/*
 * Copyright (c) 2014 DataTorrent, Inc. ALL Rights Reserved.
 *
 * 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.datatorrent.contrib.aerospike;

import javax.annotation.Nonnull;

import com.aerospike.client.AerospikeException;
import com.aerospike.client.Bin;
import com.aerospike.client.Key;
import com.aerospike.client.query.Filter;
import com.aerospike.client.query.IndexType;
import com.aerospike.client.query.RecordSet;
import com.aerospike.client.query.Statement;
import com.aerospike.client.task.IndexTask;
import com.datatorrent.api.annotation.ShipContainingJars;
import com.datatorrent.lib.db.TransactionableStore;

/**
 * <p>AerospikeTransactionalStore class which inherits AerospikeStore class and provides transaction support to the operators.</p>
 *
 * @since 1.0.4
 */
public class AerospikeTransactionalStore extends AerospikeStore implements TransactionableStore {

  public static String DEFAULT_APP_ID_COL = "dt_app_id";
  public static String DEFAULT_OPERATOR_ID_COL = "dt_operator_id";
  public static String DEFAULT_WINDOW_COL = "dt_window";
  public static String DEFAULT_META_SET = "dt_meta";

  @Nonnull
  protected String metaTableAppIdColumn;
  @Nonnull
  protected String metaTableOperatorIdColumn;
  @Nonnull
  protected String metaTableWindowColumn;
  @Nonnull
  protected String metaSet;
  @Nonnull
  protected String namespace;

  private transient boolean inTransaction;
  private transient Statement lastWindowFetchCommand;

  public AerospikeTransactionalStore() {

    super();
    metaSet = DEFAULT_META_SET;
    metaTableAppIdColumn = DEFAULT_APP_ID_COL;
    metaTableOperatorIdColumn = DEFAULT_OPERATOR_ID_COL;
    metaTableWindowColumn = DEFAULT_WINDOW_COL;
    inTransaction = false;
  }

  /**
   * Sets the name of the meta set.<br/>
   * <b>Default:</b> {@value #DEFAULT_META_SET}
   *
   * @param metaSet meta set name.
   */
  public void setMetaSet(@Nonnull String metaSet) {

    this.metaSet = metaSet;
  }

  /**
   * Sets the name of app id column.<br/>
   * <b>Default:</b> {@value #DEFAULT_APP_ID_COL}
   *
   * @param appIdColumn application id column name.
   */
  public void setMetaTableAppIdColumn(@Nonnull String appIdColumn) {

    this.metaTableAppIdColumn = appIdColumn;
  }

  /**
   * Sets the name of operator id column.<br/>
   * <b>Default:</b> {@value #DEFAULT_OPERATOR_ID_COL}
   *
   * @param operatorIdColumn operator id column name.
   */
  public void setMetaTableOperatorIdColumn(@Nonnull String operatorIdColumn) {

    this.metaTableOperatorIdColumn = operatorIdColumn;
  }

  /**
   * Sets the name of the window column.<br/>
   * <b>Default:</b> {@value #DEFAULT_WINDOW_COL}
   *
   * @param windowColumn window column name.
   */
  public void setMetaTableWindowColumn(@Nonnull String windowColumn) {

    this.metaTableWindowColumn = windowColumn;
  }

  /**
   * Sets the name of the namespace.<br/>
   *
   * @param namespace namespace.
   */
  public void setNamespace(@Nonnull String namespace) {

    this.namespace = namespace;
  }

  @Override
  public void connect() {

    super.connect();
    createIndexes();
    try {
      lastWindowFetchCommand = new Statement();
      lastWindowFetchCommand.setNamespace(namespace);
      lastWindowFetchCommand.setSetName(metaSet);
      lastWindowFetchCommand.setBinNames(metaTableWindowColumn);
    }
    catch (Exception e) {
      throw new RuntimeException(e);
    }
  }

  @Override
  public void disconnect() {

    super.disconnect();
  }

  @Override
  public void beginTransaction() {

    inTransaction = true;
  }

  @Override
  public void commitTransaction() {

    inTransaction = false;
  }

  @Override
  public void rollbackTransaction() {

    inTransaction = false;
  }

  @Override
  public boolean isInTransaction() {

    return inTransaction;
  }

  private void createIndexes() {

    IndexTask task;
    try {
      task = client.createIndex(null, namespace, metaSet, 
          "operatorIdIndex", metaTableOperatorIdColumn, IndexType.NUMERIC);
      task.waitTillComplete();
      task = client.createIndex(null, namespace, metaSet, 
          "appIdIndex", metaTableAppIdColumn, IndexType.STRING);
      task.waitTillComplete();
    } catch (AerospikeException ex) {
      throw new RuntimeException(ex);
    }

  }

  @Override
  public long getCommittedWindowId(String appId, int operatorId) {

    try {
      lastWindowFetchCommand.setFilters(Filter.equal(metaTableOperatorIdColumn, operatorId));
      lastWindowFetchCommand.setFilters(Filter.equal(metaTableAppIdColumn, appId));
      long lastWindow = -1;
      RecordSet recordSet = client.query(null, lastWindowFetchCommand);
      while(recordSet.next()) {
        lastWindow = Long.parseLong(recordSet.getRecord().getValue(metaTableWindowColumn).toString());
      }
      return lastWindow;
    }
    catch (AerospikeException ex) {
      throw new RuntimeException(ex);
    }
  }

  @Override
  public void storeCommittedWindowId(String appId, int operatorId, long windowId) {

    try {
      String keyString = appId + String.valueOf(operatorId);
      Key key = new Key(namespace,metaSet,keyString.hashCode());
      Bin bin1 = new Bin(metaTableAppIdColumn,appId);
      Bin bin2 = new Bin(metaTableOperatorIdColumn,operatorId);
      Bin bin3 = new Bin(metaTableWindowColumn,windowId);
      client.put(null, key, bin1,bin2,bin3);
    }
    catch (AerospikeException e) {
      throw new RuntimeException(e);
    }
  }

  @Override
  public void removeCommittedWindowId(String appId, int operatorId) {

    try {
      String keyString = appId + String.valueOf(operatorId);
      Key key = new Key(namespace,metaSet,keyString.hashCode());
      client.delete(null, key);
    }
    catch (AerospikeException e) {
      throw new RuntimeException(e);
    }
  }

}