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See Release Notes

  • Bug fixes for general core bugs in 4.3.x will end 7 October 2024 (12 months).
  • Bug fixes for security issues in 4.3.x will end 21 April 2025 (18 months).
  • PHP version: minimum PHP 8.0.0 Note: minimum PHP version has increased since Moodle 4.1. PHP 8.2.x is supported too.

Differences Between: [Versions 310 and 403] [Versions 311 and 403] [Versions 39 and 403]

   1  <?php
   2  // This file is part of Moodle - http://moodle.org/
   3  //
   4  // Moodle is free software: you can redistribute it and/or modify
   5  // it under the terms of the GNU General Public License as published by
   6  // the Free Software Foundation, either version 3 of the License, or
   7  // (at your option) any later version.
   8  //
   9  // Moodle is distributed in the hope that it will be useful,
  10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  // GNU General Public License for more details.
  13  //
  14  // You should have received a copy of the GNU General Public License
  15  // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  16  
  17  /**
  18   * Analytics basic actions manager.
  19   *
  20   * @package   core_analytics
  21   * @copyright 2017 David Monllao {@link http://www.davidmonllao.com}
  22   * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  23   */
  24  
  25  namespace core_analytics;
  26  
  27  defined('MOODLE_INTERNAL') || die();
  28  
  29  /**
  30   * Analytics basic actions manager.
  31   *
  32   * @package   core_analytics
  33   * @copyright 2017 David Monllao {@link http://www.davidmonllao.com}
  34   * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  35   */
  36  class manager {
  37  
  38      /**
  39       * Default mlbackend
  40       */
  41      const DEFAULT_MLBACKEND = '\mlbackend_php\processor';
  42  
  43      /**
  44       * Name of the file where components declare their models.
  45       */
  46      const ANALYTICS_FILENAME = 'db/analytics.php';
  47  
  48      /**
  49       * @var \core_analytics\predictor[]
  50       */
  51      protected static $predictionprocessors = [];
  52  
  53      /**
  54       * @var \core_analytics\local\target\base[]
  55       */
  56      protected static $alltargets = null;
  57  
  58      /**
  59       * @var \core_analytics\local\indicator\base[]
  60       */
  61      protected static $allindicators = null;
  62  
  63      /**
  64       * @var \core_analytics\local\time_splitting\base[]
  65       */
  66      protected static $alltimesplittings = null;
  67  
  68      /**
  69       * Checks that the user can manage models
  70       *
  71       * @throws \required_capability_exception
  72       * @return void
  73       */
  74      public static function check_can_manage_models() {
  75          require_capability('moodle/analytics:managemodels', \context_system::instance());
  76      }
  77  
  78      /**
  79       * Checks that the user can list that context insights
  80       *
  81       * @throws \required_capability_exception
  82       * @param \context $context
  83       * @param  bool $return The method returns a bool if true.
  84       * @return void
  85       */
  86      public static function check_can_list_insights(\context $context, bool $return = false) {
  87          global $USER;
  88  
  89          if ($context->contextlevel === CONTEXT_USER && $context->instanceid == $USER->id) {
  90              $capability = 'moodle/analytics:listowninsights';
  91          } else {
  92              $capability = 'moodle/analytics:listinsights';
  93          }
  94  
  95          if ($return) {
  96              return has_capability($capability, $context);
  97          } else {
  98              require_capability($capability, $context);
  99          }
 100      }
 101  
 102      /**
 103       * Is analytics enabled globally?
 104       *
 105       * return bool
 106       */
 107      public static function is_analytics_enabled(): bool {
 108          global $CFG;
 109  
 110          if (isset($CFG->enableanalytics)) {
 111              return $CFG->enableanalytics;
 112          }
 113  
 114          // Enabled by default.
 115          return true;
 116      }
 117  
 118      /**
 119       * Returns all system models that match the provided filters.
 120       *
 121       * @param bool $enabled
 122       * @param bool $trained
 123       * @param \context|false $predictioncontext
 124       * @return \core_analytics\model[]
 125       */
 126      public static function get_all_models($enabled = false, $trained = false, $predictioncontext = false) {
 127          global $DB;
 128  
 129          $params = array();
 130  
 131          $sql = "SELECT am.* FROM {analytics_models} am";
 132  
 133          if ($enabled || $trained || $predictioncontext) {
 134              $conditions = [];
 135              if ($enabled) {
 136                  $conditions[] = 'am.enabled = :enabled';
 137                  $params['enabled'] = 1;
 138              }
 139              if ($trained) {
 140                  $conditions[] = 'am.trained = :trained';
 141                  $params['trained'] = 1;
 142              }
 143              if ($predictioncontext) {
 144                  $conditions[] = "EXISTS (SELECT 'x'
 145                                             FROM {analytics_predictions} ap
 146                                            WHERE ap.modelid = am.id AND ap.contextid = :contextid)";
 147                  $params['contextid'] = $predictioncontext->id;
 148              }
 149              $sql .= ' WHERE ' . implode(' AND ', $conditions);
 150          }
 151          $sql .= ' ORDER BY am.enabled DESC, am.timemodified DESC';
 152  
 153          $modelobjs = $DB->get_records_sql($sql, $params);
 154  
 155          $models = array();
 156          foreach ($modelobjs as $modelobj) {
 157              $model = new \core_analytics\model($modelobj);
 158              if ($model->is_available()) {
 159                  $models[$modelobj->id] = $model;
 160              }
 161          }
 162  
 163          // Sort the models by the model name using the current session language.
