package usecase.post;
   
   import common.http.ParameterConverter;
   import common.http.interceptor.InterceptableServlet;
   import usecase.comment.CommentDTO;
   import usecase.comment.CommentService;
   
   import javax.inject.Inject;
   import javax.servlet.ServletException;
  import javax.servlet.annotation.WebServlet;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  import java.io.IOException;
  import java.util.Collections;
  import java.util.List;
  import java.util.Map;
  
  /**
   * Servlet per la visualizzazione di un post e i relativi commenti.
   */
  @WebServlet("/post")
  class PostServlet extends InterceptableServlet {
  
      @Inject private PostService postService;
      @Inject private CommentService service;
  
      @Override
      public void init() throws ServletException {
          getServletContext().setAttribute("maxCommentDepth", 3);
      }
  
      @Override
      protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
          ParameterConverter converter = new ParameterConverter(req);
          int postId = converter.getIntParameter("id").orElse(0); //viene ignorato se commentId != 0
          int commentId = converter.getIntParameter("comment").orElse(0);
  
          PostPage post;
          Map<Integer, List<CommentDTO>> comments;
          int initialIndex;
          if (commentId == 0) {
              post = postService.getPost(postId);
              comments = service.getPostComments(postId);
              initialIndex = 0; //si parte dai root comments
          } else{
              comments = service.getReplies(commentId);
              initialIndex = Collections.min(comments.keySet()); //il commento di partenza è quello all'indice più basso
              postId = comments.get(initialIndex).get(0).getPostId(); //prendi un commento qualsiasi, ricava il postId
              post = postService.getPost(postId);
          }
  
          req.setAttribute("post", post);
          req.setAttribute("comments", comments);
          req.setAttribute("initialIndex", initialIndex);
          req.getRequestDispatcher("/WEB-INF/views/section/post.jsp").forward(req, resp);
      }
  
      @Override
      protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
          doGet(req, resp);
      }
  }