Move all account link / unlink to new registration flow

Summary:
Ref T1536. Currently, we have separate panels for each link/unlink and separate controllers for OAuth vs LDAP.

Instead, provide a single "External Accounts" panel which shows all linked accounts and allows you to link/unlink more easily.

Move link/unlink over to a full externalaccount-based workflow.

Test Plan:
  - Linked and unlinked OAuth accounts.
  - Linked and unlinked LDAP accounts.
  - Registered new accounts.
  - Exercised most/all of the error cases.

Reviewers: btrahan, chad

Reviewed By: btrahan

CC: aran, mbishopim3

Maniphest Tasks: T1536

Differential Revision: https://secure.phabricator.com/D6189

src/applications/auth/controller/PhabricatorAuthUnlinkController.php

@@ -0,0 +1,140 @@
+<?php
+
+final class PhabricatorAuthUnlinkController
+  extends PhabricatorAuthController {
+
+  private $providerKey;
+
+  public function willProcessRequest(array $data) {
+    $this->providerKey = $data['pkey'];
+  }
+
+  public function processRequest() {
+    $request = $this->getRequest();
+    $viewer = $request->getUser();
+
+    list($type, $domain) = explode(':', $this->providerKey, 2);
+
+    // Check that this account link actually exists. We don't require the
+    // provider to exist because we want users to be able to delete links to
+    // dead accounts if they want.
+    $account = id(new PhabricatorExternalAccount())->loadOneWhere(
+      'accountType = %s AND accountDomain = %s AND userPHID = %s',
+      $type,
+      $domain,
+      $viewer->getPHID());
+    if (!$account) {
+      return $this->renderNoAccountErrorDialog();
+    }
+
+    // Check that the provider (if it exists) allows accounts to be unlinked.
+    $provider_key = $this->providerKey;
+    $provider = PhabricatorAuthProvider::getEnabledProviderByKey($provider_key);
+    if ($provider) {
+      if (!$provider->shouldAllowAccountUnlink()) {
+        return $this->renderNotUnlinkableErrorDialog($provider);
+      }
+    }
+
+    // Check that this account isn't the last account which can be used to
+    // login. We prevent you from removing the last account.
+    if ($account->isUsableForLogin()) {
+      $other_accounts = id(new PhabricatorExternalAccount())->loadAllWhere(
+        'userPHID = %s',
+        $viewer->getPHID());
+
+      $valid_accounts = 0;
+      foreach ($other_accounts as $other_account) {
+        if ($other_account->isUsableForLogin()) {
+          $valid_accounts++;
+        }
+      }
+
+      if ($valid_accounts < 2) {
+        return $this->renderLastUsableAccountErrorDialog();
+      }
+    }
+
+    if ($request->isDialogFormPost()) {
+      $account->delete();
+      return id(new AphrontRedirectResponse())->setURI($this->getDoneURI());
+    }
+
+    return $this->renderConfirmDialog($account);
+  }
+
+  private function getDoneURI() {
+    return '/settings/panel/external/';
+  }
+
+  private function renderNoAccountErrorDialog() {
+    $dialog = id(new AphrontDialogView())
+      ->setUser($this->getRequest()->getUser())
+      ->setTitle(pht('No Such Account'))
+      ->appendChild(
+        pht(
+          "You can not unlink this account because it is not linked."))
+      ->addCancelButton($this->getDoneURI());
+
+    return id(new AphrontDialogResponse())->setDialog($dialog);
+  }
+
+  private function renderNotUnlinkableErrorDialog(
+    PhabricatorAuthProvider $provider) {
+
+    $dialog = id(new AphrontDialogView())
+      ->setUser($this->getRequest()->getUser())
+      ->setTitle(pht('Permanent Account Link'))
+      ->appendChild(
+        pht(
+          "You can not unlink this account because the administrator has ".
+          "configured Phabricator to make links to %s accounts permanent.",
+          $provider->getProviderName()))
+      ->addCancelButton($this->getDoneURI());
+
+    return id(new AphrontDialogResponse())->setDialog($dialog);
+  }
+
+  private function renderLastUsableAccountErrorDialog() {
+    $dialog = id(new AphrontDialogView())
+      ->setUser($this->getRequest()->getUser())
+      ->setTitle(pht('Last Valid Account'))
+      ->appendChild(
+        pht(
+          "You can not unlink this account because you have no other ".
+          "valid login accounts. If you removed it, you would be unable ".
+          "to login. Add another authentication method before removing ".
+          "this one."))
+      ->addCancelButton($this->getDoneURI());
+
+    return id(new AphrontDialogResponse())->setDialog($dialog);
+  }
+
+  private function renderConfirmDialog() {
+    $provider_key = $this->providerKey;
+    $provider = PhabricatorAuthProvider::getEnabledProviderByKey($provider_key);
+
+    if ($provider) {
+      $title = pht('Unlink "%s" Account?', $provider->getProviderName());
+      $body = pht(
+        'You will no longer be able to use your %s account to '.
+        'log in to Phabricator.',
+        $provider->getProviderName());
+    } else {
+      $title = pht('Unlink Account?');
+      $body = pht(
+        'You will no longer be able to use this account to log in '.
+        'to Phabricator.');
+    }
+
+    $dialog = id(new AphrontDialogView())
+      ->setUser($this->getRequest()->getUser())
+      ->setTitle($title)
+      ->appendChild($body)
+      ->addSubmitButton(pht('Unlink Account'))
+      ->addCancelButton($this->getDoneURI());
+
+    return id(new AphrontDialogResponse())->setDialog($dialog);
+  }
+
+}