 164          \core_collator::asort_objects_by_method($models, 'get_name');
 165  
 166          return $models;
 167      }
 168  
 169      /**
 170       * Returns the provided predictions processor class.
 171       *
 172       * @param false|string $predictionclass Returns the system default processor if false
 173       * @param bool $checkisready
 174       * @return \core_analytics\predictor
 175       */
 176      public static function get_predictions_processor($predictionclass = false, $checkisready = true) {
 177  
 178          // We want 0 or 1 so we can use it as an array key for caching.
 179          $checkisready = intval($checkisready);
 180  
 181          if (!$predictionclass) {
 182              $predictionclass = get_config('analytics', 'predictionsprocessor');
 183          }
 184  
 185          if (empty($predictionclass)) {
 186              // Use the default one if nothing set.
 187              $predictionclass = self::default_mlbackend();
 188          }
 189  
 190          if (!class_exists($predictionclass)) {
 191              throw new \coding_exception('Invalid predictions processor ' . $predictionclass . '.');
 192          }
 193  
 194          $interfaces = class_implements($predictionclass);
 195          if (empty($interfaces['core_analytics\predictor'])) {
 196              throw new \coding_exception($predictionclass . ' should implement \core_analytics\predictor.');
 197          }
 198  
 199          // Return it from the cached list.
 200          if (!isset(self::$predictionprocessors[$checkisready][$predictionclass])) {
 201  
 202              $instance = new $predictionclass();
 203              if ($checkisready) {
 204                  $isready = $instance->is_ready();
 205                  if ($isready !== true) {
 206                      throw new \moodle_exception('errorprocessornotready', 'analytics', '', $isready);
 207                  }
 208              }
 209              self::$predictionprocessors[$checkisready][$predictionclass] = $instance;
 210          }
 211  
 212          return self::$predictionprocessors[$checkisready][$predictionclass];
 213      }
 214  
 215      /**
 216       * Return all system predictions processors.
 217       *
 218       * @return \core_analytics\predictor[]
 219       */
 220      public static function get_all_prediction_processors() {
 221  
 222          $mlbackends = \core_component::get_plugin_list('mlbackend');
 223  
 224          $predictionprocessors = array();
 225          foreach ($mlbackends as $mlbackend => $unused) {
 226              $classfullpath = '\mlbackend_' . $mlbackend . '\processor';
 227              $predictionprocessors[$classfullpath] = self::get_predictions_processor($classfullpath, false);
 228          }
 229          return $predictionprocessors;
 230      }
 231  
 232      /**
 233       * Resets the cached prediction processors.
 234       * @return null
 235       */
 236      public static function reset_prediction_processors() {
 237          self::$predictionprocessors = [];
 238      }
 239  
 240      /**
 241       * Returns the name of the provided predictions processor.
 242       *
 243       * @param \core_analytics\predictor $predictionsprocessor
 244       * @return string
 245       */
 246      public static function get_predictions_processor_name(\core_analytics\predictor $predictionsprocessor) {
 247              $component = substr(get_class($predictionsprocessor), 0, strpos(get_class($predictionsprocessor), '\\', 1));
 248          return get_string('pluginname', $component);
 249      }
 250  
 251      /**
 252       * Whether the provided plugin is used by any model.
 253       *
 254       * @param string $plugin
 255       * @return bool
 256       */
 257      public static function is_mlbackend_used($plugin) {
 258          $models = self::get_all_models();
 259          foreach ($models as $model) {
 260              $processor = $model->get_predictions_processor();
 261              $noprefixnamespace = ltrim(get_class($processor), '\\');
 262              $processorplugin = substr($noprefixnamespace, 0, strpos($noprefixnamespace, '\\'));
 263              if ($processorplugin == $plugin) {
 264                  return true;
 265              }
 266          }
 267  
 268          // Default predictions processor.
 269          $defaultprocessorclass = get_config('analytics', 'predictionsprocessor');
 270          $pluginclass = '\\' . $plugin . '\\processor';
 271          if ($pluginclass === $defaultprocessorclass) {
 272              return true;
 273          }
 274  
 275          return false;
 276      }
 277  
 278      /**
 279       * Get all available time splitting methods.
