#include <cstdlib>
#include <memory>
#include <cstring>

namespace {
struct Connection {
  xcb_connection_t *value=xcb_connect(nullptr,nullptr);
  ~Connection() { if (value) xcb_disconnect(value); }
};
thread_local Connection connection;
template<class T> std::unique_ptr<T,decltype(&std::free)> reply(unsigned sequence, uint64_t deadline) {
  void *value=nullptr;
  xcb_generic_error_t *error=nullptr;
  xcb_flush(connection.value);
  while (GetTickCount64()<deadline && !xcb_connection_has_error(connection.value)) {
    if (xcb_poll_for_reply(connection.value,sequence,&value,&error)) {
      std::free(error);
      return {static_cast<T*>(value),&std::free};
    }
    auto now=GetTickCount64();
    if (now>=deadline) break;
    pollfd fd{xcb_get_file_descriptor(connection.value),POLLIN,0};
    if (poll(&fd,1,static_cast<int>(deadline-now))<=0) break;
  }
  xcb_discard_reply(connection.value,sequence);
  return {nullptr,&std::free};
}
bool geometry(HWND window, RECT &bounds, uint64_t deadline) {
  auto xid=reinterpret_cast<uintptr_t>(GetPropW(window,L"__wine_x11_whole_window"));
  if (!xid || xid>UINT32_MAX || !connection.value || xcb_connection_has_error(connection.value)) return false;
  auto size=reply<xcb_get_geometry_reply_t>(xcb_get_geometry(connection.value,xid).sequence,deadline);
  if (!size || !size->width || !size->height) return false;
  auto position=reply<xcb_translate_coordinates_reply_t>(
      xcb_translate_coordinates(connection.value,xid,size->root,0,0).sequence,deadline);
  if (!position || !position->same_screen) return false;
  bounds={position->dst_x,position->dst_y,position->dst_x+size->width,position->dst_y+size->height};
  return true;
}
}
bool review_x11_geometry(HWND window, RECT &bounds, POINT &origin) {
  origin={0,0};
  // Metadata reads cannot wait indefinitely behind an unresponsive X server.
  const uint64_t deadline=GetTickCount64()+20;
  if (!geometry(window,bounds,deadline)) return false;
  USEROBJECTFLAGS flags{};
  if (GetUserObjectInformationW(GetThreadDesktop(GetCurrentThreadId()),UOI_FLAGS,&flags,sizeof(flags),nullptr) &&
      (flags.dwFlags&0x80000000)) { // Wine's DF_WINE_VIRTUAL_DESKTOP.
    RECT desktop{};
    if (!geometry(GetDesktopWindow(),desktop,deadline)) return false;
    origin={desktop.left,desktop.top};
  }
  return true;
}

bool wine_x11_desktop_focused() {
  USEROBJECTFLAGS flags{};
  if (!GetUserObjectInformationW(GetThreadDesktop(GetCurrentThreadId()), UOI_FLAGS,
          &flags, sizeof(flags), nullptr) || !(flags.dwFlags & 0x80000000))
    return false;
  const auto xid = reinterpret_cast<uintptr_t>(GetPropW(GetDesktopWindow(), L"__wine_x11_whole_window"));
  if (!xid || xid > UINT32_MAX || !connection.value || xcb_connection_has_error(connection.value))
    return false;
  const uint64_t deadline = GetTickCount64() + 20;
  auto focus = reply<xcb_get_input_focus_reply_t>(xcb_get_input_focus(connection.value).sequence, deadline);
  if (!focus || focus->focus != xid) return false;
  auto size = reply<xcb_get_geometry_reply_t>(xcb_get_geometry(connection.value, xid).sequence, deadline);
  if (!size) return false;
  constexpr char name[] = "_NET_ACTIVE_WINDOW";
  auto atom = reply<xcb_intern_atom_reply_t>(xcb_intern_atom(connection.value, 1, sizeof(name) - 1, name).sequence, deadline);
  if (!atom || !atom->atom) return false;
  auto active = reply<xcb_get_property_reply_t>(xcb_get_property(connection.value, 0, size->root,
      atom->atom, XCB_ATOM_WINDOW, 0, 1).sequence, deadline);
  uint32_t window = 0;
  if (!active || active->type != XCB_ATOM_WINDOW || active->format != 32 ||
      xcb_get_property_value_length(active.get()) != sizeof(window))
    return false;
  std::memcpy(&window, xcb_get_property_value(active.get()), sizeof(window));
  return window == xid;
}

bool wine_x11_restore_focus(HWND window) {
  if (!wine_x11_desktop_focused()) return false;
  const auto xid = reinterpret_cast<uintptr_t>(GetPropW(window, L"__wine_x11_whole_window"));
  const auto desktop = reinterpret_cast<uintptr_t>(GetPropW(GetDesktopWindow(), L"__wine_x11_whole_window"));
  if (!xid || xid > UINT32_MAX) return false;
  const uint64_t deadline = GetTickCount64() + 20;
  auto tree = reply<xcb_query_tree_reply_t>(xcb_query_tree(connection.value, xid).sequence, deadline);
  if (!tree || tree->parent != desktop) return false;
  // Native focus informs Wine's application thread of activation. A helper's
  // SetForegroundWindow can be denied by the Win32 foreground-lock policy.
  constexpr char protocolsName[] = "WM_PROTOCOLS";
  constexpr char focusName[] = "WM_TAKE_FOCUS";
  auto protocols = reply<xcb_intern_atom_reply_t>(xcb_intern_atom(connection.value, 1,
      sizeof(protocolsName) - 1, protocolsName).sequence, deadline);
  auto takeFocus = reply<xcb_intern_atom_reply_t>(xcb_intern_atom(connection.value, 1,
      sizeof(focusName) - 1, focusName).sequence, deadline);
  if (!protocols || !protocols->atom || !takeFocus || !takeFocus->atom) return false;
  if (GetForegroundWindow() || !IsWindowVisible(window) || !IsWindowEnabled(window) ||
      IsIconic(window) || !wine_x11_desktop_focused())
    return false;
  xcb_client_message_event_t event{};
  event.response_type = XCB_CLIENT_MESSAGE;
  event.format = 32;
  event.window = xid;
  event.type = protocols->atom;
  event.data.data32[0] = takeFocus->atom;
  event.data.data32[1] = XCB_CURRENT_TIME;
  xcb_send_event(connection.value, 0, xid, XCB_EVENT_MASK_NO_EVENT, reinterpret_cast<const char *>(&event));
  xcb_set_input_focus(connection.value, XCB_INPUT_FOCUS_PARENT, xid, XCB_CURRENT_TIME);
  auto focus = reply<xcb_get_input_focus_reply_t>(xcb_get_input_focus(connection.value).sequence, deadline);
  return focus && focus->focus == xid;
}