app.js

const editor = document.getElementById("editor");
const saveBtn = document.getElementById("saveBtn");
const loadBtn = document.getElementById("loadBtn");
const themeBtn = document.getElementById("themeBtn");
const linedBtn = document.getElementById("linedBtn");
const fileNameLabel = document.getElementById("fileName");

let currentFileName = "Untitled.txt";
let isDirty = false;

function updateTitle() {
  const mark = isDirty ? "*" : "";
  document.title = `${mark}JDL - ${currentFileName}`;
  fileNameLabel.textContent = currentFileName;
}

function saveFile() {
  const text = editor.value;
  const link = document.createElement("a");
  link.href = "data:text/plain;charset=utf-8," + encodeURIComponent(text);
  link.download = currentFileName;
  link.click();
  isDirty = false;
  updateTitle();
}

function loadFile() {
  const input = document.createElement("input");
  input.type = "file";
  input.accept = ".txt,text/plain,*/*";

  input.addEventListener("change", () => {
    const file = input.files && input.files[0];
    if (!file) return;

    const reader = new FileReader();

    reader.onload = () => {
      editor.value = String(reader.result ?? "");
      currentFileName = file.name || "Untitled.txt";
      isDirty = false;
      updateTitle();
      editor.focus();
    };

    reader.readAsText(file);
  });

  input.click();
}

function toggleTheme() {
  const next = document.body.dataset.theme === "light" ? "dark" : "light";
  document.body.dataset.theme = next;
  themeBtn.textContent = next === "dark" ? "Light Mode" : "Dark Mode";
  themeBtn.setAttribute("aria-pressed", String(next === "dark"));
}

function toggleLines() {
  const next = document.body.dataset.lined === "on" ? "off" : "on";
  document.body.dataset.lined = next;
  linedBtn.textContent = next === "on" ? "Lines: On" : "Lines: Off";
  linedBtn.setAttribute("aria-pressed", String(next === "on"));
}

editor.addEventListener("input", () => {
  isDirty = true;
  updateTitle();
});

saveBtn.addEventListener("click", saveFile);
loadBtn.addEventListener("click", loadFile);
themeBtn.addEventListener("click", toggleTheme);
linedBtn.addEventListener("click", toggleLines);

window.addEventListener("beforeunload", (e) => {
  if (!isDirty) return;
  e.preventDefault();
  e.returnValue = "";
});

updateTitle();
editor.focus();