 280       *
 281       * @return \core_analytics\local\time_splitting\base[]
 282       */
 283      public static function get_all_time_splittings() {
 284          if (self::$alltimesplittings !== null) {
 285              return self::$alltimesplittings;
 286          }
 287  
 288          $classes = self::get_analytics_classes('time_splitting');
 289  
 290          self::$alltimesplittings = [];
 291          foreach ($classes as $fullclassname => $classpath) {
 292              $instance = self::get_time_splitting($fullclassname);
 293              // We need to check that it is a valid time splitting method, it may be an abstract class.
 294              if ($instance) {
 295                  self::$alltimesplittings[$instance->get_id()] = $instance;
 296              }
 297          }
 298  
 299          return self::$alltimesplittings;
 300      }
 301  
 302      /**
 303       * @deprecated since Moodle 3.7 use get_time_splitting_methods_for_evaluation instead
 304       */
 305      public static function get_enabled_time_splitting_methods() {
 306          throw new coding_exception(__FUNCTION__ . '() has been removed. You can use self::get_time_splitting_methods_for_evaluation if ' .
 307              'you want to get the default time splitting methods for evaluation, or you can use self::get_all_time_splittings if ' .
 308              'you want to get all the time splitting methods available on this site.');
 309      }
 310  
 311      /**
 312       * Returns the time-splitting methods for model evaluation.
 313       *
 314       * @param  bool $all Return all the time-splitting methods that can potentially be used for evaluation or the default ones.
 315       * @return \core_analytics\local\time_splitting\base[]
 316       */
 317      public static function get_time_splitting_methods_for_evaluation(bool $all = false) {
 318  
 319          if ($all === false) {
 320              if ($enabledtimesplittings = get_config('analytics', 'defaulttimesplittingsevaluation')) {
 321                  $enabledtimesplittings = array_flip(explode(',', $enabledtimesplittings));
 322              }
 323          }
 324  
 325          $timesplittings = self::get_all_time_splittings();
 326          foreach ($timesplittings as $key => $timesplitting) {
 327  
 328              if (!$timesplitting->valid_for_evaluation()) {
 329                  unset($timesplittings[$key]);
 330              }
 331  
 332              if ($all === false) {
 333                  // We remove the ones that are not enabled. This also respects the default value (all methods enabled).
 334                  if (!empty($enabledtimesplittings) && !isset($enabledtimesplittings[$key])) {
 335                      unset($timesplittings[$key]);
 336                  }
 337              }
 338          }
 339          return $timesplittings;
 340      }
 341  
 342      /**
 343       * Returns a time splitting method by its classname.
 344       *
 345       * @param string $fullclassname
 346       * @return \core_analytics\local\time_splitting\base|false False if it is not valid.
 347       */
 348      public static function get_time_splitting($fullclassname) {
 349          if (!self::is_valid($fullclassname, '\core_analytics\local\time_splitting\base')) {
 350              return false;
 351          }
 352          return new $fullclassname();
 353      }
 354  
 355      /**
 356       * Return all targets in the system.
 357       *
 358       * @return \core_analytics\local\target\base[]
 359       */
 360      public static function get_all_targets() : array {
 361          if (self::$alltargets !== null) {
 362              return self::$alltargets;
 363          }
 364  
 365          $classes = self::get_analytics_classes('target');
 366  
 367          self::$alltargets = [];
 368          foreach ($classes as $fullclassname => $classpath) {
 369              $instance = self::get_target($fullclassname);
 370              if ($instance) {
 371                  self::$alltargets[$instance->get_id()] = $instance;
 372              }
 373          }
 374  
 375          return self::$alltargets;
 376      }
 377      /**
 378       * Return all system indicators.
 379       *
 380       * @return \core_analytics\local\indicator\base[]
 381       */
 382      public static function get_all_indicators() {
 383          if (self::$allindicators !== null) {
 384              return self::$allindicators;
 385          }
 386  
 387          $classes = self::get_analytics_classes('indicator');
 388  
 389          self::$allindicators = [];
 390          foreach ($classes as $fullclassname => $classpath) {
 391              $instance = self::get_indicator($fullclassname);
 392              if ($instance) {
 393                  self::$allindicators[$instance->get_id()] = $instance;
 394              }
 395          }
 396  
 397          return self::$allindicators;
 398      }
 399  
 400      /**
 401       * Returns the specified target
 402       *
 403       * @param mixed $fullclassname
 404       * @return \core_analytics\local\target\base|false False if it is not valid
 405       */
 406      public static function get_target($fullclassname) {
 407          if (!self::is_valid($fullclassname, 'core_analytics\local\target\base')) {
 408              return false;
 409          }
 410          return new $fullclassname();
 411      }
 412  
 413      /**
 414       * Returns an instance of the provided indicator.
