<?php

final class WarningCustomField extends DifferentialCustomField {

  public function getFieldKey() {
    return 'mycompany:mycustomfield';
  }

  public function shouldAppearInPropertyView() {
    // This is required or the field won't be loaded on the detail page.
    return true;
  }

  public function renderPropertyViewValue(array $handles) {
    // This prevents it from actually rendering a property.
    return null;
  }

  public function getWarningsForRevisionHeader(array $handles) {
    $warnings = array();

    $revision = $this->getObject();

    // Check if the revision belongs to a repository where test plans are
    // required but does not have one.


    $test_plan = $revision->getTestPlan();
    if (strlen($test_plan)) {
      // We have a test plan.
      return $warnings;
    }

    $repository = $revision->getRepository();
    if ($repository) {
      switch ($repository->getCallsign()) {
        case 'A':
        case 'B':
          // Test plans are optional in these repositories.
          return $warnings;
      }
    }

    $warnings[] = pht(
      'This revision belongs to a repository where a test plan is required, '.
      'but it does not have one.');

    return $warnings;
  }

}