<?php

final class EditRevisionDependenciesAPIMethod extends DifferentialConduitAPIMethod {

  public function getAPIMethodName() {
    return 'differential.editdependencies';
  }

  public function getMethodDescription() {
    return pht('Edit the dependencies for differential revisions.');
  }

  protected function defineParamTypes() {
    return [
      'revisionPHID'            => 'required id',
      'dependsOnRevisionPHIDs'  => 'optional list<phid>',
    ];
  }

  protected function defineReturnType() {
    return 'nonempty dict';
  }

  protected function defineErrorTypes() {
    return [
      'ERR_GRAPH_CYCLE'   => pht(
        'The relationships between objects described in this request would creates a cycle in '.
        'their dependency graph.'),
      'ERR_BAD_REVISION'  => pht(
        'The specified revision PHID does not correspond to an existing differential revision.'),
    ];
  }

  protected function execute(ConduitAPIRequest $request) {
    $user = $request->getUser();
    $phid = $request->getValue('revisionPHID');
    $attach_type = DifferentialRevisionPHIDType::TYPECONST;
    $action = PhabricatorSearchAttachController::ACTION_DEPENDENCIES;

    $revision = (new DifferentialRevisionQuery)
      ->setViewer($user)
      ->withPHIDs([$phid])
      ->needRelationships(true)
      ->executeOne();

    if (!$revision) {
      throw new ConduitException('ERR_BAD_REVISION');
    }

    $edge_type = DifferentialRevisionDependsOnRevisionEdgeType::EDGECONST;

    $phids = $request->getValue('dependsOnRevisionPHIDs', []);

    $old_phids = PhabricatorEdgeQuery::loadDestinationPHIDs(
      $phid,
      $edge_type);
    $add_phids = $phids;
    $rem_phids = array_diff($old_phids, $add_phids);

    $txn_editor = $revision->getApplicationTransactionEditor()
      ->setActor($user)
      ->setContentSourceFromConduitRequest($request)
      ->setContinueOnMissingFields(true)
      ->setContinueOnNoEffect(true);

    $txn_template = $revision->getApplicationTransactionTemplate()
      ->setTransactionType(PhabricatorTransactions::TYPE_EDGE)
      ->setMetadataValue('edge:type', $edge_type)
      ->setNewValue([
          '+' => array_fuse($add_phids),
          '-' => array_fuse($rem_phids),
        ]);

    try {
      $txn_editor->applyTransactions(
        $revision->getApplicationTransactionObject(),
        [$txn_template]);
    } catch (PhabricatorEdgeCycleException $ex) {
      throw new ConduitException('ERR_GRAPH_CYCLE');
    }

    return [
      'revision' => [
        'id' => $revision->getID(),
        'phid' => $revision->getPHID(),
        'dependencies' => $phids,
      ],
      'edits' => [
        'oldDependencies' => $old_phids,
        'newDependencies' => $add_phids,
        'removedDependencies' => $rem_phids,
      ],
    ];
  }

}