<?php

/**
 * @file
 * Module file. Defines module hooks.
 */

define('OPIGNO_QUIZ_APP_PASSED',  'passed');
define('OPIGNO_QUIZ_APP_FAILED',  'failed');
define('OPIGNO_QUIZ_APP_PENDING', 'pending');

/**
 * Implements hook_menu().
 */
function opigno_quiz_app_menu() {
  return array(
    'user/%/achievements' => array(
      'title' => "My achievements",
      'page callback' => 'opigno_quiz_app_user_results',
      'page arguments' => array(1),
      'access arguments' => array('access student results'),
      'file' => 'includes/opigno_quiz_app.pages.inc',
      'type' => MENU_LOCAL_TASK,
    ),
    'my-achievements' => array(
      'title' => "My achievements",
      'page callback' => 'opigno_quiz_app_user_results',
      'access arguments' => array('access student results'),
      'file' => 'includes/opigno_quiz_app.pages.inc',
      'type' => MENU_CALLBACK,
    ),
    'my-results' => array(
      'title' => "My results",
      'page callback' => 'opigno_quiz_app_current_user_results',
      'access callback' => 'user_is_logged_in',
      'file' => 'includes/opigno_quiz_app.pages.inc',
      'type' => MENU_CALLBACK,
    ),
    'node/%node/teacher-results' => array(
      'title' => "Student results",
      'description' => "Displays all student results to teachers",
      'page callback' => 'opigno_quiz_app_course_results',
      'page arguments' => array(1),
      'access callback' => 'opigno_quiz_app_access_node_teacher_results',
      'access arguments' => array(1, NULL),
      'file' => 'includes/opigno_quiz_app.pages.inc',
      'type' => MENU_CALLBACK,
    ),
    'node/%node/sort-quizzes' => array(
      'title' => "Sort @quiz_name_plural",
      'title arguments' => array('@quiz_name_plural' => defined('QUIZ_NAME_PLURAL') ? QUIZ_NAME_PLURAL : 'quizzes'),
      'description' => "Sort quizzes inside the course",
      'page callback' => 'drupal_get_form',
      'page arguments' => array('opigno_quiz_app_sort_course_quizzes_form', 1),
      'access callback' => 'opigno_quiz_app_access_node_sort_quizzes',
      'access arguments' => array(1),
      'file' => 'includes/opigno_quiz_app.pages.inc',
      'type' => MENU_CALLBACK,
    ),
    'admin/opigno/students/teacher-results' => array(
      'title' => "My course student results",
      'description' => "Displays all course student results to teachers",
      'page callback' => 'opigno_quiz_app_courses_results',
      'access arguments' => array('access teacher results'),
      'file' => 'includes/opigno_quiz_app.pages.inc',
    )
  );
}

/**
 * Implements hook_menu_alter().
 */
function opigno_quiz_app_menu_alter(&$items) {
  // Intercept Quiz taking rendering for fullscreen logic.
  $items['node/%node/take']['page callback'] = 'opigno_quiz_app_quiz_take';
  $items['node/%node/take']['file'] = 'includes/opigno_quiz_app.pages.inc';
  $items['node/%node/take']['file path'] = drupal_get_path('module', 'opigno_quiz_app');
}

/**
 * Implements hook_permission().
 */
function opigno_quiz_app_permission() {
  return array(
    'access student results' => array(
      'title' => t("Access student results"),
    ),
    'access teacher results' => array(
      'title' => t('Access teacher results'),
      'description' => t('Allows course teachers to access all their student results.'),
    ),
  );
}

/**
 * Implements hook_og_permission().
 */
function opigno_quiz_app_og_permission() {
  return array(
    'skip display of results' => array(
      'title' => t("Skip displaying results on teacher results page"),
      'description' => t("Some roles might be allowed to take quizzes, but these should not be shown on the teacher results page.")
    ),
    'sort quizzes' => array(
      'title' => t("Sort quizzes inside this course"),
    ),
  );
}

/**
 * Implements hook_node_insert().
 */
function opigno_quiz_app_node_insert($node) {
  if ($node->type == 'quiz' && !empty($node->nid) && !empty($node->og_group_ref)) {
    foreach ($node->og_group_ref as $lang => $items) {
      foreach ($items as $item) {
        // Set a default weight of 0.
        opigno_quiz_app_set_course_quiz_weight($item['target_id'], $node->nid);
      }
    }
  }
}

/**
 * Implements hook_node_view().
 */
function opigno_quiz_app_node_view($node) {
  
