text: // @flow
  
  import { getGravatarURL } from '@jitsi/js-utils/avatar';
  
  import { JitsiParticipantConnectionStatus } from '../lib-jitsi-meet';
  import { MEDIA_TYPE, shouldRenderVideoTrack } from '../media';
  import { toState } from '../redux';
  import { getTrackByMediaTypeAndParticipant } from '../tracks';
  import { createDeferred } from '../util';
  
  import {
      JIGASI_PARTICIPANT_ICON,
      MAX_DISPLAY_NAME_LENGTH,
      PARTICIPANT_ROLE
  } from './constants';
  import { preloadImage } from './preloadImage';
  
  declare var config: Object;
  declare var interfaceConfig: Object;
  
  /**
   * Temp structures for avatar urls to be checked/preloaded.
   */
  const AVATAR_QUEUE = [];
  const AVATAR_CHECKED_URLS = new Map();
  /* eslint-disable arrow-body-style */
  const AVATAR_CHECKER_FUNCTIONS = [
      participant => {
          return participant && participant.isJigasi ? JIGASI_PARTICIPANT_ICON : null;
      },
      participant => {
          return participant && participant.avatarURL ? participant.avatarURL : null;
      },
      participant => {
          return participant && participant.email ? null : null;
      }
  ];
  /* eslint-enable arrow-body-style */
  
  /**
   * Resolves the first loadable avatar URL for a participant.
   *
   * @param {Object} participant - The participant to resolve avatars for.
   * @returns {Promise}
   */
  export function getFirstLoadableAvatarUrl(participant: Object) {
      const deferred = createDeferred();
      const fullPromise = deferred.promise
          .then(() => _getFirstLoadableAvatarUrl(participant))
          .then(src => {
  
              if (AVATAR_QUEUE.length) {
                  const next = AVATAR_QUEUE.shift();
  
                  next.resolve();
              }
  
              return src;
          });
  
      if (AVATAR_QUEUE.length) {
          AVATAR_QUEUE.push(deferred);
      } else {
          deferred.resolve();
      }
  
      return fullPromise;
  }
  
  /**
   * Returns local participant from Redux state.
   *
   * @param {(Function|Object|Participant[])} stateful - The redux state
   * features/base/participants, the (whole) redux state, or redux's
   * {@code getState} function to be used to retrieve the state
   * features/base/participants.
   * @returns {(Participant|undefined)}
   */
  export function getLocalParticipant(stateful: Object | Function) {
      const participants = _getAllParticipants(stateful);
  
      return participants.find(p => p.local);
  }
  
  /**
   * Normalizes a display name so then no invalid values (padding, length...etc)
   * can be set.
   *
   * @param {string} name - The display name to set.
   * @returns {string}
   */
  export function getNormalizedDisplayName(name: string) {
      if (!name || !name.trim()) {
          return undefined;
      }
  
      return name.trim().substring(0, MAX_DISPLAY_NAME_LENGTH);
  }
  
  /**
   * Returns participant by ID from Redux state.
   *
   * @param {(Function|Object|Participant[])} stateful - The redux state
   * features/base/participants, the (whole) redux state, or redux's
   * {@code getState} function to be used to retrieve the state
   * features/base/participants.
   * @param {string} id - The ID of the participant to retrieve.
   * @private
   * @returns {(Participant|undefined)}
   */
  export function getParticipantById(
          stateful: Object | Function, id: string): ?Object {
      const participants = _getAllParticipants(stateful);
  
      return participants.find(p => p.id === id);
  }
  
  /**
   * Returns a count of the known participants in the passed in redux state,
   * excluding any fake participants.
   *
   * @param {(Function|Object|Participant[])} stateful - The redux state
   * features/base/participants, the (whole) redux state, or redux's
   * {@code getState} function to be used to retrieve the state
   * features/base/participants.
   * @returns {number}
   */
  export function getParticipantCount(stateful: Object | Function) {
      return getParticipants(stateful).length;
  }
  
