/*
    * 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.traffic.distsql.parser.core;
  
  import org.antlr.v4.runtime.tree.ParseTree;
  import org.apache.shardingsphere.distsql.parser.autogen.TrafficDistSQLStatementBaseVisitor;
  import org.apache.shardingsphere.distsql.parser.autogen.TrafficDistSQLStatementParser.AlgorithmDefinitionContext;
  import org.apache.shardingsphere.distsql.parser.autogen.TrafficDistSQLStatementParser.AlterTrafficRuleContext;
  import org.apache.shardingsphere.distsql.parser.autogen.TrafficDistSQLStatementParser.LabelDefinitionContext;
  import org.apache.shardingsphere.distsql.parser.autogen.TrafficDistSQLStatementParser.LoadBalancerDefinitionContext;
  import org.apache.shardingsphere.distsql.parser.autogen.TrafficDistSQLStatementParser.PropertiesDefinitionContext;
  import org.apache.shardingsphere.distsql.parser.autogen.TrafficDistSQLStatementParser.PropertyContext;
  import org.apache.shardingsphere.distsql.parser.autogen.TrafficDistSQLStatementParser.ShowTrafficRulesContext;
  import org.apache.shardingsphere.distsql.parser.autogen.TrafficDistSQLStatementParser.TrafficRuleDefinitionContext;
  import org.apache.shardingsphere.distsql.segment.AlgorithmSegment;
  import org.apache.shardingsphere.sql.parser.api.ASTNode;
  import org.apache.shardingsphere.sql.parser.api.visitor.SQLVisitor;
  import org.apache.shardingsphere.sql.parser.sql.common.value.identifier.IdentifierValue;
  import org.apache.shardingsphere.traffic.distsql.segment.TrafficRuleSegment;
  import org.apache.shardingsphere.traffic.distsql.statement.queryable.ShowTrafficRulesStatement;
  import org.apache.shardingsphere.traffic.distsql.statement.updatable.AlterTrafficRuleStatement;
  
  import java.util.Collection;
  import java.util.Collections;
  import java.util.Properties;
  import java.util.stream.Collectors;
  
  /**
   * SQL statement visitor for traffic DistSQL.
   */
  public final class TrafficDistSQLStatementVisitor extends TrafficDistSQLStatementBaseVisitor<ASTNode> implements SQLVisitor<ASTNode> {
      
      @Override
      public ASTNode visitAlterTrafficRule(final AlterTrafficRuleContext ctx) {
          return new AlterTrafficRuleStatement(ctx.trafficRuleDefinition().stream().map(each -> (TrafficRuleSegment) visit(each)).collect(Collectors.toList()));
      }
      
      @Override
      public ASTNode visitTrafficRuleDefinition(final TrafficRuleDefinitionContext ctx) {
          AlgorithmSegment loadBalancerSegment = null == ctx.loadBalancerDefinition() ? null : (AlgorithmSegment) visit(ctx.loadBalancerDefinition().algorithmDefinition());
          return new TrafficRuleSegment(
                  getIdentifierValue(ctx.ruleName()), buildLabels(ctx.labelDefinition()), (AlgorithmSegment) visit(ctx.trafficAlgorithmDefinition().algorithmDefinition()), loadBalancerSegment);
      }
      
      private Collection<String> buildLabels(final LabelDefinitionContext labelDefinition) {
          return null == labelDefinition ? Collections.emptyList() : labelDefinition.label().stream().map(this::getIdentifierValue).collect(Collectors.toList());
      }
      
      @Override
      public ASTNode visitLoadBalancerDefinition(final LoadBalancerDefinitionContext ctx) {
          return null == ctx ? null : visit(ctx.algorithmDefinition());
      }
      
      @Override
      public ASTNode visitAlgorithmDefinition(final AlgorithmDefinitionContext ctx) {
          return new AlgorithmSegment(getIdentifierValue(ctx.algorithmTypeName()), buildProperties(ctx.propertiesDefinition()));
      }
      
      private Properties buildProperties(final PropertiesDefinitionContext ctx) {
          Properties result = new Properties();
          if (null == ctx) {
              return result;
          }
          for (PropertyContext each : ctx.properties().property()) {
              result.setProperty(IdentifierValue.getQuotedContent(each.key.getText()), IdentifierValue.getQuotedContent(each.value.getText()));
          }
          return result;
      }
      
      @Override
      public ASTNode visitShowTrafficRules(final ShowTrafficRulesContext ctx) {
          return new ShowTrafficRulesStatement(null == ctx.ruleName() ? null : getIdentifierValue(ctx.ruleName()));
      }
      
      private String getIdentifierValue(final ParseTree context) {
          return null == context ? null : new IdentifierValue(context.getText()).getValue();
      }
  }