watch-party/frontend/lib/chat.mjs

import {
  setDebounce,
  setVideoTime,
  setPlaying,
} from "./watch-session.mjs?v=e9a1b";
import { emojify, emojis } from "./emojis.mjs?v=e9a1b";

function insertAtCursor(input, textToInsert) {
  const isSuccess = document.execCommand("insertText", false, textToInsert);

  // Firefox (non-standard method)
  if (!isSuccess && typeof input.setRangeText === "function") {
    const start = input.selectionStart;
    input.setRangeText(textToInsert);
    // update cursor to be at the end of insertion
    input.selectionStart = input.selectionEnd = start + textToInsert.length;

    // Notify any possible listeners of the change
    const e = document.createEvent("UIEvent");
    e.initEvent("input", true, false);
    input.dispatchEvent(e);
  }
}

const setupChatboxEvents = (socket) => {
  // clear events by just reconstructing the form
  const oldChatForm = document.querySelector("#chatbox-send");
  const chatForm = oldChatForm.cloneNode(true);
  const messageInput = chatForm.querySelector("input");
  const emojiAutocomplete = chatForm.querySelector("#emoji-autocomplete");
  oldChatForm.replaceWith(chatForm);

  let autocompleting = false;

  const replaceMessage = (message) => () => {
    messageInput.value = message;
    autocomplete();
  };
  async function autocomplete() {
    if (autocompleting) return;
    emojiAutocomplete.textContent = "";
    autocompleting = true;
    let text = messageInput.value.slice(0, messageInput.selectionStart);
    const match = text.match(/(:[^\s:]+)?:([^\s:]*)$/);
    if (!match || match[1]) return (autocompleting = false); // We don't need to autocomplete.
    const prefix = text.slice(0, match.index);
    const search = text.slice(match.index + 1);
    const suffix = messageInput.value.slice(messageInput.selectionStart);
    const select = (button) => {
      const selected = document.querySelector(".emoji-option.selected");
      if (selected) selected.classList.remove("selected");
      button.classList.add("selected");
    };
    emojiAutocomplete.append(
      ...(await emojis)
        .filter((e) => e.toLowerCase().startsWith(search.toLowerCase()))
        .map((name, i) => {
          const button = Object.assign(document.createElement("button"), {
            className: "emoji-option" + (i === 0 ? " selected" : ""),
            onmousedown: (e) => e.preventDefault(),
            onmouseup: () =>
              insertAtCursor(button, name.slice(match[2].length) + ": "),
            onmouseover: () => select(button),
            onfocus: () => select(button),
          });
          button.append(
            Object.assign(new Image(), {
              loading: "lazy",
              src: `/emojis/${name}.png`,
              className: "emoji",
            }),
            Object.assign(document.createElement("span"), { textContent: name })
          );
          return button;
        })
    );
    if (emojiAutocomplete.children[0])
      emojiAutocomplete.children[0].scrollIntoView();
    autocompleting = false;
  }
  messageInput.addEventListener("input", autocomplete);
  messageInput.addEventListener("selectionchange", autocomplete);
  messageInput.addEventListener("keydown", (event) => {
    if (event.key == "ArrowUp" || event.key == "ArrowDown") {
      let selected = document.querySelector(".emoji-option.selected");
      if (!selected) return;
      event.preventDefault();
      selected.classList.remove("selected");
      selected =
        event.key == "ArrowDown"
          ? selected.nextElementSibling || selected.parentElement.children[0]
          : selected.previousElementSibling ||
            selected.parentElement.children[
              selected.parentElement.children.length - 1
            ];
      selected.classList.add("selected");
      selected.scrollIntoView({ scrollMode: "if-needed", block: "nearest" });
    }
    if (event.key == "Tab") {
      let selected = document.querySelector(".emoji-option.selected");
      if (!selected) return;
      event.preventDefault();
      selected.onmouseup();
    }
  });

  chatForm.addEventListener("submit", async (e) => {
    e.preventDefault();
    const content = messageInput.value;
    if (content.trim().length) {
      messageInput.value = "";

