/**

  * 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.security.SecureRandom;

 import java.util.Collection;

 import java.util.Random;

 import org.xembly.Directive;

 import org.xembly.Directives;

 /**

  * Start containers.

  *

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

  * @version $Id$

  * @since 0.1

  * @checkstyle MultipleStringLiteralsCheck (500 lines)

  */

 @Immutable

 public final class StartDocker implements Agent {

     /**

      * Random.

      */

     private static final Random RND = new SecureRandom();

     /**

      * Script to use.

      */

     private final transient Script script;

     /**

      * Ctor.

      * @throws IOException If fails

      */

     public StartDocker() throws IOException {

         this(

             new Script.Default(

                 StartDocker.class.getResource("start-docker.sh")

             )

         );

     }

     /**

      * Ctor.

      * @param spt Script.

      */

     public StartDocker(final Script spt) {

         this.script = spt;

     }

     @Override

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

         final Collection<XML> images = deck.nodes(

             "/deck/images/image[not(@waste)]"

         );

         final Directives dirs = new Directives()

             .xpath("/deck").addIf("containers");

         for (final XML image : images) {

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

             final Collection<String> tanks = deck.xpath(

                 String.format(

                     // @checkstyle LineLength (1 line)

                     "/deck/tanks/tank[not(host=/deck/containers/container[not(@waste) and image='%s']/host)]/host/text()",

                     img

                 )

             );

             for (final String tank : tanks) {

                 Logger.info(

                     this,

                     "There are no Docker containers at %s for image %s yet",

                     tank, img

                 );

                 final String cid = this.start(img, tank);

                 dirs.xpath("/deck/containers").add("container")

                     .add("name").set(cid).up()

                     .add("image").set(img).up()

                     .add("host").set(tank).up()

                     .attr("state", "unknown")

                     .attr("type", image.xpath("@type").get(0));

             }

         }

         return dirs;

     }

     /**

      * Run docker in this tank.

      * @param image Docker image name

      * @param host Host name of the tank

      * @return Docker container name

      * @throws IOException If fails

      */

     private String start(final String image, final String host)

         throws IOException {

         final String name = String.format("%08x", StartDocker.RND.nextInt());

         final long start = System.currentTimeMillis();

         this.script.exec(

             host,

             new ArrayMap<String, String>()

                 .with("image", image)

                 .with("container", name)

         );

         Logger.info(

             this, "Docker container %s started at %s in %[ms]s",

             name, host,

             System.currentTimeMillis() - start

         );

         return name;

     }

 }