package book.servlet;

import java.sql.ResultSet;
import java.sql.SQLException;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.*;
import book.portal.*;
import book.portal.table.UserEO;

public class LoginServlet extends HttpServlet {
	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, java.io.IOException {
		boolean bSuccess = true;// 判斷是否登陸成功的標記
		String errMessage = "";// 顯示錯誤消息
		UserEO user = null;// 定義一個UserEO對象
		String name = request.getParameter("userName");// 獲得用戶名的值
		String password = request.getParameter("passWord");// 獲得密碼的值
		if (name == null || name.trim().equals(""))// 判斷用戶名是否為空
		{
			bSuccess = false;
			errMessage = "Please enter user name";
		}else{//如果不為空則查詢數據庫中是否存在該用戶
			String strSQL = "select user_id from ajax_user where user_name='"+ name+"'";		
			try {
				ResultSet rs = DbManager.getResultSet(strSQL);
				rs.last();
				int row = rs.getRow();
				if (row!=1)
				{
					bSuccess=false;
					errMessage = "This user name is not exist";
				}
			} catch (SQLException e) {
				bSuccess = false;
			}
		}
		if (bSuccess && (password == null || password.trim().equals("")))// 判斷密碼是否為空
		{
			bSuccess = false;
			errMessage = "Please enter password";
		}
		if (bSuccess)// 如果都不為空，則查詢數據庫
		{
			// 查詢的sql語句
			String strSQL = "select user_id from ajax_user where user_name='"
					+ name + "' and password='" + password + "'";
			try {
				ResultSet rs = DbManager.getResultSet(strSQL);// 獲得一個記錄集
				rs.last();// 移動到最后一行
				int row = rs.getRow();// 獲得總的記錄數
				if (row == 1)// 如果只找到一條記錄，則表示找到該對應的用戶
				{
					user = new UserEO(rs.getInt("USER_ID"));// 實例化該用戶
					HttpSession session = ((HttpServletRequest) request)
							.getSession(true);
					session.setAttribute("user", user.getId()+"");// 設置session;
				} else {// 如果沒找到該用戶
					bSuccess = false;
					errMessage = "Invalid password!";
				}
			} catch (SQLException e) {
				bSuccess = false;
				errMessage = "Invalid user name or password!";
			}
		}
		if (bSuccess)// 如果登陸成功，則轉向homepage.jsp頁面.
		{
			RequestDispatcher dispatcher = request.getRequestDispatcher("homepage.jsp");
			dispatcher.forward(request, response);
		} else {// 如果沒有登陸成功，返回錯誤信息
			response.setContentType("text/html");
			java.io.PrintWriter out = response.getWriter();
			out.println(errMessage);
		}
	}

	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, java.io.IOException {

		doPost(request, response);
	}

}