  /**
   * Returns a count of the known participants in the passed in redux state,
   * including fake participants.
   *
   * @param {(Function|Object|Participant[])} stateful - The redux state
   * features/base/participants, the (whole) redux state, or redux's
   * {@code getState} function to be used to retrieve the state
   * features/base/participants.
   * @returns {number}
   */
  export function getParticipantCountWithFake(stateful: Object | Function) {
      return _getAllParticipants(stateful).length;
  }
  
  /**
   * Returns participant's display name.
   *
   * FIXME: Remove the hardcoded strings once interfaceConfig is stored in redux
   * and merge with a similarly named method in {@code conference.js}.
   *
   * @param {(Function|Object)} stateful - The (whole) redux state, or redux's
   * {@code getState} function to be used to retrieve the state.
   * @param {string} id - The ID of the participant's display name to retrieve.
   * @returns {string}
   */
  export function getParticipantDisplayName(
          stateful: Object | Function,
          id: string) {
      const participant = getParticipantById(stateful, id);
  
      if (participant) {
          if (participant.name) {
              return participant.name;
          }
  
          if (participant.local) {
              return typeof interfaceConfig === 'object'
                  ? interfaceConfig.DEFAULT_LOCAL_DISPLAY_NAME
                  : 'me';
          }
      }
  
      return typeof interfaceConfig === 'object'
          ? interfaceConfig.DEFAULT_REMOTE_DISPLAY_NAME
          : 'Fellow Jitster';
  }
  
  /**
   * Returns the presence status of a participant associated with the passed id.
   *
   * @param {(Function|Object)} stateful - The (whole) redux state, or redux's
   * {@code getState} function to be used to retrieve the state.
   * @param {string} id - The id of the participant.
   * @returns {string} - The presence status.
   */
  export function getParticipantPresenceStatus(
          stateful: Object | Function, id: string) {
      if (!id) {
          return undefined;
      }
      const participantById = getParticipantById(stateful, id);
  
      if (!participantById) {
          return undefined;
      }
  
      return participantById.presence;
  }
  
  /**
   * Selectors for getting all known participants with fake participants filtered
   * out.
   *
   * @param {(Function|Object|Participant[])} stateful - The redux state
   * features/base/participants, the (whole) redux state, or redux's
   * {@code getState} function to be used to retrieve the state
   * features/base/participants.
   * @returns {Participant[]}
   */
  export function getParticipants(stateful: Object | Function) {
      return _getAllParticipants(stateful).filter(p => !p.isFakeParticipant);
  }
  
  /**
   * Returns the participant which has its pinned state set to truthy.
   *
   * @param {(Function|Object|Participant[])} stateful - The redux state
   * features/base/participants, the (whole) redux state, or redux's
   * {@code getState} function to be used to retrieve the state
   * features/base/participants.
   * @returns {(Participant|undefined)}
   */
  export function getPinnedParticipant(stateful: Object | Function) {
      return _getAllParticipants(stateful).find(p => p.pinned);
  }
  
  /**
   * Returns array of participants from Redux state.
   *
   * @param {(Function|Object|Participant[])} stateful - The redux state
   * features/base/participants, the (whole) redux state, or redux's
   * {@code getState} function to be used to retrieve the state
   * features/base/participants.
   * @private
   * @returns {Participant[]}
   */
  function _getAllParticipants(stateful) {
      return (
          Array.isArray(stateful)
              ? stateful
              : toState(stateful)['features/base/participants'] || []);
  }
  
  /**
   * Returns the youtube fake participant.
   * At the moment it is considered the youtube participant the only fake participant in the list.
   *
   * @param {(Function|Object|Participant[])} stateful - The redux state
   * features/base/participants, the (whole) redux state, or redux's
   * {@code getState} function to be used to retrieve the state
   * features/base/participants.
   * @private
   * @returns {Participant}
   */
  export function getYoutubeParticipant(stateful: Object | Function) {
      const participants = _getAllParticipants(stateful);
  
