public function processRequest()
 {
     $request = $this->getRequest();
     $user = $request->getUser();
     $slug = PhabricatorSlug::normalize($this->slug);
     if ($slug != $this->slug) {
         $uri = PhrictionDocument::getSlugURI($slug);
         // Canonicalize pages to their one true URI.
         return id(new AphrontRedirectResponse())->setURI($uri);
     }
     require_celerity_resource('phriction-document-css');
     $document = id(new PhrictionDocumentQuery())->setViewer($user)->withSlugs(array($slug))->executeOne();
     $version_note = null;
     $core_content = '';
     $move_notice = '';
     $properties = null;
     if (!$document) {
         $document = new PhrictionDocument();
         if (PhrictionDocument::isProjectSlug($slug)) {
             $project = id(new PhabricatorProjectQuery())->setViewer($user)->withPhrictionSlugs(array(PhrictionDocument::getProjectSlugIdentifier($slug)))->executeOne();
             if (!$project) {
                 return new Aphront404Response();
             }
         }
         $create_uri = '/phriction/edit/?slug=' . $slug;
         $notice = new AphrontErrorView();
         $notice->setSeverity(AphrontErrorView::SEVERITY_NODATA);
         $notice->setTitle(pht('No content here!'));
         $notice->appendChild(pht('No document found at %s. You can <strong>' . '<a href="%s">create a new document here</a></strong>.', phutil_tag('tt', array(), $slug), $create_uri));
         $core_content = $notice;
         $page_title = pht('Page Not Found');
     } else {
         $version = $request->getInt('v');
         if ($version) {
             $content = id(new PhrictionContent())->loadOneWhere('documentID = %d AND version = %d', $document->getID(), $version);
             if (!$content) {
                 return new Aphront404Response();
             }
             if ($content->getID() != $document->getContentID()) {
                 $vdate = phabricator_datetime($content->getDateCreated(), $user);
                 $version_note = new AphrontErrorView();
                 $version_note->setSeverity(AphrontErrorView::SEVERITY_NOTICE);
                 $version_note->appendChild(pht('You are viewing an older version of this document, as it ' . 'appeared on %s.', $vdate));
             }
         } else {
             $content = id(new PhrictionContent())->load($document->getContentID());
         }
         $page_title = $content->getTitle();
         $properties = $this->buildPropertyListView($document, $content, $slug);
         $doc_status = $document->getStatus();
         $current_status = $content->getChangeType();
         if ($current_status == PhrictionChangeType::CHANGE_EDIT || $current_status == PhrictionChangeType::CHANGE_MOVE_HERE) {
             $core_content = $content->renderContent($user);
         } else {
             if ($current_status == PhrictionChangeType::CHANGE_DELETE) {
                 $notice = new AphrontErrorView();
                 $notice->setSeverity(AphrontErrorView::SEVERITY_NOTICE);
                 $notice->setTitle(pht('Document Deleted'));
                 $notice->appendChild(pht('This document has been deleted. You can edit it to put new ' . 'content here, or use history to revert to an earlier version.'));
                 $core_content = $notice->render();
             } else {
                 if ($current_status == PhrictionChangeType::CHANGE_STUB) {
                     $notice = new AphrontErrorView();
                     $notice->setSeverity(AphrontErrorView::SEVERITY_NOTICE);
                     $notice->setTitle(pht('Empty Document'));
                     $notice->appendChild(pht('This document is empty. You can edit it to put some proper ' . 'content here.'));
                     $core_content = $notice->render();
                 } else {
                     if ($current_status == PhrictionChangeType::CHANGE_MOVE_AWAY) {
                         $new_doc_id = $content->getChangeRef();
                         $slug_uri = null;
                         // If the new document exists and the viewer can see it, provide a link
                         // to it. Otherwise, render a generic message.
                         $new_docs = id(new PhrictionDocumentQuery())->setViewer($user)->withIDs(array($new_doc_id))->execute();
                         if ($new_docs) {
                             $new_doc = head($new_docs);
                             $slug_uri = PhrictionDocument::getSlugURI($new_doc->getSlug());
                         }
                         $notice = id(new AphrontErrorView())->setSeverity(AphrontErrorView::SEVERITY_NOTICE);
                         if ($slug_uri) {
                             $notice->appendChild(phutil_tag('p', array(), pht('This document has been moved to %s. You can edit it to put ' . 'new content here, or use history to revert to an earlier ' . 'version.', phutil_tag('a', array('href' => $slug_uri), $slug_uri))));
                         } else {
                             $notice->appendChild(phutil_tag('p', array(), pht('This document has been moved. You can edit it to put new ' . 'contne here, or use history to revert to an earlier ' . 'version.')));
                         }
                         $core_content = $notice->render();
                     } else {
                         throw new Exception("Unknown document status '{$doc_status}'!");
                     }
                 }
             }
         }
         $move_notice = null;
         if ($current_status == PhrictionChangeType::CHANGE_MOVE_HERE) {
             $from_doc_id = $content->getChangeRef();
             $slug_uri = null;
             // If the old document exists and is visible, provide a link to it.
             $from_docs = id(new PhrictionDocumentQuery())->setViewer($user)->withIDs(array($from_doc_id))->execute();
             if ($from_docs) {
                 $from_doc = head($from_docs);
                 $slug_uri = PhrictionDocument::getSlugURI($from_doc->getSlug());
             }
             $move_notice = id(new AphrontErrorView())->setSeverity(AphrontErrorView::SEVERITY_NOTICE);
             if ($slug_uri) {
                 $move_notice->appendChild(pht('This document was moved from %s.', phutil_tag('a', array('href' => $slug_uri), $slug_uri)));
             } else {
                 // Render this for consistency, even though it's a bit silly.
                 $move_notice->appendChild(pht('This document was moved from elsewhere.'));
             }
         }
     }
     $children = $this->renderDocumentChildren($slug);
     $actions = $this->buildActionView($user, $document);
     $crumbs = $this->buildApplicationCrumbs();
     $crumbs->setActionList($actions);
     $crumb_views = $this->renderBreadcrumbs($slug);
     foreach ($crumb_views as $view) {
         $crumbs->addCrumb($view);
     }
     $header = id(new PHUIHeaderView())->setHeader($page_title);
     $prop_list = null;
     if ($properties) {
         $prop_list = new PHUIPropertyGroupView();
         $prop_list->addPropertyList($properties);
     }
     $page_content = id(new PHUIDocumentView())->setOffset(true)->setFontKit(PHUIDocumentView::FONT_SOURCE_SANS)->setHeader($header)->appendChild(array($actions, $prop_list, $version_note, $move_notice, $core_content));
     $core_page = phutil_tag('div', array('class' => 'phriction-offset'), array($page_content, $children));
     return $this->buildApplicationPage(array($crumbs->render(), $core_page), array('pageObjects' => array($document->getPHID()), 'title' => $page_title));
 }