 415       *
 416       * @param string $fullclassname
 417       * @return \core_analytics\local\indicator\base|false False if it is not valid.
 418       */
 419      public static function get_indicator($fullclassname) {
 420          if (!self::is_valid($fullclassname, 'core_analytics\local\indicator\base')) {
 421              return false;
 422          }
 423          return new $fullclassname();
 424      }
 425  
 426      /**
 427       * Returns whether a time splitting method is valid or not.
 428       *
 429       * @param string $fullclassname
 430       * @param string $baseclass
 431       * @return bool
 432       */
 433      public static function is_valid($fullclassname, $baseclass) {
 434          if (is_subclass_of($fullclassname, $baseclass)) {
 435              if ((new \ReflectionClass($fullclassname))->isInstantiable()) {
 436                  return true;
 437              }
 438          }
 439          return false;
 440      }
 441  
 442      /**
 443       * Returns the logstore used for analytics.
 444       *
 445       * @return \core\log\sql_reader|false False if no log stores are enabled.
 446       */
 447      public static function get_analytics_logstore() {
 448          $readers = get_log_manager()->get_readers('core\log\sql_reader');
 449          $analyticsstore = get_config('analytics', 'logstore');
 450  
 451          if (!empty($analyticsstore) && !empty($readers[$analyticsstore])) {
 452              $logstore = $readers[$analyticsstore];
 453          } else if (empty($analyticsstore) && !empty($readers)) {
 454              // The first one, it is the same default than in settings.
 455              $logstore = reset($readers);
 456          } else if (!empty($readers)) {
 457              $logstore = reset($readers);
 458              debugging('The selected log store for analytics is not available anymore. Using "' .
 459                  $logstore->get_name() . '"', DEBUG_DEVELOPER);
 460          }
 461  
 462          if (empty($logstore)) {
 463              debugging('No system log stores available to use for analytics', DEBUG_DEVELOPER);
 464              return false;
 465          }
 466  
 467          if (!$logstore->is_logging()) {
 468              debugging('The selected log store for analytics "' . $logstore->get_name() .
 469                  '" is not logging activity logs', DEBUG_DEVELOPER);
 470          }
 471  
 472          return $logstore;
 473      }
 474  
 475      /**
 476       * Returns this analysable calculations during the provided period.
 477       *
 478       * @param \core_analytics\analysable $analysable
 479       * @param int $starttime
 480       * @param int $endtime
 481       * @param string $samplesorigin The samples origin as sampleid is not unique across models.
 482       * @return array
 483       */
 484      public static function get_indicator_calculations($analysable, $starttime, $endtime, $samplesorigin) {
 485          global $DB;
 486  
 487          $params = array('starttime' => $starttime, 'endtime' => $endtime, 'contextid' => $analysable->get_context()->id,
 488              'sampleorigin' => $samplesorigin);
 489          $calculations = $DB->get_recordset('analytics_indicator_calc', $params, '', 'indicator, sampleid, value');
 490  
 491          $existingcalculations = array();
 492          foreach ($calculations as $calculation) {
 493              if (empty($existingcalculations[$calculation->indicator])) {
 494                  $existingcalculations[$calculation->indicator] = array();
 495              }
 496              $existingcalculations[$calculation->indicator][$calculation->sampleid] = $calculation->value;
 497          }
 498          $calculations->close();
 499          return $existingcalculations;
 500      }
 501  
 502      /**
 503       * Returns the models with insights at the provided context.
 504       *
 505       * Note that this method is used for display purposes. It filters out models whose insights
 506       * are not linked from the reports page.
 507       *
 508       * @param \context $context
 509       * @return \core_analytics\model[]
 510       */
 511      public static function get_models_with_insights(\context $context) {
 512  
 513          self::check_can_list_insights($context);
 514  
 515          $models = self::get_all_models(true, true, $context);
 516          foreach ($models as $key => $model) {
 517              // Check that it not only have predictions but also generates insights from them.
 518              if (!$model->uses_insights() || !$model->get_target()->link_insights_report()) {
 519                  unset($models[$key]);
 520              }
 521          }
 522          return $models;
 523      }
 524  
 525      /**
 526       * Returns the models that generated insights in the provided context. It can also be used to add new models to the context.
 527       *
 528       * Note that if you use this function with $newmodelid is the caller responsibility to ensure that the
 529       * provided model id generated insights for the provided context.
 530       *
 531       * @throws \coding_exception
 532       * @param  \context $context
 533       * @param  int|null $newmodelid A new model to add to the list of models with insights in the provided context.
