/*
 * 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.apache.phoenix.log;

import static org.apache.phoenix.jdbc.PhoenixDatabaseMetaData.SYSTEM_CATALOG_SCHEMA;
import static org.apache.phoenix.jdbc.PhoenixDatabaseMetaData.SYSTEM_LOG_TABLE;

import java.io.IOException;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.util.HashMap;
import java.util.Map;
import org.apache.hadoop.conf.Configuration;
import org.apache.phoenix.monitoring.MetricType;
import org.apache.phoenix.util.QueryUtil;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import org.apache.phoenix.thirdparty.com.google.common.collect.ImmutableMap;

/**
 * Writes RingBuffer log event into table
 */
public class TableLogWriter implements LogWriter {
  private static final Logger LOGGER = LoggerFactory.getLogger(LogWriter.class);
  private volatile Connection connection;
  private boolean isClosed;
  private PreparedStatement upsertStatement;
  private Configuration config;
  private Map<MetricType, Integer> metricOrdinals = new HashMap<MetricType, Integer>();

  public TableLogWriter(Configuration configuration) {
    this.config = configuration;
  }

  private PreparedStatement buildUpsertStatement(Connection conn) throws SQLException {
    StringBuilder buf =
      new StringBuilder("UPSERT INTO " + SYSTEM_CATALOG_SCHEMA + ".\"" + SYSTEM_LOG_TABLE + "\"(");
    int queryLogEntries = 0;
    for (QueryLogInfo info : QueryLogInfo.values()) {
      buf.append(info.columnName);
      buf.append(',');
      queryLogEntries++;
    }
    for (MetricType metric : MetricType.values()) {
      if (metric.logLevel() != LogLevel.OFF) {
        metricOrdinals.put(metric, ++queryLogEntries);
        buf.append(metric.columnName());
        buf.append(',');
      }
    }
    buf.setLength(buf.length() - 1);
    buf.append(") VALUES (");
    for (int i = 0; i < QueryLogInfo.values().length; i++) {
      buf.append("?,");
    }
    for (MetricType metric : MetricType.values()) {
      if (metric.logLevel() != LogLevel.OFF) {
        buf.append("?,");
      }
    }
    buf.setLength(buf.length() - 1);
    buf.append(")");
    return conn.prepareStatement(buf.toString());
  }

  @Override
  public void write(RingBufferEvent event) throws SQLException, IOException {
    if (isClosed()) {
      LOGGER.warn("Unable to commit query log as Log committer is already closed");
      return;
    }
    if (connection == null) {
      synchronized (this) {
        if (connection == null) {
          connection = QueryUtil.getConnectionForQueryLog(this.config);
          this.upsertStatement = buildUpsertStatement(connection);
        }
      }
    }

    if (connection.isReadOnly()) {
      return;
    }

    ImmutableMap<QueryLogInfo, Object> queryInfoMap = event.getQueryInfo();
    for (QueryLogInfo info : QueryLogInfo.values()) {
      if (
        queryInfoMap.containsKey(info)
          && info.logLevel.ordinal() <= event.getConnectionLogLevel().ordinal()
      ) {
        upsertStatement.setObject(info.ordinal() + 1, queryInfoMap.get(info));
      } else {
        upsertStatement.setObject(info.ordinal() + 1, null);
      }
    }
    Map<MetricType, Long> overAllMetrics = event.getOverAllMetrics();
    Map<String, Map<MetricType, Long>> readMetrics = event.getReadMetrics();

    for (MetricType metric : MetricType.values()) {
      if (
        overAllMetrics != null && overAllMetrics.containsKey(metric)
          && metric.isLoggingEnabled(event.getConnectionLogLevel())
      ) {
        upsertStatement.setObject(metricOrdinals.get(metric), overAllMetrics.get(metric));
      } else {
        if (metric.logLevel() != LogLevel.OFF) {
          upsertStatement.setObject(metricOrdinals.get(metric), null);
        }
      }
    }

    if (readMetrics != null && !readMetrics.isEmpty()) {
      for (Map.Entry<String, Map<MetricType, Long>> entry : readMetrics.entrySet()) {
        upsertStatement.setObject(QueryLogInfo.TABLE_NAME_I.ordinal() + 1, entry.getKey());
        for (MetricType metric : entry.getValue().keySet()) {
          if (metric.isLoggingEnabled(event.getConnectionLogLevel())) {
            upsertStatement.setObject(metricOrdinals.get(metric), entry.getValue().get(metric));
          }
        }
        upsertStatement.executeUpdate();
      }
    } else {
      upsertStatement.executeUpdate();
    }
    connection.commit();
  }

  @Override
  public void close() throws IOException {
    if (isClosed()) {
      return;
    }
    isClosed = true;
    try {
      if (connection != null) {
        // It should internally close all the statements
        connection.close();
      }
    } catch (SQLException e) {
      // TODO Ignore?
    }
  }

  public boolean isClosed() {
    return isClosed;
  }

}
