/*
 * JBoss, Home of Professional Open Source
 * Copyright 2009 Red Hat Inc. and/or its affiliates and other
 * contributors as indicated by the @author tags. All rights reserved.
 * See the copyright.txt in the distribution for a full listing of
 * individual contributors.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.infinispan.commands.write;

import org.infinispan.commands.Visitor;
import org.infinispan.container.entries.CacheEntry;
import org.infinispan.container.entries.MVCCEntry;
import org.infinispan.context.Flag;
import org.infinispan.context.InvocationContext;
import org.infinispan.lifecycle.ComponentStatus;
import org.infinispan.notifications.cachelistener.CacheNotifier;
import org.infinispan.util.logging.Log;
import org.infinispan.util.logging.LogFactory;

import java.util.Set;


/**
 * @author Mircea.Markus@jboss.com
 * @author <a href="mailto:galder.zamarreno@jboss.com">Galder Zamarreno</a>
 * @since 4.0
 */
public class RemoveCommand extends AbstractDataWriteCommand {
   private static final Log log = LogFactory.getLog(RemoveCommand.class);
   public static final byte COMMAND_ID = 10;
   protected CacheNotifier notifier;
   boolean successful = true;
   boolean nonExistent = false;

   /**
    * When not null, value indicates that the entry should only be removed if the key is mapped to this value. By the
    * time the RemoveCommand needs to be marshalled, the condition must have been true locally already, so there's no
    * need to marshall the value. *
    */
   protected transient Object value;

   public RemoveCommand(Object key, Object value, CacheNotifier notifier, Set<Flag> flags) {
      super(key, flags);
      this.value = value;
      this.notifier = notifier;
   }

   public void init(CacheNotifier notifier) {
      this.notifier = notifier;
   }

   public RemoveCommand() {
   }

   @Override
   public Object acceptVisitor(InvocationContext ctx, Visitor visitor) throws Throwable {
      return visitor.visitRemoveCommand(ctx, this);
   }

   @Override
   public Object perform(InvocationContext ctx) throws Throwable {
      CacheEntry e = ctx.lookupEntry(key);
      if (e == null || e.isNull()) {
         nonExistent = true;
         log.trace("Nothing to remove since the entry is null or we have a null entry");
         if (value == null) {
            return null;
         } else {
            successful = false;
            return false;
         }
      }

      if (!(e instanceof MVCCEntry)) ctx.putLookedUpEntry(key, null);

      if (value != null && e.getValue() != null && !e.getValue().equals(value)) {
         successful = false;
         return false;
      }

      final Object removedValue = e.getValue();
      notify(ctx, removedValue, true);
      e.setRemoved(true);
      e.setValid(false);


      // Eviction has no notion of pre/post event since 4.2.0.ALPHA4.
      // EvictionManagerImpl.onEntryEviction() triggers both pre and post events
      // with non-null values, so we should do the same here as an ugly workaround.
      if (this instanceof EvictCommand) {
         e.setEvicted(true);
         notify(ctx, removedValue, false);
      } else {
         // FIXME: Do we really need to notify with null when a user can be given with more information?
         notify(ctx, null, false);
      }
      return value == null ? removedValue : true;
   }

   protected void notify(InvocationContext ctx, Object value, boolean isPre) {
      notifier.notifyCacheEntryRemoved(key, value, isPre, ctx);
   }

   @Override
   public byte getCommandId() {
      return COMMAND_ID;
   }

   @Override
   public boolean equals(Object o) {
      if (this == o) {
         return true;
      }
      if (!(o instanceof RemoveCommand)) {
         return false;
      }
      if (!super.equals(o)) {
         return false;
      }

      RemoveCommand that = (RemoveCommand) o;

      if (value != null ? !value.equals(that.value) : that.value != null) {
         return false;
      }

      return true;
   }

   @Override
   public int hashCode() {
      int result = super.hashCode();
      result = 31 * result + (value != null ? value.hashCode() : 0);
      return result;
   }


   @Override
   public String toString() {
      return new StringBuilder()
         .append("RemoveCommand{key=")
         .append(key)
         .append(", value=").append(value)
         .append(", flags=").append(flags)
         .append("}")
         .toString();
   }

   @Override
   public boolean isSuccessful() {
      return successful;
   }

   @Override
   public boolean isConditional() {
      return value != null;
   }

   public boolean isNonExistent() {
      return nonExistent;
   }

   @Override
   @SuppressWarnings("unchecked")
   public void setParameters(int commandId, Object[] parameters) {
      if (commandId != COMMAND_ID) throw new IllegalStateException("Invalid method id");
      key = parameters[0];
      flags = (Set<Flag>) parameters[1];
   }

   @Override
   public Object[] getParameters() {
      return new Object[]{key, flags};
   }

   @Override
   public boolean ignoreCommandOnStatus(ComponentStatus status) {
      return false;
   }
}