 534       * @return int[]
 535       */
 536      public static function cached_models_with_insights(\context $context, int $newmodelid = null) {
 537  
 538          $cache = \cache::make('core', 'contextwithinsights');
 539          $modelids = $cache->get($context->id);
 540          if ($modelids === false) {
 541              // The cache is empty, but we don't know if it is empty because there are no insights
 542              // in this context or because cache/s have been purged, we need to be conservative and
 543              // "pay" 1 db read to fill up the cache.
 544  
 545              $models = \core_analytics\manager::get_models_with_insights($context);
 546  
 547              if ($newmodelid && empty($models[$newmodelid])) {
 548                  throw new \coding_exception('The provided modelid ' . $newmodelid . ' did not generate any insights');
 549              }
 550  
 551              $modelids = array_keys($models);
 552              $cache->set($context->id, $modelids);
 553  
 554          } else if ($newmodelid && !in_array($newmodelid, $modelids)) {
 555              // We add the context we got as an argument to the cache.
 556  
 557              array_push($modelids, $newmodelid);
 558              $cache->set($context->id, $modelids);
 559          }
 560  
 561          return $modelids;
 562      }
 563  
 564      /**
 565       * Returns a prediction
 566       *
 567       * @param int $predictionid
 568       * @param bool $requirelogin
 569       * @return array array($model, $prediction, $context)
 570       */
 571      public static function get_prediction($predictionid, $requirelogin = false) {
 572          global $DB;
 573  
 574          if (!$predictionobj = $DB->get_record('analytics_predictions', array('id' => $predictionid))) {
 575              throw new \moodle_exception('errorpredictionnotfound', 'analytics');
 576          }
 577  
 578          $context = \context::instance_by_id($predictionobj->contextid, IGNORE_MISSING);
 579          if (!$context) {
 580              throw new \moodle_exception('errorpredictioncontextnotavailable', 'analytics');
 581          }
 582  
 583          if ($requirelogin) {
 584              list($context, $course, $cm) = get_context_info_array($predictionobj->contextid);
 585              require_login($course, false, $cm);
 586          }
 587  
 588          self::check_can_list_insights($context);
 589  
 590          $model = new \core_analytics\model($predictionobj->modelid);
 591          $sampledata = $model->prediction_sample_data($predictionobj);
 592          $prediction = new \core_analytics\prediction($predictionobj, $sampledata);
 593  
 594          return array($model, $prediction, $context);
 595      }
 596  
 597      /**
 598       * Used to be used to add models included with the Moodle core.
 599       *
 600       * @deprecated Deprecated since Moodle 3.7 (MDL-61667) - Use lib/db/analytics.php instead.
 601       * @todo Remove this method in Moodle 3.11 (MDL-65186).
 602       * @return void
 603       */
 604      public static function add_builtin_models() {
 605  
 606          throw new \coding_exception('core_analytics\manager::add_builtin_models() has been removed. Core models ' .
 607                          'are now automatically updated according to their declaration in the lib/db/analytics.php file.');
 608      }
 609  
 610      /**
 611       * Cleans up analytics db tables that do not directly depend on analysables that may have been deleted.
 612       */
 613      public static function cleanup() {
 614          global $DB;
 615  
 616          $DB->execute("DELETE FROM {analytics_prediction_actions} WHERE predictionid IN
 617                            (SELECT ap.id FROM {analytics_predictions} ap
 618                          LEFT JOIN {context} ctx ON ap.contextid = ctx.id
 619                              WHERE ctx.id IS NULL)");
 620  
 621          // Cleanup analaytics predictions/calcs with MySQL friendly sub-select.
 622          $DB->execute("DELETE FROM {analytics_predictions} WHERE id IN (
 623                          SELECT oldpredictions.id
 624                          FROM (
 625                              SELECT p.id
 626                              FROM {analytics_predictions} p
 627                              LEFT JOIN {context} ctx ON p.contextid = ctx.id
 628                              WHERE ctx.id IS NULL
 629                          ) oldpredictions
 630                      )");
 631  
 632          $DB->execute("DELETE FROM {analytics_indicator_calc} WHERE id IN (
 633                          SELECT oldcalcs.id FROM (
 634                              SELECT c.id
 635                              FROM {analytics_indicator_calc} c
 636                              LEFT JOIN {context} ctx ON c.contextid = ctx.id
 637                              WHERE ctx.id IS NULL
 638                          ) oldcalcs
 639                      )");
 640  
 641          // Clean up stuff that depends on analysable ids that do not exist anymore.
 642  
 643          $models = self::get_all_models();
 644          foreach ($models as $model) {
 645  
 646              // We first dump into memory the list of analysables we have in the database (we could probably do this with 1 single
 647              // query for the 3 tables, but it may be safer to do it separately).
