Add very basic UI for creating milestones and subprojects

Summary:
Ref T10010. This has a lot of UI/UX problems but I think it:

  - technically allows subproject creation;
  - technically allows milestone creation;
  - doesn't let users unwittingly destroy their installs (probably).

Test Plan:
  - Created milestones.
  - Created subprojects.
  - Created and edited normal projects.
  - Observed some reasonable interactions (e.g., you can't create milestones for a milestone or edit a superproject's members).
  - Observed plenty of silly/confusing interactions that need additional work.

{F1046657}

{F1046658}

{F1046655}

{F1046656}

{F1046654}

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T10010

Differential Revision: https://secure.phabricator.com/D14904

src/applications/project/controller/PhabricatorProjectSubprojectsController.php

@@ -18,6 +18,63 @@ final class PhabricatorProjectSubprojectsController
     $project = $this->getProject();
     $id = $project->getID();
 
+    $can_edit = PhabricatorPolicyFilter::hasCapability(
+      $viewer,
+      $project,
+      PhabricatorPolicyCapability::CAN_EDIT);
+
+    $has_support = $project->supportsSubprojects();
+
+    if ($has_support) {
+      $subprojects = id(new PhabricatorProjectQuery())
+        ->setViewer($viewer)
+        ->withParentProjectPHIDs(array($project->getPHID()))
+        ->needImages(true)
+        ->withIsMilestone(false)
+        ->execute();
+    } else {
+      $subprojects = array();
+    }
+
+    $can_create = $can_edit && $has_support;
+
+    if ($project->getHasSubprojects()) {
+      $button_text = pht('Create Subproject');
+    } else {
+      $button_text = pht('Add Subprojects');
+    }
+
+    $header = id(new PHUIHeaderView())
+      ->setHeader(pht('Subprojects'))
+      ->addActionLink(
+        id(new PHUIButtonView())
+          ->setTag('a')
+          ->setHref("/project/edit/?parent={$id}")
+          ->setIconFont('fa-plus')
+          ->setDisabled(!$can_create)
+          ->setWorkflow(!$can_create)
+          ->setText($button_text));
+
+    $box = id(new PHUIObjectBoxView())
+      ->setHeader($header);
+
+    if (!$has_support) {
+      $no_support = pht(
+        'This project is a milestone. Milestones can not have subprojects.');
+
+      $info_view = id(new PHUIInfoView())
+        ->setErrors(array($no_support))
+        ->setSeverity(PHUIInfoView::SEVERITY_WARNING);
+
+      $box->setInfoView($info_view);
+    }
+
+    $box->setObjectList(
+      id(new PhabricatorProjectListView())
+        ->setUser($viewer)
+        ->setProjects($subprojects)
+        ->renderList());
+
     $nav = $this->buildIconNavView($project);
     $nav->selectFilter("subprojects/{$id}/");
 
@@ -27,7 +84,8 @@ final class PhabricatorProjectSubprojectsController
     return $this->newPage()
       ->setNavigation($nav)
       ->setCrumbs($crumbs)
-      ->setTitle(array($project->getName(), pht('Subprojects')));
+      ->setTitle(array($project->getName(), pht('Subprojects')))
+      ->appendChild($box);
   }
 
 }