const searchEl = document.getElementById("explorer-search");
const srsFilterEl = document.getElementById("explorer-srs-filter");
const sortEl = document.getElementById("explorer-sort");
const countEl = document.getElementById("explorer-count");
const metaEl = document.getElementById("explorer-meta");
const listEl = document.getElementById("explorer-list");

const SRS_KEY = "frenchJourney.srs";
const FORCE_KEY = "frenchJourney.forceCard";
const DEFAULT_LIST_ID = "er-verbs";
const MIN = 60000;
const DAY = 86400000;

let cards = [];
let query = "";
let srsFilter = "all";
let sortMode = "srs";
let store = { cards: {}, meta: {} };

const PRONOUNS = ["je", "tu", "il/elle", "nous", "vous", "ils/elles"];

function escapeHtml(s) {
  return String(s).replace(/[&<>"']/g, (ch) => ({
    "&": "&amp;", "<": "&lt;", ">": "&gt;", '"': "&quot;", "'": "&#39;",
  }[ch]));
}

function withPronoun(pron, form) {
  if (pron === "je" && /^[aeiouyhàâäéèêëîïôöûü]/i.test(form)) {
    return `<span class="cj-p">j'</span>${escapeHtml(form)}`;
  }
  return `<span class="cj-p">${pron} </span>${escapeHtml(form)}`;
}

function conjTable(card) {
  if (!card.present) return "";
  const cells = card.present
    .map((form, i) => `<span class="cj-cell">${withPronoun(PRONOUNS[i], form)}</span>`)
    .join("");
  return `<div class="fc-conj">
    <div class="fc-conj-label">Présent</div>
    <div class="fc-conj-grid">${cells}</div>
  </div>`;
}

function loadSrs() {
  try {
    const saved = JSON.parse(localStorage.getItem(SRS_KEY));
    if (saved && saved.cards) store = saved;
  } catch {}
}

function cardKey(card) {
  return `${DEFAULT_LIST_ID}:${card.infinitif}`;
}

function schedOf(card) {
  return store.cards[cardKey(card)];
}

function fmtUntil(ms) {
  if (ms <= 0) return "due now";
  if (ms < DAY) {
    const mins = Math.round(ms / MIN);
    if (mins < 1) return "<1m";
    if (mins < 60) return `${mins}m`;
    return `${Math.round(mins / 60)}h`;
  }
  const days = ms / DAY;
  if (days < 30) return `${Math.round(days)}d`;
  if (days < 365) return `${(days / 30).toFixed(1).replace(/\.0$/, "")}mo`;
  return `${(days / 365).toFixed(1).replace(/\.0$/, "")}y`;
}

function srsInfo(card) {
  const s = schedOf(card);
  if (!s) return { state: "new", label: "new", timeLeft: -1 };
  const isLearning = s.state === "learning" || s.state === "relearning";
  const timeLeft = Math.max(0, s.due - Date.now());
  return {
    state: s.state || "review",
    label: timeLeft === 0 ? (isLearning ? "learning now" : "due now") : fmtUntil(timeLeft),
    timeLeft,
  };
}

function matches(card, q) {
  if (!q) return true;
  return [
    card.infinitif,
    card.anglais,
    card.exemple_fr,
    card.exemple_en,
  ].join(" ").toLowerCase().includes(q);
}

function matchesSrs(card) {
  const s = schedOf(card);
  if (srsFilter === "all") return true;
  if (srsFilter === "new") return !s;
  if (srsFilter === "scheduled") return !!s;
  if (srsFilter === "due") return !!s && s.due <= Date.now();
  return true;
}

function sortCards(a, b) {
  if (sortMode === "az") return a.infinitif.localeCompare(b.infinitif, "fr");
  const ai = srsInfo(a);
  const bi = srsInfo(b);
  if (ai.timeLeft !== bi.timeLeft) return ai.timeLeft - bi.timeLeft;
  return a.infinitif.localeCompare(b.infinitif, "fr");
}

function studyCard(key) {
  localStorage.setItem(FORCE_KEY, key);
  window.location.href = "flashcards.html";
}

function render() {
  const q = query.trim().toLowerCase();
  const filtered = cards
    .filter((card) => matches(card, q) && matchesSrs(card))
    .sort(sortCards);
  countEl.textContent = String(cards.length);
  metaEl.textContent = `${filtered.length} of ${cards.length} cards`;

  if (!cards.length) {
    listEl.innerHTML = `<div class="fc-explorer-empty">No cards loaded.</div>`;
    return;
  }
  if (!filtered.length) {
    listEl.innerHTML = `<div class="fc-explorer-empty">No cards match this filter.</div>`;
    return;
  }

  listEl.innerHTML = filtered.map((card) => `
    <article class="fc-explorer-card">
      <div class="fc-explorer-side front">
        <span class="fc-label">Front</span>
        <strong>${escapeHtml(card.infinitif)}</strong>
        <span class="fc-srs-pill ${srsInfo(card).state}">${escapeHtml(srsInfo(card).label)}</span>
        <button class="fc-btn ghost fc-study-card" type="button" data-card-key="${escapeHtml(cardKey(card))}">Study this</button>
      </div>
      <div class="fc-explorer-side back">
        <span class="fc-label">Back</span>
        <strong>${escapeHtml(card.anglais)}</strong>
        ${conjTable(card)}
        <div class="fc-example">
          <code>${escapeHtml(card.exemple_fr)}</code>
          <span class="fc-ex-en">${escapeHtml(card.exemple_en)}</span>
        </div>
      </div>
    </article>
  `).join("");
  listEl.querySelectorAll("[data-card-key]").forEach((button) => {
    button.onclick = () => studyCard(button.dataset.cardKey);
  });
}

async function init() {
  try {
    loadSrs();
    const SQL = await initSqlJs({
      locateFile: (f) => `https://cdnjs.cloudflare.com/ajax/libs/sql.js/1.10.3/${f}`,
    });
    const buf = await fetch("verbs.db").then((r) => {
      if (!r.ok) throw new Error("HTTP " + r.status);
      return r.arrayBuffer();
    });
    const db = new SQL.Database(new Uint8Array(buf));
    const res = db.exec("SELECT infinitif, anglais, exemple_fr, exemple_en FROM verbs ORDER BY infinitif;");
    const rows = res[0]?.values || [];
    cards = rows.map(([infinitif, anglais, exemple_fr, exemple_en]) => ({
      infinitif, anglais, exemple_fr, exemple_en,
    }));

    const conj = {};
    const cres = db.exec("SELECT infinitif, p1, p2, p3, p4, p5, p6 FROM conjugations WHERE tense='présent';");
    if (cres[0]) {
      for (const [infinitif, ...forms] of cres[0].values) conj[infinitif] = forms;
    }
    cards.forEach((card) => { card.present = conj[card.infinitif] || null; });

    searchEl.oninput = () => {
      query = searchEl.value;
      render();
    };
    srsFilterEl.onchange = () => {
      srsFilter = srsFilterEl.value;
      render();
    };
    sortEl.onchange = () => {
      sortMode = sortEl.value;
      render();
    };
    render();
  } catch (err) {
    metaEl.textContent = "Could not load database.";
    listEl.innerHTML = `<div class="fc-error">
      <strong>Couldn't load verbs.db.</strong>
      <p>Open this app through a local server:</p>
      <code>python3 -m http.server 8000</code>
      <p class="fc-err-detail">${escapeHtml(err.message)}</p>
    </div>`;
  }
}

init();