/*
    *    Copyright 2009-2021 the original author or authors.
    *
    *    Licensed 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.ibatis.mapping;
  
  import java.sql.Connection;
  import java.sql.DatabaseMetaData;
  import java.sql.SQLException;
  import java.util.Map;
  import java.util.Properties;
  
  import javax.sql.DataSource;
  
  import org.apache.ibatis.logging.Log;
  import org.apache.ibatis.logging.LogFactory;
  
  /**
   * Vendor DatabaseId provider.
   *
   * It returns database product name as a databaseId.
   * If the user provides a properties it uses it to translate database product name
   * key="Microsoft SQL Server", value="ms" will return "ms".
   * It can return null, if no database product name or
   * a properties was specified and no translation was found.
   *
   * @author Eduardo Macarron
   */
  public class VendorDatabaseIdProvider implements DatabaseIdProvider {
  
    private Properties properties;
  
    @Override
    public String getDatabaseId(DataSource dataSource) {
      if (dataSource == null) {
        throw new NullPointerException("dataSource cannot be null");
      }
      try {
        return getDatabaseName(dataSource);
      } catch (Exception e) {
        LogHolder.log.error("Could not get a databaseId from dataSource", e);
      }
      return null;
    }
  
    @Override
    public void setProperties(Properties p) {
      this.properties = p;
    }
  
    private String getDatabaseName(DataSource dataSource) throws SQLException {
      String productName = getDatabaseProductName(dataSource);
      if (this.properties != null) {
        for (Map.Entry<Object, Object> property : properties.entrySet()) {
          if (productName.contains((String) property.getKey())) {
            return (String) property.getValue();
          }
        }
        // no match, return null
        return null;
      }
      return productName;
    }
  
    private String getDatabaseProductName(DataSource dataSource) throws SQLException {
      try (Connection con = dataSource.getConnection()) {
        DatabaseMetaData metaData = con.getMetaData();
        return metaData.getDatabaseProductName();
      }
  
    }
  
    private static class LogHolder {
      private static final Log log = LogFactory.getLog(VendorDatabaseIdProvider.class);
    }
  
  }