docbrown/app/javascript/chat/chat.jsx

import { h, Component } from 'preact';
import PropTypes from 'prop-types';
import { conductModeration, getAllMessages, sendMessage } from './actions';
import {
  hideMessages,
  scrollToBottom,
  setupObserver,
} from './util';
import Alert from './alert';
import Channels from './channels';
import Compose from './compose';
import Message from './message';
import setupPusher from './pusher';

export default class Chat extends Component {
  static propTypes = {
    pusherKey: PropTypes.number.isRequired,
    chatChannels: PropTypes.array.isRequired,
    chatOptions: PropTypes.object.isRequired,
  };

  constructor(props) {
    super(props);
    const chatChannels = JSON.parse(this.props.chatChannels);
    const chatOptions = JSON.parse(this.props.chatOptions);
    this.state = {
      messages: chatChannels.reduce(
        (accumulator, target) => ({ ...accumulator, [target.id]: [] }),
        {},
      ),
      scrolled: false,
      showAlert: false,
      chatChannels,
      activeChannelId: chatChannels[0].id,
      showChannelsList: chatOptions.showChannelsList,
      showTimestamp: chatOptions.showTimestamp,
    };
  }

  componentDidMount() {
    this.state.chatChannels.forEach(channel => {
      this.setupChannel(channel.id);
    });
    setupObserver(this.observerCallback);
  }

  componentDidUpdate() {
    if (!this.state.scrolled) {
      scrollToBottom();
    }
  }

  setupChannel = channelId => {
    getAllMessages(channelId, this.receiveAllMessages);
    setupPusher(this.props.pusherKey, {
      channelId,
      messageCreated: this.receiveNewMessage,
      channelCleared: this.clearChannel,
      redactUserMessages: this.redactUserMessages,
    });
  };

  observerCallback = entries => {
    entries.forEach(entry => {
      if (entry.isIntersecting) {
        this.setState({ scrolled: false, showAlert: false });
      } else {
        this.setState({ scrolled: true });
      }
    });
  };

  receiveAllMessages = res => {
    const { chatChannelId, messages } = res;
    const newMessages = { ...this.state.messages, [chatChannelId]: messages };
    this.setState({ messages: newMessages });
  };

  receiveNewMessage = message => {
    const receivedChatChannelId = message.chat_channel_id;
    const newMessages = this.state.messages[receivedChatChannelId].slice();
    newMessages.push(message);
    if (newMessages.length > 150) {
      newMessages.shift();
    }
    const newShowAlert =
      this.state.activeChannelId === receivedChatChannelId
        ? { showAlert: this.state.scrolled }
        : {};
    this.setState({
      ...newShowAlert,
      messages: {
        ...this.state.messages,
        [receivedChatChannelId]: newMessages,
      },
    });
  };

  redactUserMessages = res => {
    // This is shallow clone. This might cause a problem
    const clonedMessages = Object.assign({}, this.state.messages);
    const newMessages = hideMessages(clonedMessages, res.userId);
    this.setState({ messages: newMessages });
  };

  clearChannel = res => {
    const newMessages = { ...this.state.messages, [res.chat_channel_id]: [] };
    this.setState({ messages: newMessages });
  };

  handleKeyDown = e => {
    const enterPressed = e.keyCode === 13;
    const targetValue = e.target.value;
    const messageIsEmpty = targetValue.length === 0;
    const shiftPressed = e.shiftKey;

    if (enterPressed) {
      if(messageIsEmpty) {
        e.preventDefault();
      } else if (!messageIsEmpty && !shiftPressed) {
        e.preventDefault();
        this.handleMessageSubmit(e.target.value);
        e.target.value = '';
      }
    }
  };

  handleMessageSubmit = message => {
    // should check if user has the priviledge
    if (message[0] === '/') {
      conductModeration(
        this.state.activeChannelId,
        message,
        this.handleSuccess,
        this.handleFailure,
      );
    } else {
      sendMessage(
        this.state.activeChannelId,
        message,
        this.handleSuccess,
        this.handleFailure,
      );
    }
  };

  handleSwitchChannel = e => {
    e.preventDefault();
    this.setState({
      activeChannelId: e.target.dataset.channelId,
      scrolled: false,
      showAlert: false,
    });
  };

  handleSubmitOnClick = e => {
    e.preventDefault();
    const message = document.getElementById('messageform').value;
    if (message.length > 0) {
      this.handleMessageSubmit(message);
      document.getElementById('messageform').value = '';
    }
  };

  handleSuccess = response => {
    if (response.status === 'error') {
      this.receiveNewMessage(response.message);
    }
  };

  handleFailure = err => {
    console.error(err);
  };

  renderMessage = () => {
    const { activeChannelId, messages, showTimestamp } = this.state;
    return messages[activeChannelId].map(message => (
      <Message
        user={message.username}
        profileImageUrl={message.profile_image_url}
        message={message.message}
        timestamp={showTimestamp ? message.timestamp : null}
        color={message.color}
        type={message.type}
      />
    ));
  };

  renderChatChannels = () => {
    if (this.state.showChannelsList) {
      return (
        <div className="chat__channels">
          <Channels
            activeChannelId={this.state.activeChannelId}
            chatChannels={this.state.chatChannels}
            handleSwitchChannel={this.handleSwitchChannel}
          />
        </div>
      );
    }
    return '';
  };

  renderActiveChatChannel = () => (
    <div className="activechatchannel">
      <div className="activechatchannel__messages" id="messagelist">
        {this.renderMessage()}
        <div id="messagelist__sentinel" />
      </div>
      <div className="activechatchannel__alerts">
        <Alert showAlert={this.state.showAlert} />
      </div>
      <div className="activechatchannel__form">
        <Compose
          handleKeyDown={this.handleKeyDown}
          handleSubmitOnClick={this.handleSubmitOnClick}
        />
      </div>
    </div>
  );

  render() {
    return (
      <div className="chat">
        {this.renderChatChannels()}
        <div className="chat__activechat">{this.renderActiveChatChannel()}</div>
      </div>
    );
  }
}