text: // This file is part of Moodle - http://moodle.org/
  //
  // Moodle is free software: you can redistribute it and/or modify
  // it under the terms of the GNU General Public License as published by
  // the Free Software Foundation, either version 3 of the License, or
  // (at your option) any later version.
  //
  // Moodle is distributed in the hope that it will be useful,
  // but WITHOUT ANY WARRANTY; without even the implied warranty of
  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  // GNU General Public License for more details.
  //
  // You should have received a copy of the GNU General Public License
  // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  
  /**
   * Javascript to handle changing users via the user selector in the header.
   *
   * @module     mod_assign/grading_navigation
   * @package    mod_assign
   * @copyright  2016 Damyon Wiese <damyon@moodle.com>
   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
   * @since      3.1
   */
  define(['jquery', 'core/notification', 'core/str', 'core/form-autocomplete',
          'core/ajax', 'mod_assign/grading_form_change_checker'],
         function($, notification, str, autocomplete, ajax, checker) {
  
      /**
       * GradingNavigation class.
       *
       * @class GradingNavigation
       * @param {String} selector The selector for the page region containing the user navigation.
       */
      var GradingNavigation = function(selector) {
          this._regionSelector = selector;
          this._region = $(selector);
          this._filters = [];
          this._users = [];
          this._filteredUsers = [];
          this._lastXofYUpdate = 0;
          this._firstLoadUsers = true;
  
          // Get the current user list from a webservice.
          this._loadAllUsers();
  
          // We do not allow navigation while ajax requests are pending.
          // Attach listeners to the select and arrow buttons.
  
          this._region.find('[data-action="previous-user"]').on('click', this._handlePreviousUser.bind(this));
          this._region.find('[data-action="next-user"]').on('click', this._handleNextUser.bind(this));
          this._region.find('[data-action="change-user"]').on('change', this._handleChangeUser.bind(this));
          this._region.find('[data-region="user-filters"]').on('click', this._toggleExpandFilters.bind(this));
  
          $(document).on('user-changed', this._refreshSelector.bind(this));
          $(document).on('done-saving-show-next', this._handleNextUser.bind(this));
  
          // Position the configure filters panel under the link that expands it.
          var toggleLink = this._region.find('[data-region="user-filters"]');
          var configPanel = $(document.getElementById(toggleLink.attr('aria-controls')));
  
          configPanel.on('change', 'select', this._filterChanged.bind(this));
  
          var userid = $('[data-region="grading-navigation-panel"]').data('first-userid');
          if (userid) {
              this._selectUserById(userid);
          }
  
          str.get_string('changeuser', 'mod_assign').done(function(s) {
                  autocomplete.enhance('[data-action=change-user]', false, 'mod_assign/participant_selector', s);
              }
          ).fail(notification.exception);
  
          $(document).bind("start-loading-user", function() {
              this._isLoading = true;
          }.bind(this));
          $(document).bind("finish-loading-user", function() {
              this._isLoading = false;
          }.bind(this));
      };
  
      /** @type {Boolean} Boolean tracking active ajax requests. */
      GradingNavigation.prototype._isLoading = false;
  
      /** @type {String} Selector for the page region containing the user navigation. */
      GradingNavigation.prototype._regionSelector = null;
  
      /** @type {Array} The list of active filter keys */
      GradingNavigation.prototype._filters = null;
  
      /** @type {Array} The list of users */
      GradingNavigation.prototype._users = null;
  
      /** @type {JQuery} JQuery node for the page region containing the user navigation. */
      GradingNavigation.prototype._region = null;
  
      /** @type {String} Last active filters */
      GradingNavigation.prototype._lastFilters = '';
  
      /**
       * Load the list of all users for this assignment.
       *
       * @private
       * @method _loadAllUsers
       * @return {Boolean} True if the user list was fetched.
       */
      GradingNavigation.prototype._loadAllUsers = function() {
          var select = this._region.find('[data-action=change-user]');
          var assignmentid = select.attr('data-assignmentid');
          var groupid = select.attr('data-groupid');
  
          var filterPanel = this._region.find('[data-region="configure-filters"]');
          var filter = filterPanel.find('select[name="filter"]').val();
          var workflowFilter = filterPanel.find('select[name="workflowfilter"]');
          if (workflowFilter) {
              filter += ',' + workflowFilter.val();
          }
          var markerFilter = filterPanel.find('select[name="markerfilter"]');
          if (markerFilter) {
              filter += ',' + markerFilter.val();
          }
  
          if (this._lastFilters == filter) {
              return false;
          }
          this._lastFilters = filter;
  
          ajax.call([{
              methodname: 'mod_assign_list_participants',
              args: {assignid: assignmentid, groupid: groupid, filter: '', onlyids: true, tablesort: true},
              done: this._usersLoaded.bind(this),
              fail: notification.exception
          }]);
          return true;
      };
  