}

/**
 * Implements hook_og_context_negotiation_info
 */
function opigno_quiz_app_og_context_negotiation_info() {
  $providers = array();
  $paths = array();
  foreach (opigno_quiz_app_get_quiz_question_types() as $type) {
    $type = str_replace('_', '-', $type);
    $paths[] = "node/add/$type";
  }

  $providers['opigno_quiz_app_question_add'] = array(
    'name' => t('Opigno Quiz App: add question'),
    'description' => t("Determine context by checking node/add/[question type]."),
    'callback' => 'opigno_quiz_app_og_context_handler',
    'menu path' => $paths,
  );

  return $providers;
}

/**
 * OG Context provider.
 *
 * When creating a Quiz question, check the parent Quiz. If it's part
 * of a group, return the group context.
 *
 * @return array
 */
function opigno_quiz_app_og_context_handler() {
  if (opigno_quiz_app_is_node_add_question()) {
    $node = (object) array(
      'type' => str_replace('-', '_', array_pop(explode('/', current_path()))),
    );
    og_quiz_node_prepare($node);
    if (isset($node->og_group_ref)) {
      $items = array_shift($node->og_group_ref);
      $gid = $items[0]['target_id'];
      return array('node' => array($gid));
    }
  }
}

/**
 * Implements hook_opigno_breadcrumbs().
 */
function opigno_quiz_app_opigno_breadcrumbs($gid) {
  $breadcrumbs = array();

  $node = menu_get_object();
  // Must we handle this page request for the breadcrumb ?
  if ((isset($node->type) && $node->type == 'quiz') || 
      current_path() == 'node/add/quiz' ||
      preg_match('/^node\/[0-9]+\/sort-quizzes$/', current_path()) || 
      opigno_quiz_app_is_node_add_question()) {
    
    // Add the Opigno Quizzes view link.
    $breadcrumbs[] = l(opigno_quiz_app_get_quizzes_view_title(), "node/$gid/quizzes");

    // Is this a sub page of the quiz (like node/%/take) ? Add the Quiz itself.
    if (isset($node->type) && $node->type == 'quiz' && preg_match('/^node\/[0-9]+\/.+/', current_path())) {
      $breadcrumbs[] = l($node->title, "node/{$node->nid}");
    }
    // Is this a question add form ? And the parent Quiz NID is given in the URL ?
    // Add the parent Quiz title and the manage question tab.
    if (opigno_quiz_app_is_node_add_question() && !empty($_GET['quiz_nid'])) {
      $quiz = node_load($_GET['quiz_nid']);
      $breadcrumbs[] = l($quiz->title, "node/{$_GET['quiz_nid']}");
      $breadcrumbs[] = l(t("Manage questions"), "node/{$_GET['quiz_nid']}/questions");
    }
  }

  if (!empty($breadcrumbs)) {
    return $breadcrumbs;
  }
}

/**
 * Implements hook_menu_local_tasks_alter().
 */
function opigno_quiz_app_menu_local_tasks_alter(&$data, $router_item, $root_path) {
  if ($root_path == 'node/%/quizzes') {
    $gid = arg(1);
    if (og_user_access('node',$gid,'create quiz content')) {
      $item = menu_get_item('node/add/quiz');
      $item['title'] = t("Add a new @quiz_name", array('@quiz_name' => QUIZ_NAME));
      $item['options']['query']['og_group_ref'] = $item['localized_options']['query']['og_group_ref'] = $gid;
      $item['options']['attributes']['class'][] = $item['localized_options']['attributes']['class'][] = 'opigno-quiz-app-add-quiz';
      $data['actions']['output'][] = array(
        '#theme' => 'menu_local_action',
        '#link' => $item,
      );
    }
    $node=node_load($gid);
    if (opigno_quiz_app_access_node_sort_quizzes($node,NULL)) {
      $item = menu_get_item("node/$gid/sort-quizzes");
      $destination = request_path();
      $item['options']['query']['destination'] = $item['localized_options']['query']['destination'] = $destination;
      $item['options']['attributes']['class'][] = $item['localized_options']['attributes']['class'][] = 'opigno-quiz-app-sort-quizzes';
      $data['actions']['output'][] = array(
        '#theme' => 'menu_local_action',
        '#link' => $item,
      );
    }
  }
}

