package common.http;
   
   import usecase.auth.CurrentUser;
   
   import javax.inject.Inject;
   import javax.servlet.FilterChain;
   import javax.servlet.ServletException;
   import javax.servlet.annotation.WebFilter;
   import javax.servlet.http.HttpFilter;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  import java.io.IOException;
  import java.net.URI;
  import java.net.URISyntaxException;
  
  @WebFilter("*")
  class AliasFilter extends HttpFilter {
      @Inject CurrentUser currentUser;
  
      @Override
      protected void doFilter(HttpServletRequest req, HttpServletResponse res, FilterChain chain) throws IOException, ServletException {
          String requri;
          try {
              requri = new URI(req.getRequestURI())
                      .normalize() //rimuove slash multipli e simili
                      .toString()
                      .substring(req.getContextPath().length() +1 );
          } catch (URISyntaxException e) {
              chain.doFilter(req, res);
              return;
          }
          String[] splits = requri.split("/+");
          switch(splits[0]){
              case "me":{
                  if(currentUser.isLoggedIn()){
                      req.getRequestDispatcher("/user?name=" + currentUser.getUsername() + '&' + req.getQueryString())
                              .forward(req, res);
                      return;
                  } else {
                      res.sendError(HttpServletResponse.SC_UNAUTHORIZED);
                      return;
                  }
              }
              case "popular": {
                  req.getRequestDispatcher("/home?view=popular" + '&' + req.getQueryString()).forward(req, res);
                  return;
              }
              case "feed":{
                  req.getRequestDispatcher("/home?view=following" + '&' + req.getQueryString()).forward(req, res);
                  return;
              }
              case "s":{
                  if(splits.length >= 2) {
                      req.getRequestDispatcher("/s?section=" + splits[1] + '&' + req.getQueryString()).forward(req, res);
                      return;
                  }
                  break;
              }
              case "u": {
                  if (splits.length >= 2) {
                      req.getRequestDispatcher("/user?name=" + splits[1] + '&' + req.getQueryString()).forward(req, res);
                      return;
                  }
                  break;
              }
              case "post":{
                  if(splits.length >= 2){
                      req.getRequestDispatcher("/post?id=" + splits[1] + '&' + req.getQueryString()).forward(req, res);
                      return;
                  }
                  break;
              }
          }
  
          chain.doFilter(req, res);
      }
  }