/*

  * $Source: /usr/cvsroot/MelatiShopping/src/main/java/org/paneris/melati/shopping/Trolley.java,v $

  * $Revision: 1.25 $

  *

  * Copyright (C) 2000 Tim Joyce

  *

  * Part of Melati (http://melati.org/ ), a framework for the rapid

  * development of clean, maintainable web applications.

  *

  * Melati is free software; Permission is granted to copy, distribute

  * and/or modify this software under the terms either:

  *

  * a) the GNU General Public License as published by the Free Software

  *    Foundation; either version 2 of the License, or (at your option)

  *    any later version,

  *

  *    or

  *

  * b) any version of the Melati Software License, as published

  *    at http://melati.org

  *

  * You should have received a copy of the GNU General Public License and

  * the Melati Software License along with this program;

  * if not, write to the Free Software Foundation, Inc.,

  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA to obtain the

  * GNU General Public License and visit http://melati.org to obtain the

  * Melati Software License.

  *

  * Feel free to contact the Developers of Melati if you would like 

  * to work out a different arrangement than the options

  * outlined here.  It is our intention to allow Melati to be used by as

  * wide an audience as possible.

  *

  * This program is distributed in the hope that it will be useful,

  * but WITHOUT ANY WARRANTY; without even the implied warranty of

  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

  * GNU General Public License for more details.

  *

  * Contact details for copyright holder:

  *

  *     Tim Joyce <timj@paneris.org>

  *     http://paneris.org/~timj/

  *     68 Sandbanks Rd, Poole, Dorset. BH14 8BY. UK

  */

 package org.paneris.melati.shopping;

 import org.melati.Melati;

 import org.melati.servlet.Form;

 import org.melati.util.MelatiException;

 import org.melati.util.InstantiationPropertyException;

 import org.melati.template.ServletTemplateContext;

 import org.melati.servlet.TemplateServlet;

 import org.melati.PoemContext;

 import org.melati.servlet.PathInfoException;

 import org.melati.servlet.InvalidUsageException;

 import java.util.Enumeration;

 import javax.servlet.ServletConfig;

 import javax.servlet.ServletException;

 /** 

  * A servlet that handles the user's interaction with 

  * the Shopping Trolley.

  *

  * @see org.paneris.melati.shopping.ShoppingTrolley

  * @see org.paneris.melati.shopping.ShoppingTrolleyItem

  * @see org.paneris.melati.shopping.DefaultShoppingTrolley

  * @see org.paneris.melati.shopping.DefaultShoppingTrolleyItem

  *

  **/

 public class Trolley extends TemplateServlet {

   private static final long serialVersionUID = 1L;

   public MelatiShoppingConfig config;

   /**

    * Inititialise the Shopping Trolley Engine.  This will load a file called

    * org.paneris.melati.shopping.ShoppingTrolley.properties in order to 

    * find the classes that implement this shopping implementation.

    *

    * @param conf - the Servlet's config parameters

    * @see org.paneris.melati.shopping.MelatiShoppingConfig

    **/

   public void init(ServletConfig conf) throws ServletException {

     super.init(conf);

     try {

       config = new MelatiShoppingConfig();

     } catch (MelatiException e) {

       throw new ServletException(e.toString());

     }

   }

   /**

    * Main entry point for this servlet.

    *

    * @param melati - the melati for this request

    * @param context - the Template Context for this request

    *

    * @return - the name of the template to be returned to the user

    *

    * @throws InvalidUsageException - if this request has an invalid form

    */

   protected String 

       doTemplateRequest(Melati melati, ServletTemplateContext context)

       throws Exception {

     if (config==null) 

        throw new ShoppingConfigException("Shopping Trolley not Configured");

     // at any point, the user can be forced to login, 

     // by simply appending "?login"

     // to the url

     if (Form.getFormNulled(context,"login") != null) assertLogin(melati);

     ShoppingContext shoppingContext = (ShoppingContext)melati.getPoemContext();

     if (shoppingContext.getMethod().equals("Load")) 

       return Load(melati, shoppingContext.stid);

     if (shoppingContext.getMethod().equals("View")) return View(melati);

     if (shoppingContext.getMethod().equals("Update")) return Update(melati);

     if (shoppingContext.getMethod().equals("Add")) 

       return Add(melati, shoppingContext.stid, shoppingContext.quantity);

     if (shoppingContext.getMethod().equals("MultipleAdd")) 

       return MultipleAdd(melati);

     if (shoppingContext.getMethod().equals("Remove")) 

       return Remove(melati, shoppingContext.stid);

     if (shoppingContext.getMethod().equals("Set")) 

       return Set(melati, shoppingContext.stid, shoppingContext.quantity);

     if (shoppingContext.getMethod().equals("Details")) return Details(melati);

     if (shoppingContext.getMethod().equals("Confirm")) return Confirm(melati);

     if (shoppingContext.getMethod().equals("Paid")) return Paid(melati);

     if (shoppingContext.getMethod().equals("Abandon")) return Abandon(melati);

     throw new InvalidUsageException(this, shoppingContext);

   }

   /** 

    * Load the trolley from something persistent.