/**
 * Implements hook_theme().
 */
function opigno_quiz_app_theme() {
  return array(
    'opigno_quiz_app_user_results' => array(
      'variables' => array('user' => NULL, 'results' => NULL),
    ),
    'opigno_quiz_app_user_course_results' => array(
      'variables' => array('user' => NULL, 'course_node' => NULL, 'course_results' => NULL),
    ),
    'opigno_quiz_app_course_results' => array(
      'variables' => array('course' => NULL, 'results' => NULL),
    ),
    'opigno_quiz_app_course_user_results' => array(
      'variables' => array('course' => NULL, 'user' => NULL, 'results' => NULL),
    ),
    'opigno_quiz_app_sort_course_quizzes_form' => array(
      'render element' => 'form',
    ),
  );
}

/**
 * Implements hook_views_api().
 */
function opigno_quiz_app_views_api() {
  return array(
    'api' => '3.0',
  );
}

/**
 * Implements hook_views_data().
 */
function opigno_quiz_app_views_data() {
  $data['opigno_quiz_app_quiz_sort']['table']['group'] = t("Opigno Quiz App");
  $data['opigno_quiz_app_quiz_sort']['table']['join'] = array(
    'node' => array(
      'left_field' => 'nid',
      'field' => 'quiz_nid',
    ),
  );
  $data['opigno_quiz_app_quiz_sort']['gid'] = array(
    'title' => t("The Quiz group"),
    'relationship' => array(
      'base' => 'node',
      'base field' => 'nid',
      'handler' => 'views_handler_relationship',
      'label' => t("Group"),
    ),
  );
  $data['opigno_quiz_app_quiz_sort']['quiz_nid'] = array(
    'title' => t("The Quiz weight (as in order) inside a group"),
    'relationship' => array(
      'base' => 'node',
      'base field' => 'nid',
      'label' => t("Quiz"),
    ),
  );
  $data['opigno_quiz_app_quiz_sort']['weight'] = array(
    'title' => t("Quiz weight (as in order)"),
    'help' => t("The weight of the quiz inside a specific group"),
    'field' => array(
      'handler' => 'opigno_quiz_app_field_course_quiz_weight',
      'click sortable' => TRUE,
    ),
    'filter' => array(
      'handler' => 'opigno_quiz_app_field_course_quiz_weight',
    ),
    'sort' => array(
      'handler' => 'opigno_quiz_app_sort_course_quiz_weight',
    ),
    'argument' => array(
      'handler' => 'views_handler_argument_numeric',
    ),
  );
  return $data;
}

/**
 * Implements hook_modules_enabled().
 */
function opigno_quiz_app_modules_enabled($modules) {
  if (in_array('opigno_calendar_app', $modules)) {
    module_load_install('opigno_quiz_app');
    opigno_quiz_app_enable_calendar_integration();
  }
}

/**
 * Implements hook_quiz_finished().
 */
function opigno_quiz_app_quiz_finished($quiz, $score, $rid, $taker = NULL) {
  if (module_exists('rules')) {
    global $user;

    $taker = isset($taker) ? $taker : clone $user;
    $author = user_load(array('uid' => $quiz->uid));
    $quiz = node_load($quiz->nid);

    rules_invoke_event('opigno_quiz_app_rules_quiz_taken', $taker, $author, $quiz);

    if ($score['percentage_score'] >= $quiz->pass_rate) {
      rules_invoke_event('opigno_quiz_app_rules_quiz_passed', $taker, $author, $quiz);
    }
    else {
      rules_invoke_event('opigno_quiz_app_rules_quiz_failed', $taker, $author, $quiz);
    }
  }

  // Make sure we're NOT in fullscreen anymore.
  setcookie('opigno_quiz_app_fs', 'false');
}

/**
 * Implements hook_quiz_scored().
 */
function opigno_quiz_app_quiz_scored($quiz, $score, $rid) {
  $taker = user_load(array('uid' => db_select('quiz_node_results', 'r')
    ->fields('r', array('uid'))
    ->condition('result_id', $rid)
    ->execute()
    ->fetchField()));

  opigno_quiz_app_quiz_finished($quiz, $score, $rid, $taker);
}

/**
 * Implements hook_opigno_tool().
 */
function opigno_quiz_app_opigno_tool($node = NULL) {
  return array(
    'quiz' => array(
      'name' => t("Quiz"),
      'path' => isset($node) ? "node/{$node->nid}/quizzes" : '',
      'description' => t("Quizzes allow teachers to assess students and provide scenario-like information."),
      'actions' => array(
        'add_quiz' => array(
          'title' => t("Add a new Quiz"),
          'href' => 'node/add/quiz',
          'access_arguments' => array('node', isset($node) ? $node->nid : 0, 'create quiz content'),
          'access_callback' => 'og_user_access',
          'query' => array(
            'og_group_ref' => isset($node) ? $node->nid : '',
          )
        ),
      ),
    ),
  );
}

