AjaxServlet (Handler)

package servlets;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import model.Bill;
import model.Category;
import model.Component;
import model.Device;
import model.Item;
import model.User;
import model.UserRole;

import org.json.JSONException;
import org.json.simple.JSONObject;
import org.json.simple.parser.JSONParser;

import DB.WebShop;
import functions.UndoAction;

public class AjaxServlet extends HttpServlet {

    /**
     *
     */
    private static final long serialVersionUID = -5279877218992865295L;

    public AjaxServlet()
    {
        super();
    }
    @SuppressWarnings("unchecked")
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        HttpSession session = request.getSession();
        User user = (User) session.getAttribute("user");

        if (user == null)
        {
            response.sendError(401, "You are not authorised for this action. Please log in.");
            return;
        }

        String data = request.getParameter("data");
        JSONObject ajaxRequest = null;

        if (data != null)
        {
            JSONParser parser = new JSONParser();
            try
            {
                Object tmp = parser.parse(data);
                ajaxRequest = (JSONObject) tmp;

            } catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }

        // Let's get action:
        if (ajaxRequest != null)
        {
            try {
                if (ajaxRequest.get("action") != null)
                {
                    String key = (String) ajaxRequest.get("key");
                    String bean = (String) ajaxRequest.get("bean");
                    JSONObject obj = new JSONObject();

                    if (ajaxRequest.get("action").equals("delete"))
                    {
                        doDelete(bean, key, request, response);
                    }
                    // This action is only available for devices
                    else if (ajaxRequest.get("action").equals("unpublish"))
                    {
                        doUnpublish(key, request, response);
                    }
                    // This action is only available for devices
                    else if (ajaxRequest.get("action").equals("publish"))
                    {
                        doPublish(key, request, response);
                    }
                    else if (ajaxRequest.get("action").equals("addcart"))
                    {
                        String amount = (String)ajaxRequest.get("amount");
                        Boolean edit = (ajaxRequest.get("edit") != null);
                        System.out.println(edit);
                        doAddCart(bean, key, amount, edit, request, response);
                    }
                    else if (ajaxRequest.get("action").equals("removeCart"))
                    {
                        doRemoveCart(bean, key, request, response);
                    }
                    else
                    {
                        response.setContentType("application/json; charset=UTF-8");
                        obj.put("error", new Boolean(true));
                        obj.put("message", "Action is not defined.");
                        PrintWriter pw = response.getWriter();
                        pw.print(obj);
                    }
                }
            } catch (JSONException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }

    @SuppressWarnings("unchecked")
    private void doDelete(String bean, String key, HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        HttpSession session = request.getSession();
        WebShop ws = (WebShop) getServletContext().getAttribute("webShop");
        User user = (User) session.getAttribute("user");

        // We can do this and use SessionCheckFilter too...just in case
        if(user.getRole() != UserRole.ADMIN.getValue())
        {
            response.sendError(401, "You are not authorised for this action. Only admins can delete users.");
            return;
        }

        UndoAction undoer = UndoAction.getInstance();
        response.setContentType("application/json; charset=UTF-8");
        JSONObject obj = new JSONObject();

        if (bean == null || key == null)
        {
            response.sendError(400, "Invalid request!");
            return;
        }

        if (bean.equals("user"))
        {
            // Let's try not to delete ourselves...
            User logged = (User) session.getAttribute("user");
            User deletedUser = null;

            if (!logged.getKey().equals(key) )
            {
                deletedUser = (User)ws.getUsers().remove(key);
            }

