package au.gov.amsa.ais.message;
   
   import java.util.Calendar;
   import java.util.TimeZone;
   
   import com.google.common.annotations.VisibleForTesting;
   
   import au.gov.amsa.ais.AisExtractor;
   import au.gov.amsa.ais.AisExtractorFactory;
  import au.gov.amsa.ais.AisMessage;
  import au.gov.amsa.ais.AisMessageType;
  import au.gov.amsa.ais.HasMmsi;
  import au.gov.amsa.ais.Util;
  
  /**
   * An AIS base station message (message id 4).
   * 
   * @author dxm
   * 
   */
  public class AisBaseStation implements AisMessage, HasMmsi {
      @VisibleForTesting
      static final int MIN_LENGTH = 168;
      private final AisExtractor extractor;
      private final String source;
      private final int messageId;
  
      /**
       * Constructor.
       * 
       * @param message
       */
      public AisBaseStation(String message, int padBits) {
          this(message, null, padBits);
      }
  
      /**
       * Constructor.
       * 
       * @param message
       *            encapsulated message taken from nmea line.
       */
      public AisBaseStation(String message, String source, int padBits) {
          this(Util.getAisExtractorFactory(), message, source, padBits);
      }
  
      /**
       * Constructor.
       * 
       * @param factory
       * @param message
       * @param time
       * @param source
       */
      public AisBaseStation(AisExtractorFactory factory, String message, String source, int padBits) {
          this.source = source;
          this.extractor = factory.create(message, MIN_LENGTH, padBits);
          messageId = extractor.getMessageId();
          Util.checkMessageId(messageId, AisMessageType.BASE_STATION_REPORT);
          Util.checkLatLong(getLatitude(), getLongitude());
  
      }
  
      @Override
      public int getMessageId() {
          return messageId;
      }
  
      public int getRepeatIndicator() {
          return extractor.getValue(6, 8);
      }
  
      @Override
      public int getMmsi() {
          return extractor.getValue(8, 38);
      }
  
      public int getYear() {
          return extractor.getValue(38, 52);
      }
  
      public int getMonth() {
          return extractor.getValue(52, 56);
      }
  
      public int getDay() {
          return extractor.getValue(56, 61);
      }
  
      public int getHour() {
          return extractor.getValue(61, 66);
      }
  
      public int getMinute() {
          return extractor.getValue(66, 72);
      }
  
      public int getSecond() {
          return extractor.getValue(72, 78);
     }
 
     public int getPositionAccuracy() {
         return extractor.getValue(78, 79);
     }
 
     private long calculateTimestamp() {
         Calendar cal = Calendar.getInstance(TimeZone.getTimeZone("UTC"));
         cal.set(getYear(), getMonth() - 1, getDay(), getHour(), getMinute(), getSecond());
         cal.set(Calendar.MILLISECOND, 0);
         return cal.getTimeInMillis();
     }
 
     public long getTimestamp() {
         return calculateTimestamp();
     }
 
     public double getLatitude() {
         return extractor.getSignedValue(107, 134) / 600000.0;
     }
 
     public double getLongitude() {
         return extractor.getSignedValue(79, 107) / 600000.0;
     }
 
     public int getDeviceType() {
         return extractor.getValue(134, 138);
     }
 
     @Override
     public String getSource() {
         return source;
     }
 
     @Override
     public String toString() {
         StringBuilder builder = new StringBuilder();
         builder.append("AisBaseStation [source=");
         builder.append(source);
         builder.append(", year=");
         builder.append(getYear());
         builder.append(", messageId=");
         builder.append(messageId);
         builder.append(", repeatIndicator=");
         builder.append(getRepeatIndicator());
         builder.append(", mmsi=");
         builder.append(getMmsi());
         builder.append(", month=");
         builder.append(getMonth());
         builder.append(", day=");
         builder.append(getDay());
         builder.append(", hour=");
         builder.append(getHour());
         builder.append(", minute=");
         builder.append(getMinute());
         builder.append(", second=");
         builder.append(getSecond());
         builder.append(", positionAccuracy=");
         builder.append(getPositionAccuracy());
         builder.append(", timestamp=");
         builder.append(getTimestamp());
         builder.append(", latitude=");
         builder.append(getLatitude());
         builder.append(", longitude=");
         builder.append(getLongitude());
         builder.append(", deviceType=");
         builder.append(getDeviceType());
         builder.append("]");
         return builder.toString();
     }
 
 }