/**
    * Copyright (c) 2014, stateful.co
    * All rights reserved.
    *
    * Redistribution and use in source and binary forms, with or without
    * modification, are permitted provided that the following conditions
    * are met: 1) Redistributions of source code must retain the above
    * copyright notice, this list of conditions and the following
    * disclaimer. 2) Redistributions in binary form must reproduce the above
   * copyright notice, this list of conditions and the following
   * disclaimer in the documentation and/or other materials provided
   * with the distribution. 3) Neither the name of the stateful.co nor
   * the names of its contributors may be used to endorse or promote
   * products derived from this software without specific prior written
   * permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT
   * NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
   * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
   * THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
   * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
   * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
   * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
   * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
   * OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  package co.stateful.core;
  
  import co.stateful.spi.Counter;
  import co.stateful.spi.Counters;
  import com.amazonaws.services.dynamodbv2.model.AttributeValue;
  import com.google.common.base.Function;
  import com.google.common.base.Predicates;
  import com.google.common.collect.Iterables;
  import com.google.common.collect.Iterators;
  import com.jcabi.aspects.Cacheable;
  import com.jcabi.aspects.Immutable;
  import com.jcabi.aspects.Loggable;
  import com.jcabi.dynamo.Attributes;
  import com.jcabi.dynamo.Conditions;
  import com.jcabi.dynamo.Item;
  import com.jcabi.dynamo.QueryValve;
  import com.jcabi.dynamo.Table;
  import com.jcabi.urn.URN;
  import java.io.IOException;
  import java.util.concurrent.TimeUnit;
  import lombok.EqualsAndHashCode;
  import lombok.ToString;
  
  /**
   * Counters in DynamoDB.
   *
   * @author Yegor Bugayenko (yegor@tpc2.com)
   * @version $Id$
   */
  @Immutable
  @ToString
  @EqualsAndHashCode(of = "owner")
  @Loggable(Loggable.DEBUG)
  final class DyCounters implements Counters {
  
      /**
       * Table name.
       */
      public static final String TBL = "counters";
  
      /**
       * Hash.
       */
      public static final String HASH = "urn";
  
      /**
       * Range.
       */
      public static final String RANGE = "name";
  
      /**
       * Value attribute.
       */
      public static final String ATTR_VALUE = "value";
  
      /**
       * Dynamo table.
       */
      private final transient Table table;
  
      /**
       * Name of the user.
       */
      private final transient URN owner;
  
      /**
       * Ctor.
       * @param tbl Dynamo table
       * @param urn Owner of them
       */
     DyCounters(final Table tbl, final URN urn) {
         this.table = tbl;
         this.owner = urn;
     }
 
     @Override
     @Cacheable.FlushAfter
     public void create(final String name) throws IOException {
         this.table.put(
             new Attributes()
                 .with(DyCounters.HASH, this.owner)
                 .with(DyCounters.RANGE, name)
                 .with(DyCounters.ATTR_VALUE, new AttributeValue().withN("0"))
         );
     }
 
     @Override
     @Cacheable.FlushAfter
     public void delete(final String name) {
         Iterators.removeIf(
             this.table.frame()
                 .through(new QueryValve().withLimit(1))
                 .where(DyCounters.HASH, Conditions.equalTo(this.owner))
                 .where(DyCounters.RANGE, Conditions.equalTo(name))
                 .iterator(),
             Predicates.alwaysTrue()
         );
     }
 
     @Override
     @Cacheable(lifetime = 1, unit = TimeUnit.HOURS)
     public Counter get(final String name) {
         return new DyCounter(
             this.table.frame()
                 .through(new QueryValve().withLimit(1))
                 .where(DyCounters.HASH, Conditions.equalTo(this.owner))
                 .where(DyCounters.RANGE, Conditions.equalTo(name))
                 .iterator()
                 .next()
         );
     }
 
     @Override
     @Cacheable(lifetime = 1, unit = TimeUnit.HOURS)
     public Iterable<String> names() {
         return Iterables.transform(
             this.table.frame()
                 .through(new QueryValve())
                 .where(DyCounters.HASH, Conditions.equalTo(this.owner)),
             new Function<Item, String>() {
                 @Override
                 public String apply(final Item item) {
                     try {
                         return item.get(DyCounters.RANGE).getS();
                     } catch (final IOException ex) {
                         throw new IllegalStateException(ex);
                     }
                 }
             }
         );
     }
 }