      /**
       * Call back to rebuild the user selector and x of y info when the user list is updated.
       *
       * @private
       * @method _usersLoaded
       * @param {Array} users
       */
      GradingNavigation.prototype._usersLoaded = function(users) {
          this._firstLoadUsers = false;
          this._filteredUsers = this._users = users;
          if (this._users.length) {
              // Position the configure filters panel under the link that expands it.
              var toggleLink = this._region.find('[data-region="user-filters"]');
              var configPanel = $(document.getElementById(toggleLink.attr('aria-controls')));
  
              configPanel.find('select[name="filter"]').trigger('change');
          } else {
              this._selectNoUser();
          }
          this._triggerNextUserEvent();
      };
  
      /**
       * Close the configure filters panel if a click is detected outside of it.
       *
       * @private
       * @method _checkClickOutsideConfigureFilters
       * @param {Event} event
       */
      GradingNavigation.prototype._checkClickOutsideConfigureFilters = function(event) {
          var configPanel = this._region.find('[data-region="configure-filters"]');
  
          if (!configPanel.is(event.target) && configPanel.has(event.target).length === 0) {
              var toggleLink = this._region.find('[data-region="user-filters"]');
  
              configPanel.hide();
              configPanel.attr('aria-hidden', 'true');
              toggleLink.attr('aria-expanded', 'false');
              $(document).unbind('click.mod_assign_grading_navigation');
          }
      };
  
      /**
       * Close the configure filters panel if a click is detected outside of it.
       *
       * @private
       * @method _updateFilterPreference
       * @param {Number} userId The current user id.
       * @param {Array} filterList The list of current filter values.
       * @param {Array} preferenceNames The names of the preferences to update
       * @return {Promise} Resolved when all the preferences are updated.
       */
      GradingNavigation.prototype._updateFilterPreferences = function(userId, filterList, preferenceNames) {
          var preferences = [],
              i = 0;
  
          if (filterList.length == 0 || this._firstLoadUsers) {
              // Nothing to update.
              var deferred = $.Deferred();
              deferred.resolve();
              return deferred;
          }
          // General filter.
          // Set the user preferences to the current filters.
          for (i = 0; i < filterList.length; i++) {
              var newValue = filterList[i];
              if (newValue == 'none') {
                  newValue = '';
              }
  
              preferences.push({
                  userid: userId,
                  name: preferenceNames[i],
                  value: newValue
              });
          }
  
          return ajax.call([{
              methodname: 'core_user_set_user_preferences',
              args: {
                  preferences: preferences
              }
          }])[0];
      };
      /**
       * Turn a filter on or off.
       *
       * @private
       * @method _filterChanged
       * @param {Event} event
       */
      GradingNavigation.prototype._filterChanged = function() {
          // There are 3 types of filter right now.
          var filterPanel = this._region.find('[data-region="configure-filters"]');
          var filters = filterPanel.find('select');
          var preferenceNames = [];
  
          this._filters = [];
          filters.each(function(idx, ele) {
              var element = $(ele);
              this._filters.push(element.val());
              preferenceNames.push('assign_' + element.prop('name'));
          }.bind(this));
  
          // Update the active filter string.
          var filterlist = [];
          filterPanel.find('option:checked').each(function(idx, ele) {
              filterlist[filterlist.length] = $(ele).text();
          });
          if (filterlist.length) {
              this._region.find('[data-region="user-filters"] span').text(filterlist.join(', '));
          } else {
              str.get_string('nofilters', 'mod_assign').done(function(s) {
                  this._region.find('[data-region="user-filters"] span').text(s);
              }.bind(this)).fail(notification.exception);
          }
  
          var select = this._region.find('[data-action=change-user]');
          var currentUserID = select.data('currentuserid');
          this._updateFilterPreferences(currentUserID, this._filters, preferenceNames).done(function() {
              // Reload the list of users to apply the new filters.
              if (!this._loadAllUsers()) {
                  var userid = parseInt(select.attr('data-selected'));
                  var foundIndex = 0;
                  // Search the returned users for the current selection.
                  $.each(this._filteredUsers, function(index, user) {
                      if (userid == user.id) {
                          foundIndex = index;
                      }
                  });
  
                  if (this._filteredUsers.length) {
                      this._selectUserById(this._filteredUsers[foundIndex].id);
                  } else {
                      this._selectNoUser();
                  }
  
              }
          }.bind(this)).fail(notification.exception);
          this._refreshCount();
      };
  
