package com.github.triceo.splitlog;
   
   import java.util.HashSet;
   
   import org.apache.commons.collections4.BidiMap;
   import org.apache.commons.collections4.bidimap.DualHashBidiMap;
   
   import com.github.triceo.splitlog.api.Message;
   import com.github.triceo.splitlog.api.MessageDeliveryStatus;
  import com.github.triceo.splitlog.api.MessageMeasure;
  import com.github.triceo.splitlog.api.MessageMetric;
  import com.github.triceo.splitlog.api.MessageMetricProducer;
  import com.github.triceo.splitlog.api.MessageSource;
  
  final class MessageMetricManager implements MessageMetricProducer, MessageListener<MessageSource> {
  
      private final BidiMap<String, DefaultMessageMetric<? extends Number>> metrics = new DualHashBidiMap<String, DefaultMessageMetric<? extends Number>>();
  
      @Override
      public synchronized MessageMetric<? extends Number> getMetric(final String id) {
          return this.metrics.get(id);
      }
  
      @Override
      public synchronized String getMetricId(final MessageMetric<? extends Number> measure) {
          return this.metrics.getKey(measure);
      }
  
      @Override
      public boolean isMeasuring(final MessageMetric<? extends Number> metric) {
          return this.metrics.containsValue(metric);
      }
  
      @Override
      public boolean isMeasuring(final String id) {
          return this.metrics.containsKey(id);
      }
  
      @Override
      public synchronized void messageReceived(final Message msg, final MessageDeliveryStatus status,
          final MessageSource source) {
          for (final DefaultMessageMetric<? extends Number> metric : this.metrics.values()) {
              metric.messageReceived(msg, status, source);
          }
      }
  
      @Override
      public synchronized <T extends Number> MessageMetric<T> startMeasuring(final MessageMeasure<T> measure,
          final String id) {
          if (measure == null) {
              throw new IllegalArgumentException("Measure may not be null.");
          } else if (id == null) {
              throw new IllegalArgumentException("ID may not be null.");
          } else if (this.metrics.containsKey(id)) {
              throw new IllegalArgumentException("Duplicate ID:" + id);
          }
          final DefaultMessageMetric<T> metric = new DefaultMessageMetric<T>(measure);
          this.metrics.put(id, metric);
          return metric;
      }
  
      @Override
      public synchronized boolean stopMeasuring(final MessageMetric<? extends Number> measure) {
          final String removed = this.metrics.removeValue(measure);
          return (removed != null);
      }
  
      @Override
      public synchronized boolean stopMeasuring(final String id) {
          final MessageMetric<? extends Number> removed = this.metrics.remove(id);
          return (removed != null);
      }
  
      /**
       * Will immediately terminate every measurement that hasn't yet been
       * terminated.
       */
      public synchronized void terminateMeasuring() {
          for (final String metricId : new HashSet<String>(this.metrics.keySet())) {
              this.stopMeasuring(metricId);
          }
      }
  
  }