/*
    * Copyright (C) 2015 Alberto Irurueta Carro (alberto@irurueta.com)
    *
    * Licensed under the Apache License, Version 2.0 (the "License");
    * you may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    *
    *         http://www.apache.org/licenses/LICENSE-2.0
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package com.irurueta.numerical;
  
  import java.lang.ref.SoftReference;
  import java.text.SimpleDateFormat;
  import java.util.Date;
  import java.util.Locale;
  import java.util.Properties;
  import java.util.logging.Level;
  import java.util.logging.Logger;
  
  /**
   * Contains build data of this library.
   */
  public class BuildInfo {
  
      /**
       * This class logger.
       */
      private static final Logger LOGGER = Logger.getLogger(BuildInfo.class.getName());
  
      /**
       * Location of properties file that contains build data.
       * Build data is stored in this file, which is modified each time that
       * compilation is run in the CI server.
       */
      private static final String BUILD_INFO_PROPERTIES = "build-info.properties";
  
      /**
       * Key to obtain build timestamp from properties file.
       */
      private static final String BUILD_TIMESTAMP_KEY = "BUILD_TIMESTAMP";
  
      /**
       * Key to obtain groupID of this library from properties file.
       */
      private static final String GROUP_ID_KEY = "GROUP_ID";
  
      /**
       * Key to obtain artifactId of this library from properties file.
       */
      private static final String ARTIFACT_ID_KEY = "ARTIFACT_ID";
  
      /**
       * Key to obtain version of this library from properties file.
       */
      private static final String VERSION_KEY = "VERSION";
  
      /**
       * Key to obtain build number from properties file.
       */
      private static final String BUILD_NUMBER_KEY = "BUILD_NUMBER";
  
      /**
       * Key to obtain build commit from properties file.
       */
      private static final String COMMIT_KEY = "COMMIT";
  
      /**
       * Key to obtain build branch from properties file.
       */
      private static final String BRANCH_KEY = "BRANCH";
  
      /**
       * Format for build timestamp.
       */
      private static final String TIMESTAMP_FORMAT = "yy-MM-dd HH:mm:ss";
  
      /**
       * Singleton stored in a soft reference (to keep it cached in memory unless
       * memory is claimed).
       */
      private static SoftReference<BuildInfo> reference;
  
      /**
       * Build timestamp.
       */
      private Date buildTimestamp;
  
      /**
       * GroupId of this library.
       */
      private String groupId;
  
      /**
      * ArtifactId of this library.
      */
     private String artifactId;
 
     /**
      * Version of this library.
      */
     private String version;
 
     /**
      * Build number.
      */
     private String buildNumber;
 
     /**
      * Build commit.
      */
     private String commit;
 
     /**
      * Build branch.
      */
     private String branch;
 
     /**
      * Constructor.
      */
     private BuildInfo() {
         // loads properties file data
         try (final var stream = BuildInfo.class.getResourceAsStream(BUILD_INFO_PROPERTIES)) {
             final var props = new Properties();
             props.load(stream);
 
             final var buildTimestampString = props.getProperty(BUILD_TIMESTAMP_KEY);
             final var format = new SimpleDateFormat(TIMESTAMP_FORMAT, Locale.ENGLISH);
             buildTimestamp = format.parse(buildTimestampString);
 
             groupId = props.getProperty(GROUP_ID_KEY);
             artifactId = props.getProperty(ARTIFACT_ID_KEY);
             version = props.getProperty(VERSION_KEY);
             buildNumber = props.getProperty(BUILD_NUMBER_KEY);
             commit = props.getProperty(COMMIT_KEY);
             branch = props.getProperty(BRANCH_KEY);
         } catch (final Exception e) {
             LOGGER.log(Level.WARNING, "Failed to load build info", e);
         }
     }
 
     /**
      * Obtains singleton instance.
      *
      * @return singleton instance.
      */
     public static synchronized BuildInfo getInstance() {
         BuildInfo info;
         if (reference == null || (info = reference.get()) == null) {
             info = new BuildInfo();
             reference = new SoftReference<>(info);
         }
 
         return info;
     }
 
     /**
      * Obtains build timestamp.
      *
      * @return build timestamp.
      */
     public Date getBuildTimestamp() {
         return (Date) buildTimestamp.clone();
     }
 
     /**
      * Obtains groupId of this library.
      *
      * @return groupId of this library.
      */
     public String getGroupId() {
         return groupId;
     }
 
     /**
      * Obtains artifactId of this library.
      *
      * @return artifactId of this library.
      */
     public String getArtifactId() {
         return artifactId;
     }
 
     /**
      * Obtains version of this library.
      *
      * @return version of this library.
      */
     public String getVersion() {
         return version;
     }
 
     /**
      * Obtains build number.
      *
      * @return build number.
      */
     public String getBuildNumber() {
         return buildNumber;
     }
 
     /**
      * Obtains build commit.
      *
      * @return build commit.
      */
     public String getCommit() {
         return commit;
     }
 
     /**
      * Obtains build branch.
      *
      * @return build branch.
      */
     public String getBranch() {
         return branch;
     }
 }