#include <csignal>
#include <cstdio>
#include <cstdlib>
#include <fcntl.h>
#include <optional>
#include <signal.h>
#include <sys/file.h>
#include <sys/types.h>
#include <unistd.h>

#include "App.hpp"

bool signal_running();

std::optional<App> g_app{};

auto main() -> int {
  if (signal_running()) {
    return 0;
  }

  std::signal(SIGINT, [](int) {
    if (g_app)
      g_app->stop();
  });

  g_app.emplace();
  g_app->run();
}

bool signal_running() {
  const char *lock_path = "/tmp/waylight.lock";
  int fd = open(lock_path, O_CREAT | O_RDWR, 0666);
  if (fd == -1)
    return false;

  if (flock(fd, LOCK_EX | LOCK_NB) == -1) {
    FILE *f = fopen(lock_path, "r");
    if (f) {
      pid_t pid;
      if (fscanf(f, "%d", &pid) == 1)
        kill(pid, SIGUSR1);
      fclose(f);
    }
    close(fd);
    return true;
  }

  if (ftruncate(fd, 0) == -1) {
      close(fd);
      unlink(lock_path);
      return false;
  }

  dprintf(fd, "%d\n", getpid());
  return false;
}