RequestHandler

package controller;

import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.security.NoSuchAlgorithmException;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import domain.Person;
import domain.PersonService;
import domain.Product;
import domain.ProductService;
import enums.FormServletActions;
import enums.Pages;
import exceptions.DomainException;

@WebServlet("/ShopController")
public class ShopController extends HttpServlet {
    private static final long serialVersionUID = 1L;
    private PersonService personService;
    private ProductService productService;

    public ShopController() {
        super();
        personService = new PersonService();
        productService = new ProductService();
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        processRequest(request, response);
    }

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        processRequest(request, response);
    }

    private void processRequest(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String action = request.getParameter("action");
        if(action == null || action.isEmpty()){
            System.out.println("Something went wrong with the action.");
            System.out.println(action);
        }
        else {
            if(action.equals(FormServletActions.index.toString()))
                gotoIndexPage(request, response);
            else if(action.equals(FormServletActions.usersOverview.toString()))
                gotoUsersOverviewPage(request, response);
            else if(action.equals(FormServletActions.signUp.toString()))
                gotoSignUpPage(request, response);
            else if(action.equals(FormServletActions.signUpForm.toString()))
                signUpFormAddNewUser(request, response);
            else if(action.equals(FormServletActions.productsOverview.toString()))
                gotoProductOverviewPage(request, response);
            else if(action.equals(FormServletActions.gotoAddProductsForm.toString()))
                gotoAddProductsFormPage(request, response);
            else if(action.equals(FormServletActions.addProductsForm.toString()))
                productFormAddNewProduct(request, response);
            else if(action.equals(FormServletActions.updateProduct.toString()))
                updateProduct(request, response);
            else if(action.equals(FormServletActions.updateProductWithGivenId.toString()))
                updateProduct(request, response);
            else if(action.equals(FormServletActions.deleteProductWithGivenId.toString()))
                gotoDeleteProduct(request, response);
            else if(action.equals(FormServletActions.deleteProductForm.toString()))
                deleteProduct(request, response);
            else if(action.equals(FormServletActions.updateProductValid.toString()))
                updateProductValid(request, response);
            else if(action.equals(FormServletActions.cancelProductDeletion.toString()))
                gotoProductOverviewPage(request, response);
            else if(action.equals(FormServletActions.deletePersonWithGivenId.toString()))
                deletePerson(request, response);
            else if(action.equals(FormServletActions.cancelPersonDeletion.toString()))
                gotoUsersOverviewPage(request, response);
            else if(action.equals(FormServletActions.deletePersonForm.toString()))
                deletePersonValid(request, response);
            else
                System.out.println("Nothing works, try again.");
        }
    }

    private void gotoIndexPage(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        RequestDispatcher view = request.getRequestDispatcher(Pages.indexPage.toString());
        view.forward(request, response);
    }

    private void gotoUsersOverviewPage(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        List<String> errors = new ArrayList<String>();
        try {
            request.setAttribute("persons", personService.getAllAsList());
        } catch (SQLException | NoSuchAlgorithmException | DomainException e) {
            errors.add(e.getMessage());
        }
        request.setAttribute("errors", errors);
        RequestDispatcher view = request.getRequestDispatcher(Pages.usersOverviewPage.toString());
        view.forward(request, response);
    }

    private void gotoSignUpPage(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        RequestDispatcher view = request.getRequestDispatcher(Pages.signUpPage.toString());
        view.forward(request, response);
    }

    private void gotoProductOverviewPage(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        List<String> errors = new ArrayList<String>();
        try {
            request.setAttribute("products", productService.getAllAsList());
        } catch (NumberFormatException | SQLException | DomainException e) {
            errors.add(e.getMessage());
        }
        request.setAttribute("errors", errors);
        RequestDispatcher view = request.getRequestDispatcher(Pages.productsOverviewPage.toString());
        view.forward(request, response);
    }

    private void gotoAddProductsFormPage(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        RequestDispatcher view = request.getRequestDispatcher(Pages.addProductsFormPage.toString());
        view.forward(request, response);
    }

