import java.io.*;
import java.sql.*;
import javax.servlet.*;
import javax.servlet.http.*;
import myBean.Teach;

public class TeachSvlt extends HttpServlet{
	
public void doGet(HttpServletRequest req, HttpServletResponse res)
    throws ServletException, IOException {
    	
    String class_id =req.getParameter("class_id");
    int success = 0;
    String action = req.getParameter("action");
    Teach tea = null;
    String message="",tea_id,cour_id,cour_time,room_id;
    
   if ("new".equalsIgnoreCase(action)) {
   	  room_id=req.getParameter("room_id");
      tea_id=req.getParameter("tea_id");
      cour_id=req.getParameter("cour_id");
      cour_time=req.getParameter("cour_time");
      if(isTrue(req,res,class_id,cour_time) && hasMoreclass(tea_id,cour_id,cour_time,room_id,req,res)
      && hasMoreteacher(tea_id,cour_time,room_id,req,res)&&hasMoretea(req,res) ){
          tea = doNew(req,res,class_id,tea_id,cour_id,cour_time);
          sendBean(req, res, tea,"/getTeach.jsp");
        }
    }  
    
    if ("update".equalsIgnoreCase(action)) {
    	room_id=req.getParameter("room_id");
    	tea_id=req.getParameter("tea_id");
      cour_id=req.getParameter("cour_id");
      cour_time=req.getParameter("cour_time");
      if(isTrue(req,res,class_id,cour_time) && hasMoreclass(tea_id,cour_id,cour_time,room_id,req,res)
      && hasMoreteacher(tea_id,cour_time,room_id,req,res)&&hasMoretea(req,res)){
    	   try{		
     	       tea = doUpdate(req,res,class_id,tea_id,cour_id,cour_time);
     	       sendBean(req,res,tea,"/getTeach.jsp");
     	     }catch(SQLException e){}
     	  }
    }
			   
    if ("delete".equalsIgnoreCase(action)) {
    	cour_id=req.getParameter("cour_id");
    	cour_time=req.getParameter("cour_time");
    	
    	try{			
      	 success = doDelete(class_id,cour_id,cour_time);	
      	    }
      	    catch(SQLException e){}				
    	if (success < 1) {
    		doError(req, res, "TeachSvlt: Delete unsuccessful. Rows affected: " + success);
    	} else {
    		res.sendRedirect("http://localhost:8080/0903/getTeach.jsp");
    	}
    	}
       
}
    
public Teach doNew(HttpServletRequest req,HttpServletResponse res,String class_id,String tea_id,String cour_id,String cour_time)
                           throws ServletException,IOException{
      Teach tea= new Teach();                     	
      String room_id=req.getParameter("room_id");
   
       tea.setClass_Id(class_id);
       tea.setTea_id(tea_id);   
       tea.setCour_id(cour_id);
       tea.setRoom_id(room_id);
       tea.setCour_time(cour_time);
       tea.addTeach();
      return tea;                	                           	
}

private boolean hasMoretea(HttpServletRequest req,HttpServletResponse res)
          throws ServletException,IOException{
	String class_id = req.getParameter("class_id");
	String cour_id = req.getParameter("cour_id");
	String tea_id = req.getParameter("tea_id");
	boolean f = true;
	Teach tea = new Teach();
	String temp = tea.hasMoretea(class_id,cour_id);
	if(temp.equals("no")||temp.equals(tea_id))
	   f = true;
	else{
	   f = false;
	   temp = "對不起,該班級("+class_id+")的該課程("+cour_id+")已經有老師("+tea_id+")";
	   doError(req,res,temp);
  }
  return f;
	}

private boolean hasMoreteacher(String tea_id,String cour_time,String room_id,HttpServletRequest req,HttpServletResponse res)
                          throws ServletException,IOException{
   String temp = "";
   boolean f = true;
   Teach tea=new Teach();
   temp=tea.hasMoreteacher(cour_time,room_id);
   if(temp.equals("no")||temp.equals(tea_id))
     f=true;
   else{
     f=false;
     temp="對不起，該教室("+room_id+")在該時間已經安排有課"+temp;
     doError(req,res,temp);
  } 
  return f;  
 }
                           	
 public boolean hasMoreclass(String tea_id,String cour_id,String cour_time,String room_id,HttpServletRequest req,HttpServletResponse res)
       throws ServletException,IOException{
      	boolean f=true;
      	String temp="";
      	String message="";
      	Teach tea=new Teach();
      	ResultSet rs=tea.hasMorecourse(tea_id,cour_time);
     try{ 	
      	if(rs.next()){
      		 temp = rs.getString("COUR_ID");
      	   if(temp.equals(cour_id)&&rs.getString("ROOM").equals(room_id))
              f=true;
           else {
        	    f=false;
              message="對不起，該教師("+tea_id+")在"+cour_time+"時間已經安排有課"+temp;
              doError(req,res,message);
        	} 
        }
      }catch(SQLException e){ System.out.print(e.getMessage());}       	
      	return f;     	
 }
      	
   public boolean hasChange(String tea_id,String cour_time,
   HttpServletRequest req,HttpServletResponse res)throws ServletException,IOException{
   	boolean f=false;
   	String tea_id0=req.getParameter("tea_id0");
   	String cour_time0=req.getParameter("cour_time0");
   	if(!tea_id.equals(tea_id0) || !cour_time.equals(cour_time0) )
  	  f=true;
   	return f;
   	}   	                       	
                           	
  public Teach doUpdate(HttpServletRequest req,HttpServletResponse res,String id,String tea_id,String cour_id,String cour_time)
                           throws ServletException,IOException,SQLException {                      	
      Teach tea = new Teach();                    
      String room_id=req.getParameter("room_id");
      
     if(hasChange(tea_id,cour_time,req,res)){          
        tea.updateTeach(id,tea_id,cour_id,room_id,cour_time);
      }else{
        tea.updateTeach(id,cour_id,room_id);	   	
    	}
		return tea;
  }                        	
                           	
   public int doDelete(String id,String cour_id,String cour_time) throws SQLException {
  	int num=0;
    Teach tea=new Teach();
    num=tea.deleteTeach(id,cour_id,cour_time);
    return num;
  } 
  
  
  public void sendBean(HttpServletRequest req, HttpServletResponse res,
                       Teach tea, String target)
                       throws ServletException, IOException {
    req.setAttribute("tea", tea);
    RequestDispatcher rd = getServletContext().getRequestDispatcher(target);
    rd.forward(req, res);
  }
  
  
  public void doError(HttpServletRequest req,
                      HttpServletResponse res,
                      String str)
                      throws ServletException, IOException {


    req.setAttribute("problem", str);
    RequestDispatcher rd = getServletContext().getRequestDispatcher("/errorpage.jsp");
    rd.forward(req, res);
  }
  
                          	
  public boolean isTrue(HttpServletRequest req, HttpServletResponse res,
                        String id,String cour_time)
                        throws ServletException, IOException {
   Teach tea = new Teach();                     	
   boolean f=true;                     	
   String message ="";
   if(id==null || id.equals(""))  {
   	  f=false;
   	  message="錯誤，班級號不能為空！";
   	  doError(req,res,message);
   	}
   else if(tea.hasLogin(id,cour_time)){
     	f=false;
     	message="對不起，記錄重復了！";
      doError(req,res,message);
   	} 
     return f;
     
  }
  
  public void doPost(HttpServletRequest req, HttpServletResponse res)
    throws ServletException, IOException {

    doGet(req, res);

  }
  
  
}