package org.apache.ibatis.logging.jdbc;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.sql.CallableStatement;
import java.sql.PreparedStatement;
import java.sql.ResultSet;

import org.apache.ibatis.logging.Log;
import org.apache.ibatis.logging.LogFactory;
import org.apache.ibatis.reflection.ExceptionUtil;

/**
 * PreparedStatement proxy to add logging
 */
public class PreparedStatementLogger extends BaseJdbcLogger implements InvocationHandler {

  private static final Log log = LogFactory.getLog(PreparedStatement.class);

  private PreparedStatement statement;
  private String sql;

  private PreparedStatementLogger(PreparedStatement stmt, String sql) {
    this.statement = stmt;
    this.sql = sql;
  }

  public Object invoke(Object proxy, Method method, Object[] params) throws Throwable {
    try {
      if (EXECUTE_METHODS.contains(method.getName())) {
        if (log.isDebugEnabled()) {
          log.debug("==>  Executing: " + removeBreakingWhitespace(sql));
          log.debug("==> Parameters: " + getParameterValueString());
        }
        clearColumnInfo();
        if ("executeQuery".equals(method.getName())) {
          ResultSet rs = (ResultSet) method.invoke(statement, params);
          if (rs != null) {
            return ResultSetLogger.newInstance(rs);
          } else {
            return null;
          }
        } else {
          return method.invoke(statement, params);
        }
      } else if (SET_METHODS.contains(method.getName())) {
        if ("setNull".equals(method.getName())) {
          setColumn(params[0], null);
        } else {
          setColumn(params[0], params[1]);
        }
        return method.invoke(statement, params);
      } else if ("getResultSet".equals(method.getName())) {
        ResultSet rs = (ResultSet) method.invoke(statement, params);
        if (rs != null) {
          return ResultSetLogger.newInstance(rs);
        } else {
          return null;
        }
      } else if ("equals".equals(method.getName())) {
        Object ps = params[0];
        return ps instanceof Proxy && proxy == ps;
      } else if ("hashCode".equals(method.getName())) {
        return proxy.hashCode();
      } else {
        return method.invoke(statement, params);
      }
    } catch (Throwable t) {
      throw ExceptionUtil.unwrapThrowable(t);
    }
  }

  /**
   * Creates a logging version of a PreparedStatement
   *
   * @param stmt - the statement
   * @param sql  - the sql statement
   * @return - the proxy
   */
  public static PreparedStatement newInstance(PreparedStatement stmt, String sql) {
    InvocationHandler handler = new PreparedStatementLogger(stmt, sql);
    ClassLoader cl = PreparedStatement.class.getClassLoader();
    return (PreparedStatement) Proxy.newProxyInstance(cl, new Class[]{PreparedStatement.class, CallableStatement.class}, handler);
  }

  /**
   * Return the wrapped prepared statement
   *
   * @return the PreparedStatement
   */
  public PreparedStatement getPreparedStatement() {
    return statement;
  }

}
