import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import jep.Interpreter;
import jep.JepConfig;
import jep.MainInterpreter;
import jep.SubInterpreter;
import jep.SubInterpreterOptions;

public class Application {
  private static final String JEP_PATH_ENV_VAR = "JEP_PATH";

  /**
   * @param args command line arguments for the application.
   */
  public static void main(String... args) {
    ExecutorService executor = Executors.newFixedThreadPool(12);
    MainInterpreter.setJepLibraryPath(System.getProperty("tp_lib.python.jep-path", System.getenv(JEP_PATH_ENV_VAR)));
    JepProvider provider = new JepProvider();
    List<CompletableFuture<?>> futures = new ArrayList<>();
    for (int i = 0; i < 1000; i++) {
      futures.add(CompletableFuture.supplyAsync(() -> {
        System.out.println(provider.getInterpreter().getValue("1 + 2"));
        return null;
      }, executor));
    }
    CompletableFuture.allOf(futures.toArray(new CompletableFuture[0])).join();
  }


  public static class JepProvider {
    private static final JepConfig JEP_CONFIG = new JepConfig()
        .setSubInterpreterOptions(SubInterpreterOptions.legacy().setOwnGIL(true));

    private final ThreadLocal<Interpreter> subInterpreter = ThreadLocal.withInitial(() -> new SubInterpreter(JEP_CONFIG));

    public Interpreter getInterpreter() {
      return this.subInterpreter.get();
    }
  }
}