/*
 * Copyright 2018 Confluent Inc.
 *
 * Licensed under the Confluent Community License (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.confluent.io/confluent-community-license
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OF ANY KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations under the License.
 */

package io.confluent.ksql.rest.util;

import io.confluent.ksql.KsqlExecutionContext;
import io.confluent.ksql.util.KsqlConfig;
import io.confluent.ksql.util.KsqlException;

public final class QueryCapacityUtil {
  private QueryCapacityUtil() {
  }

  public static boolean exceedsPersistentQueryCapacity(
      final KsqlExecutionContext executionContext,
      final KsqlConfig ksqlConfig,
      final long additionalQueries
  ) {
    final long newTotal = executionContext.numberOfPersistentQueries() + additionalQueries;
    return newTotal > getQueryLimit(ksqlConfig);
  }

  public static void throwTooManyActivePersistentQueriesException(
      final KsqlExecutionContext executionContext,
      final KsqlConfig ksqlConfig,
      final String statementStr
  ) {
    throw new KsqlException(
        String.format(
            "Not executing statement(s) '%s' as it would cause the number "
                + "of active, persistent queries to exceed the configured limit. "
                + "Use the TERMINATE command to terminate existing queries, "
                + "or increase the '%s' setting via the 'ksql-server.properties' file. "
                + "Current persistent query count: %d. Configured limit: %d.",
            statementStr,
            KsqlConfig.KSQL_ACTIVE_PERSISTENT_QUERY_LIMIT_CONFIG,
            executionContext.numberOfPersistentQueries(),
            getQueryLimit(ksqlConfig)
        )
    );
  }

  private static int getQueryLimit(final KsqlConfig ksqlConfig) {
    return ksqlConfig.getInt(KsqlConfig.KSQL_ACTIVE_PERSISTENT_QUERY_LIMIT_CONFIG);
  }
}
