/*
    * 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.sql.parser.postgresql.visitor.statement.type;
  
  import org.apache.shardingsphere.sql.parser.api.ASTNode;
  import org.apache.shardingsphere.sql.parser.api.visitor.statement.type.DCLStatementVisitor;
  import org.apache.shardingsphere.sql.parser.autogen.PostgreSQLStatementParser.AlterRoleContext;
  import org.apache.shardingsphere.sql.parser.autogen.PostgreSQLStatementParser.AlterUserContext;
  import org.apache.shardingsphere.sql.parser.autogen.PostgreSQLStatementParser.CreateGroupContext;
  import org.apache.shardingsphere.sql.parser.autogen.PostgreSQLStatementParser.CreateRoleContext;
  import org.apache.shardingsphere.sql.parser.autogen.PostgreSQLStatementParser.CreateUserContext;
  import org.apache.shardingsphere.sql.parser.autogen.PostgreSQLStatementParser.DropRoleContext;
  import org.apache.shardingsphere.sql.parser.autogen.PostgreSQLStatementParser.DropUserContext;
  import org.apache.shardingsphere.sql.parser.autogen.PostgreSQLStatementParser.GrantContext;
  import org.apache.shardingsphere.sql.parser.autogen.PostgreSQLStatementParser.PrivilegeClauseContext;
  import org.apache.shardingsphere.sql.parser.autogen.PostgreSQLStatementParser.ReassignOwnedContext;
  import org.apache.shardingsphere.sql.parser.autogen.PostgreSQLStatementParser.RevokeContext;
  import org.apache.shardingsphere.sql.parser.postgresql.visitor.statement.PostgreSQLStatementVisitor;
  import org.apache.shardingsphere.sql.parser.sql.common.segment.generic.table.SimpleTableSegment;
  import org.apache.shardingsphere.sql.parser.sql.common.value.collection.CollectionValue;
  import org.apache.shardingsphere.sql.parser.sql.dialect.statement.postgresql.dcl.PostgreSQLAlterRoleStatement;
  import org.apache.shardingsphere.sql.parser.sql.dialect.statement.postgresql.dcl.PostgreSQLAlterUserStatement;
  import org.apache.shardingsphere.sql.parser.sql.dialect.statement.postgresql.dcl.PostgreSQLCreateGroupStatement;
  import org.apache.shardingsphere.sql.parser.sql.dialect.statement.postgresql.dcl.PostgreSQLCreateRoleStatement;
  import org.apache.shardingsphere.sql.parser.sql.dialect.statement.postgresql.dcl.PostgreSQLCreateUserStatement;
  import org.apache.shardingsphere.sql.parser.sql.dialect.statement.postgresql.dcl.PostgreSQLDropRoleStatement;
  import org.apache.shardingsphere.sql.parser.sql.dialect.statement.postgresql.dcl.PostgreSQLDropUserStatement;
  import org.apache.shardingsphere.sql.parser.sql.dialect.statement.postgresql.dcl.PostgreSQLGrantStatement;
  import org.apache.shardingsphere.sql.parser.sql.dialect.statement.postgresql.dcl.PostgreSQLReassignOwnedStatement;
  import org.apache.shardingsphere.sql.parser.sql.dialect.statement.postgresql.dcl.PostgreSQLRevokeStatement;
  
  import java.util.Collection;
  
  /**
   * DCL statement visitor for PostgreSQL.
   */
  public final class PostgreSQLDCLStatementVisitor extends PostgreSQLStatementVisitor implements DCLStatementVisitor {
      
      @Override
      public ASTNode visitGrant(final GrantContext ctx) {
          PostgreSQLGrantStatement result = new PostgreSQLGrantStatement();
          if (containsTableSegment(ctx.privilegeClause())) {
              result.getTables().addAll(getTableSegments(ctx.privilegeClause()));
          }
          return result;
      }
      
      @Override
      public ASTNode visitRevoke(final RevokeContext ctx) {
          PostgreSQLRevokeStatement result = new PostgreSQLRevokeStatement();
          if (containsTableSegment(ctx.privilegeClause())) {
              result.getTables().addAll(getTableSegments(ctx.privilegeClause()));
          }
          return result;
      }
      
      private boolean containsTableSegment(final PrivilegeClauseContext ctx) {
          return null != ctx && null != ctx.onObjectClause() && null != ctx.onObjectClause().privilegeLevel() && null != ctx.onObjectClause().privilegeLevel().tableNames();
      }
      
      @SuppressWarnings("unchecked")
      private Collection<SimpleTableSegment> getTableSegments(final PrivilegeClauseContext ctx) {
          return ((CollectionValue<SimpleTableSegment>) visit(ctx.onObjectClause().privilegeLevel().tableNames())).getValue();
      }
      
      @Override
      public ASTNode visitCreateUser(final CreateUserContext ctx) {
          return new PostgreSQLCreateUserStatement();
      }
      
      @Override
      public ASTNode visitDropUser(final DropUserContext ctx) {
          return new PostgreSQLDropUserStatement();
      }
      
      @Override
      public ASTNode visitAlterUser(final AlterUserContext ctx) {
          return new PostgreSQLAlterUserStatement();
      }
      
      @Override
      public ASTNode visitCreateRole(final CreateRoleContext ctx) {
          return new PostgreSQLCreateRoleStatement();
      }
     
     @Override
     public ASTNode visitAlterRole(final AlterRoleContext ctx) {
         return new PostgreSQLAlterRoleStatement();
     }
     
     @Override
     public ASTNode visitDropRole(final DropRoleContext ctx) {
         return new PostgreSQLDropRoleStatement();
     }
     
     @Override
     public ASTNode visitReassignOwned(final ReassignOwnedContext ctx) {
         return new PostgreSQLReassignOwnedStatement();
     }
     
     @Override
     public ASTNode visitCreateGroup(final CreateGroupContext ctx) {
         return new PostgreSQLCreateGroupStatement();
     }
 }