/**
 * Access callback: check if user has access to student results for the specified course.
 *
 * @param  stdClass $node
 *         The group node.
 * @param  stdClass $quiz = NULL
 *         (optional) The quiz to check permissions for.
 * @param  stdClass $account = NULL
 *
 * @return bool
 */
function opigno_quiz_app_access_node_teacher_results($node, $quiz = NULL, $account = NULL) {
  if (!isset($account)) {
    global $user;
    $account = clone $user;
  }
  $access = user_access('view any quiz results', $account) || og_user_access('node', $node->nid, 'view any quiz results', $account);
  if (!$access && isset($quiz)) {
    $access = (user_access('view results for own quiz', $account) || og_user_access('node', $node->nid, 'view results for own quiz', $account)) && $quiz->uid == $account->uid;
  }
  return $access;
}

/**
 * Access callback: check if user has access to sort quizzes inside the course.
 *
 * @param  stdClass $node
 * @param  stdClass $account = NULL
 *
 * @return bool
 */
function opigno_quiz_app_access_node_sort_quizzes($node, $account = NULL) {
  if (!isset($account)) {
    global $user;
    $account = clone $user;
  }
  return og_user_access('node', $node->nid, 'sort quizzes', $account);
}

/**
 * Access callback: check if user has access to take quizzes inside the course.
 *
 * @param  stdClass $node
 * @param  stdClass $account = NULL
 *
 * @return bool
 */
function opigno_quiz_app_take_access($node, $account = NULL) {
  if (!isset($account)) {
    global $user;
    $account = clone $user;
  }
  return og_user_access('node', $node->nid, 'access quiz', $account);
}

/**
 * Helper function to get the Opigno Quizzes View title.
 *
 * As the title might change depending on individual configuration,
 * fetch it here and cache it for better performance.
 *
 * @return string
 */
function opigno_quiz_app_get_quizzes_view_title() {
  $cache = cache_get('opigno_quiz_app:view_title:opigno_quizzes');
  if ($cache) {
    return $cache->data;
  }
  else {
    $view = views_get_view('opigno_quizzes');
    if (!empty($view->display['default']->display_options['title'])) {
      $quiz_view_title = $view->display['default']->display_options['title'];
    }
    else {
      $quiz_view_title = t("Quizzes");
    }
    cache_set('opigno_quiz_app:view_title:opigno_quizzes', $quiz_view_title, 'cache', CACHE_TEMPORARY);
    return $quiz_view_title;
  }
}

/**
 * Helper function to fetch all course quizzes.
 *
 * @param  stdClass $node
 *
 * @return array
 */
function opigno_quiz_app_get_course_quizzes($node) {
  $quizzes = &drupal_static(__FUNCTION__);

  if (!isset($quizzes[$node->nid])) {
    $quizzes[$node->nid] = array();

    $query = new EntityFieldQuery();
    $query->entityCondition('entity_type', 'node')
      ->entityCondition('bundle', 'quiz')
      ->fieldCondition('og_group_ref', 'target_id', $node->nid, '=')
      ->addMetaData('account', user_load(1));
    $result = $query->execute();

    $temp = array();
    if (!empty($result['node'])) {
      foreach (array_keys($result['node']) as $quiz_nid) {
        $temp[$quiz_nid] = opigno_quiz_app_get_course_quiz_weight($node->nid, $quiz_nid);
      }
    }
    // Sort by weight.
    asort($temp);
    $quizzes[$node->nid] = array_keys($temp);
  }

  return $quizzes[$node->nid];
}

/**
 * Helper function to fetch the weight of a quiz inside a course.
 *
 * @param  int $gid
 * @param  int $nid
 *
 * @return int
 */
function opigno_quiz_app_get_course_quiz_weight($gid, $nid) {
  $weight = db_select('opigno_quiz_app_quiz_sort', 'w')
              ->fields('w', array('weight'))
              ->condition('w.gid', $gid)
              ->condition('w.quiz_nid', $nid)
              ->execute()
              ->fetchField();

  return empty($weight) ? 0 : $weight;
}

/**
 * Helper function to insert the weight of a quiz inside a course.
 *
 * @param  int $gid
 * @param  int $nid
 * @param  int $weight
 */
function opigno_quiz_app_set_course_quiz_weight($gid, $nid, $weight = 0) {
  db_merge('opigno_quiz_app_quiz_sort')
    ->key(array(
      'gid' => $gid,
      'quiz_nid' => $nid,
    ))
    ->fields(array(
      'gid' => $gid,
      'quiz_nid' => $nid,
      'weight' => $weight,
    ))
    ->execute();
}