      /**
       * Select no users, because no users match the filters.
       *
       * @private
       * @method _selectNoUser
       */
      GradingNavigation.prototype._selectNoUser = function() {
          // Detect unsaved changes, and offer to save them - otherwise change user right now.
          if (this._isLoading) {
              return;
          }
          if (checker.checkFormForChanges('[data-region="grade-panel"] .gradeform')) {
              // Form has changes, so we need to confirm before switching users.
              str.get_strings([
                  {key: 'unsavedchanges', component: 'mod_assign'},
                  {key: 'unsavedchangesquestion', component: 'mod_assign'},
                  {key: 'saveandcontinue', component: 'mod_assign'},
                  {key: 'cancel', component: 'core'},
              ]).done(function(strs) {
                  notification.confirm(strs[0], strs[1], strs[2], strs[3], function() {
                      $(document).trigger('save-changes', -1);
                  });
              });
          } else {
              $(document).trigger('user-changed', -1);
          }
      };
  
      /**
       * Select the specified user by id.
       *
       * @private
       * @method _selectUserById
       * @param {Number} userid
       */
      GradingNavigation.prototype._selectUserById = function(userid) {
          var select = this._region.find('[data-action=change-user]');
          var useridnumber = parseInt(userid, 10);
  
          // Detect unsaved changes, and offer to save them - otherwise change user right now.
          if (this._isLoading) {
              return;
          }
          if (checker.checkFormForChanges('[data-region="grade-panel"] .gradeform')) {
              // Form has changes, so we need to confirm before switching users.
              str.get_strings([
                  {key: 'unsavedchanges', component: 'mod_assign'},
                  {key: 'unsavedchangesquestion', component: 'mod_assign'},
                  {key: 'saveandcontinue', component: 'mod_assign'},
                  {key: 'cancel', component: 'core'},
              ]).done(function(strs) {
                  notification.confirm(strs[0], strs[1], strs[2], strs[3], function() {
                      $(document).trigger('save-changes', useridnumber);
                  });
              });
          } else {
              select.attr('data-selected', userid);
  
              if (!isNaN(useridnumber) && useridnumber > 0) {
                  $(document).trigger('user-changed', userid);
              }
          }
      };
  
      /**
       * Expand or collapse the filter config panel.
       *
       * @private
       * @method _toggleExpandFilters
       * @param {Event} event
       */
      GradingNavigation.prototype._toggleExpandFilters = function(event) {
          event.preventDefault();
          var toggleLink = $(event.target).closest('[data-region="user-filters"]');
          var expanded = toggleLink.attr('aria-expanded') == 'true';
          var configPanel = $(document.getElementById(toggleLink.attr('aria-controls')));
  
          if (expanded) {
              configPanel.hide();
              configPanel.attr('aria-hidden', 'true');
              toggleLink.attr('aria-expanded', 'false');
              $(document).unbind('click.mod_assign_grading_navigation');
          } else {
              configPanel.css('display', 'inline-block');
              configPanel.attr('aria-hidden', 'false');
              toggleLink.attr('aria-expanded', 'true');
              event.stopPropagation();
              $(document).on('click.mod_assign_grading_navigation', this._checkClickOutsideConfigureFilters.bind(this));
          }
      };
  
      /**
       * Change to the previous user in the grading list.
       *
       * @private
       * @method _handlePreviousUser
       * @param {Event} e
       */
      GradingNavigation.prototype._handlePreviousUser = function(e) {
          e.preventDefault();
          var select = this._region.find('[data-action=change-user]');
          var currentUserId = select.attr('data-selected');
          var i = 0;
          var currentIndex = 0;
  
          for (i = 0; i < this._filteredUsers.length; i++) {
              if (this._filteredUsers[i].id == currentUserId) {
                  currentIndex = i;
                  break;
              }
          }
  
          var count = this._filteredUsers.length;
          var newIndex = (currentIndex - 1);
          if (newIndex < 0) {
              newIndex = count - 1;
          }
  
          if (count) {
              this._selectUserById(this._filteredUsers[newIndex].id);
          }
      };
  
