Creating an action to do a moderation state transition automatically

As a followup, since I needed to get this done ASAP for a project, I went ahead and wrote the code using hook_action_info(). I've pasted it below for review from the maintainer / community.

I've done a small amount of testing and so far it is working for me.

It seems like the next natural step would be to add some validation to the action to make sure the state transition is applicable to the current state of the revision, as well as the content type of the node. Perhaps it would be better to change the "from source state to destination state" concept in the action config to simply the destination state.

function content_moderation_action_info() {
  $info = array();

  $info['content_moderation_transition_action'] = array(
      'type' => 'node',
      'description' => t('Perform a transition between content moderation states'),
      'configurable' => TRUE,
      'hooks' => array(
        'nodeapi' => array('presave', 'update', 'insert'),
      ),
  );

  return $info;
}

function content_moderation_transition_action_form($context) {
  static $transitions = array();

  // caching
  if(count($transitions) == 0) {
    $states = _content_moderation_states();

    foreach($states as $from_state) {
      $to_states = _content_moderation_next_states($from_state);
        // Values are translated.
      $to_states = array_keys($to_states);
      foreach($to_states as $to_state) {
        $transitions["{$from_state}|~|{$to_state}"] =
          t("@from_state to @to_state", array('@from_state' => $from_state, '@to_state' => $to_state));
      }
    }
  }

  $form['transition'] = array(
      '#type' => 'select',
      '#title' => t('Transition to Perform'),
      '#description' => t('Choose the state transition to execute on the new node revision'),
      '#options' => $transitions,
      '#default_value' => isset($context['transition']) ? $context['transition'] : NULL,
      '#required' => TRUE,
  );

  return $form;
}

function content_moderation_transition_action_submit($form, $form_state) {
  return array(
      'transition' => $form_state['values']['transition'],
  );
}

function content_moderation_transition_action($node, $context) {
  list($oldstate, $newstate) = explode('|~|', $context['transition']);

  // Change the revision state.
  _content_moderation_update_revision_state($node->vid, $node->nid, $newstate);

  if($nextstate == 'live') {
    _content_moderation_set_live($node->vid,$node->nid);
  }

  // History entry.
  _content_moderation_save_history($node,$curstate,$nextstate,$user->uid,$comment);
}