Live chat box on canvas (Update 2)

// === Single-Line Chat Display (with full clear + username fix + double-line border) ===

// --- Constants ---
const CHAT_START_X = cursor.x;
const CHAT_START_Y = cursor.y;
const CHAT_LINE_LENGTH = 180;

const BORDER_TOP_Y = CHAT_START_Y - 1;
const BORDER_MID_Y = CHAT_START_Y;
const BORDER_BOTTOM_Y = CHAT_START_Y + 1;

const INNER_WIDTH = CHAT_LINE_LENGTH;
const BLANK_LINE = " ".repeat(INNER_WIDTH);

let lastDrawn = "";
let scheduledFrame = false;
let nextText = "";

// Cursor helper
function setCursor(x, y) {
  cursor.x = x;
  cursor.y = y;
}

// Write string via writeChar()
function writeString(str) {
  for (let i = 0; i < str.length; i++) {
    writeChar(str[i], 1);  // keep attribute
  }
}

// === Draw static DOUBLE-LINE border ===
function drawBorder() {
  // Top: ╔══════════╗
  setCursor(CHAT_START_X, BORDER_TOP_Y);
  writeString("╔" + "═".repeat(INNER_WIDTH) + "╗");

  // Middle empty line: ║          ║
  setCursor(CHAT_START_X, BORDER_MID_Y);
  writeString("║" + " ".repeat(INNER_WIDTH) + "║");

  // Bottom: ╚══════════╝
  setCursor(CHAT_START_X, BORDER_BOTTOM_Y);
  writeString("╚" + "═".repeat(INNER_WIDTH) + "╝");
}

// Clear inside the double-line border
function clearInner() {
  setCursor(CHAT_START_X + 1, BORDER_MID_Y);
  writeString(BLANK_LINE);
}

// Draw updated chat text
function drawSingleLine() {
  const newText = nextText.slice(0, INNER_WIDTH);

  clearInner();

  setCursor(CHAT_START_X + 1, BORDER_MID_Y);
  writeString(newText);

  lastDrawn = newText;
  scheduledFrame = false;
}

// Schedule a single-frame redraw
function scheduleDraw(text) {
  nextText = text;
  if (!scheduledFrame) {
    scheduledFrame = true;
    requestAnimationFrame(drawSingleLine);
  }
}

// === Chat listener ===
w.on("msg", (data) => {
  const nick =
    data?.nick?.trim() ||
    data?.user?.name?.trim() ||
    data?.username?.trim() ||
    "Unknown";

  const line = `${nick}: ${data.msg}`;

  scheduleDraw(line);

  // Original save logic
  if (data.msg.startsWith("save ") && nick === "CalculatorBot") {
    save = Number(data.msg.substring(5)) - b;
  }
});

// Draw border once at startup
drawBorder();

// Startup message