package info.ejava.examples.jaxrs.todos.ui;
   
   import java.io.IOException;
   import java.util.HashMap;
   import java.util.Map;
   
   import javax.ejb.EJB;
   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 org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import info.ejava.examples.jaxrs.todos.dto.TodoItemDTO;
  import info.ejava.examples.jaxrs.todos.dto.TodoListDTO;
  import info.ejava.examples.jaxrs.todos.dto.TodoListListDTO;
  import info.ejava.examples.jaxrs.todos.ejb.ClientErrorException;
  import info.ejava.examples.jaxrs.todos.ejb.TodosMgmtRemote;
  
  @WebServlet(urlPatterns= {"/ui/todo_lists/*"})
  public class TodoListController extends HttpServlet {
      private static final long serialVersionUID = 1L;
      private static final Logger logger = LoggerFactory.getLogger(TodoListController.class);
      
      @EJB
      private TodosMgmtRemote todosMgmt;
      private Map<String, Action> actions = new HashMap<>();
      
      @Override
      public void init() throws ServletException {
          actions.put("deleteList", new DeleteTodoListAction());
          actions.put("setPriority", new SetPriorityAction());        
          actions.put("deleteItem", new DeleteTodoItemAction());        
      }
      
      private int getInt(String value, int defaultValue) {
          try {
              return value==null ? 0 : Integer.parseInt(value);
          } catch (Exception ex) {
              return 0;
          }
      }
      
      private Map<String, String> getPathParams(HttpServletRequest req) {
          String pathInfo = req.getPathInfo();
          String[] tokens = pathInfo.split("/");
          String listName = null;
          String itemName = null;
          for (int i=0; i<tokens.length; i++) {
              if (i==1) {
                  listName = tokens[i];                
              } else if ("todo_items".equals(tokens[i]) && i+1<tokens.length) {
                  itemName = tokens[++i];
              }
          }
          Map<String, String> pathParams = new HashMap<>();
          if (listName!=null) {
              pathParams.put("listName", listName);
              if (itemName!=null) {
                  pathParams.put("itemName", itemName);
              } 
          }
          return pathParams;
      }
      
      @Override
      protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
          Map<String, String> pathParams = getPathParams(req);
          String listName = pathParams.get("listName");
  
          try {
              TodoListDTO todoList = todosMgmt.getTodoList(listName);
              req.setAttribute("todoList", todoList);
              RequestDispatcher rd = getServletContext().getRequestDispatcher(
                      "/WEB-INF/content/DisplayTodoList.jsp");
              rd.forward(req, resp);
          } catch (Exception ex) {
              logger.error("error getting todoList:" + ex);
              req.setAttribute("exception", ex);
              RequestDispatcher rd = getServletContext().getRequestDispatcher(
                  "/WEB-INF/content/DisplayException.jsp");
              rd.forward(req, resp);
          }
      }
      
      @Override
      protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
          Map<String, String> pathParams = getPathParams(req);
          String listName = pathParams.get("listName");
          String itemName = pathParams.get("itemName");
          
          try {
              String actionName = req.getParameter("action");
              if (actionName==null) {
                  throw new ServletException("no action provided");
             }
             
             Action action = actions.get(actionName);
             if (action==null) {
                 throw new ServletException("no action found");
             }
             
             TodoListDTO todoList = todosMgmt.getTodoList(listName);
             if (todoList==null) {
                 throw new ServletException("listName not found");                
             }
             
             TodoItemDTO todoItem = itemName!=null ? todoList.getListItem(itemName) : null;
             if (itemName!=null && todoItem==null) {
                 throw new ServletException("itemName not found within todoList");
             }
             
             action.execute(req, resp, todoList, todoItem);
         } catch (Exception ex) {
             logger.error("error getting todoList:" + ex);
             req.setAttribute("exception", ex);
             RequestDispatcher rd = getServletContext().getRequestDispatcher(
                 "/WEB-INF/content/DisplayException.jsp");
             rd.forward(req, resp);
         }
     }
 
     private interface Action {
         void execute(HttpServletRequest req, HttpServletResponse resp,
                 TodoListDTO todoList, TodoItemDTO todoItem) 
                 throws ClientErrorException, ServletException, IOException;
     }
     
     private class DeleteTodoListAction implements Action {
         @Override
         public void execute(HttpServletRequest req, HttpServletResponse resp,
                 TodoListDTO todoList, TodoItemDTO todoItem) 
                         throws ClientErrorException, ServletException, IOException {
             todosMgmt.deleteTodoList(todoList.getName());
             TodoListListDTO todoLists = todosMgmt.getTodoLists(0, 0);
             
             req.setAttribute("todoLists", todoLists.getTodoLists());
             RequestDispatcher rd = getServletContext().getRequestDispatcher(
                     "/WEB-INF/content/DisplayTodoLists.jsp");
             rd.forward(req, resp);
         }        
     }
     
     private class SetPriorityAction implements Action {
         @Override
         public void execute(HttpServletRequest req, HttpServletResponse resp,
                 TodoListDTO todoList, TodoItemDTO todoItem) 
                         throws ClientErrorException, ServletException, IOException {
             int priority = getInt(req.getParameter("priority"), 10);
             todoItem.setPriority(priority);
             todosMgmt.updateTodoListItem(todoList.getName(), todoItem.getName(), todoItem);
                 //get list with new sorted order
             todoList = todosMgmt.getTodoList(todoList.getName());
             
             req.setAttribute("todoList", todoList);
             RequestDispatcher rd = getServletContext().getRequestDispatcher(
                     "/WEB-INF/content/DisplayTodoList.jsp");
             rd.forward(req, resp);
         }
     }
     
     private class DeleteTodoItemAction implements Action {
         @Override
         public void execute(HttpServletRequest req, HttpServletResponse resp,
                 TodoListDTO todoList, TodoItemDTO todoItem) 
                         throws ClientErrorException, ServletException, IOException {
             todosMgmt.deleteTodoListItem(todoList.getName(), todoItem.getName());
                 //get list with new sorted order
             todoList = todosMgmt.getTodoList(todoList.getName());
             
             req.setAttribute("todoList", todoList);
             RequestDispatcher rd = getServletContext().getRequestDispatcher(
                     "/WEB-INF/content/DisplayTodoList.jsp");
             rd.forward(req, resp);
         }
     }
 }