            // Return removed user:
            if (deletedUser != null)
            {
                String undoKey = undoer.add(deletedUser);
                obj.put("undoKey", undoKey);
                obj.put("error", new Boolean(false));
                obj.put("deletedKeys", deletedUser.getKey());
                obj.put("message", "User successfully deleted.");
            }
            // Something terribly wrong happened and user was not deleted
            else
            {
                obj.put("error", new Boolean(true));
                obj.put("deletedKeys", null);
                obj.put("message", "Error deleting user.");
            }
        }
        else if (bean.equals("category"))
        {
            Category deletedCategory = (Category)ws.getCategories().remove(key);
            if (deletedCategory != null)
            {
                ArrayList<Category> recursiveDelete = new ArrayList<Category>();
                ArrayList<String> deletedKeys = new ArrayList<String>();
                ArrayList<String> deletedComponents = new ArrayList<String>();
                deletedKeys.add(deletedCategory.getKey());
                String additionalMessage = "";

                // If we are removing a category, we might as well remove subcategories too, riiiiight?
                // TODO: Add some warning before removing subcats and components XDD
                deletedComponents.addAll(deletedCategory.removeComponents()); // Remove components that were under root category
                for (Category c : deletedCategory.getSubcategories())
                {
                    recursiveDelete.add(c);
                }

                for (Category category : recursiveDelete) {
                    ws.getCategories().remove(category.getKey());
                    deletedKeys.add(category.getKey());
                    deletedComponents.addAll(category.removeComponents()); // remove components that were under subcategory
                }

                if(recursiveDelete.size() > 0)
                    additionalMessage = "Subcategories deleted as well.";

                obj.put("error", new Boolean(false));
                obj.put("deletedKeys", deletedKeys);
                obj.put("deletedComponents", deletedComponents);
                obj.put("message", "Category successfully deleted. " + additionalMessage);

            }
            else { //delete failed
                obj.put("error", new Boolean(true));
                obj.put("deletedKeys", null);
                obj.put("message", "Error deleting category.");
            }

        }
        else if (bean.equals("component"))
        {
            Component deletedComponent = (Component)ws.getComponents().remove(key);

            // Return removed component:
            if (deletedComponent != null)
            {
                String undoKey = undoer.add(deletedComponent);
                obj.put("undoKey", undoKey);
                obj.put("error", new Boolean(false));
                obj.put("deletedKeys", deletedComponent.getKey());
                obj.put("message", "Component successfully deleted.");
            }
            // Something terribly wrong happened...
            else
            {
                obj.put("error", new Boolean(true));
                obj.put("deletedKeys", null);
                obj.put("message", "Error deleting component.");
            }
        }
        else if(bean.equals("device"))
        {
            Device deletedDevice = (Device) ws.getDevices().remove(key);

            if (deletedDevice != null)
            {
                String undoKey = undoer.add(deletedDevice);
                obj.put("undoKey", undoKey);
                obj.put("error", new Boolean(false));
                obj.put("deletedKeys", deletedDevice.getKey());
                obj.put("message", "Device successfully deleted.");
            }
            else
            { //delete failed
                obj.put("error", new Boolean(true));
                obj.put("deletedKeys", null);
                obj.put("message", "Error deleting device.");
            }
        }
        else {
            obj.put("error", new Boolean(true));
            obj.put("message", "Action is not defined.");
        }

        PrintWriter pw = response.getWriter();
        pw.print(obj);
    }

    @SuppressWarnings("unchecked")
    private void doUnpublish(String key, HttpServletRequest request, HttpServletResponse response) throws IOException, JSONException
    {
        HttpSession session = request.getSession();
        WebShop ws = (WebShop) getServletContext().getAttribute("webShop");
        User user = (User) session.getAttribute("user");

        // TODO: Add check in SessionCheckFilter as well
        if(user.getRole() != UserRole.ADMIN.getValue())
        {
            response.sendError(401, "You are not authorised for this action. Only admins can unpublish devices.");
            return;
        }

        response.setContentType("application/json; charset=UTF-8");
        JSONObject obj = new JSONObject();

        if(key == null)
        {
            response.sendError(400, "Invalid request!");
            return;
        }

        if (ws.getDevices().containsKey(key))
        {
            ws.getDevices().get(key).setAvailable(false);
            obj.put("error", new Boolean(false));
            obj.put("message", "Device unpublished successfully.");
        }
        else
        {
            obj.put("error", new Boolean(true));
            obj.put("message", "Error unpublishing device.");
        }

