?using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Data.SqlClient;
using System.IO;

/*************************************************************************************************
 * 文件名:login.cs
 * 信息:有關登陸的信息
 * 作者:mcz
 * 函數(shù): checkUser(ref stirng,ref string) 檢查學生的登陸情況
 *       dsDelay(DateTime):取得一個比系統(tǒng)時間少min分鐘的時間
**************************************************************************************************/

namespace ExamOnline
{
    
    public class Login
    {
        string strcon = "";
        public Login()
        {
            if (strcon == "")
            {
                if (HttpContext.Current.Application["strcon"] == null)
                {
                    string path = HttpContext.Current.Request.PhysicalApplicationPath + "DBSet.ini";//獲取文件物理路徑
                    StreamReader sr = new StreamReader(path, System.Text.Encoding.Default);
                    strcon = sr.ReadLine();//讀取文件內(nèi)容
                    HttpContext.Current.Application["strcon"] = strcon;
                }
                else
                {
                    strcon = HttpContext.Current.Application["strcon"].ToString();
                }
            }
        }
        
        
        /// <summary>
        /// 檢查學生的登陸情況   
        /// 0:學號或密碼錯誤；1：改時段內(nèi)沒有考試；2：登陸考試狀態(tài)；3：無權(quán)限參加這場考試或者已經(jīng)考過 4：遲到30分鐘以上或者考試還未開始
        /// </summary>
        /// <param name="userID"></param>
        /// <param name="userPWD"></param>
        /// <returns></returns>
        public int checkUser(ref string userID,ref string userPWD)
        {
            
            SqlConnection con = new SqlConnection(strcon);
            string strcmd = "select * from students where stu_id = @ID and pwd = @PWD";
            SqlCommand cmd = new SqlCommand(strcmd,con);
            cmd.Parameters.Add("@ID",SqlDbType.VarChar,20).Value = userID;
            cmd.Parameters.Add("@PWD",SqlDbType.VarChar,20).Value = userPWD;
            con.Open();
            SqlDataReader dr = cmd.ExecuteReader();
            
            if (dr.Read())  //學號和密碼正確，再判斷是登陸考試還是登陸練習
            {
                dr.Close();
                string strcmdExam = "select * from testpaper_list where paper_time > @dtNow and test=1 and audit=1 order by paper_time asc ";
                SqlCommand cmdExam = new SqlCommand(strcmdExam,con);
                cmdExam.Parameters.Add("@dtNow", SqlDbType.DateTime).Value = dsDelay(30);//調(diào)用自定義函數(shù)dsDelay()
                SqlDataReader drExam = cmdExam.ExecuteReader();

                if (drExam.Read())
                {
                    DateTime dsExam = drExam.GetDateTime(2);      //取得試卷的考試時間
                    //int examID = drExam.GetInt32(0);
                    string strcmdpaperID = "select * from paper_students where paper_id=@paperID and stu_id=@userID and stu_state=0";
                    SqlCommand cmdpaperID = new SqlCommand(strcmdpaperID,con);
                    cmdpaperID.Parameters.Add("@paperID", SqlDbType.Int).Value = drExam.GetInt32(0);
                    cmdpaperID.Parameters.Add("@userID",SqlDbType.VarChar,20).Value = userID;
                    drExam.Close();
                    SqlDataReader drpaperID = cmdpaperID.ExecuteReader();
                    
                    if (drpaperID.Read())
                    {
                        if (dsExam <= dsDelay(-10))  //允許提前10分鐘登陸考試
                        {
                            drpaperID.Close();
                            con.Close();
                            
                            return 2;
                        }
                        else
                        {
                            drpaperID.Close();
                            con.Close();
                            return 4;
                        }
                        
                    }
                    else
                    {
                        drpaperID.Close();
                        con.Close();
                        return 3;
                    }

                }
                else
                {
                    drExam.Close();
                    con.Close();
                    return 1;
                }

            }
            else
            {
                dr.Close();
                con.Close();
                return 0;
            }
        }

        /// <summary>
        /// 考生在遲到min分鐘之前都可以進入考試系統(tǒng)考試，遲到min分鐘后則不允許考試
        /// 取得一個比系統(tǒng)時間少min分鐘的時間
        /// </summary>
        /// <param name="min"></param>
        /// <returns></returns>
        public DateTime dsDelay(int min)
        {
            TimeSpan ts = new TimeSpan(0,min,0);
            DateTime ds = DateTime.Now.Subtract(ts);
            return ds;
        }
        /// <summary>
        /// 學生修改登陸密碼的時候檢查用戶的合法性
        /// </summary>
        /// <param name="userID"></param>
        /// <param name="userPWD"></param>
        /// <returns></returns>
        public bool checkPWD(ref string userID, ref string userPWD,ref string newPWD)
        {
            SqlConnection con = new SqlConnection(strcon);
            string strcmd = "select * from students where stu_id = @ID and pwd = @PWD";
            SqlCommand cmd = new SqlCommand(strcmd, con);
            cmd.Parameters.Add("@ID", SqlDbType.VarChar, 20).Value = userID;
            cmd.Parameters.Add("@PWD", SqlDbType.VarChar, 20).Value = userPWD;
            con.Open();
            SqlDataReader dr = cmd.ExecuteReader();
            if(dr.Read())
            {
                dr.Close();
                string strrepwd = "update students set pwd='" + newPWD + "' where stu_id='" + userID + "'";
                try
                {
                    (new ExamOnline.Exam()).exec(strrepwd);
                    con.Close();
                    return true;
                }
                catch(Exception ee)
                {
                    ExamOnline.Common.ShowMess(ee.Message);
                }
            }
            con.Close();
            return false;
        }

        /// <summary>
        /// 學生修改登陸密碼的時候檢查用戶的合法性
        /// </summary>
        /// <param name="userID"></param>
        /// <param name="userPWD"></param>
        /// <returns></returns>
        public bool checkPWD(ref string userID, ref string userPWD)
        {
            SqlConnection con = new SqlConnection(strcon);
            string strcmd = "select * from students where stu_id = @ID and pwd = @PWD";
            SqlCommand cmd = new SqlCommand(strcmd, con);
            cmd.Parameters.Add("@ID", SqlDbType.VarChar, 20).Value = userID;
            cmd.Parameters.Add("@PWD", SqlDbType.VarChar, 20).Value = userPWD;
            con.Open();
            SqlDataReader dr = cmd.ExecuteReader();
            if (dr.Read())
            {
                con.Close();
                return true;
            }
            con.Close();
            return false;
        }
    }
}