    private void signUpFormAddNewUser(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        List<String> errors = new ArrayList<String>();
        String userId = request.getParameter("email");
        request.setAttribute("email", userId);
        String password = request.getParameter("password");
        request.setAttribute("password", password);
        String firstName = request.getParameter("firstName");
        request.setAttribute("firstName", firstName);
        String lastName = request.getParameter("lastName");
        request.setAttribute("lastName", lastName);
        errors = createNewUser(userId, password, firstName, lastName, errors);
        request.setAttribute("errors", errors);
        if(errors.size() > 0)
            gotoSignUpPage(request, response);
        else
            gotoIndexPage(request, response);
    }

    private List<String> createNewUser(String userId, String password, String firstName, String lastName, List<String> errors){
        Person person = new Person();
        try{
            person.setUserId(userId);
        }catch(IllegalArgumentException e){
            errors.add(e.getMessage());
        }
        try{
            person.setPassword(password);
        }catch(IllegalArgumentException | NoSuchAlgorithmException | UnsupportedEncodingException | DomainException e){
            errors.add(e.getMessage());
        }
        try{
            person.setFirstName(firstName);
        }catch(IllegalArgumentException e){
            errors.add(e.getMessage());
        }
        try{
            person.setLastName(lastName);
        }catch(IllegalArgumentException e){
            errors.add(e.getMessage());
        }
        if(errors.isEmpty())
            try {
                personService.addPerson(person);
            } catch (IllegalArgumentException | SQLException | NoSuchAlgorithmException | UnsupportedEncodingException | DomainException e) {
                errors.add(e.getMessage());
            }
        return errors;
    }

    private void productFormAddNewProduct(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        List<String> errors = new ArrayList<String>();
        String description = null;
        double price = 0;
        if(request.getParameterMap().containsKey("description")){
            description = request.getParameter("description");
            request.setAttribute("description", description);
        }
        if(request.getParameterMap().containsKey("price")){
            try{
                price = Double.parseDouble(request.getParameter("price"));
                request.setAttribute("price", price);
            } catch(NumberFormatException e){
                errors.add("Give a valid number");
            }
        }
        errors = createNewProduct(description, price, errors);
        request.setAttribute("errors", errors);
        if(errors.size() > 0)
            gotoAddProductsFormPage(request, response);
        else
            gotoProductOverviewPage(request, response);
    }

    private List<String> createNewProduct(String description, double price, List<String> errors){
        Product product = new Product();
        try{
            product.setId(productService.getNewIdToUseForNewProduct());
        }catch(DomainException | NumberFormatException | SQLException e){
            errors.add(e.getMessage());
        }
        try{
            product.setDescription(description);
        }catch(DomainException e){
            errors.add(e.getMessage());
        }
        try{
            product.setPrice(price);
        }catch(DomainException e){
            errors.add(e.getMessage());
        }
        if(errors.isEmpty()){
            try {
                productService.addProduct(product);
            } catch (DomainException | NumberFormatException | SQLException e) {
                errors.add(e.getMessage());
            }
        }
        return errors;
    }

    private void updateProduct(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        List<String> errors = new ArrayList<String>();
        Product product = null;
        int id = 0;
        if(request.getParameterMap().containsKey("id")){
            try{
                id = Integer.parseInt(request.getParameter("id"));
            }catch(NumberFormatException e){
                errors.add("Fill in a valid number, it may not be left empty.");
            }
        } else {
            try{
                id = Integer.parseInt(request.getParameter("updateProductID"));
                request.setAttribute("updateProductID", request.getParameter("updateProductID"));
            } catch(NumberFormatException e){
                errors.add("The id may not be empty");
            }
        }
        try {
            product = productService.getProduct(id);
        } catch (DomainException | SQLException e) {
            errors.add(e.getMessage());
        }
        if(product == null){
            errors.add("The given id is out of range.");
            request.setAttribute("errors", errors);
            gotoProductOverviewPage(request, response);
        }
        else{
            request.setAttribute("errors", errors);
            gotoProductUpdatePage(request, response, product);
        }
    }