        PrintWriter pw = response.getWriter();
        pw.print(obj);
    }

    @SuppressWarnings("unchecked")
    private void doPublish(String key, HttpServletRequest request, HttpServletResponse response) throws IOException, JSONException
    {
        HttpSession session = request.getSession();
        WebShop ws = (WebShop) getServletContext().getAttribute("webShop");
        User user = (User) session.getAttribute("user");

        if(user.getRole() != UserRole.ADMIN.getValue())
        {
            response.sendError(401, "You are not authorised for this action. Only admins can publish devices.");
            return;
        }

        response.setContentType("application/json; charset=UTF-8");
        JSONObject obj = new JSONObject();

        if (key == null)
        {
            response.sendError(400, "Invalid request!");
            return;
        }

        if (ws.getDevices().containsKey(key))
        {
            ws.getDevices().get(key).setAvailable(true);
            obj.put("error", new Boolean(false));
            obj.put("message", "Device published successfully.");
        }
        else
        {
            outputError(response, "Error publishing device.");
        }

        PrintWriter pw = response.getWriter();
        pw.print(obj);
    }

    @SuppressWarnings("unchecked")
    private void doAddCart(String bean, String key, String amount, Boolean edit, HttpServletRequest request, HttpServletResponse response) throws IOException, JSONException
    {
        HttpSession session = request.getSession();
        WebShop ws = (WebShop) getServletContext().getAttribute("webShop");
        User user = (User) session.getAttribute("user");
        Bill cart = (Bill) session.getAttribute("cart");
        int _amountRequested = 1;

        try{
            _amountRequested = Integer.parseInt(amount);
        } catch (Exception ex) {
        //  ex.printStackTrace();
        }

        // We don't want to have admins going around and randomly buying stuff...ehehe only users can do such thing!
        if(user.getRole() == UserRole.ADMIN.getValue())
        {
            response.sendError(401, "You are not authorised for this action. Only users can add to their carts.");
            return;
        }

        response.setContentType("application/json; charset=UTF-8");
        JSONObject obj = new JSONObject();

        if (bean == null || key == null)
        {
            response.sendError(400, "Invalid request!");
            return;
        }

        bean = bean.toLowerCase();
        if (bean.equals("component") || bean.equals("device"))
        {
            Item item = null;

            if (ws.getComponents().containsKey(key))
            {
                item = ws.getComponents().get(key);
            }
            else if(ws.getDevices().containsKey(key))
            {
                item = ws.getDevices().get(key);
            }
            else
            {
                outputError(response, "Item does not exist.");
                return;
            }

            Boolean inCart = cart.getItems().containsKey(item);
            int inCartAmout = 0;
            String itemName = "n/a", itemType = "n/a", itemDesc = "n/a", itemKey = "n/a";
            double itemPrice = 0.0;
            if (inCart)
            {
                inCartAmout = cart.getItems().get(item);
            }

            // Checking if item is available in stock && we have enough for user to buy:
            if (item instanceof Component)
            {
                itemName = item.getName();
                itemType = item.getTypeof();
                itemDesc = item.getDescription();
                itemPrice = item.getPrice();
                itemKey = item.getKey();

                int afterAdding = ((Component)item).getAmount();
                if (edit)
                {
                    afterAdding -= _amountRequested; // Current inCartAmout will be overwritten
                }
                else
                {
                    afterAdding -= (inCartAmout + 1);
                }

                if (afterAdding < 0)
                {
                    outputError(response, "You cannot order more items than available amount.");
                    return;
                }
            }

            itemName = item.getName();
            itemType = item.getTypeof();
            itemDesc = item.getDescription();
            itemPrice = item.getPrice();
            itemKey = item.getKey();

