package com.atlassian.refapp.decorator;
   
   import com.atlassian.refapp.auth.external.WebSudoSessionManager;
   import com.atlassian.soy.renderer.SoyException;
   import com.atlassian.soy.renderer.SoyTemplateRenderer;
   import com.atlassian.templaterenderer.RenderingException;
   import com.atlassian.templaterenderer.TemplateRenderer;
   import com.google.common.collect.ImmutableMap;
   import com.opensymphony.module.sitemesh.HTMLPage;
  import com.opensymphony.module.sitemesh.Page;
  import com.opensymphony.module.sitemesh.RequestConstants;
  import com.opensymphony.module.sitemesh.util.OutputConverter;
  import org.apache.commons.io.IOUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import javax.servlet.ServletContext;
  import javax.servlet.ServletException;
  import javax.servlet.http.HttpServlet;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.PrintWriter;
  import java.io.StringWriter;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.Map;
  import java.util.Properties;
  
  public class DecoratorServlet extends HttpServlet {
      private static final Logger log = LoggerFactory.getLogger(DecoratorServlet.class);
      private static final String SERVLET_PATH = "/refappdecorator";
      private static final String PROPERTIES_LOCATION = "/META-INF/maven/com.atlassian.refapp/atlassian-refapp/pom.properties";
  
      private final TemplateRenderer templateRenderer;
      private final SoyTemplateRenderer soyTemplateRenderer;
      private final WebSudoSessionManager webSudoSessionManager;
  
      public DecoratorServlet(TemplateRenderer templateRenderer, WebSudoSessionManager webSudoSessionManager, final SoyTemplateRenderer soyTemplateRenderer) {
          this.templateRenderer = templateRenderer;
          this.webSudoSessionManager = webSudoSessionManager;
          this.soyTemplateRenderer = soyTemplateRenderer;
      }
  
      protected void service(HttpServletRequest request, HttpServletResponse response)
              throws ServletException, IOException {
          Page page = (Page) request.getAttribute(RequestConstants.PAGE);
          if (page != null) {
              applyDecoratorUsingVelocity(request, page, response);
          } else {
              String servletPath = (String) request.getAttribute("javax.servlet.include.servlet_path");
              if (servletPath == null) {
                  servletPath = request.getServletPath();
              }
              throw new ServletException("No sitemesh page to decorate. This servlet should not be invoked directly. " +
                      "The path invoked was " + servletPath);
          }
      }
  
      private void applyDecoratorUsingVelocity(HttpServletRequest request, Page page, HttpServletResponse response) throws
              IOException {
          String template;
          String pathInfo = (String) request.getAttribute("javax.servlet.include.path_info");
          if (pathInfo == null) {
              pathInfo = request.getPathInfo();
          }
          if (pathInfo != null) {
              template = mapPathToTemplate(pathInfo);
          } else {
              template = "/templates/general.vmd";
          }
  
          Map<String, Object> velocityParams = getVelocityParams(request, page, response);
  
          final PrintWriter writer = response.getWriter();
          try {
              response.setContentType("text/html");
              templateRenderer.render(template, velocityParams, writer);
          } catch (RenderingException e) {
              writer.write("Exception rendering velocity file " + template);
              writer.write("<br><pre>");
              e.printStackTrace(writer);
              writer.write("</pre>");
          }
      }
  
      private String mapPathToTemplate(String pathInfo) {
          if (pathInfo.startsWith(SERVLET_PATH)) {
              return pathInfo.replace(SERVLET_PATH, "templates");
          }
  
          return pathInfo;
      }
  
      private Properties getPropertiesFromServletContext(String location) throws IOException {
          ServletContext servletContext = getServletConfig().getServletContext();
          InputStream in = servletContext.getResourceAsStream(location);
  
         if (in == null) {
             throw new IOException("Resource '" + location + "' not found");
         }
 
         try {
             Properties properties = new Properties();
             properties.load(in);
             return properties;
         } finally {
             IOUtils.closeQuietly(in);
         }
     }
 
     private Map<String, Object> getVelocityParams(HttpServletRequest request, Page page, HttpServletResponse response)
             throws IOException {
         Map<String, Object> velocityParams = new HashMap<String, Object>();
 
         String version;
         try {
             Properties properties = getPropertiesFromServletContext(PROPERTIES_LOCATION);
             version = properties.getProperty("version");
         } catch (IOException e) {
             version = "(unknown)";
         }
         velocityParams.put("version", version);
 
         velocityParams.put("page", page);
 
         if (webSudoSessionManager.isWebSudoSession(request)) {
             velocityParams.put("websudosession", Boolean.TRUE.toString());
         }
 
         String titleHtml = page.getTitle();
         if (titleHtml == null || titleHtml.isEmpty()) {
             titleHtml = "Welcome!";
         }
 
         velocityParams.put("titleHtml", titleHtml);
 
         String htmlClass = page.getProperty("class");
 
         if (htmlClass != null) {
             velocityParams.put("headClass", htmlClass);
         }
 
         String bodyClass = page.getProperty("body.class");
         if (bodyClass != null) {
             velocityParams.put("bodyClass", bodyClass);
         }
 
         StringWriter bodyBuffer = new StringWriter();
         page.writeBody(OutputConverter.getWriter(bodyBuffer));
         velocityParams.put("bodyHtml", bodyBuffer);
 
         if (page instanceof HTMLPage) {
             HTMLPage htmlPage = (HTMLPage) page;
             StringWriter buffer = new StringWriter();
             htmlPage.writeHead(OutputConverter.getWriter(buffer));
             velocityParams.put("headHtml", buffer.toString());
         }
 
         try {
             velocityParams.put("headerBeforeContent", soyTemplateRenderer.render("com.atlassian.plugins.atlassian-nav-links-plugin:rotp-menu",
                     "navlinks.templates.appswitcher.switcher", Collections.<String, Object>emptyMap()));
 
 
             // Build secondary navigation
             StringWriter secondaryNavigation = new StringWriter();
             templateRenderer.render("/templates/navigation.vm", new ImmutableMap.Builder<String, Object>()
                             .put("request", request)
                             .put("response", response)
                             .build(),
                     secondaryNavigation);
 
             velocityParams.put("secondaryNavContent", secondaryNavigation.toString());
         } catch (SoyException e) {
             log.error("Failed to render Soy template due to {}", e.getMessage(), e);
         }
 
         velocityParams.put("request", request);
         velocityParams.put("response", response);   // as of 2.5.0 both req and resp must be available in all apps
         velocityParams.put("soy", soyTemplateRenderer);
         return velocityParams;
     }
 }