/**
 * Helper function to fetch all the required quizzes for the passed course node.
 *
 * @param  stdClass $node
 *
 * @return array
 */
function opigno_quiz_app_get_all_required_quizzes($node) {
  $quizzes = &drupal_static(__FUNCTION__);

  if (!isset($quizzes[$node->nid])) {
    $quizzes[$node->nid] = array();
    if (isset($node->course_required_quiz_ref[LANGUAGE_NONE])) {
      foreach ($node->course_required_quiz_ref[LANGUAGE_NONE] as $item) {
        $quizzes[$node->nid][$item['target_id']] = node_load($item['target_id']);
      }
    }
  }

  return $quizzes[$node->nid];
}

/**
 * Helper function to check if the user passed all required quizzes inside the course.
 *
 * @param  int $nid
 * @param  int $uid
 *
 * @return bool
 */
function opigno_quiz_app_user_passed($nid, $uid) {
  $cache = &drupal_static(__FUNCTION__);

  if (!isset($cache["$nid:$uid"])) {
    // Always false for none-courses.
    $cache["$nid:$uid"] = FALSE;
    $node = node_load($nid);

    if ($node->type == OPIGNO_COURSE_BUNDLE) {
      // Default to true (if no quizzes).
      $cache["$nid:$uid"] = TRUE;
      $quizzes = opigno_quiz_app_get_all_required_quizzes($node);
      $all_scores = quiz_get_score_data(array_keys($quizzes), $uid);
      foreach ($all_scores as $score) {
        if ($score->percent_pass > $score->percent_score) {
          $cache["$nid:$uid"] = FALSE;
          break;
        }
      }
    }
  }

  return $cache["$nid:$uid"];
}

/**
 * Helper function to get all results for a given course and user.
 *
 * @param  int $uid
 * @param  int $nid
 * @param  bool $filter_access = FALSE
 *
 * @return array|false
 */
function opigno_quiz_app_get_course_data_result($uid, $nid, $filter_access = FALSE) {
  $cache = &drupal_static(__FUNCTION__);

  $filter_access = (int) $filter_access;

  if (!isset($cache["$nid:$uid:$filter_access"])) {
    $node = node_load($nid);
    $quizzes = opigno_quiz_app_get_all_required_quizzes($node);
    $final_score = 0;
    $failed = OPIGNO_QUIZ_APP_PASSED;
    $total_time = 0;
    $count = 0;

    if ($filter_access) {
      $temp = array();
      foreach ($quizzes as $quiz_nid => $quiz) {
        if (opigno_quiz_app_access_node_teacher_results($node, $quiz)) {
          $temp[$quiz_nid] = $quiz;
        }
      }
      $quizzes = $temp;
    }

    if (empty($quizzes)) {
      $cache["$nid:$uid:$filter_access"] = FALSE;
      return FALSE;
    }

    $nids = array_keys($quizzes);

    // Fetch all scores to calculate the total time spent.
    $all_scores = opigno_quiz_app_get_score_data($nids, $uid);
    $quiz_total_time = array();
    foreach ($all_scores as $quiz_nid => $results) {
      foreach ($results as $rid => $score) {
        if ($score->time_end != 0) {
          if (!isset($quiz_total_time[$quiz_nid])) {
            $quiz_total_time[$quiz_nid] = 0;
          }
          $total_time += $score->time_end - $score->time_start;
          $quiz_total_time[$quiz_nid] += $score->time_end - $score->time_start;
        }
      }
    }

    // Get only best scores for final table.
    $all_scores = quiz_get_score_data($nids, $uid);
    foreach ($all_scores as $score) {
      if (isset($quizzes[$score->nid])) {
        $info['quizzes'][$quizzes[$score->nid]->title]['passed'] = isset($score->percent_score) ? ($score->percent_score >= $score->percent_pass ? OPIGNO_QUIZ_APP_PASSED : OPIGNO_QUIZ_APP_FAILED) : OPIGNO_QUIZ_APP_PENDING;
        $info['quizzes'][$quizzes[$score->nid]->title]['score'] = isset($score->percent_score) ? $score->percent_score : NULL;
        $info['quizzes'][$quizzes[$score->nid]->title]['total_time'] = isset($quiz_total_time[$score->nid]) ? $quiz_total_time[$score->nid] : NULL;