      /**
       * Change to the next user in the grading list.
       *
       * @param {Event} e
       * @param {Boolean} saved Has the form already been saved? Skips checking for changes if true.
       */
      GradingNavigation.prototype._handleNextUser = function(e, saved) {
          e.preventDefault();
          var select = this._region.find('[data-action=change-user]');
          var currentUserId = select.attr('data-selected');
          var i = 0;
          var currentIndex = 0;
  
          for (i = 0; i < this._filteredUsers.length; i++) {
              if (this._filteredUsers[i].id == currentUserId) {
                  currentIndex = i;
                  break;
              }
          }
  
          var count = this._filteredUsers.length;
          var newIndex = (currentIndex + 1) % count;
  
          if (saved && count) {
              // If we've already saved the grade, skip checking if we've made any changes.
              var userid = this._filteredUsers[newIndex].id;
              var useridnumber = parseInt(userid, 10);
              select.attr('data-selected', userid);
              if (!isNaN(useridnumber) && useridnumber > 0) {
                  $(document).trigger('user-changed', userid);
              }
          } else if (count) {
              this._selectUserById(this._filteredUsers[newIndex].id);
          }
      };
  
      /**
       * Set count string. This method only sets the value for the last time it was ever called to deal
       * with promises that return in a non-predictable order.
       *
       * @private
       * @method _setCountString
       * @param {Number} x
       * @param {Number} y
       */
      GradingNavigation.prototype._setCountString = function(x, y) {
          var updateNumber = 0;
          this._lastXofYUpdate++;
          updateNumber = this._lastXofYUpdate;
  
          var param = {x: x, y: y};
          str.get_string('xofy', 'mod_assign', param).done(function(s) {
              if (updateNumber == this._lastXofYUpdate) {
                  this._region.find('[data-region="user-count-summary"]').text(s);
              }
          }.bind(this)).fail(notification.exception);
      };
  
      /**
       * Rebuild the x of y string.
       *
       * @private
       * @method _refreshCount
       */
      GradingNavigation.prototype._refreshCount = function() {
          var select = this._region.find('[data-action=change-user]');
          var userid = select.attr('data-selected');
          var i = 0;
          var currentIndex = 0;
  
          if (isNaN(userid) || userid <= 0) {
              this._region.find('[data-region="user-count"]').hide();
          } else {
              this._region.find('[data-region="user-count"]').show();
  
              for (i = 0; i < this._filteredUsers.length; i++) {
                  if (this._filteredUsers[i].id == userid) {
                      currentIndex = i;
                      break;
                  }
              }
              var count = this._filteredUsers.length;
              if (count) {
                  currentIndex += 1;
              }
              this._setCountString(currentIndex, count);
              // Update window URL
              if (currentIndex > 0) {
                  var url = new URL(window.location);
                  if (parseInt(url.searchParams.get('blindid')) > 0) {
                      var newid = this._filteredUsers[currentIndex - 1].recordid;
                      url.searchParams.set('blindid', newid);
                  } else {
                      url.searchParams.set('userid', userid);
                  }
                  // We do this so a browser refresh will return to the same user.
                  window.history.replaceState({}, "", url);
              }
          }
      };
  
      /**
       * Respond to a user-changed event by updating the selector.
       *
       * @private
       * @method _refreshSelector
       * @param {Event} event
       * @param {String} userid
       */
      GradingNavigation.prototype._refreshSelector = function(event, userid) {
          var select = this._region.find('[data-action=change-user]');
          userid = parseInt(userid, 10);
  
          if (!isNaN(userid) && userid > 0) {
              select.attr('data-selected', userid);
          }
          this._refreshCount();
      };
  
      /**
       * Trigger the next user event depending on the number of filtered users
       *
       * @private
       * @method _triggerNextUserEvent
       */
      GradingNavigation.prototype._triggerNextUserEvent = function() {
          if (this._filteredUsers.length > 1) {
              $(document).trigger('next-user', {nextUserId: null, nextUser: true});
          } else {
              $(document).trigger('next-user', {nextUser: false});
          }
      };
  
      /**
       * Change to a different user in the grading list.
       *
       * @private
       * @method _handleChangeUser
       * @param {Event} event
       */
      GradingNavigation.prototype._handleChangeUser = function() {
          var select = this._region.find('[data-action=change-user]');
          var userid = parseInt(select.val(), 10);
  
          if (this._isLoading) {
              return;
          }
          if (checker.checkFormForChanges('[data-region="grade-panel"] .gradeform')) {
              // Form has changes, so we need to confirm before switching users.
              str.get_strings([
                  {key: 'unsavedchanges', component: 'mod_assign'},
                  {key: 'unsavedchangesquestion', component: 'mod_assign'},
                  {key: 'saveandcontinue', component: 'mod_assign'},
                  {key: 'cancel', component: 'core'},
              ]).done(function(strs) {
                  notification.confirm(strs[0], strs[1], strs[2], strs[3], function() {
                      $(document).trigger('save-changes', userid);
                  });
              });
          } else {
              if (!isNaN(userid) && userid > 0) {
                  select.attr('data-selected', userid);
  
                  $(document).trigger('user-changed', userid);
              }
          }
      };
  
      return GradingNavigation;
  });
  