      // handle commands
      if (content.startsWith("/")) {
        const command = content.toLowerCase().match(/^\/\S+/)[0];
        const args = content.slice(command.length).trim();

        let handled = false;
        switch (command) {
          case "/ping":
            socket.send(
              JSON.stringify({
                op: "Ping",
                data: args,
              })
            );
            handled = true;
            break;
          case "/sync":
            const sessionId = window.location.hash.slice(1);
            const { current_time_ms, is_playing } = await fetch(
              `/sess/${sessionId}`
            ).then((r) => r.json());

            setDebounce();
            setPlaying(is_playing);
            setVideoTime(current_time_ms);

            const syncMessageContent = document.createElement("span");
            syncMessageContent.appendChild(
              document.createTextNode("resynced you to ")
            );
            syncMessageContent.appendChild(
              document.createTextNode(formatTime(current_time_ms))
            );
            printChatMessage("set-time", "/sync", "b57fdc", syncMessageContent);
            handled = true;
            break;
          case "/help":
            const helpMessageContent = document.createElement("span");
            helpMessageContent.innerHTML =
              "Available commands:<br>" +
              "&emsp;<code>/help</code> - display this help message<br>" +
              "&emsp;<code>/ping [message]</code> - ping all viewers<br>" +
              "&emsp;<code>/sync</code> - resyncs you with other viewers";

            printChatMessage(
              "command-message",
              "/help",
              "b57fdc",
              helpMessageContent
            );
            handled = true;
            break;
          default:
            break;
        }

        if (handled) {
          return;
        }
      }

      // handle regular chat messages
      socket.send(
        JSON.stringify({
          op: "ChatMessage",
          data: content,
        })
      );
    }
  });
};

/**
 * @param {WebSocket} socket
 */
export const setupChat = async (socket) => {
  document.querySelector("#chatbox-container").style["display"] = "flex";
  setupChatboxEvents(socket);

  window.addEventListener("keydown", (event) => {
    try {
      const isSelectionEmpty = window.getSelection().toString().length === 0;
      if (event.code.match(/Key\w/) && isSelectionEmpty) messageInput.focus();
    } catch (_err) {}
  });
};

const addToChat = (node) => {
  const chatbox = document.querySelector("#chatbox");
  chatbox.appendChild(node);
  chatbox.scrollTop = chatbox.scrollHeight;
};

let lastTimeMs = null;
let lastPlaying = false;

const checkDebounce = (event) => {
  let timeMs = null;
  let playing = null;
  if (event.op == "SetTime") {
    timeMs = event.data;
  } else if (event.op == "SetPlaying") {
    timeMs = event.data.time;
    playing = event.data.playing;
  }

  let shouldIgnore = false;

  if (timeMs != null) {
    if (lastTimeMs && Math.abs(lastTimeMs - timeMs) < 500) {
      shouldIgnore = true;
    }
    lastTimeMs = timeMs;
  }

  if (playing != null) {
    if (lastPlaying != playing) {
      shouldIgnore = false;
    }
    lastPlaying = playing;
  }

  return shouldIgnore;
};

/**
 * @returns {string}
 */
const getCurrentTimestamp = () => {
  const t = new Date();
  return `${matpad(t.getHours())}:${matpad(t.getMinutes())}:${matpad(
    t.getSeconds()
  )}`;
};

/**
 * https://media.discordapp.net/attachments/834541919568527361/931678814751301632/66d2c68c48daa414c96951381665ec2e.png
 */
const matpad = (n) => {
  return ("00" + n).slice(-2);
};

