/*
    * 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.commons.beanutils2.sql;
  
  import java.sql.Date;
  import java.sql.ResultSet;
  import java.sql.ResultSetMetaData;
  import java.sql.SQLException;
  import java.sql.Time;
  import java.sql.Timestamp;
  import java.util.ArrayList;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  import java.util.Objects;
  
  import org.apache.commons.beanutils2.DynaBean;
  import org.apache.commons.beanutils2.DynaClass;
  import org.apache.commons.beanutils2.DynaProperty;
  
  /**
   * <p>
   * Provides common logic for JDBC implementations of {@link DynaClass}.
   * </p>
   */
  abstract class AbstractJdbcDynaClass implements DynaClass {
  
      /**
       * Cross Reference for column name --> dyna property name (needed when lowerCase option is true)
       */
      private Map<String, String> columnNameXref;
  
      /**
       * <p>
       * Flag defining whether column names should be lower cased when converted to property names.
       * </p>
       */
      protected boolean lowerCase = true;
  
      /**
       * <p>
       * The set of dynamic properties that are part of this {@link DynaClass}.
       * </p>
       */
      protected DynaProperty[] properties;
  
      /**
       * <p>
       * The set of dynamic properties that are part of this {@link DynaClass}, keyed by the property name. Individual descriptor instances will be the same
       * instances as those in the {@code properties} list.
       * </p>
       */
      protected Map<String, DynaProperty> propertiesMap = new HashMap<>();
  
      /**
       * <p>
       * Flag defining whether column names or labels should be used.
       */
      private boolean useColumnLabel;
  
      /**
       * <p>
       * Factory method to create a new DynaProperty for the given index into the result set metadata.
       * </p>
       *
       * @param metadata is the result set metadata
       * @param i        is the column index in the metadata
       * @return the newly created DynaProperty instance
       * @throws SQLException If an error occurs accessing the SQL metadata
       */
      protected DynaProperty createDynaProperty(final ResultSetMetaData metadata, final int i) throws SQLException {
          String columnName = null;
          if (useColumnLabel) {
              columnName = metadata.getColumnLabel(i);
          }
          if (columnName == null || columnName.trim().isEmpty()) {
              columnName = metadata.getColumnName(i);
          }
          final String name = lowerCase ? columnName.toLowerCase() : columnName;
          if (!name.equals(columnName)) {
              if (columnNameXref == null) {
                  columnNameXref = new HashMap<>();
              }
              columnNameXref.put(name, columnName);
         }
         String className = null;
         try {
             final int sqlType = metadata.getColumnType(i);
             switch (sqlType) {
             case java.sql.Types.DATE:
                 return new DynaProperty(name, java.sql.Date.class);
             case java.sql.Types.TIMESTAMP:
                 return new DynaProperty(name, java.sql.Timestamp.class);
             case java.sql.Types.TIME:
                 return new DynaProperty(name, java.sql.Time.class);
             default:
                 className = metadata.getColumnClassName(i);
             }
         } catch (final SQLException e) {
             // this is a patch for HsqlDb to ignore exceptions
             // thrown by its metadata implementation
         }
 
         // Default to Object type if no class name could be retrieved
         // from the metadata
         Class<?> clazz = Object.class;
         if (className != null) {
             clazz = loadClass(className);
         }
         return new DynaProperty(name, clazz);
     }
 
     /**
      * Gets the table column name for the specified property name.
      *
      * @param name The property name
      * @return The column name (which can be different if the <em>lowerCase</em> option is used).
      */
     protected String getColumnName(final String name) {
         if (columnNameXref != null && columnNameXref.containsKey(name)) {
             return columnNameXref.get(name);
         }
         return name;
     }
 
     /**
      * <p>
      * Gets an array of {@code PropertyDescriptor} for the properties currently defined in this DynaClass. If no properties are defined, a zero-length array
      * will be returned.
      * </p>
      */
     @Override
     public DynaProperty[] getDynaProperties() {
         return properties;
     }
 
     /**
      * <p>
      * Gets a property descriptor for the specified property, if it exists; otherwise, return {@code null}.
      * </p>
      *
      * @param name Name of the dynamic property for which a descriptor is requested
      * @throws IllegalArgumentException if no property name is specified
      */
     @Override
     public DynaProperty getDynaProperty(final String name) {
         return propertiesMap.get(Objects.requireNonNull(name, "name"));
 
