/**

  * 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.agents;

 import com.jcabi.aspects.Immutable;

 import com.jcabi.immutable.ArrayMap;

 import com.jcabi.log.Logger;

 import com.jcabi.xml.XML;

 import com.thindeck.api.Agent;

 import java.io.IOException;

 import java.util.Collection;

 import org.xembly.Directive;

 import org.xembly.Directives;

 /**

  * Check docker container existence and remove if absent.

  *

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

  * @version $Id$

  * @since 0.5

  * @checkstyle MultipleStringLiteralsCheck (500 lines)

  */

 @Immutable

 public final class PingContainers implements Agent {

     /**

      * Script to use.

      */

     private final transient Script script;

     /**

      * Ctor.

      * @throws IOException If fails

      */

     public PingContainers() throws IOException {

         this(

             new Script.Default(

                 PingContainers.class.getResource("ping-container.sh")

             )

         );

     }

     /**

      * Ctor.

      * @param spt Script.

      */

     public PingContainers(final Script spt) {

         this.script = spt;

     }

     @Override

     public Iterable<Directive> exec(final XML deck) throws IOException {

         final Collection<XML> containers = deck.nodes(

             "/deck/containers/container"

         );

         final Directives dirs = new Directives();

         for (final XML ctr : containers) {

             final String name = ctr.xpath("name/text()").get(0);

             final String tank = ctr.xpath("host/text()").get(0);

             if (!this.exists(name, tank)) {

                 dirs.xpath(

                     String.format("/deck/containers/container[name='%s']", name)

                 ).remove();

             }

         }

         return dirs;

     }

     /**

      * Check docker container existence.

      * @param name Docker container name

      * @param host Host name of the tank

      * @return TRUE if exists

      * @throws IOException If fails

      */

     private boolean exists(final String name, final String host)

         throws IOException {

         final String stdout = this.script.exec(

             host,

             new ArrayMap<String, String>().with("container", name)

         );

         final boolean exists = !stdout.contains("DEAD");

         if (!exists) {

             Logger.error(

                 this, "Docker container %s is absent at %s",

                 name, host

             );

         }

         return exists;

     }

 }