const slug = (s) =>
  s.toLowerCase()
    .normalize("NFD").replace(/[̀-ͯ]/g, "")
    .replace(/[^a-z0-9]+/g, "-").replace(/(^-|-$)/g, "");

const navEl = document.getElementById("nav");
const contentEl = document.getElementById("content");
const searchEl = document.getElementById("search");

const STORE_KEY = "frenchJourney.completed";

function loadDone() {
  try { return JSON.parse(localStorage.getItem(STORE_KEY)) || {}; }
  catch { return {}; }
}
function saveDone(done) {
  localStorage.setItem(STORE_KEY, JSON.stringify(done));
}
let done = loadDone();

function chapterId(niveau, titre) {
  return slug(niveau.niveau + "-" + titre);
}

function render(filter = "") {
  const q = filter.trim().toLowerCase();
  navEl.innerHTML = "";
  contentEl.innerHTML = "";
  let anyContent = false;

  GRAMMAIRE.forEach((niveau) => {
    const chapitres = niveau.chapitres.filter((c) => {
      if (!q) return true;
      const ex = c.exemples.map((e) => e.fr + " " + e.en).join(" ");
      const hay = (c.titre + " " + c.points.join(" ") + " " + ex).toLowerCase();
      return hay.includes(q) || niveau.niveau.toLowerCase().includes(q);
    });
    if (chapitres.length === 0) return;
    anyContent = true;

    const total = chapitres.length;
    const completed = chapitres.filter((c) => done[chapterId(niveau, c.titre)]).length;

    // --- Sidebar group ---
    const group = document.createElement("div");
    group.className = "level-group";
    group.innerHTML = `
      <div class="level-label">
        <span>${niveau.niveau} <span class="lvl-name">${niveau.titre}</span></span>
        <span class="lvl-count">${completed}/${total}</span>
      </div>`;
    chapitres.forEach((c) => {
      const id = chapterId(niveau, c.titre);
      const a = document.createElement("a");
      a.href = "#" + id;
      a.dataset.id = id;
      a.innerHTML = `<span class="dot${done[id] ? " on" : ""}"></span>${c.titre.split(" (")[0]}`;
      group.appendChild(a);
    });
    navEl.appendChild(group);

    // --- Content header ---
    const header = document.createElement("div");
    header.className = "level-header";
    header.innerHTML = `
      <span class="badge">${niveau.niveau}</span>
      <h1>${niveau.titre}</h1>
      <p>${niveau.description}</p>
      <div class="progress">
        <div class="progress-bar"><span style="width:${total ? (completed / total) * 100 : 0}%"></span></div>
        <span class="progress-text">${completed} of ${total} completed</span>
      </div>`;
    contentEl.appendChild(header);

    // --- Chapters ---
    chapitres.forEach((c) => {
      const id = chapterId(niveau, c.titre);
      const isDone = !!done[id];
      const sec = document.createElement("section");
      sec.className = "chapter" + (isDone ? " done" : "");
      sec.id = id;

      const points = c.points.map((p) => `<li>${p}</li>`).join("");
      const ex = c.exemples
        .map((e) => `<div class="ex"><code>${e.fr}</code><span class="ex-en">${e.en}</span></div>`)
        .join("");

      sec.innerHTML = `
        <div class="chapter-head">
          <h2>${c.titre}</h2>
          <button class="mark" data-id="${id}">
            <span class="check">${isDone ? "✓" : ""}</span>
            ${isDone ? "Completed" : "Mark as completed"}
          </button>
        </div>
        <ul>${points}</ul>
        <div class="examples">
          <div class="ex-label">Examples</div>
          ${ex}
        </div>`;
      contentEl.appendChild(sec);
    });
  });

  if (!anyContent) {
    contentEl.innerHTML = `<p class="empty">No results for “${filter}”.</p>`;
  }

  bindMarks();
  setupScrollSpy();
}

function bindMarks() {
  contentEl.querySelectorAll(".mark").forEach((btn) => {
    btn.addEventListener("click", () => {
      const id = btn.dataset.id;
      if (done[id]) delete done[id];
      else done[id] = true;
      saveDone(done);
      render(searchEl.value);
    });
  });
}

function setupScrollSpy() {
  const links = [...navEl.querySelectorAll("a")];
  const sections = links
    .map((a) => document.getElementById(a.dataset.id))
    .filter(Boolean);
  if (!sections.length) return;

  const obs = new IntersectionObserver(
    (entries) => {
      entries.forEach((entry) => {
        if (entry.isIntersecting) {
          links.forEach((l) => l.classList.remove("active"));
          const active = links.find((l) => l.dataset.id === entry.target.id);
          if (active) active.classList.add("active");
        }
      });
    },
    { rootMargin: "-60px 0px -70% 0px", threshold: 0 }
  );
  sections.forEach((s) => obs.observe(s));
}

searchEl.addEventListener("input", (e) => render(e.target.value));
render();