/*
 * 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.flink.table.api

import _root_.java.io.Serializable

import org.apache.flink.api.common.time.Time

class QueryConfig private[table] extends Serializable {

  /**
    * The [[QueryConfig]] holds parameters that exits in [[TableConfig]] also. If the user gives
    * a [[QueryConfig]], put all parameters of it to override [[TableConfig]].
    */
  private[flink] def overrideTableConfig(tableConfig: TableConfig): Unit = {}

}

/**
  * The [[BatchQueryConfig]] holds parameters to configure the behavior of batch queries.
  */
class BatchQueryConfig private[table] extends QueryConfig

/**
  * The [[StreamQueryConfig]] holds parameters to configure the behavior of streaming queries.
  *
  * An empty [[StreamQueryConfig]] can be generated using the [[StreamTableEnvironment.queryConfig]]
  * method.
  */
class StreamQueryConfig private[table] extends QueryConfig {

  /**
    * The minimum time until state which was not updated will be retained.
    * State might be cleared and removed if it was not updated for the defined period of time.
    */
  private var minIdleStateRetentionTime: Long = 0L

  /**
    * The maximum time until state which was not updated will be retained.
    * State will be cleared and removed if it was not updated for the defined period of time.
    */
  private var maxIdleStateRetentionTime: Long = 0L

  /**
    * Specifies a minimum and a maximum time interval for how long idle state, i.e., state which
    * was not updated, will be retained.
    * State will never be cleared until it was idle for less than the minimum time and will never
    * be kept if it was idle for more than the maximum time.
    *
    * When new data arrives for previously cleaned-up state, the new data will be handled as if it
    * was the first data. This can result in previous results being overwritten.
    *
    * Set to 0 (zero) to never clean-up the state.
    *
    * NOTE: Cleaning up state requires additional bookkeeping which becomes less expensive for
    * larger differences of minTime and maxTime. The difference between minTime and maxTime must be
    * at least 5 minutes.
    *
    * @param minTime The minimum time interval for which idle state is retained. Set to 0 (zero) to
    *                never clean-up the state.
    * @param maxTime The maximum time interval for which idle state is retained. Must be at least
    *                5 minutes greater than minTime. Set to 0 (zero) to never clean-up the state.
    */
  def withIdleStateRetentionTime(minTime: Time, maxTime: Time): StreamQueryConfig = {

    if (maxTime.toMilliseconds - minTime.toMilliseconds < 300000 &&
        !(maxTime.toMilliseconds == 0 && minTime.toMilliseconds == 0)) {
      throw new IllegalArgumentException(
        s"Difference between minTime: ${minTime.toString} and maxTime: ${maxTime.toString} " +
            s"shoud be at least 5 minutes.")
    }
    minIdleStateRetentionTime = minTime.toMilliseconds
    maxIdleStateRetentionTime = maxTime.toMilliseconds
    this
  }

  def getMinIdleStateRetentionTime: Long = {
    minIdleStateRetentionTime
  }

  def getMaxIdleStateRetentionTime: Long = {
    maxIdleStateRetentionTime
  }

  override private[flink] def overrideTableConfig(tableConfig: TableConfig): Unit = {
    if (minIdleStateRetentionTime != 0 || maxIdleStateRetentionTime != 0) {
      tableConfig.withIdleStateRetentionTime(Time.milliseconds(minIdleStateRetentionTime),
        Time.milliseconds(maxIdleStateRetentionTime))
    }
  }
}