 648              $predictsamplesanalysableids = $DB->get_fieldset_select('analytics_predict_samples', 'DISTINCT analysableid',
 649                  'modelid = :modelid', ['modelid' => $model->get_id()]);
 650              $predictsamplesanalysableids = array_flip($predictsamplesanalysableids);
 651              $trainsamplesanalysableids = $DB->get_fieldset_select('analytics_train_samples', 'DISTINCT analysableid',
 652                  'modelid = :modelid', ['modelid' => $model->get_id()]);
 653              $trainsamplesanalysableids = array_flip($trainsamplesanalysableids);
 654              $usedanalysablesanalysableids = $DB->get_fieldset_select('analytics_used_analysables', 'DISTINCT analysableid',
 655                  'modelid = :modelid', ['modelid' => $model->get_id()]);
 656              $usedanalysablesanalysableids = array_flip($usedanalysablesanalysableids);
 657  
 658              $analyser = $model->get_analyser(array('notimesplitting' => true));
 659  
 660              // We do not honour the list of contexts in this model as it can contain stale records.
 661              $analysables = $analyser->get_analysables_iterator();
 662  
 663              $analysableids = [];
 664              foreach ($analysables as $analysable) {
 665                  if (!$analysable) {
 666                      continue;
 667                  }
 668                  unset($predictsamplesanalysableids[$analysable->get_id()]);
 669                  unset($trainsamplesanalysableids[$analysable->get_id()]);
 670                  unset($usedanalysablesanalysableids[$analysable->get_id()]);
 671              }
 672  
 673              $param = ['modelid' => $model->get_id()];
 674  
 675              if ($predictsamplesanalysableids) {
 676                  list($idssql, $idsparams) = $DB->get_in_or_equal(array_flip($predictsamplesanalysableids), SQL_PARAMS_NAMED);
 677                  $DB->delete_records_select('analytics_predict_samples', "modelid = :modelid AND analysableid $idssql",
 678                      $param + $idsparams);
 679              }
 680              if ($trainsamplesanalysableids) {
 681                  list($idssql, $idsparams) = $DB->get_in_or_equal(array_flip($trainsamplesanalysableids), SQL_PARAMS_NAMED);
 682                  $DB->delete_records_select('analytics_train_samples', "modelid = :modelid AND analysableid $idssql",
 683                      $param + $idsparams);
 684              }
 685              if ($usedanalysablesanalysableids) {
 686                  list($idssql, $idsparams) = $DB->get_in_or_equal(array_flip($usedanalysablesanalysableids), SQL_PARAMS_NAMED);
 687                  $DB->delete_records_select('analytics_used_analysables', "modelid = :modelid AND analysableid $idssql",
 688                      $param + $idsparams);
 689              }
 690          }
 691  
 692          // Clean up calculations table.
 693          $calclifetime = get_config('analytics', 'calclifetime');
 694          if (!empty($calclifetime)) {
 695              $lifetime = time() - ($calclifetime * DAYSECS); // Value in days.
 696              $DB->delete_records_select('analytics_indicator_calc', 'timecreated < ?', [$lifetime]);
 697          }
 698      }
 699  
 700      /**
 701       * Default system backend.
 702       *
 703       * @return string
 704       */
 705      public static function default_mlbackend() {
 706          return self::DEFAULT_MLBACKEND;
 707      }
 708  
 709      /**
 710       * Returns the provided element classes in the site.
 711       *
 712       * @param string $element
 713       * @return string[] Array keys are the FQCN and the values the class path.
 714       */
 715      private static function get_analytics_classes($element) {
 716  
 717          // Just in case...
 718          $element = clean_param($element, PARAM_ALPHANUMEXT);
 719  
 720          $classes = \core_component::get_component_classes_in_namespace(null, 'analytics\\' . $element);
 721  
 722          return $classes;
 723      }
 724  
 725      /**
 726       * Check that all the models declared by the component are up to date.
 727       *
 728       * This is intended to be called during the installation / upgrade to automatically create missing models.
 729       *
 730       * @param string $componentname The name of the component to load models for.
 731       * @return array \core_analytics\model[] List of actually created models.
 732       */
 733      public static function update_default_models_for_component(string $componentname): array {
 734  
 735          $result = [];
 736  
 737          foreach (static::load_default_models_for_component($componentname) as $definition) {
 738              if (!\core_analytics\model::exists(static::get_target($definition['target']))) {
 739                  $result[] = static::create_declared_model($definition);
 740              }
 741          }
 742  
 743          return $result;
 744      }
 745  
 746      /**
 747       * Return the list of models declared by the given component.
 748       *
 749       * @param string $componentname The name of the component to load models for.
 750       * @throws \coding_exception Exception thrown in case of invalid syntax.
 751       * @return array The $models description array.
