/*
    * 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.segment.select.projection.util;
  
  import lombok.AccessLevel;
  import lombok.NoArgsConstructor;
  import org.apache.shardingsphere.infra.database.core.metadata.database.enums.QuoteCharacter;
  import org.apache.shardingsphere.infra.database.core.type.DatabaseType;
  import org.apache.shardingsphere.infra.database.opengauss.type.OpenGaussDatabaseType;
  import org.apache.shardingsphere.infra.database.oracle.type.OracleDatabaseType;
  import org.apache.shardingsphere.infra.database.postgresql.type.PostgreSQLDatabaseType;
  import org.apache.shardingsphere.sql.parser.sql.common.segment.dml.item.SubqueryProjectionSegment;
  import org.apache.shardingsphere.sql.parser.sql.common.value.identifier.IdentifierValue;
  
  /**
   * Projection utility class.
   */
  @NoArgsConstructor(access = AccessLevel.PRIVATE)
  public final class ProjectionUtils {
      
      /**
       * Get column label from alias.
       * 
       * @param alias alias
       * @param databaseType database type
       * @return column label
       */
      public static String getColumnLabelFromAlias(final IdentifierValue alias, final DatabaseType databaseType) {
          return getIdentifierValueByDatabaseType(alias, databaseType);
      }
      
      private static String getIdentifierValueByDatabaseType(final IdentifierValue identifierValue, final DatabaseType databaseType) {
          if (QuoteCharacter.NONE != identifierValue.getQuoteCharacter()) {
              return identifierValue.getValue();
          }
          if (databaseType instanceof PostgreSQLDatabaseType || databaseType instanceof OpenGaussDatabaseType) {
              return identifierValue.getValue().toLowerCase();
          }
          if (databaseType instanceof OracleDatabaseType) {
              return identifierValue.getValue().toUpperCase();
          }
          return identifierValue.getValue();
      }
      
      /**
       * Get column name from column.
       *
       * @param columnName column name
       * @param databaseType database type
       * @return column name
       */
      public static String getColumnNameFromColumn(final IdentifierValue columnName, final DatabaseType databaseType) {
          return getIdentifierValueByDatabaseType(columnName, databaseType);
      }
      
      /**
       * Get column name from function.
       * 
       * @param functionName function name
       * @param functionExpression function expression
       * @param databaseType database type
       * @return column name
       */
      public static String getColumnNameFromFunction(final String functionName, final String functionExpression, final DatabaseType databaseType) {
          if (databaseType instanceof PostgreSQLDatabaseType || databaseType instanceof OpenGaussDatabaseType) {
              return functionName.toLowerCase();
          }
          if (databaseType instanceof OracleDatabaseType) {
              return functionExpression.replace(" ", "").toUpperCase();
          }
          return functionExpression;
      }
      
      /**
       * Get column name from expression.
       * 
       * @param expression expression
       * @param databaseType database type
       * @return column name
       */
      public static String getColumnNameFromExpression(final String expression, final DatabaseType databaseType) {
          if (databaseType instanceof PostgreSQLDatabaseType || databaseType instanceof OpenGaussDatabaseType) {
              return "?column?";
          }
         if (databaseType instanceof OracleDatabaseType) {
             return expression.replace(" ", "").toUpperCase();
         }
         return expression;
     }
     
     /**
      * Get column name from subquery segment.
      * 
      * @param subquerySegment subquery segment
      * @param databaseType database type
      * @return column name
      */
     public static String getColumnNameFromSubquery(final SubqueryProjectionSegment subquerySegment, final DatabaseType databaseType) {
         // TODO support postgresql subquery projection
         if (databaseType instanceof OracleDatabaseType) {
             return subquerySegment.getText().replace(" ", "").toUpperCase();
         }
         return subquerySegment.getText();
     }
 }