<?php

final class WaitForPreviousBuildStepImplementation
  extends BuildStepImplementation {

  public function getName() {
    return pht('Wait for Previous Commits to Build');
  }

  public function getGenericDescription() {
    return pht(
      'Wait for previous commits to finish building the current plan '.
      'before continuing.');
  }

  public function getDescription() {
    return pht(
      'Wait for previous commits to finish building the current plan '.
      'before continuing.');
  }

  public function execute(
    HarbormasterBuild $build,
    HarbormasterBuildTarget $build_target) {

    // We can only wait when building against commits.
    $buildable = $build->getBuildable();
    $object = $buildable->getBuildableObject();
    if (!($object instanceof PhabricatorRepositoryCommit)) {
      return;
    }

    // We are blocked until all previous builds finish.
    $build->setBuildStatus(HarbormasterBuild::STATUS_WAITING);
    $build->save();

    // Block until all previous builds of the same build plan have
    // finished.
    $plan = $build->getBuildPlan();

    $log = null;
    $log_start = null;
    $blockers = $this->getBlockers($object, $plan, $build);
    while (count($blockers) > 0) {
      if ($build->checkForCancellation()) {
        if ($log !== null) {
          $log->finalize($log_start);
        }
        return;
      }

      if ($log === null) {
        $log = $build->createLog($build_target, "waiting", "blockers");
        $log_start = $log->start();
      }

      $log->append("Blocked by: ".implode(",", $blockers)."\n");

      sleep(1);
      $blockers = $this->getBlockers($object, $plan, $build);
    }
    if ($log !== null) {
      $log->finalize($log_start);
    }

    // Move back into building status.
    $build->setBuildStatus(HarbormasterBuild::STATUS_BUILDING);
    $build->save();
  }

  private function getBlockers(
    PhabricatorRepositoryCommit $commit,
    HarbormasterBuildPlan $plan,
    HarbormasterBuild $source) {

    $call = new ConduitCall(
      'diffusion.commitparentsquery',
      array(
        'commit'   => $commit->getCommitIdentifier(),
        'callsign' => $commit->getRepository()->getCallsign()
      ));
    $call->setUser(PhabricatorUser::getOmnipotentUser());
    $parents = $call->execute();

    $parents = id(new DiffusionCommitQuery())
      ->setViewer(PhabricatorUser::getOmnipotentUser())
      ->withRepository($commit->getRepository())
      ->withIdentifiers($parents)
      ->execute();

    $blockers = array();

    $build_objects = array();
    foreach ($parents as $parent) {
      if (!$parent->isImported()) {
        $blockers[] = pht('Commit %s', $parent->getCommitIdentifier());
      } else {
        $build_objects[] = $parent->getPHID();
      }
    }

    $buildables = id(new HarbormasterBuildableQuery())
      ->setViewer(PhabricatorUser::getOmnipotentUser())
      ->withBuildablePHIDs($build_objects)
      ->withManualBuildables(false)
      ->execute();
    $buildable_phids = mpull($buildables, 'getPHID');

    $builds = id(new HarbormasterBuildQuery())
      ->setViewer(PhabricatorUser::getOmnipotentUser())
      ->withBuildablePHIDs($buildable_phids)
      ->withBuildPlanPHIDs(array($plan->getPHID()))
      ->execute();

    foreach ($builds as $build) {
      if ($build->isBuilding()) {
        $blockers[] = pht('Build %d', $build->getID());
      }
    }

    return $blockers;
  }
}