        if (isset($score->percent_score) && isset($quizzes[$score->nid]->quiz_weight[LANGUAGE_NONE][0]['value'])) {
          $final_score += $quizzes[$score->nid]->quiz_weight[LANGUAGE_NONE][0]['value'] * $score->percent_score;
          $count += $quizzes[$score->nid]->quiz_weight[LANGUAGE_NONE][0]['value'];
        }
        elseif (isset($score->percent_score)) {
          $final_score += $score->percent_score;
          $count++;
        }
        else {
          $failed = OPIGNO_QUIZ_APP_PENDING;
        }

        if ($failed !== OPIGNO_QUIZ_APP_PENDING && $failed !== OPIGNO_QUIZ_APP_FAILED && $score->percent_score < $score->percent_pass) {
          $failed = OPIGNO_QUIZ_APP_FAILED;
        }
      }
    }

    // Failsafe. There were no visible results for allowed quizzes.
    if (empty($info['quizzes'])) {
      $cache["$nid:$uid:$filter_access"] = FALSE;
      return FALSE;
    }

    $info['passed'] = $failed;
    $info['total_score'] = $count ? round($final_score / $count) : 0;
    $info['total_time'] = $total_time;

    $cache["$nid:$uid:$filter_access"] = $info;
  }

  return $cache["$nid:$uid:$filter_access"];
}

/**
 * DEPRECATED.
 * A typo in the function name omitted the 'app' word.
 * This is now an alias to opigno_quiz_app_get_score_data(), which should be used instead.
 * @see opigno_quiz_app_get_score_data().
 */
function opigno_quiz_get_score_data($nids, $uid) {
  drupal_set_message('Called deprecated opigno_quiz_get_score_data(). Should be replaced with opigno_quiz_app_get_score_data()', 'warning');
  if (function_exists('dpm')) {
    dpm(debug_backtrace(), 'Callstack to deprecated opigno_quiz_get_score_data()');
  }
  return opigno_quiz_app_get_score_data($nids, $uid);
}

/**
 * Helper function to fetch score data for quizzes. The difference with the core quiz function is that
 * this function gets all results (not just the best one) and also returns the start and end time.
 *
 * @param  array $nids
 * @param  int $uid
 *
 * @return array
 */
function opigno_quiz_app_get_score_data($nids, $uid) {
  $scores = array();
  $query = db_select('quiz_node_results', 'r');
  $query->leftJoin('quiz_node_properties', 'p', 'r.vid = p.vid');
  $query->addField('r', 'score', 'percent_score');
  $query->addField('p', 'pass_rate', 'percent_pass');
  $result = $query
    ->fields('r', array('result_id', 'nid', 'time_start', 'time_end'))
    ->condition('r.uid', $uid)
    ->condition('r.time_end', 0, '>')
    ->condition('r.nid', $nids, 'IN')
    ->execute();

  while ($score = $result->fetchObject()) {
    $scores[$score->nid][$score->result_id] = $score;
  }

  return $scores;
}

/**
 * Helper function to get the certificate download link from the Opigno Certificate App.
 *
 * @param  int $nid
 * @param  int $uid
 *
 * @return string
 */
function opigno_quiz_app_get_certificate($nid, $uid) {
  $download_certificate = '';
  if (function_exists('opigno_certificate_app_get_certificate_path')) {
    $certificate_path = opigno_certificate_app_get_certificate_path($nid, $uid);

    if ($certificate_path) {
      $download_certificate = ' (' . l(t("download certificate"), $certificate_path, array('attributes' => array('class' => array('opigno-quiz-app-download-certificate', 'opigno-certificate-app-download-certificate-link')))) . ')';
    }
  }
  return $download_certificate;
}

/**
 * Theme callback: display user results.
 */
function theme_opigno_quiz_app_user_results($vars) {
  $html = '';
  foreach ($vars['results'] as $course_info) {
    $html .= theme('opigno_quiz_app_user_course_results', array('user' => $vars['user'], 'course_node' => $course_info['node'], 'course_results' => $course_info));
  }
  return $html;
}

