package e4s.tutorial;

import java.util.Hashtable;

import e4s.application.CountryCode;
import e4s.html.*;
import e4s.html.input.extended.E4InputFieldName;
import e4s.html.input.extended.LONGFIELD;
import e4s.html.input.grid.E4Grid;
import e4s.html.input.grid.E4GridSize;
import e4s.servlet.E4ModuleImplementation;


/**
 * A grid example (editing several rows/columns of data).
 * 
 * This example shall demonstrate a grid which holds data for each 
 * country (vertically) within 2 years (horizontally). This could 
 * be some comercial data about sales figures. What we what we want to 
 * do here is a input of this data (but it would be too huge to be 
 * edited on one screen completley, so we use the Grid element).
 * 
 * {@tutorial Example_Grid}
 */
public class Example_Grid extends E4ModuleImplementation
{
   public static E4Method start = null;

   
   /**
    * This is the class providing data and painting on the screen. .
    */
   public class MyData extends E4Grid
   {
      /**
       * Hold the actuals but changed values
       */
      private Hashtable m_hash = new Hashtable();

      public MyData()
      {
         // create a grid with 2 label cells each for vertical and horizontal headers and use method refresh for
         super(2,2);
         
         // set captions to be displayed
         super.setCaption_vertical("Country");
         super.setCaption_horizontal("Period");
         
         // define some alternative sizes the user can choose from
         super.addDisplaySize(new E4GridSize(25,12));
         super.addDisplaySize(new E4GridSize(15,15));
         super.addDisplaySize(new E4GridSize(20,20));
         super.addDisplaySize(new E4GridSize(30,30));
         
         //populate some random test data
         for( int col = 0; col < horizontalSize(); col++ )
            for( int row = 0; row < verticalSize(); row++ )
            {
               int rnd = (int)(Math.random() * 1000.0f);
               setData(Integer.toString(rnd),row,col);
            }
      }

      /*
       * Get the data associated with row and col.
       * Typically this could be a database selection, but in this case data is stored in a Hashtable.
       */
      private String getData( int row, int col )
      {
         String key = Integer.toString(row) + "/" + Integer.toString(col);
         return (String)m_hash.get(key);
      }

      /*
       * set the data associated with row and col.
       * Typically this could be a database update, but in this case data is stored in a Hashtable.
       */
      private void setData( String data, int row, int col )
      {
         String key = Integer.toString(row) + "/" + Integer.toString(col);
         
         m_hash.remove(key);
         
         if (data != null)
            m_hash.put(key,data);
      }

      /**
       * This are 24 month.
       * @return 24.
       */
      public int horizontalSize()
      {
         return 24;
      }

      /**
       * Draw one header for the horizontal row. 
       * @param td contains an TD element for each header-column specified on construction (we expect 2 here)
       * @param row the actual row
       */
      public void drawHorizontalHeader_Screen( TD td[], int row) 
      throws Exception
      {
         CountryCode.COUNTRY[] cc = CountryCode.getCountries();
         
         td[0].print(cc[row].getCode());
         td[1].NOBR().print(cc[row].getName());
      }

      /**
       * This are all countries.
       * @return the size of the country array.
       */
      public int verticalSize()
      {
         CountryCode.COUNTRY[] cc = CountryCode.getCountries();
         return cc.length;
      }

      /**
       * Draw one header for the vertical row. 
       * @param tr contains an TR element for each header-row (we expect 2 here)
       * @param row_from the first actual row
       * @param row_end the last actual row (including)
       */
      public void drawVerticalHeaders_Screen(TR tr[], int col_start, int col_end) 
      throws Exception
      {
         final String LABELS[] = { "Jan","Feb","Mar","Apr","Mai","Jun","Jul","Aug","Sep","Oct","Nov","Dec"};

         for( int col = col_start; col <= col_end; col++ )
         {
            int month = col % 12;
            int year = 2007 + col / 12;

            tr[0].TD().print(year);
            tr[1].TD().print(LABELS[month]);
         }
      }

      /**
       * Draw a cell on the screen: add some input field (without any validation in this example).
       */
      public void drawCell_Screen(TD td, E4InputFieldName fieldname, int row, int col)
      throws Exception
      {
         LONGFIELD field = new LONGFIELD(fieldname,(String)null,3);
         field.setValue(getData(row,col));
         td.addElement(field);
      }

      /**
       * Draw a data cell in printing mode.
       */
      public void drawCell_Printer(TD td, int row, int col) 
      throws Exception
      {
         td.print(getData(row,col));
         td.setAlign(Align.RIGHT);
      }
      
      /**
       * Save the updated value, stored in the params and named by fieldname, associated by row/col.
       */
      public boolean saveValue(E4InputFieldName fieldname, E4CgiParams params, int row, int col) 
      throws Exception
      {
         String value = params.get(fieldname);
         setData(value,row,col);
         return true;
      }

   }
   
   /**
    * This is our start method, it will be initially called.
    */
   public void start( HTML html, E4CgiParams params )
   throws Exception
   {
      // create the data object 
      MyData data = new MyData();
      
      // save it for later usage as session persistant object
      setSessionObject(data);
      
      // add the data element to the body
      data.add2body(html.BODY(),getServlet());
   }
   
}