import { el, clear, onTeardown } from '../lib/dom.js';
import { loadSnapshot } from '../data/snapshot.js';
import { Sprite } from '../components/Sprite.js';
import { whosThat, recordResult } from '../store/whosThat.js';
import { prefersReducedMotion } from '../store/settings.js';
import { closeEnough } from '../lib/fuzzy.js';

const loose = (s) => s.toLowerCase().replace(/[^a-z0-9]/g, '');
const pretty = (name) => name.replace(/-/g, ' ');

/**
 * Hidden mini-game — reachable by the Konami code (↑↑↓↓←→←→BA), seven quick
 * taps on the dex feed's game title, or the bare #/whos-that hash. Guess
 * the Pokémon from its silhouette; a light typo tolerance and a ghost-text
 * completion (once your prefix is unambiguous) keep the typing painless.
 */
export async function WhosThatView() {
  const view = el('section', { class: 'view wtp' });
  const snap = await loadSnapshot();
  const GENS = [...new Set(snap.species.map((s) => s.generation))]
    .filter(Boolean)
    .sort((a, b) => a - b);

  let genFilter = GENS.includes(whosThat.get().gen) ? whosThat.get().gen : 0;
  let pool = [];
  let NAMES = [];
  function rebuildPool() {
    pool = genFilter ? snap.species.filter((s) => s.generation === genFilter) : snap.species;
    NAMES = pool.map((s) => ({ loose: loose(s.name), display: pretty(s.name) }));
  }
  rebuildPool();

  let current = null;
  let revealed = false;
  let wrong = 0;
  let streak = 0;

  const genSelect = el(
    'select',
    {
      class: 'wtp__gen',
      'aria-label': 'Which generations to pull from',
      onchange: (e) => {
        genFilter = Number(e.target.value) || 0;
        whosThat.set((s) => ({ ...s, gen: genFilter }));
        streak = 0;
        rebuildPool();
        next();
      },
    },
    el('option', { value: '0', selected: genFilter === 0 }, 'All generations'),
    ...GENS.map((g) => el('option', { value: String(g), selected: genFilter === g }, `Gen ${g}`)),
  );

  const art = el('div', { class: 'wtp__art' });
  const caption = el('div', { class: 'wtp__caption' }, 'Who’s that Pokémon?');
  const hint = el('div', { class: 'wtp__hint' });
  const feedback = el('div', { class: 'wtp__feedback' });
  const scoreEl = el('div', { class: 'wtp__score' });

  const ghostTyped = el('span', { class: 'wtp__ghost-typed' });
  const ghostRest = el('span', { class: 'wtp__ghost-rest' });
  const ghost = el(
    'div',
    { class: 'wtp__ghost', 'aria-hidden': 'true', hidden: true },
    ghostTyped,
    ghostRest,
  );

  const input = el('input', {
    class: 'wtp__input',
    type: 'text',
    placeholder: 'Your guess…',
    autocomplete: 'off',
    autocapitalize: 'off',
    autocorrect: 'off',
    spellcheck: 'false',
    oninput: updateGhost,
    onkeydown: (e) => {
      if (e.key === 'Enter') {
        submitGuess();
        return;
      }
      const atEnd =
        input.selectionStart === input.value.length && input.selectionStart === input.selectionEnd;
      const wantsAccept = e.key === 'Tab' || e.key === 'End' || (e.key === 'ArrowRight' && atEnd);
      if (wantsAccept && !ghost.hidden && acceptGhost()) e.preventDefault();
    },
  });
  const inputWrap = el('div', { class: 'wtp__inputwrap' }, ghost, input);

  const guessBtn = el(
    'button',
    { class: 'button wtp__go', type: 'button', onclick: submitGuess },
    'Guess',
  );
  const revealBtn = el(
    'button',
    { class: 'button button--ghost', type: 'button', onclick: () => reveal(false) },
    'Reveal',
  );
  const nextBtn = el('button', { class: 'button', type: 'button', onclick: next }, 'Next →');

