bigbuffet-rw/app/soapbox/reducers/chat_messages.ts

import { Map as ImmutableMap, fromJS } from 'immutable';

import {
  CHATS_FETCH_SUCCESS,
  CHATS_EXPAND_SUCCESS,
  CHAT_MESSAGES_FETCH_SUCCESS,
  CHAT_MESSAGE_SEND_REQUEST,
  CHAT_MESSAGE_SEND_SUCCESS,
  CHAT_MESSAGE_DELETE_REQUEST,
  CHAT_MESSAGE_DELETE_SUCCESS,
} from 'soapbox/actions/chats';
import { STREAMING_CHAT_UPDATE } from 'soapbox/actions/streaming';
import { normalizeChatMessage } from 'soapbox/normalizers';

import type { AnyAction } from 'redux';

type ChatMessageRecord = ReturnType<typeof normalizeChatMessage>;
type APIEntity = Record<string, any>;
type APIEntities = Array<APIEntity>;

type State = ImmutableMap<string, ChatMessageRecord>;

const importMessage = (state: State, message: APIEntity) => {
  return state.set(message.id, normalizeChatMessage(message));
};

const importMessages = (state: State, messages: APIEntities) =>
  state.withMutations(mutable =>
    messages.forEach(message => importMessage(mutable, message)));

const importLastMessages = (state: State, chats: APIEntities) =>
  state.withMutations(mutable =>
    chats.forEach(chat => {
      if (chat.last_message)
        importMessage(mutable, chat.last_message);
    }));

const initialState: State = ImmutableMap();

export default function chatMessages(state = initialState, action: AnyAction) {
  switch (action.type) {
    case CHAT_MESSAGE_SEND_REQUEST:
      return importMessage(state, fromJS({
        id: action.uuid, // Make fake message to get overriden later
        chat_id: action.chatId,
        account_id: action.me,
        content: action.params.content,
        created_at: (new Date()).toISOString(),
        pending: true,
      }));
    case CHATS_FETCH_SUCCESS:
    case CHATS_EXPAND_SUCCESS:
      return importLastMessages(state, action.chats);
    case CHAT_MESSAGES_FETCH_SUCCESS:
      return importMessages(state, action.chatMessages);
    case CHAT_MESSAGE_SEND_SUCCESS:
      return importMessage(state, fromJS(action.chatMessage)).delete(action.uuid);
    case STREAMING_CHAT_UPDATE:
      return importLastMessages(state, [action.chat]);
    case CHAT_MESSAGE_DELETE_REQUEST:
      return state.update(action.messageId, chatMessage =>
      chatMessage!.set('pending', true).set('deleting', true));
    case CHAT_MESSAGE_DELETE_SUCCESS:
      return state.delete(action.messageId);
    default:
      return state;
  }
}