    *

    * @param melati - the melati for this request

    * @param id - an id that can be used to identify the trolley to be loaded

    *

    * @return - "Trolley" - the page where users manipulate their 

    *           Shopping Trolley

    *

    * @throws InstantiationPropertyException - if we cannot construct trolley

    */

   protected String Load(Melati melati, Integer id)

       throws InstantiationPropertyException {

     ShoppingTrolley trolley = ShoppingTrolley.newTrolley(config);

     trolley.initialise(melati,config,id);

     melati.getTemplateContext().put("trolley", trolley);

     return shoppingTemplate(melati, "Trolley");

   }

   /** 

    * Load the trolley from something persistent.

    *

    * @param melati - the melati for this request

    *

    * @return - "Trolley" - the page where users manipulate their 

    *           Shopping Trolley

    *

    * @throws InstantiationPropertyException - if we cannot construct trolley

    **/

   protected String Save(Melati melati)

       throws InstantiationPropertyException {

     ShoppingTrolley trolley = ShoppingTrolley.getInstance(melati,config);

     trolley.save();

     melati.getTemplateContext().put("trolley", trolley);

     return shoppingTemplate(melati, "Trolley");

   }

   /** 

    * View the trolley.

    *

    * @param melati - the melati for this request

    *

    * @return - "Trolley" - the page where users manipulate their 

    *           Shopping Trolley

    *

    * @throws InstantiationPropertyException if we cannot construct the trolley

    */

   protected String View(Melati melati)

       throws InstantiationPropertyException {

     melati.getTemplateContext().put("trolley", 

         ShoppingTrolley.getInstance(melati,config));

     return shoppingTemplate(melati, "Trolley");

   }

   /** 

    * Update the entire trolley, changing quantities

    * and removing items.  The POSTed form is analysed for fields with names of 

    * the form:

    *

    * trolleyitem_<item id>_quantity - the new quantity of the item (if set)

    * trolleyitem_<item id>_deleted - remove this item from the trolley (if set)

    *

    * items will also be deleted if the quantity is set to 0

    *

    * @param melati - the melati for this request

    *

    * @return - "Trolley" - the page where users manipulate their 

    *           Shopping Trolley

    *

    * @throws InstantiationPropertyException if we cannot construct the trolley

    */

   protected String Update(Melati melati) 

       throws InstantiationPropertyException {

     ShoppingTrolley trolley = ShoppingTrolley.getInstance(melati,config);

     for (Enumeration c = trolley.getItems(); c.hasMoreElements();) {

       ShoppingTrolleyItem item = (ShoppingTrolleyItem)c.nextElement();

       String formName = "trolleyitem_" + item.getId();

       String formQuantity = formName + "_quantity";

       String formDeleted = formName + "_deleted";

       String deleted = 

              Form.getFormNulled(melati.getServletTemplateContext(),

                                       formDeleted);

       String quantity = 

              Form.getFormNulled(melati.getServletTemplateContext(),

                                       formQuantity);

       System.err.println(deleted + " " + quantity);

       if (deleted != null || quantity == null || quantity.equals("0")) {

         trolley.removeItem(item);

       } else {

         item.setQuantity(new Double(quantity).doubleValue());

       }

     }

     melati.getTemplateContext().put("trolley",trolley);

     return shoppingTemplate(melati, "Trolley");

   }

   /** 

    * Add multiple items to the trolley, 

    * or add to the quantities already in the 

    * trolley.  

    * The POSTed form is analysed for fields with names of 

    * the form:

    *

    * product_<item id> - the id of the item to be added

    * quantity_<item id> - the quantity to add

    *

    * If no quantity is set, a single item will be added.

    *

    * @param melati - the melati for this request

    *

    * @return - "Trolley" - the page where users manipulate their 

    *           Shopping Trolley

    *

    * @throws InstantiationPropertyException - if we cannot construct trolley

    */

   protected String MultipleAdd(Melati melati)

       throws InstantiationPropertyException {

     ShoppingTrolley trolley = ShoppingTrolley.getInstance(melati,config);

     for (Enumeration e = melati.getRequest().getParameterNames(); 

                      e.hasMoreElements();) {

       String name = (String)e.nextElement();

       if (name.length() > 8) {

         String p = name.substring(0,7);

         if (p.equals("product")) {

           String id = name.substring(8);

           Integer idInt = new Integer(id);