 752       */
 753      public static function load_default_models_for_component(string $componentname): array {
 754  
 755          $dir = \core_component::get_component_directory($componentname);
 756  
 757          if (!$dir) {
 758              // This is either an invalid component, or a core subsystem without its own root directory.
 759              return [];
 760          }
 761  
 762          $file = $dir . '/' . self::ANALYTICS_FILENAME;
 763  
 764          if (!is_readable($file)) {
 765              return [];
 766          }
 767  
 768          $models = null;
 769          include($file);
 770  
 771          if (!isset($models) || !is_array($models) || empty($models)) {
 772              return [];
 773          }
 774  
 775          foreach ($models as &$model) {
 776              if (!isset($model['enabled'])) {
 777                  $model['enabled'] = false;
 778              } else {
 779                  $model['enabled'] = clean_param($model['enabled'], PARAM_BOOL);
 780              }
 781          }
 782  
 783          static::validate_models_declaration($models);
 784  
 785          return $models;
 786      }
 787  
 788      /**
 789       * Return the list of all the models declared anywhere in this Moodle installation.
 790       *
 791       * Models defined by the core and core subsystems come first, followed by those provided by plugins.
 792       *
 793       * @return array indexed by the frankenstyle component
 794       */
 795      public static function load_default_models_for_all_components(): array {
 796  
 797          $tmp = [];
 798  
 799          foreach (\core_component::get_component_list() as $type => $components) {
 800              foreach (array_keys($components) as $component) {
 801                  if ($loaded = static::load_default_models_for_component($component)) {
 802                      $tmp[$type][$component] = $loaded;
 803                  }
 804              }
 805          }
 806  
 807          $result = [];
 808  
 809          if ($loaded = static::load_default_models_for_component('core')) {
 810              $result['core'] = $loaded;
 811          }
 812  
 813          if (!empty($tmp['core'])) {
 814              $result += $tmp['core'];
 815              unset($tmp['core']);
 816          }
 817  
 818          foreach ($tmp as $components) {
 819              $result += $components;
 820          }
 821  
 822          return $result;
 823      }
 824  
 825      /**
 826       * Validate the declaration of prediction models according the syntax expected in the component's db folder.
 827       *
 828       * The expected structure looks like this:
 829       *
 830       *  [
 831       *      [
 832       *          'target' => '\fully\qualified\name\of\the\target\class',
 833       *          'indicators' => [
 834       *              '\fully\qualified\name\of\the\first\indicator',
 835       *              '\fully\qualified\name\of\the\second\indicator',
 836       *          ],
 837       *          'timesplitting' => '\optional\name\of\the\time_splitting\class',
 838       *          'enabled' => true,
 839       *      ],
 840       *  ];
 841       *
 842       * @param array $models List of declared models.
 843       * @throws \coding_exception Exception thrown in case of invalid syntax.
 844       */
 845      public static function validate_models_declaration(array $models) {
 846  
 847          foreach ($models as $model) {
 848              if (!isset($model['target'])) {
 849                  throw new \coding_exception('Missing target declaration');
 850              }
 851  
 852              if (!static::is_valid($model['target'], '\core_analytics\local\target\base')) {
 853                  throw new \coding_exception('Invalid target classname', $model['target']);
 854              }
 855  
 856              if (empty($model['indicators']) || !is_array($model['indicators'])) {
 857                  throw new \coding_exception('Missing indicators declaration');
 858              }
 859  
 860              foreach ($model['indicators'] as $indicator) {
 861                  if (!static::is_valid($indicator, '\core_analytics\local\indicator\base')) {
 862                      throw new \coding_exception('Invalid indicator classname', $indicator);
 863                  }
 864              }
 865  
 866              if (isset($model['timesplitting'])) {
 867                  if (substr($model['timesplitting'], 0, 1) !== '\\') {
 868                      throw new \coding_exception('Expecting fully qualified time splitting classname', $model['timesplitting']);
 869                  }
 870                  if (!static::is_valid($model['timesplitting'], '\core_analytics\local\time_splitting\base')) {
 871                      throw new \coding_exception('Invalid time splitting classname', $model['timesplitting']);
 872                  }
 873              }
 874  
 875              if (!empty($model['enabled']) && !isset($model['timesplitting'])) {
 876                  throw new \coding_exception('Cannot enable a model without time splitting method specified');
 877              }
 878          }
 879      }
 880  
 881      /**
 882       * Create the defined model.
 883       *
 884       * @param array $definition See {@link self::validate_models_declaration()} for the syntax.
 885       * @return \core_analytics\model
 886       */
 887      public static function create_declared_model(array $definition): \core_analytics\model {
 888  
 889          list($target, $indicators) = static::get_declared_target_and_indicators_instances($definition);
 890  
 891          if (isset($definition['timesplitting'])) {
 892              $timesplitting = $definition['timesplitting'];
 893          } else {
 894              $timesplitting = false;
 895          }
 896  
 897          $created = \core_analytics\model::create($target, $indicators, $timesplitting);
 898  
 899          if (!empty($definition['enabled'])) {
 900              $created->enable();
 901          }
 902  
 903          return $created;
 904      }
 905  
 906      /**
 907       * Returns a string uniquely representing the given model declaration.