/**
 * @param {string} eventType
 * @param {string?} user
 * @param {Node?} content
 */
const printChatMessage = (eventType, user, colour, content) => {
  const chatMessage = document.createElement("div");
  chatMessage.classList.add("chat-message");
  chatMessage.classList.add(eventType);
  chatMessage.title = getCurrentTimestamp();

  if (user != null) {
    const userName = document.createElement("strong");
    userName.style = `--user-color: #${colour}`;
    userName.textContent = user;
    chatMessage.appendChild(userName);
  }

  chatMessage.appendChild(document.createTextNode(" "));

  if (content != null) {
    chatMessage.appendChild(content);
  }

  addToChat(chatMessage);

  return chatMessage;
};

const formatTime = (ms) => {
  const seconds = Math.floor((ms / 1000) % 60);
  const minutes = Math.floor((ms / (60 * 1000)) % 60);
  const hours = Math.floor((ms / (3600 * 1000)) % 3600);
  return `${hours < 10 ? "0" + hours : hours}:${
    minutes < 10 ? "0" + minutes : minutes
  }:${seconds < 10 ? "0" + seconds : seconds}`;
};

export const logEventToChat = async (event) => {
  if (checkDebounce(event)) {
    return;
  }

  switch (event.op) {
    case "UserJoin": {
      printChatMessage(
        "user-join",
        event.user,
        event.colour,
        document.createTextNode("joined")
      );
      break;
    }
    case "UserLeave": {
      printChatMessage(
        "user-leave",
        event.user,
        event.colour,
        document.createTextNode("left")
      );
      break;
    }
    case "ChatMessage": {
      const messageContent = document.createElement("span");
      messageContent.classList.add("message-content");
      messageContent.append(...(await emojify(event.data)));
      printChatMessage(
        "chat-message",
        event.user,
        event.colour,
        messageContent
      );
      break;
    }
    case "SetTime": {
      const messageContent = document.createElement("span");
      if (event.data.from != undefined) {
        messageContent.appendChild(
          document.createTextNode("set the time from ")
        );

        messageContent.appendChild(
          document.createTextNode(formatTime(event.data.from))
        );

        messageContent.appendChild(document.createTextNode(" to "));
      } else {
        messageContent.appendChild(document.createTextNode("set the time to "));
      }

      messageContent.appendChild(
        document.createTextNode(formatTime(event.data.to))
      );

      printChatMessage("set-time", event.user, event.colour, messageContent);
      break;
    }
    case "SetPlaying": {
      const messageContent = document.createElement("span");
      messageContent.appendChild(
        document.createTextNode(
          event.data.playing ? "started playing" : "paused"
        )
      );
      messageContent.appendChild(document.createTextNode(" at "));
      messageContent.appendChild(
        document.createTextNode(formatTime(event.data.time))
      );

      printChatMessage("set-playing", event.user, event.colour, messageContent);
      break;
    }
    case "Ping": {
      const messageContent = document.createElement("span");
      if (event.data) {
        messageContent.appendChild(document.createTextNode("pinged saying: "));
        messageContent.appendChild(document.createTextNode(event.data));
      } else {
        messageContent.appendChild(document.createTextNode("pinged"));
      }

      printChatMessage("ping", event.user, event.colour, messageContent);
      beep();
      break;
    }
  }
};

const beep = () => {
  const context = new AudioContext();

  const gain = context.createGain();
  gain.connect(context.destination);
  gain.gain.value = 0.1;

  const oscillator = context.createOscillator();
  oscillator.connect(gain);
  oscillator.frequency.value = 520;
  oscillator.type = "square";

  oscillator.start(context.currentTime);
  oscillator.stop(context.currentTime + 0.22);
};

export const updateViewerList = (viewers) => {
  const listContainer = document.querySelector("#viewer-list");

  // empty out the current list
  listContainer.innerHTML = "";

  // display the updated list
  for (const viewer of viewers) {
    const viewerElem = document.createElement("div");
    const content = document.createElement("strong");
    content.textContent = viewer.nickname;
    content.style = `--user-color: #${viewer.colour}`;
    viewerElem.appendChild(content);
    listContainer.appendChild(viewerElem);
  }
};