/**
 * Theme callback: display user results for a specific course.
 */
function theme_opigno_quiz_app_user_course_results($vars) {
  $download_certificate = opigno_quiz_app_get_certificate($vars['course_node']->nid, $vars['user']->uid);
  $header = array(
    array(
      'data' => t("@title (!status - <a href='!url'>see details</a>)", array('@title' => $vars['course_node']->title, '!status' => $vars['course_results']['passed'] == OPIGNO_QUIZ_APP_PASSED ? t("Passed") : ($vars['course_results']['passed'] == OPIGNO_QUIZ_APP_FAILED ? t("Failed") : t("Pending")), '!url' => "node/{$vars['course_node']->nid}/my-quiz-results")) . $download_certificate,
      'class' => array('opigno-quiz-app-course-status', 'opigno-quiz-app-course-status-' . ($vars['course_results']['passed'] == OPIGNO_QUIZ_APP_PASSED ? 'passed' : ($vars['course_results']['passed'] == OPIGNO_QUIZ_APP_FAILED ? 'failed' : 'pending')))
    ),
    array(
      'data' => isset($vars['course_results']['total_score']) ? $vars['course_results']['total_score'] : '-',
      'class' => array('opigno-quiz-app-course-total-score')
    ),
    array(
      'data' => isset($vars['course_results']['total_time']) ? gmdate('H:i:s', $vars['course_results']['total_time']) : '-',
      'class' => array('opigno-quiz-app-course-total-time')
    ),
  );

  $rows = array();
  if (!empty($vars['course_results']['quizzes'])) {
    foreach ($vars['course_results']['quizzes'] as $quiz_title => $score) {
      $rows[] = array(
        'class' => array('opigno-quiz-app-quiz-result', 'opigno-quiz-app-quiz-result-' . ($score['passed'] == OPIGNO_QUIZ_APP_PASSED ? 'passed' : ($score['passed'] == OPIGNO_QUIZ_APP_FAILED ? 'failed' : 'pending'))),
        'data' => array(
          check_plain($quiz_title),
          isset($score['score']) ? $score['score'] : '-',
          isset($score['total_time']) ? gmdate('H:i:s', $score['total_time']) : '-',
        )
      );
    }
  }

  return theme('table', array('header' => $header, 'rows' => $rows, 'attributes' => array('class' => array('opigno-quiz-app-results-table', 'opigno-quiz-app-results-collapsible-table', 'opigno-quiz-app-user-course-results-table'))));
}

/**
 * Theme callback: display course results.
 */
function theme_opigno_quiz_app_course_results($vars) {
  $html = '';
  foreach ($vars['results'] as $results) {
    $html .= theme('opigno_quiz_app_course_user_results', array('user' => $results['user'], 'course' => $vars['course'], 'results' => $results));
  }
  return $html;
}

/**
 * Theme callback: display course results for a specific user.
 */
function theme_opigno_quiz_app_course_user_results($vars) {
  $download_certificate = opigno_quiz_app_get_certificate($vars['course']->nid, $vars['user']->uid);
  $header = array(
    array(
      'data' => t("@name (!status)", array('@name' => $vars['user']->name, '!status' => $vars['results']['passed'] == OPIGNO_QUIZ_APP_PASSED ? t("Passed") : ($vars['results']['passed'] == OPIGNO_QUIZ_APP_FAILED ? t("Failed") : t("Pending")))) . $download_certificate,
      'class' => array('opigno-quiz-app-course-status', 'opigno-quiz-app-course-status-' . ($vars['results']['passed'] == OPIGNO_QUIZ_APP_PASSED ? 'passed' : ($vars['results']['passed'] == OPIGNO_QUIZ_APP_FAILED ? 'failed' : 'pending')))
    ),
    array(
      'data' => isset($vars['results']['total_score']) ? $vars['results']['total_score'] : '-',
      'class' => array('opigno-quiz-app-course-total-score')
    ),
    array(
      'data' => isset($vars['results']['total_time']) ? gmdate('H:i:s', $vars['results']['total_time']) : '-',
      'class' => array('opigno-quiz-app-course-total-time')
    ),
  );

  $rows = array();
  if (!empty($vars['results']['quizzes'])) {
    foreach ($vars['results']['quizzes'] as $quiz_title => $score) {
      $rows[] = array(
        'class' => array('opigno-quiz-app-quiz-result', 'opigno-quiz-app-quiz-result-' . ($score['passed'] == OPIGNO_QUIZ_APP_PASSED ? 'passed' : ($score['passed'] == OPIGNO_QUIZ_APP_FAILED ? 'failed' : 'pending'))),
        'data' => array(
          check_plain($quiz_title),
          isset($score['score']) ? $score['score'] : '-',
          isset($score['total_time']) ? gmdate('H:i:s', $score['total_time']) : '-',
        )
      );
    }
  }

  return theme('table', array('header' => $header, 'rows' => $rows, 'attributes' => array('class' => array('opigno-quiz-app-results-table', 'opigno-quiz-app-results-collapsible-table', 'opigno-quiz-app-course-user-results-table'))));
}

