#include <rex/ui/windowed_app_context_sdl.h>
#include <rex/ui/window_sdl.h>

#include <rex/logging.h>

#include <cstdlib>

namespace rex {
namespace ui {

namespace {

constexpr uint32_t kPendingFunctionsEvent = SDL_EVENT_USER;

}  // namespace

void SDLWindowedAppContext::NotifyUILoopOfPendingFunctions() {
  bool expected = false;
  if (!pending_functions_event_queued_.compare_exchange_strong(expected, true)) {
    return;
  }

  SDL_Event event = {};
  event.type = kPendingFunctionsEvent;
  if (!SDL_PushEvent(&event)) {
    pending_functions_event_queued_ = false;
  }
}

void SDLWindowedAppContext::PlatformQuitFromUIThread() {
  SDL_Event event = {};
  event.type = SDL_EVENT_QUIT;
  SDL_PushEvent(&event);
}

int SDLWindowedAppContext::RunMainLoop() {
  if (HasQuitFromUIThread()) {
    return EXIT_SUCCESS;
  }

  SDL_Event event;
  while (!HasQuitFromUIThread() && SDL_WaitEvent(&event)) {
    DispatchEvent(event);
  }

  if (!HasQuitFromUIThread()) {
    REXLOG_WARN("SDL event loop exited unexpectedly: {}", SDL_GetError());
    QuitFromUIThread();
  }
  return EXIT_SUCCESS;
}

void SDLWindowedAppContext::DispatchEvent(const SDL_Event& event) {
  if (event.type == kPendingFunctionsEvent) {
    pending_functions_event_queued_ = false;
    ExecutePendingFunctionsFromUIThread();
    return;
  }

  if (event.type == SDL_EVENT_QUIT) {
    REXLOG_INFO("SDL quit event received");
    QuitFromUIThread();
    return;
  }

  SDLWindow::HandleSDLEvent(event);
}

}  // namespace ui
}  // namespace rex