package org.infinispan.xsite.statetransfer;

import java.util.Collection;
import java.util.HashSet;
import java.util.Set;

import org.infinispan.remoting.transport.Address;
import org.infinispan.util.logging.Log;
import org.infinispan.util.logging.LogFactory;

/**
 * It collects the acknowledgements sent from local site member to signal the ending of the state sent.
 *
 * @author Pedro Ruivo
 * @since 7.0
 */
public final class XSiteStateTransferCollector {

   private static final Log log = LogFactory.getLog(XSiteStateTransferCollector.class);
   private static final boolean trace = log.isTraceEnabled();
   private final Set<Address> collector;
   private boolean statusOk;

   public XSiteStateTransferCollector(Collection<Address> confirmationPending) {
      if (confirmationPending == null) {
         throw new NullPointerException("Pending confirmations must be non-null.");
      } else if (confirmationPending.isEmpty()) {
         throw new IllegalArgumentException("Pending confirmations must be non-empty.");
      }
      this.collector = new HashSet<>(confirmationPending);
      if (log.isDebugEnabled()) {
         log.debugf("Created collector with %s pending!", collector);
      }
      this.statusOk = true;
   }

   public boolean confirmStateTransfer(Address node, boolean statusOk) {
      synchronized (collector) {
         if (trace) {
            log.tracef("Remove %s from %s. Status=%s", node, collector, statusOk);
         }
         if (this.statusOk && !statusOk) {
            this.statusOk = false;
         }
         return collector.remove(node) && collector.isEmpty();
      }
   }

   public boolean isStatusOk() {
      synchronized (collector) {
         return statusOk;
      }
   }

   public boolean updateMembers(Collection<Address> members) {
      synchronized (collector) {
         if (trace) {
            log.tracef("Retain %s from %s", members, collector);
         }
         return collector.retainAll(members) && collector.isEmpty();
      }
   }

   @Override
   public boolean equals(Object o) {
      if (this == o) return true;
      if (o == null || getClass() != o.getClass()) return false;

      XSiteStateTransferCollector that = (XSiteStateTransferCollector) o;

      return collector.equals(that.collector);
   }

   @Override
   public int hashCode() {
      return collector.hashCode();
   }

   @Override
   public String toString() {
      return "XSiteStateTransferCollector{" +
            "collector=" + collector +
            '}';
   }
}