           ShoppingTrolleyItem item = trolley.getItem(idInt);

           String quantityName = "quantity_" + id;

           String priceName = "price_" + id;

           String descriptionName = "description_" + id;

           double quantity = 1;

           Double price = null;

           String quantitySring = 

                  Form.getFormNulled

                  (melati.getServletTemplateContext(), quantityName);

           String priceString = 

                  Form.getFormNulled

                  (melati.getServletTemplateContext(), priceName);

           String description = 

                  Form.getFormNulled

                  (melati.getServletTemplateContext(), descriptionName);

           if (quantitySring != null) 

             quantity = (new Double(quantitySring)).doubleValue();

           if (priceString != null) price = new Double(priceString);

           if (item == null) {

             item = newItem(trolley,idInt,price,description);

           }

           item.setQuantity(item.getQuantity() + quantity);

         }

       }

     }

     melati.getTemplateContext().put("trolley",trolley);

     return shoppingTemplate(melati, "Trolley");

   }

   /** 

    * Add a single item to the trolley, or add to the quantity already in the 

    * trolley.  The product is specified on the pathinfo which should be of the

    * form:

    *

    * /<logicaldatabase>/<id>/<quantity>/Add/

    *

    * if no quantity is set, a single item will be added.  The form parmaeters

    * will be parsed to see if they contain "price" and/or "description" fields.

    * if they are present, they will be used to set up the item

    *

    * @param melati - the melati for this request

    * @param id - the id of the item to be added

    *

    * @return - "Trolley" - the page where users manipulate their 

    *           Shopping Trolley

    *

    * @throws InstantiationPropertyException - if we cannot construct trolley

    **/

   protected String Add(Melati melati, Integer id, double quantity)

       throws InstantiationPropertyException {

      System.err.println("Adding");

     // the quantity is defaulted to 1, so if you don't set it you will get one

     if (quantity == 0) quantity = 1;

     ShoppingTrolley trolley = ShoppingTrolley.getInstance(melati,config);

     ShoppingTrolleyItem item = trolley.getItem(id);

     if (item == null) {

       Double price = null;

       String priceString = 

              Form.getFormNulled(melati.getServletTemplateContext(), 

                                       "price");

       if (priceString != null) price = new Double(priceString);

       item = newItem(trolley,id,price,

           Form.getFormNulled(melati.getServletTemplateContext(), 

                                    "description"));

     }    

     item.setQuantity(item.getQuantity() + quantity);

     melati.getTemplateContext().put("trolley",trolley);

     return shoppingTemplate(melati, "Trolley");

   }

   /** 

    * Remove a single item from the trolley, the product is specified on the 

    * pathinfo which should be of the form:

    *

    * /<logicaldatabase>/<id>/Remove/

    *

    * @param melati - the melati for this request

    *

    * @return - "Trolley" - the page where users manipulate their 

    *           Shopping Trolley

    *

    * @throws InstantiationPropertyException - if we cannot construct trolley

    */

   protected String Remove(Melati melati, Integer id)

       throws InstantiationPropertyException {

     ShoppingTrolley trolley = ShoppingTrolley.getInstance(melati, config);

     ShoppingTrolleyItem item = trolley.getItem(id);

     trolley.removeItem(item);

     melati.getTemplateContext().put("trolley", trolley);

     return shoppingTemplate(melati, "Trolley");

   }

   /** 

    * Set the quantity of an item in the trolley, 

    * the product and new quantity is

    * specified on the pathinfo which should be of the form:

    *

    * /<logicaldatabase>/<id>/<quantity>/Set/

    *

    * @param melati - the melati for this request

    * @param id - the id of the item to be removed

    *

    * @return - "Trolley" - the page where users manipulate their 

    *           Shopping Trolley

    *

    * @throws InstantiationPropertyException - if we cannot construct trolley

    */

   protected String Set(Melati melati, Integer id, double quantity)

       throws InstantiationPropertyException {

     ShoppingTrolley trolley = ShoppingTrolley.getInstance(melati,config);

     ShoppingTrolleyItem item = trolley.getItem(id);

     if (item == null) item = newItem(trolley,id, null, null);

     item.setQuantity(quantity);

     melati.getTemplateContext().put("trolley",trolley);

     return shoppingTemplate(melati, "Trolley");

   }

   /** 

    * Return the page where the user enters their details.

    *

    * @param melati - the melati for this request

    *

    * @return - "Details" - the page where users enter their details

    *

    * @throws InstantiationPropertyException - if we cannot construct trolley

    */

   protected String Details(Melati melati)

       throws InstantiationPropertyException {

     ShoppingTrolley trolley = ShoppingTrolley.getInstance(melati,config);

     trolley.setDefaultDetails(melati);

     melati.getTemplateContext().put("trolley",trolley);

     return shoppingTemplate(melati, "Details");

   }

   /** 

    * Update the user's information and return the

    * confirmation page.

