/*
 * Copyright © 2016-2025 The LmdbJava Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.lmdbjava;

import java.util.EnumSet;
import java.util.Set;

/** Flags for use when opening a {@link Dbi}. */
public enum DbiFlags implements MaskedFlag, DbiFlagSet {

  /**
   * Use reverse string keys.
   *
   * <p>Keys are strings to be compared in reverse order, from the end of the strings to the
   * beginning. By default, keys are treated as strings and compared from beginning to end.
   */
  MDB_REVERSEKEY(0x02),
  /**
   * Use sorted duplicates.
   *
   * <p>Duplicate keys may be used in the database. Or, from another perspective, keys may have
   * multiple data items, stored in sorted order. By default, keys must be unique and may have only
   * a single data item.
   */
  MDB_DUPSORT(0x04),
  /**
   * Numeric keys in native byte order: either unsigned int or size_t. <strong>The keys must all be
   * of the same size.</strong>
   *
   * <p>This is an optimisation that is available when your keys are 4 or 8 byte unsigned numeric
   * values. There are performance benefits for both ordered and un-ordered puts as compared to not
   * using this flag.
   *
   * <p>When writing the key to the buffer you must write it in native order and subsequently read
   * any keys retrieved from LMDB (via cursor or get method) also using native order.
   *
   * <p>For more information, see <a
   * href="https://github.com/lmdbjava/lmdbjava/wiki/Keys#numeric-keys">Numeric Keys</a> in the
   * LmdbJava wiki.
   */
  MDB_INTEGERKEY(0x08),
  /**
   * With {@link #MDB_DUPSORT}, sorted dup items have fixed size.
   *
   * <p>This flag may only be used in combination with {@link #MDB_DUPSORT}. This option tells the
   * library that the data items for this database are all the same size, which allows further
   * optimizations in storage and retrieval. When all data items are the same size, the {@link
   * SeekOp#MDB_GET_MULTIPLE} and {@link SeekOp#MDB_NEXT_MULTIPLE} cursor operations may be used to
   * retrieve multiple items at once.
   */
  MDB_DUPFIXED(0x10),
  /**
   * With {@link #MDB_DUPSORT}, dups are {@link #MDB_INTEGERKEY}-style integers.
   *
   * <p>This option specifies that duplicate data items are binary integers, similar to {@link
   * #MDB_INTEGERKEY} keys.
   */
  MDB_INTEGERDUP(0x20),
  /**
   * With {@link #MDB_DUPSORT}, use reverse string dups.
   *
   * <p>This option specifies that duplicate data items should be compared as strings in reverse
   * order.
   */
  MDB_REVERSEDUP(0x40),
  /**
   * Create the named database if it doesn't exist.
   *
   * <p>This option is not allowed in a read-only transaction or a read-only environment.
   */
  MDB_CREATE(0x4_0000);

  private final int mask;

  DbiFlags(final int mask) {
    this.mask = mask;
  }

  @Override
  public int getMask() {
    return mask;
  }

  @Override
  public Set<DbiFlags> getFlags() {
    return EnumSet.of(this);
  }

  @Override
  public boolean isSet(final DbiFlags flag) {
    return this == flag;
  }

  @Override
  public int size() {
    return 1;
  }

  @Override
  public boolean isEmpty() {
    return false;
  }

  @Override
  public String toString() {
    return FlagSet.asString(this);
  }
}