/**

  * Copyright (c) 2014-2015, Thindeck.com

  * 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 thindeck.com 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 com.thindeck.dynamo;

 import com.amazonaws.services.dynamodbv2.model.Select;

 import com.google.common.collect.Iterables;

 import com.jcabi.aspects.Immutable;

 import com.jcabi.dynamo.AttributeUpdates;

 import com.jcabi.dynamo.Item;

 import com.jcabi.dynamo.QueryValve;

 import com.jcabi.dynamo.Region;

 import com.jcabi.xml.StrictXML;

 import com.jcabi.xml.XML;

 import com.jcabi.xml.XMLDocument;

 import com.jcabi.xml.XSL;

 import com.jcabi.xml.XSLDocument;

 import com.thindeck.api.Agent;

 import com.thindeck.api.Deck;

 import com.thindeck.api.Events;

 import java.io.IOException;

 import java.util.Iterator;

 import lombok.EqualsAndHashCode;

 import lombok.ToString;

 import org.xembly.Directive;

 import org.xembly.Xembler;

 /**

  * Dynamo implementation of {@link com.thindeck.api.Deck}.

  *

  * @author Krzysztof Krason (Krzysztof.Krason@gmail.com)

  * @author Yegor Bugayenko (yegor@teamed.io)

  * @version $Id$

  */

 @ToString

 @Immutable

 @EqualsAndHashCode(of = { "region", "user", "deck" })

 final class DyDeck implements Deck {

     /**

      * Table name.

      */

     public static final String TBL = "decks";

     /**

      * Name of the deck owner.

      */

     public static final String HASH = "user";

     /**

      * Unique name of the deck, for that user.

      */

     public static final String RANGE = "name";

     /**

      * When updated.

      */

     public static final String ATTR_UPDATED = "updated";

     /**

      * Deck.

      */

     public static final String ATTR_MEMO = "deck";

     /**

      * Clean-up XSL.

      */

     private static final XSL CLEANUP = XSLDocument.make(

         DyDeck.class.getResourceAsStream("cleanup.xsl")

     );

     /**

      * Region.

      */

     private final transient Region region;

     /**

      * Name of the owner.

      */

     private final transient String user;

     /**

      * Name of the deck.

      */

     private final transient String deck;

     /**

      * Ctor.

      * @param reg Region

      * @param owner Name of the owner

      * @param name Deck name

      */

     DyDeck(final Region reg, final String owner, final String name) {

         this.region = reg;

         this.user = owner;

         this.deck = name;

     }

     @Override

     public String name() {

         return this.deck;

     }

     @Override

     public void exec(final Agent agent) throws IOException {

         final String text = this.item().get(DyDeck.ATTR_MEMO).getS();

         final XML xml = new StrictXML(

             Deck.UPGRADE.transform(

                 DyDeck.CLEANUP.transform(new XMLDocument(text))

             ),

             Deck.SCHEMA

         );

         final Iterable<Directive> dirs = agent.exec(xml);

         if (!Iterables.isEmpty(dirs)) {

             final String update = new StrictXML(

                 new XMLDocument(

                     new Xembler(dirs).applyQuietly(xml.node())

                 ),

                 Deck.SCHEMA

             ).toString();

             if (!text.equals(update)) {

                 this.item().put(

                     new AttributeUpdates().with(

                         DyDeck.ATTR_MEMO,

                         update

                     )

                 );

             }

         }

     }

     @Override

     public Events events() {

         return new DyEvents(this.region, this.name());

     }

     /**

      * Item.

      * @return Item

      */

     private Item item() {

         final Iterator<Item> items = this.region

             .table(DyDeck.TBL)

             .frame()

             .through(

                 new QueryValve()

                     .withSelect(Select.ALL_ATTRIBUTES)

                     .withLimit(1)

             )

             .where(DyDeck.HASH, this.user)

             .where(DyDeck.RANGE, this.deck)

             .iterator();

         if (!items.hasNext()) {

             throw new IllegalArgumentException(

                 String.format("deck '%s' not found", this.deck)

             );

         }

         return items.next();

     }

 }