/**
    * Copyright (c) 2012-2017, s3auth.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 s3auth.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.s3auth.hosts;
  
  import com.jcabi.aspects.Immutable;
  import com.jcabi.aspects.Loggable;
  import com.jcabi.jdbc.JdbcSession;
  import com.jcabi.jdbc.Outcome;
  import java.io.File;
  import java.io.IOException;
  import java.sql.Connection;
  import java.sql.ResultSet;
  import java.sql.SQLException;
  import java.sql.Statement;
  import java.util.HashMap;
  import java.util.Map;
  import java.util.Properties;
  import lombok.EqualsAndHashCode;
  import org.h2.Driver;
  
  /**
   * Storage of {@link Stats} per domain with H2 Database.
   *
   * @author Carlos Miranda (miranda.cma@gmail.com)
   * @version $Id: ddaa83d1fff1c1b2db9310b1e08741bfacd822ea $
   * @checkstyle ClassDataAbstractionCouplingCheck (500 lines)
   */
  @Immutable
  @EqualsAndHashCode(of = "jdbc")
  @Loggable(Loggable.DEBUG)
  final class H2DomainStatsData implements DomainStatsData {
      /**
       * Create Table statement.
       */
      private static final String CREATE = new StringBuilder("CREATE TABLE ")
          .append("IF NOT EXISTS DOMAIN_STATS( ")
          .append("ID INT IDENTITY,")
          .append("DOMAIN VARCHAR(255),")
          .append("BYTES INT,")
          .append("CREATE_TIME TIMESTAMP")
          .append(" )").toString();
  
      /**
       * Insert statement.
       */
      private static final String INSERT = new StringBuilder("INSERT INTO ")
          .append("DOMAIN_STATS (DOMAIN, BYTES, CREATE_TIME) ")
          .append("values (?, ?, CURRENT_TIMESTAMP())").toString();
  
      /**
       * Outcome for obtaining a single Stats per domain.
       */
      private static final Outcome<Stats> STATS = new Outcome<Stats>() {
          @Override
          public Stats handle(final ResultSet rset, final Statement stmt)
              throws SQLException {
              rset.next();
              return new Stats.Simple(rset.getLong(1));
          }
      };
  
      /**
       * Outcome for obtaining a single Stats for all domains.
       */
      private static final Outcome<Map<String, Stats>> STATS_ALL =
          new Outcome<Map<String, Stats>>() {
              @Override
              @SuppressWarnings("PMD.UseConcurrentHashMap")
              public Map<String, Stats> handle(final ResultSet rset,
                  final Statement stmt) throws SQLException {
                  final Map<String, Stats> stats = new HashMap<String, Stats>();
                  while (rset.next()) {
                     stats.put(
                         rset.getString(1), new Stats.Simple(rset.getLong(2))
                     );
                 }
                 return stats;
             }
         };
 
     /**
      * The JDBC URL.
      */
     private final transient String jdbc;
 
     /**
      * Public ctor.
      * @throws IOException If an IO Exception occurs.
      */
     H2DomainStatsData() throws IOException {
         this(new File("s3auth-domainStats"));
     }
 
     /**
      * Public ctor.
      * @param file The file pointing to the database to use.
      * @throws IOException If an IO Exception occurs.
      */
     H2DomainStatsData(final File file) throws IOException {
         this.jdbc = String.format("jdbc:h2:file:%s", file.getAbsolutePath());
         try {
             new JdbcSession(this.connection()).sql(CREATE).execute();
         } catch (final SQLException ex) {
             throw new IOException(ex);
         }
     }
 
     @Override
     public void put(final String domain, final Stats stats) throws IOException {
         try {
             new JdbcSession(this.connection())
                 .sql(INSERT)
                 .set(domain)
                 .set(stats.bytesTransferred())
                 .execute();
         } catch (final SQLException ex) {
             throw new IOException(ex);
         }
     }
 
     @Override
     public Stats get(final String domain) throws IOException {
         try {
             final JdbcSession session = new JdbcSession(this.connection())
                 .autocommit(false);
             // @checkstyle LineLength (2 lines)
             final Stats result = session
                 .sql("SELECT SUM(BYTES) FROM DOMAIN_STATS WHERE DOMAIN = ? FOR UPDATE")
                 .set(domain)
                 .select(STATS);
             session.sql("DELETE FROM DOMAIN_STATS WHERE DOMAIN = ?")
                 .set(domain)
                 .execute()
                 .commit();
             return result;
         } catch (final SQLException ex) {
             throw new IOException(ex);
         }
     }
 
     @Override
     @SuppressWarnings("PMD.UseConcurrentHashMap")
     public Map<String, Stats> all() throws IOException {
         try {
             final JdbcSession session = new JdbcSession(this.connection())
                 .autocommit(false);
             // @checkstyle LineLength (2 lines)
             final Map<String, Stats> result = session
                 .sql("SELECT DOMAIN, SUM(BYTES) FROM DOMAIN_STATS GROUP BY DOMAIN FOR UPDATE")
                 .select(STATS_ALL);
             session.sql("DELETE FROM DOMAIN_STATS").execute().commit();
             return result;
         } catch (final SQLException ex) {
             throw new IOException(ex);
         }
     }
 
     /**
      * Make data source.
      * @return Data source for JDBC
      * @throws SQLException If it fails
      */
     private Connection connection() throws SQLException {
         return new Driver().connect(this.jdbc, new Properties());
     }
 }