/*
    * 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.shardingsphere.sqlfederation.rule;
  
  import lombok.Getter;
  import org.apache.shardingsphere.infra.exception.ShardingSpherePreconditions;
  import org.apache.shardingsphere.infra.metadata.database.ShardingSphereDatabase;
  import org.apache.shardingsphere.infra.rule.scope.GlobalRule;
  import org.apache.shardingsphere.sqlfederation.compiler.context.CompilerContext;
  import org.apache.shardingsphere.sqlfederation.compiler.context.CompilerContextFactory;
  import org.apache.shardingsphere.sqlfederation.compiler.exception.InvalidExecutionPlanCacheConfigException;
  import org.apache.shardingsphere.sqlfederation.config.SQLFederationCacheOption;
  import org.apache.shardingsphere.sqlfederation.config.SQLFederationRuleConfiguration;
  import org.apache.shardingsphere.sqlfederation.constant.SQLFederationOrder;
  
  import java.util.Collection;
  import java.util.concurrent.atomic.AtomicReference;
  
  /**
   * SQL federation rule.
   */
  @Getter
  public final class SQLFederationRule implements GlobalRule {
      
      private final SQLFederationRuleConfiguration configuration;
      
      private final AtomicReference<CompilerContext> compilerContext;
      
      public SQLFederationRule(final SQLFederationRuleConfiguration ruleConfig, final Collection<ShardingSphereDatabase> databases) {
          configuration = ruleConfig;
          compilerContext = new AtomicReference<>(CompilerContextFactory.create(databases));
          checkExecutionPlanCacheConfiguration(ruleConfig.getExecutionPlanCache());
      }
      
      private void checkExecutionPlanCacheConfiguration(final SQLFederationCacheOption executionPlanCache) {
          ShardingSpherePreconditions.checkState(executionPlanCache.getInitialCapacity() > 0,
                  () -> new InvalidExecutionPlanCacheConfigException("initialCapacity", executionPlanCache.getInitialCapacity()));
          ShardingSpherePreconditions.checkState(executionPlanCache.getMaximumSize() > 0, () -> new InvalidExecutionPlanCacheConfigException("maximumSize", executionPlanCache.getMaximumSize()));
      }
      
      /**
       * Get compiler context.
       *
       * @return compiler context
       */
      public CompilerContext getCompilerContext() {
          return compilerContext.get();
      }
      
      @Override
      public void refresh(final Collection<ShardingSphereDatabase> databases, final GlobalRuleChangedType changedType) {
          compilerContext.set(CompilerContextFactory.create(databases));
      }
      
      @Override
      public int getOrder() {
          return SQLFederationOrder.ORDER;
      }
  }