/*
 * 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.core.sql;

import java.io.IOException;
import java.util.Map;

import com.orientechnologies.orient.core.command.OCommandDistributedReplicateRequest;
import com.orientechnologies.orient.core.command.OCommandRequest;
import com.orientechnologies.orient.core.command.OCommandRequestText;
import com.orientechnologies.orient.core.db.record.ODatabaseRecord;
import com.orientechnologies.orient.core.exception.OCommandExecutionException;
import com.orientechnologies.orient.core.metadata.security.ODatabaseSecurityResources;
import com.orientechnologies.orient.core.metadata.security.ORole;
import com.orientechnologies.orient.core.storage.OCluster;
import com.orientechnologies.orient.core.storage.OStorageEmbedded;

/**
 * SQL TRUNCATE CLUSTER command: Truncates an entire record cluster.
 * 
 * @author Luca Garulli
 * 
 */
public class OCommandExecutorSQLTruncateCluster extends OCommandExecutorSQLAbstract implements OCommandDistributedReplicateRequest {
  public static final String KEYWORD_TRUNCATE = "TRUNCATE";
  public static final String KEYWORD_CLUSTER  = "CLUSTER";
  private String             clusterName;

  @SuppressWarnings("unchecked")
  public OCommandExecutorSQLTruncateCluster parse(final OCommandRequest iRequest) {
    final ODatabaseRecord database = getDatabase();
    database.checkSecurity(ODatabaseSecurityResources.COMMAND, ORole.PERMISSION_READ);

    init(((OCommandRequestText) iRequest).getText());

    StringBuilder word = new StringBuilder();

    int oldPos = 0;
    int pos = nextWord(parserText, parserTextUpperCase, oldPos, word, true);
    if (pos == -1 || !word.toString().equals(KEYWORD_TRUNCATE))
      throw new OCommandSQLParsingException("Keyword " + KEYWORD_TRUNCATE + " not found. Use " + getSyntax(), parserText, oldPos);

    oldPos = pos;
    pos = nextWord(parserText, parserTextUpperCase, oldPos, word, true);
    if (pos == -1 || !word.toString().equals(KEYWORD_CLUSTER))
      throw new OCommandSQLParsingException("Keyword " + KEYWORD_CLUSTER + " not found. Use " + getSyntax(), parserText, oldPos);

    oldPos = pos;
    pos = nextWord(parserText, parserText, oldPos, word, true);
    if (pos == -1)
      throw new OCommandSQLParsingException("Expected cluster name. Use " + getSyntax(), parserText, oldPos);

    clusterName = word.toString();

    if (database.getClusterIdByName(clusterName) == -1)
      throw new OCommandSQLParsingException("Cluster '" + clusterName + "' not found", parserText, oldPos);
    return this;
  }

  /**
   * Execute the command.
   */
  public Object execute(final Map<Object, Object> iArgs) {
    if (clusterName == null)
      throw new OCommandExecutionException("Cannot execute the command because it has not been parsed yet");

    final OCluster cluster = ((OStorageEmbedded) getDatabase().getStorage()).getClusterByName(clusterName);

    final long recs = cluster.getEntries();

    try {
      cluster.truncate();
    } catch (IOException e) {
      throw new OCommandExecutionException("Error on executing command", e);
    }

    return recs;
  }

  @Override
  public String getSyntax() {
    return "TRUNCATE CLUSTER <cluster-name>";
  }
}
