package com.atlassian.refapp.decorator;
   
   import com.atlassian.templaterenderer.TemplateRenderer;
   
   import javax.servlet.Filter;
   import javax.servlet.FilterChain;
   import javax.servlet.FilterConfig;
   import javax.servlet.ServletException;
   import javax.servlet.ServletRequest;
  import javax.servlet.ServletResponse;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  import java.io.IOException;
  import java.util.HashMap;
  import java.util.Map;
  
  public class DecoratorServletFilter implements Filter {
      private final TemplateRenderer templateRenderer;
  
      public DecoratorServletFilter(TemplateRenderer templateRenderer) {
          this.templateRenderer = templateRenderer;
      }
  
      public void init(FilterConfig filterConfig) throws ServletException {
      }
  
      public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain)
              throws IOException, ServletException {
          if (!(servletRequest instanceof HttpServletRequest)) {
              filterChain.doFilter(servletRequest, servletResponse);
              return;
          }
          HttpServletRequest request = (HttpServletRequest) servletRequest;
          HttpServletResponse response = (HttpServletResponse) servletResponse;
          if (request.getServletPath().equals("/index.jsp") && !request.getRequestURI().contains("index.jsp")) {
              // The container has sent us to the welcome page
              render("/templates/index.vm", request, response);
              return;
          }
          if (request.getServletPath().equals("/admin")) {
              render("/templates/admin.vm", request, response);
              return;
          }
          filterChain.doFilter(servletRequest, servletResponse);
      }
  
      public void destroy() {
      }
  
      private void render(String template, HttpServletRequest request, HttpServletResponse response) throws
              IOException {
          response.setContentType("text/html");
          templateRenderer.render(template, getContext(request), response.getWriter());
      }
  
      private Map<String, Object> getContext(HttpServletRequest request) {
          Map<String, Object> context = new HashMap<String, Object>();
          context.put("request", request);
          return context;
      }
  }