  /** The one display name whose loose form starts with what's typed, else ''. */
  function currentCompletion() {
    const raw = input.value;
    if (!raw || revealed) return '';
    const key = loose(raw);
    if (!key) return '';
    const hits = NAMES.filter((n) => n.loose.startsWith(key));
    if (hits.length !== 1) return '';
    const full = hits[0].display;
    // Only when what's typed is a literal prefix of the pretty name — keeps
    // us from mangling the space in "mr mime" etc.
    if (
      full.length <= raw.length ||
      full.slice(0, raw.length).toLowerCase() !== raw.toLowerCase()
    ) {
      return '';
    }
    return full;
  }

  function updateGhost() {
    const full = currentCompletion();
    ghost.hidden = !full;
    if (!full) return;
    ghostTyped.textContent = input.value;
    ghostRest.textContent = full.slice(input.value.length);
  }

  function acceptGhost() {
    const full = currentCompletion();
    if (!full) return false;
    input.value = full;
    updateGhost();
    return true;
  }

  function renderScore() {
    const s = whosThat.get();
    const pct = s.plays ? Math.round((s.wins / s.plays) * 100) : 0;
    clear(scoreEl).append(
      el('span', { class: 'wtp__pill' }, `Streak ${streak}`),
      el('span', { class: 'wtp__pill' }, `Best ${s.best}`),
      el('span', { class: 'wtp__pill wtp__pill--dim' }, `${s.wins}/${s.plays} · ${pct}%`),
    );
  }

  function syncButtons() {
    inputWrap.hidden = revealed;
    guessBtn.hidden = revealed;
    revealBtn.hidden = revealed;
    nextBtn.hidden = !revealed;
  }

  function next() {
    current = pool[Math.floor(Math.random() * pool.length)];
    revealed = false;
    wrong = 0;
    art.classList.remove('is-revealed');
    clear(art).append(Sprite(current.id, { style: 'official', size: 260, alt: 'Mystery Pokémon' }));
    caption.textContent = 'Who’s that Pokémon?';
    hint.textContent = '';
    feedback.textContent = '';
    feedback.className = 'wtp__feedback';
    input.value = '';
    updateGhost();
    syncButtons();
    input.focus();
  }

  function reveal(win) {
    revealed = true;
    art.classList.add('is-revealed');
    updateGhost();
    caption.textContent = `It’s ${pretty(current.name)}!  #${String(current.id).padStart(4, '0')}`;
    if (win) {
      streak += 1;
      feedback.textContent = wrong === 0 ? 'Nailed it!' : 'Got there!';
      feedback.className = 'wtp__feedback is-good';
    } else {
      streak = 0;
      feedback.textContent = 'That one got away.';
      feedback.className = 'wtp__feedback is-bad';
    }
    recordResult(win, streak);
    renderScore();
    syncButtons();
    if (win && !prefersReducedMotion()) {
      art.animate(
        [{ transform: 'scale(0.9)' }, { transform: 'scale(1.05)' }, { transform: 'scale(1)' }],
        { duration: 380, easing: 'cubic-bezier(.34,1.4,.64,1)' },
      );
    }
    nextBtn.focus();
  }

  function submitGuess() {
    if (revealed || !input.value.trim()) return;
    if (closeEnough(loose(input.value), loose(current.name))) {
      reveal(true);
      return;
    }
    wrong += 1;
    input.value = '';
    updateGhost();
    feedback.className = 'wtp__feedback is-bad';
    if (wrong === 1) {
      feedback.textContent = 'Nope — try again.';
      hint.textContent = `${loose(current.name).length} letters`;
    } else if (wrong === 2) {
      feedback.textContent = 'Last clue…';
      hint.textContent = `Starts with “${current.name[0].toUpperCase()}”, ${loose(current.name).length} letters`;
    } else {
      reveal(false); // three strikes
      return;
    }
    input.focus();
  }

  view.append(
    el(
      'nav',
      { class: 'lookup__nav' },
      el('a', { class: 'link', href: '#/' }, '‹ Dex'),
      el('span', {}, ' · '),
      el('a', { class: 'link', href: '#/pinball' }, 'Pinball'),
    ),
    el(
      'header',
      { class: 'view__header' },
      el('h1', {}, 'Who’s that Pokémon?'),
      el('p', {}, 'Name it from the silhouette. Three misses and it’s revealed.'),
    ),
    el('div', { class: 'wtp__genrow' }, el('span', {}, 'Pull from'), genSelect),
    scoreEl,
    el('div', { class: 'wtp__stage' }, art),
    caption,
    hint,
    el('div', { class: 'wtp__controls' }, inputWrap, guessBtn, revealBtn, nextBtn),
    feedback,
  );

  renderScore();
  next();

  const off = whosThat.subscribe(() => {
    if (revealed) renderScore();
  });
  onTeardown(view, off);
  return view;
}