    private void gotoProductUpdatePage(HttpServletRequest request, HttpServletResponse response, Product product) throws ServletException, IOException {
        request.setAttribute("id", product.getId());
        request.setAttribute("description", product.getDescription());
        request.setAttribute("price", product.getPrice());
        RequestDispatcher view = request.getRequestDispatcher(Pages.updateProductPage.toString());
        view.forward(request, response);
    }

    private void gotoDeleteProduct(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        List<String> errors = new ArrayList<String>();
        if(request.getParameterMap().containsKey("id")){
            Product product = null;
            try {
                product = productService.getProduct(Integer.parseInt(request.getParameter("id")));
            } catch (NumberFormatException | DomainException | SQLException e) {
                errors.add(e.getMessage());
            }
            if(product != null){
                request.setAttribute("id", product.getId());
                request.setAttribute("description", product.getDescription());
                request.setAttribute("price", product.getPrice());
                request.setAttribute("errors", errors);
                gotoDeleteProductPage(request, response);
            } else {
                gotoProductOverviewPage(request, response);
            }
        } else {
            errors.add("Something went wrong.");
            request.setAttribute("errors", errors);
            gotoUsersOverviewPage(request, response);
        }
    }

    private void gotoDeleteProductPage(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        RequestDispatcher view = request.getRequestDispatcher(Pages.deleteProductPage.toString());
        view.forward(request, response);
    }

    private void deleteProduct(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        List<String> errors = new ArrayList<String>();
        if(request.getParameterMap().containsKey("id")){
            try {
                productService.delete(Integer.parseInt(request.getParameter("id")));
            } catch (NumberFormatException | DomainException | SQLException e) {
                errors.add(e.getMessage());
            }
            request.setAttribute("errors", errors);
            gotoProductOverviewPage(request, response);
        } else {
            errors.add("Something went super wrong, system is broken :)");
            request.setAttribute("errors", errors);
            gotoDeleteProductPage(request, response);
        }
    }

    private void updateProductValid(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        List<String> errors = new ArrayList<String>();
        Product product = new Product();
        if(request.getParameterMap().containsKey("id")){
            try{
                product.setId(Integer.parseInt(request.getParameter("id")));
            }catch(DomainException e){
                errors.add(e.getMessage());
            }
            try{
                product.setDescription(request.getParameter("description"));
            }catch(DomainException e){
                errors.add(e.getMessage());
            }
            try{
                product.setPrice(Double.parseDouble(request.getParameter("price")));
            }catch(DomainException e){
                errors.add(e.getMessage());
            }
            if(errors.isEmpty()){
                try {
                    productService.addProduct(product);
                } catch (DomainException | NumberFormatException | SQLException e) {
                    errors.add(e.getMessage());
                }
            }
            request.setAttribute("errors", errors);
            gotoProductOverviewPage(request, response);
        } else {
            request.setAttribute("errors", errors);
            gotoProductUpdatePage(request, response, product);
        }
    }

    private void deletePerson(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        List<String> errors = new ArrayList<String>();
        Person person = null;
        if(request.getParameterMap().containsKey("id")){
            try {
                person = personService.getPerson(request.getParameter("id"));
            } catch (SQLException | NoSuchAlgorithmException | DomainException e) {
                errors.add(e.getMessage());
            }
            request.setAttribute("errors", errors);
            request.setAttribute("person", person);
            gotoDeletePersonPage(request, response);
        } else {
            errors.add("Please give a valid id, or chose another person.");
            request.setAttribute("errors", errors);
            gotoUsersOverviewPage(request, response);
        }
    }

    private void gotoDeletePersonPage(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        RequestDispatcher view = request.getRequestDispatcher(Pages.deletePersonPage.toString());
        view.forward(request, response);
    }

    private void deletePersonValid(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        List<String> errors = new ArrayList<String>();
        if(request.getParameterMap().containsKey("id")){
            try {
                personService.deletePerson(request.getParameter("id"));
            } catch (SQLException e) {
                errors.add(e.getMessage());
            }
            gotoUsersOverviewPage(request, response);
        } else {
            errors.add("Something went wrong while deleting this user");
            request.setAttribute("errors", errors);
            gotoDeletePersonPage(request, response);
        }
    }
}