/*
    *    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.logging.jdbc;
  
  import java.lang.reflect.InvocationHandler;
  import java.lang.reflect.Method;
  import java.lang.reflect.Proxy;
  import java.sql.ResultSet;
  import java.sql.ResultSetMetaData;
  import java.sql.SQLException;
  import java.sql.Types;
  import java.util.HashSet;
  import java.util.Set;
  import java.util.StringJoiner;
  
  import org.apache.ibatis.logging.Log;
  import org.apache.ibatis.reflection.ExceptionUtil;
  
  /**
   * ResultSet proxy to add logging.
   *
   * @author Clinton Begin
   * @author Eduardo Macarron
   *
   */
  public final class ResultSetLogger extends BaseJdbcLogger implements InvocationHandler {
  
    private static final Set<Integer> BLOB_TYPES = new HashSet<>();
    private boolean first = true;
    private int rows;
    private final ResultSet rs;
    private final Set<Integer> blobColumns = new HashSet<>();
  
    static {
      BLOB_TYPES.add(Types.BINARY);
      BLOB_TYPES.add(Types.BLOB);
      BLOB_TYPES.add(Types.CLOB);
      BLOB_TYPES.add(Types.LONGNVARCHAR);
      BLOB_TYPES.add(Types.LONGVARBINARY);
      BLOB_TYPES.add(Types.LONGVARCHAR);
      BLOB_TYPES.add(Types.NCLOB);
      BLOB_TYPES.add(Types.VARBINARY);
    }
  
    private ResultSetLogger(ResultSet rs, Log statementLog, int queryStack) {
      super(statementLog, queryStack);
      this.rs = rs;
    }
  
    @Override
    public Object invoke(Object proxy, Method method, Object[] params) throws Throwable {
      try {
        if (Object.class.equals(method.getDeclaringClass())) {
          return method.invoke(this, params);
        }
        Object o = method.invoke(rs, params);
        if ("next".equals(method.getName())) {
          if ((Boolean) o) {
            rows++;
            if (isTraceEnabled()) {
              ResultSetMetaData rsmd = rs.getMetaData();
              final int columnCount = rsmd.getColumnCount();
              if (first) {
                first = false;
                printColumnHeaders(rsmd, columnCount);
              }
              printColumnValues(columnCount);
            }
          } else {
            debug("     Total: " + rows, false);
          }
        }
        clearColumnInfo();
        return o;
      } catch (Throwable t) {
        throw ExceptionUtil.unwrapThrowable(t);
      }
    }
  
    private void printColumnHeaders(ResultSetMetaData rsmd, int columnCount) throws SQLException {
      StringJoiner row = new StringJoiner(", ", "   Columns: ", "");
      for (int i = 1; i <= columnCount; i++) {
        if (BLOB_TYPES.contains(rsmd.getColumnType(i))) {
          blobColumns.add(i);
        }
        row.add(rsmd.getColumnLabel(i));
     }
     trace(row.toString(), false);
   }
 
   private void printColumnValues(int columnCount) {
     StringJoiner row = new StringJoiner(", ", "       Row: ", "");
     for (int i = 1; i <= columnCount; i++) {
       try {
         if (blobColumns.contains(i)) {
           row.add("<<BLOB>>");
         } else {
           row.add(rs.getString(i));
         }
       } catch (SQLException e) {
         // generally can't call getString() on a BLOB column
         row.add("<<Cannot Display>>");
       }
     }
     trace(row.toString(), false);
   }
 
   /**
    * Creates a logging version of a ResultSet.
    *
    * @param rs
    *          the ResultSet to proxy
    * @param statementLog
    *          the statement log
    * @param queryStack
    *          the query stack
    * @return the ResultSet with logging
    */
   public static ResultSet newInstance(ResultSet rs, Log statementLog, int queryStack) {
     InvocationHandler handler = new ResultSetLogger(rs, statementLog, queryStack);
     ClassLoader cl = ResultSet.class.getClassLoader();
     return (ResultSet) Proxy.newProxyInstance(cl, new Class[]{ResultSet.class}, handler);
   }
 
   /**
    * Get the wrapped result set.
    *
    * @return the resultSet
    */
   public ResultSet getRs() {
     return rs;
   }
 
 }