package jalview.util;

import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;

import jalview.bin.Console;

public class IdUtils
{
  /**
   * id generating tools avoiding Random.nextLong() for JalviewJS. Avoids
   * collisions.
   */

  public static enum IdType
  {
    GENERAL, PROGRESS;
  }

  private static int count = 0;

  private static Map<IdType, Set<Long>> typeMap = new HashMap<>();

  static
  {
    for (IdType t : IdType.values())
    {
      typeMap.put(t, new HashSet<>());
    }
  }

  public static long newId()
  {
    return newId(IdType.GENERAL, null);
  }

  public static long newId(IdType t)
  {
    return newId(t, null);
  }

  public static long newId(IdType t, Object o)
  {
    Set<Long> idSet = typeMap.get(t);
    long newId = 0;
    if (o == null)
    {
      // get a new hashCode -- not tied to an object.
      // Adding Integer.MAX_VALUE should avoid collisions with object generated
      // Ids.
      newId = Integer.MAX_VALUE + t.hashCode() + System.currentTimeMillis()
              + count;
      while (idSet.contains(newId))
      {
        newId += count;
      }
    }
    else
    {
      // generate the hashcode tied to this object for this type
      newId = t.hashCode() + o.hashCode();
      if (idSet.contains(newId))
      {
        Console.debug("Using an existing id for Type " + t.name()
                + " and object " + o.toString() + ": '" + newId + "'");
      }
      else
      {
        idSet.add(newId);
      }
    }
    count++;
    return newId;
  }

  public static void NOTremoveId(IdType t, Object o)
  {
    if (o == null)
    {
      return;
    }
    Set<Long> idSet = typeMap.get(t);
    long id = t.hashCode() + o.hashCode();
    idSet.remove(id);
  }

  public static void NOTremoveId(IdType t, long id)
  {
    Set<Long> idSet = typeMap.get(t);
    idSet.remove(id);
  }

}