/*
    * 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.infra.binder.context.statement.ddl;
  
  import lombok.Getter;
  import org.apache.shardingsphere.infra.binder.context.segment.table.TablesContext;
  import org.apache.shardingsphere.infra.binder.context.statement.CommonSQLStatementContext;
  import org.apache.shardingsphere.infra.binder.context.type.ConstraintAvailable;
  import org.apache.shardingsphere.infra.binder.context.type.IndexAvailable;
  import org.apache.shardingsphere.infra.binder.context.type.TableAvailable;
  import org.apache.shardingsphere.sql.parser.sql.common.segment.ddl.column.ColumnDefinitionSegment;
  import org.apache.shardingsphere.sql.parser.sql.common.segment.ddl.column.alter.AddColumnDefinitionSegment;
  import org.apache.shardingsphere.sql.parser.sql.common.segment.ddl.column.alter.ModifyColumnDefinitionSegment;
  import org.apache.shardingsphere.sql.parser.sql.common.segment.ddl.constraint.ConstraintSegment;
  import org.apache.shardingsphere.sql.parser.sql.common.segment.ddl.constraint.alter.AddConstraintDefinitionSegment;
  import org.apache.shardingsphere.sql.parser.sql.common.segment.ddl.constraint.alter.DropConstraintDefinitionSegment;
  import org.apache.shardingsphere.sql.parser.sql.common.segment.ddl.constraint.alter.ValidateConstraintDefinitionSegment;
  import org.apache.shardingsphere.sql.parser.sql.common.segment.ddl.index.DropIndexDefinitionSegment;
  import org.apache.shardingsphere.sql.parser.sql.common.segment.ddl.index.IndexSegment;
  import org.apache.shardingsphere.sql.parser.sql.common.segment.ddl.index.RenameIndexDefinitionSegment;
  import org.apache.shardingsphere.sql.parser.sql.common.segment.dml.column.ColumnSegment;
  import org.apache.shardingsphere.sql.parser.sql.common.segment.generic.table.SimpleTableSegment;
  import org.apache.shardingsphere.sql.parser.sql.common.statement.ddl.AlterTableStatement;
  
  import java.util.Collection;
  import java.util.LinkedList;
  
  /**
   * Alter table statement context.
   */
  @Getter
  public final class AlterTableStatementContext extends CommonSQLStatementContext implements TableAvailable, IndexAvailable, ConstraintAvailable {
      
      private final TablesContext tablesContext;
      
      public AlterTableStatementContext(final AlterTableStatement sqlStatement) {
          super(sqlStatement);
          tablesContext = new TablesContext(sqlStatement.getTable(), getDatabaseType());
      }
      
      @Override
      public AlterTableStatement getSqlStatement() {
          return (AlterTableStatement) super.getSqlStatement();
      }
      
      @Override
      public Collection<SimpleTableSegment> getAllTables() {
          Collection<SimpleTableSegment> result = new LinkedList<>();
          result.add(getSqlStatement().getTable());
          if (getSqlStatement().getRenameTable().isPresent()) {
              result.add(getSqlStatement().getRenameTable().get());
          }
          for (AddColumnDefinitionSegment each : getSqlStatement().getAddColumnDefinitions()) {
              for (ColumnDefinitionSegment columnDefinition : each.getColumnDefinitions()) {
                  result.addAll(columnDefinition.getReferencedTables());
              }
          }
          for (ModifyColumnDefinitionSegment each : getSqlStatement().getModifyColumnDefinitions()) {
              result.addAll(each.getColumnDefinition().getReferencedTables());
          }
          for (AddConstraintDefinitionSegment each : getSqlStatement().getAddConstraintDefinitions()) {
              each.getConstraintDefinition().getReferencedTable().ifPresent(result::add);
          }
          return result;
      }
      
      @Override
      public Collection<IndexSegment> getIndexes() {
          Collection<IndexSegment> result = new LinkedList<>();
          for (AddConstraintDefinitionSegment each : getSqlStatement().getAddConstraintDefinitions()) {
              each.getConstraintDefinition().getIndexName().ifPresent(result::add);
          }
          getSqlStatement().getDropIndexDefinitions().stream().map(DropIndexDefinitionSegment::getIndexSegment).forEach(result::add);
          for (RenameIndexDefinitionSegment each : getSqlStatement().getRenameIndexDefinitions()) {
              result.add(each.getIndexSegment());
              result.add(each.getRenameIndexSegment());
          }
          return result;
      }
      
      @Override
      public Collection<ConstraintSegment> getConstraints() {
          Collection<ConstraintSegment> result = new LinkedList<>();
          for (AddConstraintDefinitionSegment each : getSqlStatement().getAddConstraintDefinitions()) {
             each.getConstraintDefinition().getConstraintName().ifPresent(result::add);
         }
         getSqlStatement().getValidateConstraintDefinitions().stream().map(ValidateConstraintDefinitionSegment::getConstraintName).forEach(result::add);
         getSqlStatement().getDropConstraintDefinitions().stream().map(DropConstraintDefinitionSegment::getConstraintName).forEach(result::add);
         return result;
     }
     
     @Override
     public Collection<ColumnSegment> getIndexColumns() {
         Collection<ColumnSegment> result = new LinkedList<>();
         for (AddConstraintDefinitionSegment each : getSqlStatement().getAddConstraintDefinitions()) {
             result.addAll(each.getConstraintDefinition().getIndexColumns());
         }
         return result;
     }
 }