Give Diviner a non-legacy root controller

Summary: Ref T988. Instead of hard-coding the application landing page, make the Diviner root show books if any have been generated. Otherwise, show a helpful message about how to generate documentation locally.

Test Plan:
{F122723}

{F122724}

Reviewers: chad, btrahan

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T988

Differential Revision: https://secure.phabricator.com/D8416

src/applications/diviner/controller/DivinerMainController.php

@@ -0,0 +1,85 @@
+<?php
+
+final class DivinerMainController extends DivinerController {
+
+  public function processRequest() {
+    $request = $this->getRequest();
+    $viewer = $request->getUser();
+
+    $books = id(new DivinerBookQuery())
+      ->setViewer($viewer)
+      ->execute();
+
+    $crumbs = $this->buildApplicationCrumbs();
+    $crumbs->addTextCrumb(pht('Books'));
+
+    $search_icon = id(new PHUIIconView())
+      ->setSpriteIcon('search')
+      ->setSpriteSheet(PHUIIconView::SPRITE_ICONS);
+
+    $query_button = id(new PHUIButtonView())
+      ->setTag('a')
+      ->setHref($this->getApplicationURI('query/'))
+      ->setText(pht('Advanced Search'))
+      ->setIcon($search_icon);
+
+    $header = id(new PHUIHeaderView())
+      ->setHeader(pht('Documentation Books'))
+      ->addActionLink($query_button);
+
+    $document = new PHUIDocumentView();
+    $document->setHeader($header);
+
+    if ($books) {
+      $list = id(new PHUIObjectItemListView())
+        ->setUser($viewer)
+        ->setPlain(true);
+
+      $books = msort($books, 'getTitle');
+      foreach ($books as $book) {
+        $item = id(new PHUIObjectItemView())
+          ->setHref('/book/'.$book->getName().'/')
+          ->setHeader($book->getTitle())
+          ->addAttribute($book->getPreface());
+
+        $list->addItem($item);
+      }
+
+      $document->appendChild($list);
+    } else {
+      $text = pht(
+        "(NOTE) **Looking for Phabricator documentation?** If you're looking ".
+        "for help and information about Phabricator, you can ".
+        "[[ https://secure.phabricator.com/diviner/ | browse the public ".
+        "Phabricator documentation ]] on the live site.\n\n".
+        "Diviner is the documentation generator used to build the Phabricator ".
+        "documentation.\n\n".
+        "You haven't generated any Diviner documentation books yet, so ".
+        "there's nothing to show here. If you'd like to generate your own ".
+        "local copy of the Phabricator documentation and have it appear ".
+        "here, run this command:\n\n".
+        "  phabricator/ $ ./bin/diviner generate\n\n".
+        "Right now, Diviner isn't very useful for generating documentation ".
+        "for projects other than Phabricator. If you're interested in using ".
+        "it in your own projects, leave feedback for us on ".
+        "[[ https://secure.phabricator.com/T4558 | T4558 ]].");
+
+      $text = PhabricatorMarkupEngine::renderOneObject(
+        id(new PhabricatorMarkupOneOff())->setContent($text),
+        'default',
+        $viewer);
+
+      $document->appendChild($text);
+    }
+
+    return $this->buildApplicationPage(
+      array(
+        $crumbs,
+        $document,
+      ),
+      array(
+        'title' => pht('Documentation Books'),
+        'device' => true,
+      ));
+  }
+}