 908       *
 909       * @param array $model Model declaration
 910       * @return string complying with PARAM_ALPHANUM rules and starting with an 'id' prefix
 911       */
 912      public static function model_declaration_identifier(array $model) : string {
 913          return 'id'.sha1(serialize($model));
 914      }
 915  
 916      /**
 917       * Given a model definition, return actual target and indicators instances.
 918       *
 919       * @param array $definition See {@link self::validate_models_declaration()} for the syntax.
 920       * @return array [0] => target instance, [1] => array of indicators instances
 921       */
 922      public static function get_declared_target_and_indicators_instances(array $definition): array {
 923  
 924          $target = static::get_target($definition['target']);
 925  
 926          $indicators = [];
 927  
 928          foreach ($definition['indicators'] as $indicatorname) {
 929              $indicator = static::get_indicator($indicatorname);
 930              $indicators[$indicator->get_id()] = $indicator;
 931          }
 932  
 933          return [$target, $indicators];
 934      }
 935  
 936      /**
 937       * Return the context restrictions that can be applied to the provided context levels.
 938       *
 939       * @throws \coding_exception
 940       * @param  array|null $contextlevels The list of context levels provided by the analyser. Null if all of them.
 941       * @param  string|null $query
 942       * @return array Associative array with contextid as key and the short version of the context name as value.
 943       */
 944      public static function get_potential_context_restrictions(?array $contextlevels = null, string $query = null) {
 945          global $DB;
 946  
 947          if (empty($contextlevels) && !is_null($contextlevels)) {
 948              return false;
 949          }
 950  
 951          if (!is_null($contextlevels)) {
 952              foreach ($contextlevels as $contextlevel) {
 953                  if ($contextlevel !== CONTEXT_COURSE && $contextlevel !== CONTEXT_COURSECAT) {
 954                      throw new \coding_exception('Only CONTEXT_COURSE and CONTEXT_COURSECAT are supported at the moment.');
 955                  }
 956              }
 957          }
 958  
 959          $contexts = [];
 960  
 961          // We have a separate process for each context level for performance reasons (to iterate through mdl_context calling
 962          // get_context_name() would be too slow).
 963          $contextsystem = \context_system::instance();
 964          if (is_null($contextlevels) || in_array(CONTEXT_COURSECAT, $contextlevels)) {
 965  
 966              $sql = "SELECT cc.id, cc.name, ctx.id AS contextid
 967                        FROM {course_categories} cc
 968                        JOIN {context} ctx ON ctx.contextlevel = :ctxlevel AND ctx.instanceid = cc.id";
 969              $params = ['ctxlevel' => CONTEXT_COURSECAT];
 970  
 971              if ($query) {
 972                  $sql .= " WHERE " . $DB->sql_like('cc.name', ':query', false, false);
 973                  $params['query'] = '%' . $query . '%';
 974              }
 975  
 976              $coursecats = $DB->get_recordset_sql($sql, $params);
 977              foreach ($coursecats as $record) {
 978                  $contexts[$record->contextid] = get_string('category') . ': ' .
 979                      format_string($record->name, true, array('context' => $contextsystem));
 980              }
 981              $coursecats->close();
 982          }
 983  
 984          if (is_null($contextlevels) || in_array(CONTEXT_COURSE, $contextlevels)) {
 985  
 986              $sql = "SELECT c.id, c.shortname, ctx.id AS contextid
 987                        FROM {course} c
 988                        JOIN {context} ctx ON ctx.contextlevel = :ctxlevel AND ctx.instanceid = c.id
 989                        WHERE c.id != :siteid";
 990              $params = ['ctxlevel' => CONTEXT_COURSE, 'siteid' => SITEID];
 991  
 992              if ($query) {
 993                  $sql .= ' AND (' . $DB->sql_like('c.fullname', ':query1', false, false) . ' OR ' .
 994                      $DB->sql_like('c.shortname', ':query2', false, false) . ')';
 995                  $params['query1'] = '%' . $query . '%';
 996                  $params['query2'] = '%' . $query . '%';
 997              }
 998  
 999              $courses = $DB->get_recordset_sql($sql, $params);
1000              foreach ($courses as $record) {
1001                  $contexts[$record->contextid] = get_string('course') . ': ' .
1002                      format_string($record->shortname, true, array('context' => $contextsystem));
1003              }
1004              $courses->close();
1005          }
1006  
1007          return $contexts;
1008      }
1009  
1010  }