package org.lsst.ccs.plugin.jas3.trending.timeselection;
   
   import java.text.ParseException;
   import java.text.SimpleDateFormat;
   import java.util.Comparator;
   import java.util.Date;
   
   /**
    * Time window for use by trending plots.
   *
   * @author turri
   */
  public class TimeSelection {
      
  // -- Public fields : ----------------------------------------------------------
      
      static public final String DATE_PATTERN = "MM/dd/yyyy HH:mm:ss";
      static public final SimpleDateFormat DATE_FORMAT = new SimpleDateFormat(DATE_PATTERN);
      static private final String DELIMITER_RE = "\\$";
      static private final String DELIMITER = "$";
      
      /** Time window name. */
      public String name;
      /** String that defines time window start. */
      public String lowerEdgeString;
      /** String that defines time window end. */
      public String upperEdgeString;
      
  // -- Private parts : ----------------------------------------------------------
      
      private boolean persist; // true if this time window should be persisted between sessions
      private long lastUsed; // time when this window was last selected
      
  // -- Construction : -----------------------------------------------------------
      
      public TimeSelection(String name, String start, String end, boolean persistent) {
          this.name = name;
          lowerEdgeString = start;
          upperEdgeString = end;
          persist = persistent;
          lastUsed = System.currentTimeMillis();
      }
      
  // -- Setters and getters : ----------------------------------------------------
      
      /** Returns the current value of this window start time in milliseconds. */
      public long getLowerEdge() {
          return getEdge(lowerEdgeString);
      }
      
      /** Returns the current value of this window end time in milliseconds. */
      public long getUpperEdge() {
          return getEdge(upperEdgeString);
      }
      
      private long getEdge(String edgeString) {
          try {
              Date d = DATE_FORMAT.parse(edgeString);
              return d.getTime();
          } catch (ParseException x) {
          }
          try {
              return (long)(1000*TimeSelectionUtils.getSecondsForString(edgeString));        
          } catch (Throwable t) {
              throw new RuntimeException(t);
          }
      }
      
      /** Returns <tt>true</tt> if this time window should be persisted between sessions. */
      public boolean isPersistent() {
          return persist;
      }
      
      /** Sets the flag that indicate whether or not this time window should be persisted between sessions. */
      public void setPersistent(boolean persistent) {
          persist = persistent;
      }
      
      /** Returns the time in milliseconds when this time window was last selected. */
      public long getLastUseTime() {
          return lastUsed;
      }
      
      /** Sets the time when this time window was last selected to the current system time. */
      public void touch() {
          lastUsed = System.currentTimeMillis();
      }
  
      /** Returns user-readable string representation of this time window. */
      @Override
      public String toString() {
          return name +" : "+ lowerEdgeString +" through "+ upperEdgeString;
      }
      
      /** Returns string representation of this time window used for saving it in application properties. */
      public String toCompressedString() {
          return name + DELIMITER + lowerEdgeString + DELIMITER + upperEdgeString;
      }
      
     /** Parses string representation of this time window used for saving it in application properties. */
     static public TimeSelection parseCompressedString(String s) {
         String[] tokens = s.split(DELIMITER_RE);
         try {
             TimeSelection ts = new TimeSelection(tokens[0], tokens[1], tokens[2], true);
             ts.getLowerEdge();
             ts.getUpperEdge();
             return ts;
         } catch (RuntimeException x) {
             throw new IllegalArgumentException(x);
         }
     
     }
     
 // -- Comparators : ------------------------------------------------------------
     
     /** Returns comparator that compares time windows by names. */
     static public Comparator<TimeSelection> compareByName() {
         return new Comparator<TimeSelection>() {
             public int compare(TimeSelection o1, TimeSelection o2) {
                 return o1.name.compareTo(o2.name);
             }
         };
     }
     
     /** Returns comparator that compares time windows by last use times, most recent first. */
     static public Comparator compareByTime() {
         return new Comparator() {
             public int compare(Object o1, Object o2) {
                 return (int) Math.signum(((TimeSelection)o2).getLastUseTime() - ((TimeSelection)o1).getLastUseTime());
             }
         };
     }
     
     
 }