package net.horizoncode.tickettest.manager;

import com.google.common.util.concurrent.ListenableFuture;
import com.google.common.util.concurrent.ListeningExecutorService;
import com.google.common.util.concurrent.MoreExecutors;
import lombok.Builder;
import lombok.Getter;
import net.horizoncode.tickettest.TicketTest;

import java.util.HashSet;
import java.util.Set;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;

@Builder(
    toBuilder = true,
    builderClassName = "InternalTicketManagerBuilder",
    builderMethodName = "internalBuilder")
@Getter
public class TicketManager {

  private ListeningExecutorService service;
  private Set<Ticket> ticketSet;
  private int maxTicketsExisting;
  private long ticketLifespan;

  public Ticket addTicket(Runnable onExpire) {
    ListenableFuture<Ticket> asyncTask =
        service.submit(
            () -> {
              if (waitForFreeTicket())
                TicketTest.getInstance().getLogger().warning("max amount of tickets reached, waiting...");

              while (waitForFreeTicket()) {
                TimeUnit.MILLISECONDS.sleep(1);
              }
              Ticket t =
                  Ticket.builder().timeTicketCreated(ticketLifespan).onExpire(onExpire).ticketManager(this).build();
              TicketTest.getInstance().getLogger().info("Got ticket with UUID: " + t.getTicketID());
              return t;
            });
    try {
      return asyncTask.get();
    } catch (InterruptedException | ExecutionException e) {
      e.printStackTrace();
      return null;
    }
  }

  private boolean waitForFreeTicket() {
    return ticketSet.size() >= maxTicketsExisting;
  }

  void init() {
    service = MoreExecutors.listeningDecorator(Executors.newFixedThreadPool(10));
    ticketSet = new HashSet<>();
  }

  public static Builder builder() {
    return new Builder();
  }

  public static class Builder extends InternalTicketManagerBuilder {

    Builder() {
      super();
    }

    @Override
    public TicketManager build() {
      TicketManager ticketManager = super.build();
      ticketManager.init();
      return ticketManager;
    }
  }
}