/*
 * Copyright 2010-2012 Luca Garulli (l.garulli--at--orientechnologies.com)
 *
 * Licensed 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 com.orientechnologies.orient.graph.sql.functions;

import com.orientechnologies.common.util.OCallable;
import com.orientechnologies.orient.core.command.OCommandContext;
import com.orientechnologies.orient.core.db.record.OIdentifiable;
import com.orientechnologies.orient.core.exception.OCommandExecutionException;
import com.orientechnologies.orient.core.record.impl.ODocument;
import com.orientechnologies.orient.core.sql.OSQLEngine;
import com.orientechnologies.orient.core.sql.functions.OSQLFunctionConfigurableAbstract;
import com.orientechnologies.orient.graph.sql.OGraphCommandExecutorSQLFactory;
import com.tinkerpop.blueprints.impls.orient.OrientBaseGraph;
import com.tinkerpop.blueprints.impls.orient.OrientEdge;
import com.tinkerpop.blueprints.impls.orient.OrientEdgeType;
import com.tinkerpop.blueprints.impls.orient.OrientVertex;
import com.tinkerpop.blueprints.impls.orient.OrientVertexType;

/**
 * Hi-level function that return the label for both edges and vertices. The label could be bound to the class name.
 * 
 * @author Luca Garulli (l.garulli--at--orientechnologies.com)
 * 
 */
public class OSQLFunctionLabel extends OSQLFunctionConfigurableAbstract {
  public static final String NAME = "label";

  public OSQLFunctionLabel() {
    super(NAME, 0, 0);
  }

  public Object execute(Object iThis, final OIdentifiable iCurrentRecord, final Object iCurrentResult, final Object[] iParameters, OCommandContext iContext) {
    final OrientBaseGraph graph = OGraphCommandExecutorSQLFactory.getGraph(false);

    if (iCurrentResult != null) {
      return OSQLEngine.foreachRecord(new OCallable<Object, OIdentifiable>() {
        @Override
        public Object call(final OIdentifiable iArgument) {
          return getLabel(graph, iArgument);
        }
      }, iCurrentResult, iContext);
    } else
      return getLabel(graph, iCurrentRecord);
  }

  private Object getLabel(final OrientBaseGraph graph, final OIdentifiable iCurrentRecord) {
    final ODocument rec = iCurrentRecord.getRecord();

    if (rec.getSchemaClass().isSubClassOf(OrientVertexType.CLASS_NAME)) {
      // VERTEX
      final OrientVertex vertex = graph.getVertex(iCurrentRecord);
      return vertex.getLabel();

    } else if (rec.getSchemaClass().isSubClassOf(OrientEdgeType.CLASS_NAME)) {
      // EDGE
      final OrientEdge edge = graph.getEdge(iCurrentRecord);
      return edge.getLabel();

    } else
      throw new OCommandExecutionException("Invalid record: is neither a vertex nor an edge. Found class: " + rec.getSchemaClass());
  }

  public String getSyntax() {
    return "Syntax error: label()";
  }
}