     }
 
     /**
      * <p>
      * Gets the name of this DynaClass (analogous to the {@code getName()</code> method of <code>java.lang.Class}, which allows the same {@code DynaClass}
      * implementation class to support different dynamic classes, with different sets of properties.
      * </p>
      */
     @Override
     public String getName() {
         return this.getClass().getName();
 
     }
 
     /**
      * Gets a column value from a {@link ResultSet} for the specified name.
      *
      * @param resultSet The result set
      * @param name      The property name
      * @return The value
      * @throws SQLException if an error occurs
      */
     protected Object getObject(final ResultSet resultSet, final String name) throws SQLException {
         final DynaProperty property = getDynaProperty(name);
         if (property == null) {
             throw new IllegalArgumentException("Invalid name '" + name + "'");
         }
         final String columnName = getColumnName(name);
         final Class<?> type = property.getType();
 
         // java.sql.Date
         if (type.equals(Date.class)) {
             return resultSet.getDate(columnName);
         }
 
         // java.sql.Timestamp
         if (type.equals(Timestamp.class)) {
             return resultSet.getTimestamp(columnName);
         }
 
         // java.sql.Time
         if (type.equals(Time.class)) {
             return resultSet.getTime(columnName);
         }
 
         return resultSet.getObject(columnName);
     }
 
     /**
      * <p>
      * Introspect the metadata associated with our result set, and populate the {@code properties</code> and <code>propertiesMap} instance variables.
      * </p>
      *
      * @param resultSet The {@code resultSet} whose metadata is to be introspected
      * @throws SQLException if an error is encountered processing the result set metadata
      */
     protected void introspect(final ResultSet resultSet) throws SQLException {
         // Accumulate an ordered list of DynaProperties
         final List<DynaProperty> list = new ArrayList<>();
         final ResultSetMetaData metadata = resultSet.getMetaData();
         final int n = metadata.getColumnCount();
         for (int i = 1; i <= n; i++) { // JDBC is one-relative!
             final DynaProperty dynaProperty = createDynaProperty(metadata, i);
             if (dynaProperty != null) {
                 list.add(dynaProperty);
             }
         }
 
         // Convert this list into the internal data structures we need
         properties = list.toArray(DynaProperty.EMPTY_ARRAY);
         for (final DynaProperty property : properties) {
             propertiesMap.put(property.getName(), property);
         }
     }
 
     /**
      * <p>
      * Loads and returns the {@code Class} of the given name. By default, a load from the thread context class loader is attempted. If there is no such class
      * loader, the class loader used to load this class will be utilized.
      * </p>
      *
      * @param className The name of the class to load
      * @return The loaded class
      * @throws SQLException if an exception was thrown trying to load the specified class
      */
     protected Class<?> loadClass(final String className) throws SQLException {
         try {
             ClassLoader cl = Thread.currentThread().getContextClassLoader();
             if (cl == null) {
                 cl = this.getClass().getClassLoader();
             }
             // use Class.forName() - see BEANUTILS-327
             return Class.forName(className, false, cl);
         } catch (final Exception e) {
             throw new SQLException("Cannot load column class '" + className + "': " + e);
         }
     }
 
     /**
      * <p>
      * Instantiate and return a new DynaBean instance, associated with this DynaClass. <strong>NOTE</strong> - This operation is not supported, and throws an
      * exception.
      * </p>
      *
      * @throws IllegalAccessException if the Class or the appropriate constructor is not accessible
      * @throws InstantiationException if this Class represents an abstract class, an array class, a primitive type, or void; or if instantiation fails for some
      *                                other reason
      */
     @Override
     public DynaBean newInstance() throws IllegalAccessException, InstantiationException {
         throw new UnsupportedOperationException("newInstance() not supported");
     }
 
     /**
      * Sets whether the column label or name should be used for the property name.
      *
      * @param useColumnLabel true if the column label should be used, otherwise false
      */
     public void setUseColumnLabel(final boolean useColumnLabel) {
         this.useColumnLabel = useColumnLabel;
     }
 
 }