    *

    * @param melati - the melati for this request

    *

    * @return - "Confirm" - the page where users confirm their order

    *

    * @throws InstantiationPropertyException - if we cannot construct trolley

    */

   protected String Confirm(Melati melati)

       throws InstantiationPropertyException {

     ShoppingTrolley trolley = ShoppingTrolley.getInstance(melati,config);

     if (Form.getFormNulled(melati.getServletTemplateContext(),

                                  "submittoken") != null) 

       trolley.setFromForm(melati);

     trolley.save();

     melati.getTemplateContext().put("trolley",trolley);

     return shoppingTemplate(melati, "Confirm");

   }

   /** 

    * Complete the user's shopping experience, and remove their Shopping Trolley

    * from the Session.

    *

    * If you need to do something (like send an email) following confirmation 

    * of payment, define the method in <Your>ShoppingTrolley.java:

    * 

    *  public void confirmPayment(Melati melati) {}

    *

    * Because the callback request (typically) comes from the Payment Server, 

    * you will not have the user's shoping trolley (Session) available to them.

    * You will therefore need to get whatever information you require from 

    * something persistent.

    *

    * The alternative is to get the Payment Server to generate the emails (or 

    * whatever) for you.  Most Payment Servers offer this facility. 

    *

    * @param melati - the melati for this request

    *

    * @return - "Paid" - a message thanking the user for their order

    *

    * @throws InstantiationPropertyException - if we cannot construct trolley

    */

   protected String Paid(Melati melati) 

       throws InstantiationPropertyException {

     ShoppingTrolley trolley = ShoppingTrolley.getInstance(melati, config);

     trolley.confirmPayment(melati);

     // and get rid of it

     trolley.remove(melati);

     return shoppingTemplate(melati, "Paid");

   }

   /** 

    * Abandon a trolley. 

    *

    * @param melati - the melati for this request

    *

    * @return - "Trolley" - the initial trolley page

    *

    * @throws InstantiationPropertyException - if we cannot construct trolley

    */

   protected String Abandon(Melati melati) 

       throws InstantiationPropertyException {

     ShoppingTrolley trolley = ShoppingTrolley.getInstance(melati, config);

     // and get rid of it

     trolley.remove(melati);

     return shoppingTemplate(melati, "Trolley");

   }

   /** 

    * Force a user to login.

    *

    * @param melati - the melati for this request

    */

   protected void assertLogin(Melati melati) 

       throws InstantiationPropertyException {

     ShoppingTrolley trolley = ShoppingTrolley.getInstance(melati, config);

     // deligate to your trolley

     trolley.assertLogin(melati);

   }

   /** 

    * Create the full name of the template to be returned.

    *

    * @param melati - the melati for this request (not used)

    * @param name - the name of the template

    *

    * @return - the full path to the template

    */

   protected String shoppingTemplate(Melati melati, String name) {

     return "shopping/" + name;

   }

   /** 

    * Create a new item and add it to the ShoppingTrolley 

    * if a non null price is passed in.

    *

    * @param trolley - the trolley to add the item to 

    * @param id - the id of the item to be added

    *

    * @return - the new shopping trolley item

    */

   private ShoppingTrolleyItem newItem(ShoppingTrolley trolley, Integer id,

                                       Double price, String description)

       throws InstantiationPropertyException {

     return trolley.newItem(id, description, price);

   }

   /** 

    * Override the building of the PoemContext in order to glean the 

    * additional information required for the Shopping Trolley system.

    *

    * @param melati - the melati for this request

    *

    * @return - the ShoppingContext with as many bits set up as possible

    *

    * @throws PathInfoException - if we don't understand the PathInfo

    */

   protected PoemContext poemContext(Melati melati)

       throws PathInfoException {

     ShoppingContext it = new ShoppingContext();

     String[] parts = melati.getPathInfoParts();

     if (parts.length < 2) 

       throw new PathInfoException(

           "The servlet expects to see pathinfo in the form " +

           "/db/method/ or /db/method/troid or /db/method/troid/quantity");

     it.setLogicalDatabase(parts[0]);

     it.setMethod(parts[1]);

     try {

       if (parts.length > 2 && !parts[2].equals("")) 

         it.stid = new Integer(parts[2]);

       if (parts.length > 3 && !parts[3].equals(""))

         it.quantity = (new Double(parts[3])).doubleValue();

     } catch (NumberFormatException e) {

       throw new PathInfoException(

           "The servlet expects to see pathinfo in the form " +

           "/db/method/ or /db/troid/method/ or /db/troid/quantity/method/ " +

           "where the troid is an integer and the quantity is a number");

     }

     return it;

   }

 }