/*
 *
 *  *  Copyright 2014 Orient Technologies LTD (info(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.
 *  *
 *  * For more information: http://www.orientechnologies.com
 *
 */
package com.orientechnologies.orient.core.sql;

import com.orientechnologies.common.comparator.OCaseInsentiveComparator;
import com.orientechnologies.common.util.OCollections;
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.config.OGlobalConfiguration;
import com.orientechnologies.orient.core.db.document.ODatabaseDocument;
import com.orientechnologies.orient.core.exception.OCommandExecutionException;
import com.orientechnologies.orient.core.index.OIndex;
import com.orientechnologies.orient.core.metadata.schema.OClassImpl;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;

/**
 * SQL CREATE PROPERTY command: Creates a new property in the target class.
 *
 * @author Luca Garulli
 */
@SuppressWarnings("unchecked")
public class OCommandExecutorSQLDropProperty extends OCommandExecutorSQLAbstract implements OCommandDistributedReplicateRequest {
  public static final String KEYWORD_DROP     = "DROP";
  public static final String KEYWORD_PROPERTY = "PROPERTY";

  private String className;
  private String fieldName;
  private boolean ifExists;
  private boolean force = false;

  public OCommandExecutorSQLDropProperty parse(final OCommandRequest iRequest) {
    final OCommandRequestText textRequest = (OCommandRequestText) iRequest;

    String queryText = textRequest.getText();
    String originalQuery = queryText;
    try {
      queryText = preParse(queryText, iRequest);
      textRequest.setText(queryText);

      init((OCommandRequestText) iRequest);

      final StringBuilder word = new StringBuilder();

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

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

      pos = nextWord(parserText, parserTextUpperCase, pos, word, false);
      if (pos == -1)
        throw new OCommandSQLParsingException("Expected <class>.<property>. Use " + getSyntax(), parserText, pos);

      String[] parts = word.toString().split("\\.");
      if (parts.length != 2)
        throw new OCommandSQLParsingException("Expected <class>.<property>. Use " + getSyntax(), parserText, pos);

      className = decodeClassName(parts[0]);
      if (className == null)
        throw new OCommandSQLParsingException("Class not found", parserText, pos);
      fieldName = decodeClassName(parts[1]);

      pos = nextWord(parserText, parserTextUpperCase, pos, word, false);
      if (pos != -1) {
        final String forceParameter = word.toString();
        if ("FORCE".equals(forceParameter)) {
          force = true;
        } else if ("IF".equals(word.toString())) {
          pos = nextWord(parserText, parserTextUpperCase, pos, word, false);
          if ("EXISTS".equals(word.toString())) {
            this.ifExists = true;
          }else{
            throw new OCommandSQLParsingException("Wrong query parameter, expecting EXISTS after IF", parserText, pos);
          }
        } else {
          throw new OCommandSQLParsingException("Wrong query parameter", parserText, pos);
        }
      }
    } finally {
      textRequest.setText(originalQuery);
    }

    return this;
  }

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

    final ODatabaseDocument database = getDatabase();
    final OClassImpl sourceClass = (OClassImpl) database.getMetadata().getSchema().getClass(className);
    if (sourceClass == null)
      throw new OCommandExecutionException("Source class '" + className + "' not found");

    if(ifExists && !sourceClass.existsProperty(fieldName)){
      return null;
    }

    final List<OIndex<?>> indexes = relatedIndexes(fieldName);
    if (!indexes.isEmpty()) {
      if (force) {
        dropRelatedIndexes(indexes);
      } else {
        final StringBuilder indexNames = new StringBuilder();

        boolean first = true;
        for (final OIndex<?> index : sourceClass.getClassInvolvedIndexes(fieldName)) {
          if (!first) {
            indexNames.append(", ");
          } else {
            first = false;
          }
          indexNames.append(index.getName());
        }

        throw new OCommandExecutionException("Property used in indexes (" + indexNames.toString()
            + "). Please drop these indexes before removing property or use FORCE parameter.");
      }
    }

    // REMOVE THE PROPERTY
    sourceClass.dropProperty(fieldName);

    return null;
  }

  @Override
  public long getDistributedTimeout() {
    return OGlobalConfiguration.DISTRIBUTED_COMMAND_TASK_SYNCH_TIMEOUT.getValueAsLong();
  }

  @Override
  public QUORUM_TYPE getQuorumType() {
    return QUORUM_TYPE.ALL;
  }

  private void dropRelatedIndexes(final List<OIndex<?>> indexes) {
    final ODatabaseDocument database = getDatabase();
    for (final OIndex<?> index : indexes) {
      database.command(new OCommandSQL("DROP INDEX " + index.getName())).execute();
    }
  }

  private List<OIndex<?>> relatedIndexes(final String fieldName) {
    final List<OIndex<?>> result = new ArrayList<OIndex<?>>();

    final ODatabaseDocument database = getDatabase();
    for (final OIndex<?> oIndex : database.getMetadata().getIndexManager().getClassIndexes(className)) {
      if (OCollections.indexOf(oIndex.getDefinition().getFields(), fieldName, new OCaseInsentiveComparator()) > -1) {
        result.add(oIndex);
      }
    }

    return result;
  }

  @Override
  public String getSyntax() {
    return "DROP PROPERTY <class>.<property> [ IF EXISTS ] [FORCE]";
  }
}