/**
 * Theme callback: render the order form.
 */
function theme_opigno_quiz_app_sort_course_quizzes_form($vars) {
  $form = $vars['form'];
  drupal_add_tabledrag('opigno-quiz-app-sort-course-quizzes', 'order', 'sibling', 'opigno-quiz-app-sort-course-quizzes-weight');

  $header = array(
    function_exists('locale') ? locale(QUIZ_NAME) : QUIZ_NAME,
    t("Weight"),
  );

  $rows = array();
  foreach ($form['table'] as $key => $item) {
    if (preg_match('/quiz_[0-9]+/', $key)) {
      $data = array();
      $data[] = drupal_render($item['title']) . drupal_render($item['nid']);
      $data[] = drupal_render($item['weight']);

      $rows[] = array(
        'data' => $data,
        'class' => array('draggable'),
      );
    }
  }

  $form['table'] = array(
    '#markup' => theme('table', array('header' => $header, 'rows' => $rows, 'attributes' => array('id' => 'opigno-quiz-app-sort-course-quizzes'))),
    '#weight' => 1,
  );

  return drupal_render_children($form);
}

/**
 * Enable fullscreen mode for the passed Quiz node.
 *
 * @param object $node
 */
function _opigno_quiz_app_enable_fullscreen($node) {
  $included = &drupal_static(__FUNCTION__);
  if (empty($included)) {
    drupal_add_library('system', 'jquery.cookie');
    $path = drupal_get_path('module', 'opigno_quiz_app');
    drupal_add_css("$path/css/opigno_quiz_app.css");
    drupal_add_js("$path/js/opigno_quiz_app.fullscreen.js");

    $included = TRUE;
  }
  drupal_add_js(array(
    'opignoQuizApp' => array(
      'fullScreen' => array(
        array('nid' => $node->nid),
      )
    )
  ), 'setting');
}

/**
 * Helper function to determine if we're adding a Question node.
 *
 * @return bool
 */
function opigno_quiz_app_is_node_add_question() {
  static $result;
  if (!isset($result)) {
    $question_types = opigno_quiz_app_get_quiz_question_types();
    $result = preg_match('/^node\/add\/(' . str_replace('_', '-', implode('|', $question_types)) . ')$/', current_path());
  }
  return $result;
}

/**
 * Helper function to get the available quiz question types.
 * 
 * Statically cached for better performance.
 *
 * @return array
 */
function opigno_quiz_app_get_quiz_question_types() {
  static $types;
  if (!isset($types)) {
    $types = array_keys(_quiz_question_get_implementations());
  }
  return $types;
}

/**
 * Quiz node form alter
 *
 * Shows/Hides calendar date field
 */
function opigno_quiz_app_form_alter(&$form, &$form_state, $form_id) {
  if ($form_id=="quiz_node_form") {
    $form['field_add_to_calendar']['#parent']='quiz_availability';
    $form['opigno_calendar_date']['#parent']='quiz_availability';
    $form['opigno_calendar_date']['#states'] = array(
      'invisible' => array(
        '#edit-field-add-to-calendar-und' => array('checked' => FALSE),
      ),
    );
    $form['quiz_availability']['field_add_to_calendar']=$form['field_add_to_calendar'];
    $form['quiz_availability']['opigno_calendar_date']=$form['opigno_calendar_date'];
    $form['#submit'][] = 'opigno_quiz_app_unset_opigno_calendar_date';
    unset($form['field_add_to_calendar']);
    unset($form['opigno_calendar_date']);
  }
  elseif ($form_id == 'quiz_question_answering_form') {
    $path = drupal_get_path('module', 'opigno_quiz_app');
    drupal_add_js("$path/js/opigno_quiz_app.js");
  }
}

/**
 * Quiz node submit function
 *
 * Removes calendar field in case of not beeing used
 */
function opigno_quiz_app_unset_opigno_calendar_date($form, &$form_state)
{
  if ($form_state['values']['field_add_to_calendar'][LANGUAGE_NONE][0]['value']==0)
  {
    $form_state['values']['opigno_calendar_date'][LANGUAGE_NONE][0]['value']=NULL;
    $form_state['values']['opigno_calendar_date'][LANGUAGE_NONE][0]['value2']=NULL;
    $form_state['values']['opigno_calendar_date'][LANGUAGE_NONE][0]['timezone']=NULL;
    $form_state['values']['opigno_calendar_date'][LANGUAGE_NONE][0]['offset']=NULL;
    $form_state['values']['opigno_calendar_date'][LANGUAGE_NONE][0]['offset2']=NULL;
    $form_state['values']['opigno_calendar_date'][LANGUAGE_NONE][0]['rrule']=NULL;
  }
}