            System.out.println("Adding to cart '" + key + "'... Item already in cart: " + inCart + " :: add amount: " + _amountRequested);

            if (edit)
            {
                cart.changeAmount(item, _amountRequested);
                obj.put("message", "Successfully increased \"" + key + "\" amount.");
            }
            else
            {
                cart.insert(item, _amountRequested);
                obj.put("message", "Successfully added item \"" + key + "\" to the cart.");

            }

            obj.put("error", new Boolean(false));
            obj.put("itemKey", itemKey);
            obj.put("itemName", itemName);
            obj.put("itemType", itemType);
            obj.put("itemDesc", itemDesc);
            obj.put("itemPrice", itemPrice);
            obj.put("itemAmount", _amountRequested);
            obj.put("cartItems", cart.getCount());
            obj.put("type", "addedit");

        }
        else
        {
            outputError(response,  "Error adding to cart, invalid device type.");
            return;
        }
        PrintWriter pw = response.getWriter();
        pw.print(obj);
    }

    @SuppressWarnings("unchecked")
    private void outputError(HttpServletResponse response, String message) throws IOException, JSONException
    {
        JSONObject obj = new JSONObject();
        obj.put("error", new Boolean(true));
        obj.put("message", message);

        PrintWriter pw = response.getWriter();
        pw.print(obj);
    }

    @SuppressWarnings("unchecked")
    private void doRemoveCart(String bean, String key, HttpServletRequest request, HttpServletResponse response) throws IOException, JSONException
    {
        HttpSession session = request.getSession();
        WebShop ws = (WebShop) getServletContext().getAttribute("webShop");
        User user = (User) session.getAttribute("user");
        Bill cart = (Bill) session.getAttribute("cart");

        if(user.getRole() == UserRole.ADMIN.getValue()){
            response.sendError(401, "You are not authorised for this action. Only users can add to their carts.");
            return;
        }

        response.setContentType("application/json; charset=UTF-8");
        JSONObject obj = new JSONObject();

        if(bean == null || key == null){
            response.sendError(400, "Invalid request!");
            return;
        }

        bean = bean.toLowerCase();

        if (bean.equals("component"))
        {
            if (ws.getComponents().containsKey(key))
            {
                Component c = ws.getComponents().get(key);
                cart.getItems().remove(c);
                obj.put("error", new Boolean(false));
                obj.put("message", "Successfully removed component \""+key+"\" from the cart.");
                obj.put("cartItems", cart.getCount());
                obj.put("cartPrice", cart.getTotalPrice());
                obj.put("removedKey", key);
                obj.put("type", "remove");
            }
            else
            {
                obj.put("error", new Boolean(true));
                obj.put("message", "Component \""+key+"\" could not be deleted form cart.");
                obj.put("cartItems", cart.getCount());
                obj.put("cartPrice", cart.getTotalPrice());
                obj.put("type", "remove");
            }

        }
        else if (bean.equals("device"))
        {
            if (ws.getDevices().containsKey(key))
            {
                Device d = ws.getDevices().get(key);
                cart.getItems().remove(d);
                obj.put("error", new Boolean(false));
                obj.put("message", "Successfully removed device \""+key+"\" from the cart.");
                obj.put("cartItems", cart.getCount());
                obj.put("cartPrice", cart.getTotalPrice());
                obj.put("removedKey", key);
                obj.put("type", "remove");
            }
            else
            {
                obj.put("error", new Boolean(true));
                obj.put("message", "Device \""+key+"\" could not be deleted form cart.");
                obj.put("cartItems", cart.getCount());
                obj.put("cartPrice", cart.getTotalPrice());
                obj.put("type", "remove");
            }
        }
        else
        {
            outputError(response, "Error removing from, invalid device type.");
            return;
        }

        PrintWriter pw = response.getWriter();
        pw.print(obj);
    }
}