mastodon/app/assets/javascripts/components/reducers/statuses.jsx

import {
  REBLOG_REQUEST,
  REBLOG_SUCCESS,
  REBLOG_FAIL,
  UNREBLOG_SUCCESS,
  FAVOURITE_REQUEST,
  FAVOURITE_SUCCESS,
  FAVOURITE_FAIL,
  UNFAVOURITE_SUCCESS
} from '../actions/interactions';
import {
  STATUS_FETCH_SUCCESS,
  CONTEXT_FETCH_SUCCESS
} from '../actions/statuses';
import {
  TIMELINE_REFRESH_SUCCESS,
  TIMELINE_UPDATE,
  TIMELINE_DELETE,
  TIMELINE_EXPAND_SUCCESS
} from '../actions/timelines';
import {
  ACCOUNT_TIMELINE_FETCH_SUCCESS,
  ACCOUNT_TIMELINE_EXPAND_SUCCESS,
  ACCOUNT_BLOCK_SUCCESS
} from '../actions/accounts';
import {
  NOTIFICATIONS_UPDATE,
  NOTIFICATIONS_REFRESH_SUCCESS,
  NOTIFICATIONS_EXPAND_SUCCESS
} from '../actions/notifications';
import Immutable from 'immutable';

const normalizeStatus = (state, status) => {
  if (!status) {
    return state;
  }

  status.account = status.account.id;

  if (status.reblog && status.reblog.id) {
    state         = normalizeStatus(state, status.reblog);
    status.reblog = status.reblog.id;
  }

  return state.set(status.id, Immutable.fromJS(status));
};

const normalizeStatuses = (state, statuses) => {
  statuses.forEach(status => {
    state = normalizeStatus(state, status);
  });

  return state;
};

const deleteStatus = (state, id, references) => {
  references.forEach(ref => {
    state = deleteStatus(state, ref[0], []);
  });

  return state.delete(id);
};

const filterStatuses = (state, relationship) => {
  state.forEach(status => {
    if (status.get('account') !== relationship.id) {
      return;
    }

    state = deleteStatus(state, status.get('id'), state.filter(item => item.get('reblog') === status.get('id')));
  });

  return state;
};

const initialState = Immutable.Map();

export default function statuses(state = initialState, action) {
  switch(action.type) {
    case TIMELINE_UPDATE:
    case STATUS_FETCH_SUCCESS:
    case NOTIFICATIONS_UPDATE:
      return normalizeStatus(state, action.status);
    case REBLOG_SUCCESS:
    case UNREBLOG_SUCCESS:
    case FAVOURITE_SUCCESS:
    case UNFAVOURITE_SUCCESS:
      return normalizeStatus(state, action.response);
    case FAVOURITE_REQUEST:
      return state.setIn([action.status.get('id'), 'favourited'], true);
    case FAVOURITE_FAIL:
      return state.setIn([action.status.get('id'), 'favourited'], false);
    case REBLOG_REQUEST:
      return state.setIn([action.status.get('id'), 'reblogged'], true);
    case REBLOG_FAIL:
      return state.setIn([action.status.get('id'), 'reblogged'], false);
    case TIMELINE_REFRESH_SUCCESS:
    case TIMELINE_EXPAND_SUCCESS:
    case ACCOUNT_TIMELINE_FETCH_SUCCESS:
    case ACCOUNT_TIMELINE_EXPAND_SUCCESS:
    case CONTEXT_FETCH_SUCCESS:
    case NOTIFICATIONS_REFRESH_SUCCESS:
    case NOTIFICATIONS_EXPAND_SUCCESS:
      return normalizeStatuses(state, action.statuses);
    case TIMELINE_DELETE:
      return deleteStatus(state, action.id, action.references);
    case ACCOUNT_BLOCK_SUCCESS:
      return filterStatuses(state, action.relationship);
    default:
      return state;
  }
};