/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.exoplatform.services.jcr.impl.core.query;

import org.exoplatform.services.jcr.core.nodetype.NodeTypeData;
import org.exoplatform.services.jcr.core.nodetype.NodeTypeDataManager;
import org.exoplatform.services.jcr.core.nodetype.PropertyDefinitionData;
import org.exoplatform.services.jcr.datamodel.InternalQName;
import org.exoplatform.services.jcr.impl.core.nodetype.NodeTypeManagerListener;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import javax.jcr.PropertyType;

/**
 * The <code>PropertyTypeRegistry</code> keeps track of registered node type
 * definitions and its property types. It provides a fast type lookup for a
 * given property name.
 */
public class PropertyTypeRegistry implements NodeTypeManagerListener
{

   /**
    * Empty <code>TypeMapping</code> array as return value if no type is
    * found
    */
   private static final TypeMapping[] EMPTY = new TypeMapping[0];

   /** The NodeTypeRegistry */
   private final NodeTypeDataManager registry;

   /** Property Name to TypeMapping[] mapping */
   private final Map<InternalQName, TypeMapping[]> typeMapping = new HashMap<InternalQName, TypeMapping[]>();

   /**
    * Creates a new <code>PropertyTypeRegistry</code> instance. This instance
    * is *not* registered as listener to the NodeTypeRegistry in the constructor!
    * @param reg the <code>NodeTypeRegistry</code> where to read the property
    * type information.
    */
   public PropertyTypeRegistry(NodeTypeDataManager reg)
   {
      this.registry = reg;
      fillCache();

      registry.addListener(this);
   }

   /**
    * Returns an array of type mappings for a given property name
    * <code>propName</code>. If <code>propName</code> is not defined as a property
    * in any registered node type an empty array is returned.
    * @param propName the name of the property.
    * @return an array of <code>TypeMapping</code> instances.
    */
   public TypeMapping[] getPropertyTypes(InternalQName propName)
   {
      synchronized (typeMapping)
      {
         TypeMapping[] types = typeMapping.get(propName);
         if (types != null)
         {
            return types;
         }
         else
         {
            return EMPTY;
         }
      }
   }

   public void nodeTypeRegistered(InternalQName ntName)
   {
      NodeTypeData def = registry.getNodeType(ntName);
      if (def != null)
      {
         PropertyDefinitionData[] propDefs = def.getDeclaredPropertyDefinitions();
         synchronized (typeMapping)
         {
            for (int i = 0; i < propDefs.length; i++)
            {
               int type = propDefs[i].getRequiredType();
               if (!propDefs[i].isResidualSet() && type != PropertyType.UNDEFINED)
               {
                  InternalQName name = propDefs[i].getName();
                  // only remember defined property types
                  TypeMapping[] types = typeMapping.get(name);
                  if (types == null)
                  {
                     types = new TypeMapping[1];
                  }
                  else
                  {
                     TypeMapping[] tmp = new TypeMapping[types.length + 1];
                     System.arraycopy(types, 0, tmp, 0, types.length);
                     types = tmp;
                  }
                  types[types.length - 1] = new TypeMapping(ntName, type, propDefs[i].isMultiple());
                  typeMapping.put(name, types);
               }
            }
         }
      }
   }

   public void nodeTypeReRegistered(InternalQName ntName)
   {
      nodeTypeUnregistered(ntName);
      nodeTypeRegistered(ntName);
   }

   public void nodeTypeUnregistered(InternalQName ntName)
   {
      // remove all TypeMapping instances refering to this ntName
      synchronized (typeMapping)
      {
         Map<InternalQName, TypeMapping[]> modified = new HashMap<InternalQName, TypeMapping[]>();
         for (Iterator<InternalQName> it = typeMapping.keySet().iterator(); it.hasNext();)
         {
            InternalQName propName = it.next();
            TypeMapping[] mapping = typeMapping.get(propName);
            List<TypeMapping> remove = null;
            for (int i = 0; i < mapping.length; i++)
            {
               if (mapping[i].ntName.equals(ntName))
               {
                  if (remove == null)
                  {
                     // not yet created
                     remove = new ArrayList<TypeMapping>(mapping.length);
                  }
                  remove.add(mapping[i]);
               }
            }
            if (remove != null)
            {
               it.remove();
               if (mapping.length == remove.size())
               {
                  // all removed -> done
               }
               else
               {
                  // only some removed
                  List<TypeMapping> remaining = new ArrayList<TypeMapping>(Arrays.asList(mapping));
                  remaining.removeAll(remove);
                  modified.put(propName, remaining.toArray(new TypeMapping[remaining.size()]));
               }
            }
         }
         // finally re-add the modified mappings
         typeMapping.putAll(modified);
      }
   }

   /**
    * Initially fills the cache of this registry with property type definitions
    * from the {@link org.apache.jackrabbit.core.nodetype.NodeTypeRegistry}.
    */
   private void fillCache()
   {
      Collection<NodeTypeData> ntTypes = registry.getAllNodeTypes();
      for (NodeTypeData nodeTypeData : ntTypes)
      {
         nodeTypeRegistered(nodeTypeData.getName());
      }
   }

   public static class TypeMapping
   {

      /** The property type as an integer */
      public final int type;

      /** The Name of the node type where this type mapping originated */
      final InternalQName ntName;

      /** True if the property type is multi-valued */
      public final boolean isMultiValued;

      private TypeMapping(InternalQName ntName, int type, boolean isMultiValued)
      {
         this.type = type;
         this.ntName = ntName;
         this.isMultiValued = isMultiValued;
      }
   }
}