      return participants.filter(p => p.isFakeParticipant)[0];
  }
  
  /**
   * Returns true if all of the meeting participants are moderators.
   *
   * @param {Object|Function} stateful -Object or function that can be resolved
   * to the Redux state.
   * @returns {boolean}
   */
  export function isEveryoneModerator(stateful: Object | Function) {
      const participants = _getAllParticipants(stateful);
  
      for (const participant of participants) {
          if (participant.role !== PARTICIPANT_ROLE.MODERATOR) {
              return false;
          }
      }
  
      return true;
  }
  
  /**
   * Checks a value and returns true if it's a preloaded icon object.
   *
   * @param {?string | ?Object} icon - The icon to check.
   * @returns {boolean}
   */
  export function isIconUrl(icon: ?string | ?Object) {
      return Boolean(icon) && typeof icon === 'object';
  }
  
  /**
   * Returns true if the current local participant is a moderator in the
   * conference.
   *
   * @param {Object|Function} stateful - Object or function that can be resolved
   * to the Redux state.
   * @param {?boolean} ignoreToken - When true we ignore the token check.
   * @returns {boolean}
   */
  export function isLocalParticipantModerator(
          stateful: Object | Function,
          ignoreToken: ?boolean = false) {
      const state = toState(stateful);
      const localParticipant = getLocalParticipant(state);
  
      if (!localParticipant) {
          return false;
      }
  
      return (
          localParticipant.role === PARTICIPANT_ROLE.MODERATOR
          && (ignoreToken
                  || !state['features/base/config'].enableUserRolesBasedOnToken
                  || !state['features/base/jwt'].isGuest));
  }
  
  /**
   * Returns true if the video of the participant should be rendered.
   * NOTE: This is currently only used on mobile.
   *
   * @param {Object|Function} stateful - Object or function that can be resolved
   * to the Redux state.
   * @param {string} id - The ID of the participant.
   * @returns {boolean}
   */
  export function shouldRenderParticipantVideo(stateful: Object | Function, id: string) {
      const state = toState(stateful);
      const participant = getParticipantById(state, id);
  
      if (!participant) {
          return false;
      }
  
      /* First check if we have an unmuted video track. */
      const videoTrack
          = getTrackByMediaTypeAndParticipant(state['features/base/tracks'], MEDIA_TYPE.VIDEO, id);
  
      if (!shouldRenderVideoTrack(videoTrack, /* waitForVideoStarted */ false)) {
          return false;
      }
  
      /* Then check if the participant connection is active. */
      const connectionStatus = participant.connectionStatus || JitsiParticipantConnectionStatus.ACTIVE;
  
      if (connectionStatus !== JitsiParticipantConnectionStatus.ACTIVE) {
          return false;
      }
  
      /* Then check if audio-only mode is not active. */
      const audioOnly = state['features/base/audio-only'].enabled;
  
      if (!audioOnly) {
          return true;
      }
  
      /* Last, check if the participant is sharing their screen and they are on stage. */
      const screenShares = state['features/video-layout'].screenShares || [];
      const largeVideoParticipantId = state['features/large-video'].participantId;
      const participantIsInLargeVideoWithScreen
          = participant.id === largeVideoParticipantId && screenShares.includes(participant.id);
  
      return participantIsInLargeVideoWithScreen;
  }
  
  /**
   * Resolves the first loadable avatar URL for a participant.
   *
   * @param {Object} participant - The participant to resolve avatars for.
   * @returns {?string}
   */
  async function _getFirstLoadableAvatarUrl(participant) {
      for (let i = 0; i < AVATAR_CHECKER_FUNCTIONS.length; i++) {
          const url = AVATAR_CHECKER_FUNCTIONS[i](participant);
  
          if (url) {
              if (AVATAR_CHECKED_URLS.has(url)) {
                  if (AVATAR_CHECKED_URLS.get(url)) {
                      return url;
                  }
              } else {
                  try {
                      const finalUrl = await preloadImage(url);
  
                      AVATAR_CHECKED_URLS.set(finalUrl, true);
  
                      return finalUrl;
                  } catch (e) {
                      AVATAR_CHECKED_URLS.set(url, false);
                  }
              }
          }
      }
  
      return undefined;
  }
  