/*
 * ToroDB
 * Copyright © 2014 8Kdata Technology (www.8kdata.com)
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */

package com.torodb.kvdocument.values;

import com.google.common.hash.Hashing;
import com.torodb.kvdocument.types.BinaryType;
import com.torodb.kvdocument.values.utils.NonIoByteSource;

public abstract class KvBinary extends KvValue<KvBinary> {

  private static final long serialVersionUID = -5093890945096588600L;

  /**
   * Returns the ByteSource that contains the binary data.
   *
   * The associated ByteSource <b>shall not</b> throw IO exceptions for
   *
   * @return
   */
  public abstract NonIoByteSource getByteSource();

  public abstract KvBinarySubtype getSubtype();

  /**
   * Returns the category on which the binary is encoded.
   *
   * The category is a 'subsubtype'. Most subtypes are going to accept just one category, but others
   * could can accept some of them. Two different categories of the same subtype represents
   * different encodecs with a common subtype. For example, the subtype
   * {@link KvBinarySubtype#MONGO_USER_DEFINED} have several user defined categories.

 ToroDB is category-agnostic, which means it does not provide any special functionality on
 categories. It just stores the value to be able to return the specify user defined category
 when the KvBinary is retrieved.
   *
   * @return the category on which the binary is encoded.
   */
  public abstract byte getCategory();

  @Override
  public KvBinary getValue() {
    return this;
  }

  @Override
  public Class<? extends KvBinary> getValueClass() {
    return getClass();
  }

  @Override
  public BinaryType getType() {
    return BinaryType.INSTANCE;
  }

  public long size() {
    return getByteSource().size();
  }

  @Override
  public String toString() {
    return "KVBinary[subtype= " + getSubtype() + "(" + getCategory() + "), size= " + size() + "]";
  }

  @Override
  public int hashCode() {
    return Hashing.goodFastHash(32)
        .newHasher()
        .putInt(getSubtype().hashCode())
        .putLong(size())
        .hash()
        .asInt();
  }

  /**
   * Two KvBinary are equal if their subtypes are the same and their contain the same bytes.
   *
   * @param obj
   * @return
   */
  @Override
  public boolean equals(Object obj) {
    if (obj == this) {
      return true;
    }
    if (obj == null) {
      return false;
    }
    if (!(obj instanceof KvBinary)) {
      return false;
    }
    KvBinary other = (KvBinary) obj;
    if (this.getSubtype() != other.getSubtype()) {
      return false;
    }
    return this.getByteSource().contentEquals(other.getByteSource());
  }

  @Override
  public <R, A> R accept(KvValueVisitor<R, A> visitor, A arg) {
    return visitor.visit(this, arg);
  }

  public static enum KvBinarySubtype {
    UNDEFINED,
    MONGO_GENERIC,
    MONGO_FUNCTION,
    MONGO_OLD_BINARY,
    MONGO_OLD_UUID,
    MONGO_UUID,
    MONGO_MD5,
    MONGO_USER_DEFINED
  }
}