/**

  * Copyright (c) 2012-2014, jcabi.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 jcabi.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.jcabi.heroku.maven.plugin;

 import com.jcabi.aspects.Immutable;

 import com.jcabi.aspects.RetryOnFailure;

 import com.jcabi.log.Logger;

 import com.jcabi.log.VerboseProcess;

 import java.io.File;

 import java.io.IOException;

 import java.util.ArrayList;

 import java.util.List;

 import javax.validation.constraints.NotNull;

 import lombok.EqualsAndHashCode;

 import lombok.ToString;

 import org.apache.commons.io.FileUtils;

 import org.apache.commons.lang3.StringUtils;

 /**

  * Git engine.

  *

  * @author Yegor Bugayenko (yegor@tpc2.com)

  * @version $Id$

  * @since 0.4

  * @checkstyle ClassDataAbstractionCoupling (500 lines)

  */

 @Immutable

 @ToString

 @EqualsAndHashCode(of = "script")

 final class Git {

     /**

      * Permissions to set to SSH key file.

      */

     @SuppressWarnings("PMD.AvoidUsingOctalValues")

     private static final int PERMS = 0600;

     /**

      * Default SSH location.

      */

     private static final String SSH = "/usr/bin/ssh";

     /**

      * Location of shell script.

      */

     private final transient String script;

     /**

      * Public ctor.

      * @param key Location of SSH key

      * @param temp Temp directory

      * @throws IOException If some error inside

      */

     public Git(@NotNull final File key,

         @NotNull final File temp) throws IOException {

         if (!new File(Git.SSH).exists()) {

             throw new IllegalStateException(

                 String.format("SSH is not installed at '%s'", Git.SSH)

             );

         }

         final File kfile = new File(temp, "heroku.pem");

         FileUtils.copyFile(key, kfile);

         this.chmod(kfile, Git.PERMS);

         final File file = new File(temp, "git-ssh.sh");

         this.script = file.getAbsolutePath();

         FileUtils.writeStringToFile(

             new File(this.script),

             String.format(

                 // @checkstyle LineLength (1 line)

                 "set -x && %s -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -i '%s' $@",

                 Git.SSH,

                 kfile.getAbsolutePath()

             )

         );

         file.setExecutable(true);

     }

     /**

      * Execute git with these arguments.

      * @param dir In which directory to run it

      * @param args Arguments to pass to it

      * @return Stdout

      * @checkstyle MagicNumber (2 lines)

      */

     @RetryOnFailure(delay = 3000, attempts = 2)

     public String exec(@NotNull final File dir, @NotNull final String... args) {

         final List<String> commands = new ArrayList<String>(args.length + 1);

         commands.add("git");

         for (final String arg : args) {

             commands.add(arg);

         }

         Logger.info(this, "%s:...", StringUtils.join(commands, " "));

         final ProcessBuilder builder = new ProcessBuilder(commands);

         builder.directory(dir);

         builder.environment().put("GIT_SSH", this.script);

         return new VerboseProcess(builder).stdout();

     }

     /**

      * Change file permissions.

      * @param file The file to change

      * @param mode Permissions to set

      * @throws IOException If some error inside

      * @see http://stackoverflow.com/questions/664432

      * @see http://stackoverflow.com/questions/1556119

      */

     private void chmod(final File file, final int mode) throws IOException {

         new VerboseProcess(

             new ProcessBuilder(

                 "chmod",

                 String.format("%04o", mode),

                 file.getAbsolutePath()

             )

         ).stdout();

         Logger.debug(

             this,

             "chmod(%s, %3o): succeeded",

             file,

             mode

         );

     }

 }