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package org.apache.kafka.streams.query;  

/**
 * Interactive query for retrieving a set of records with the same specified key and different timestamps within the specified time range.
 * No ordering is guaranteed for the results, but the results can be sorted by timestamp (ascendinglyin ascending or descendinglydescending order) by calling the corresponding defined methods.
 *
 *  @param <K> The type of the key.
 *  @param <V> The type of the result returned by this query.
 */

@Evolving
public final class MultiVersionedKeyQuery<K, V> implements Query<VersionedRecordIterator<V>> {

  private final K key;
  private final Optional<Instant> fromTime;
  private final Optional<Instant> toTime;
  private final boolean isAscending;

  private MultiVersionedKeyQuery(
      final K key,
      final Optional<Instant> fromTime,
      final Optional<Instant> toTime,
      final boolean isAscending) {
    this.key = Objects.requireNonNull(key);
    this.fromTime = fromTime;
    this.toTime = toTime;
    this.isAscending = isAscending;
  }     


  /**
   * Creates a query that will retrieve the set of records identified by {@code key} if any exists
   * (or {@code null} otherwise).
   *
   * <p>
   * While the query by default returns the all the record versions of the specified {@code key}, setting
   * the {@code fromTimestamp} (by calling the {@link #fromTime(Instant)} method), and the {@code toTimestamp}
   * (by calling the {@link #toTime(Instant)} method) makes the query to return the record versions associated 
   * to the specified time range.
   *
   * @param key The specified key by the query
   * @param <K> The type of the key
   * @param <V> The type of the value that will be retrieved
   * @throws NullPointerException if @param key is null
   */   

  public static <K, V> MultiVersionedKeyQuery<K, V> withKey(final K key);

  /**
   * Specifies the starting time point for the key query.
   * <p>
   * The key query returns all the records that are still existing in the time range starting from the timestamp {@code fromTime}. There can
   * be records which have been inserted before the {@code fromTime} and are still valid in the query specified time range (the whole time range
   * or even partially). The key query in fact returns all the records that have NOT become tombstone at or after {@code fromTime}.  
   *
   * @param fromTime The starting time point
   * If {@code fromTime} is null, will be considered as negative infinity, ie, no lower bound
   */
  public MultiVersionedKeyQuery<K, V> fromTime(final Instant fromTime);

  /**
   * Specifies the ending time point for the key query.
   * The key query returns all the records that have timestamp <= toTime.
   * 
   * @param toTime The ending time point
   * If @param toTime is null, will be considered as positive infinity, ie, no upper bound
   */
  public MultiVersionedKeyQuery<K, V> toTime(final Instant toTime);

  /**
   * Specifies the order of the returned records by the query as descending by timestamp.
   */
  public MultiVersionedKeyQuery<K, V> withDescendingTimestamps();

  /**
   * Specifies the order of the returned records by the query as ascending by timestamp.
   */
  public MultiVersionedKeyQuery<K, V> withAscendingTimestamps();

   /**
   * The key that was specified for this query.
   * The specified {@code key} of the query.
   */
  public K key();

  /**
   * The starting time point of the query, if specified
   * @return The specified {@code fromTime} of the query. 
   */
  public Optional<Instant> fromTime();

  /**
   * The ending time point of the query, if specified
   * @return The specified {@code toTime} of the query. 
   */
  public Optional<Instant> toTime();

  /**
  * The order of the returned records by timestamp. 
  * @return true if the query returns records in ascending order of timestamps
  */
  public boolean isAscending ();
}