// DOM layer: overlay messages, toolbar and the settings sheet.

import { t, setLang, getLang, detectLang, LANGS } from './i18n.js';
import { MODES } from './modes.js';
import { TIMING } from './game.js';
import { pick } from './random.js';
import { canVibrate, audioUnlocked } from './audio.js';
import { fullscreenSupported, isFullscreen, toggleFullscreen, onFullscreenChange } from './device.js';

const $ = (sel) => document.querySelector(sel);

export function stakeText(s) {
  return s.stakeId ? t(`stakePresets.${s.stakeId}`) : s.stakeText.trim();
}

export function createUI({ settings, debug, showDesktopHint }) {
  const msgMain = $('#msg-main');
  const msgSub = $('#msg-sub');
  const toolbar = $('#toolbar');
  const sheet = $('#sheet');
  const backdrop = $('#sheet-backdrop');
  const btnSettings = $('#btn-settings');
  const btnSound = $('#btn-sound');
  const btnFull = $('#btn-fullscreen');
  const stakeInput = $('#stake-input');
  const hud = $('#debug-hud');

  let chickenMsg = '';
  let shownMain = null;
  let shownSub = null;
  let shownClass = null;
  let toolbarShown = null;

  // ---- toolbar ----

  btnSettings.addEventListener('click', openSheet);
  btnSound.addEventListener('click', () => settings.set({ muted: !settings.get().muted }));
  const standaloneFull = matchMedia('(display-mode: fullscreen)').matches;
  btnFull.hidden = !fullscreenSupported() || standaloneFull;
  btnFull.addEventListener('click', toggleFullscreen);
  onFullscreenChange(syncToolbar);

  // ---- sheet ----

  function openSheet() {
    sheet.hidden = false;
    backdrop.hidden = false;
    requestAnimationFrame(() => document.body.classList.add('sheet-open'));
    sheet.focus({ preventScroll: true });
  }

  function closeSheet() {
    document.body.classList.remove('sheet-open');
    stakeInput.blur();
    setTimeout(() => {
      if (!document.body.classList.contains('sheet-open')) {
        sheet.hidden = true;
        backdrop.hidden = true;
      }
    }, 250);
    btnSettings.focus({ preventScroll: true });
  }

  backdrop.addEventListener('click', closeSheet);
  sheet.querySelector('.sheet-close').addEventListener('click', closeSheet);
  window.addEventListener('keydown', (e) => {
    if (e.key === 'Escape' && !sheet.hidden) closeSheet();
  });

  // Segmented controls: <div class="seg" data-setting="mode"> buttons with data-value.
  function buildSeg(el, values, labelFn) {
    el.replaceChildren(
      ...values.map((v) => {
        const b = document.createElement('button');
        b.type = 'button';
        b.dataset.value = String(v);
        b.textContent = labelFn(v);
        return b;
      }),
    );
  }

  sheet.addEventListener('click', (e) => {
    const btn = e.target.closest('button');
    if (!btn) return;
    const seg = btn.closest('.seg');
    if (seg && btn.dataset.value != null) {
      const key = seg.dataset.setting;
      let v = btn.dataset.value;
      if (key === 'teams') v = Number(v);
      if (key === 'muted') v = v === 'true';
      if (key === 'haptics') v = v === 'true';
      if (key === 'lang') setLang(v);
      settings.set({ [key]: v });
      return;
    }
    if (btn.dataset.step) {
      const n = Math.max(1, Math.min(9, settings.get().pickN + Number(btn.dataset.step)));
      settings.set({ pickN: n });
      return;
    }
    if (btn.dataset.preset) {
      const id = btn.dataset.preset;
      settings.set(settings.get().stakeId === id ? { stakeId: null, stakeText: '' } : { stakeId: id, stakeText: '' });
      return;
    }
    if (btn.id === 'stake-clear') settings.set({ stakeId: null, stakeText: '' });
  });

  stakeInput.addEventListener('input', () => settings.set({ stakeId: null, stakeText: stakeInput.value.slice(0, 60) }));
  stakeInput.addEventListener('keydown', (e) => {
    if (e.key === 'Enter') stakeInput.blur();
  });

  function applyTranslations() {
    document.title = t('appTitle');
    for (const el of document.querySelectorAll('[data-i18n]')) el.textContent = t(el.dataset.i18n);
    for (const el of document.querySelectorAll('[data-i18n-aria]')) el.setAttribute('aria-label', t(el.dataset.i18nAria));
    stakeInput.placeholder = t('stakesPlaceholder');
    buildSeg($('#seg-mode'), MODES, (m) => t(`mode.${m}`));
    buildSeg($('#seg-teams'), [2, 3, 4], String);
    buildSeg($('#seg-theme'), ['neon', 'pastel', 'contrast'], (v) => t(`theme.${v}`));
    buildSeg($('#seg-lang'), LANGS, (v) => ({ en: 'English', nl: 'Nederlands' })[v]);
    buildSeg($('#seg-sound'), [false, true], (v) => t(v ? 'off' : 'on'));
    buildSeg($('#seg-haptics'), [true, false], (v) => t(v ? 'on' : 'off'));
    const presets = $('#stake-presets');
    presets.replaceChildren(
      ...Object.keys(t('stakePresets')).map((id) => {
        const b = document.createElement('button');
        b.type = 'button';
        b.className = 'chip';
        b.dataset.preset = id;
        b.textContent = t(`stakePresets.${id}`);
        return b;
      }),
    );
  }

  function syncSheet() {
    const s = settings.get();
    const lang = getLang();
    const sel = { mode: s.mode, teams: String(s.teams), theme: s.theme, lang, muted: String(s.muted), haptics: String(s.haptics) };
    for (const seg of sheet.querySelectorAll('.seg')) {
      const cur = sel[seg.dataset.setting];
      for (const b of seg.children) b.setAttribute('aria-pressed', String(b.dataset.value === cur));
    }
    $('#mode-desc').textContent = t(`modeDesc.${s.mode}`);
    $('#row-pickn').hidden = s.mode !== 'pickN';
    $('#row-teams').hidden = s.mode !== 'teams';
    $('#row-haptics').hidden = !canVibrate;
    $('#pickn-value').textContent = String(s.pickN);
    for (const b of $('#stake-presets').children) b.setAttribute('aria-pressed', String(b.dataset.preset === s.stakeId));
    if (document.activeElement !== stakeInput) stakeInput.value = s.stakeId ? '' : s.stakeText;
    $('#stake-clear').hidden = !s.stakeId && !s.stakeText;
    syncToolbar();
  }

  function syncToolbar() {
    const s = settings.get();
    btnSound.classList.toggle('is-muted', s.muted);
    btnSound.setAttribute('aria-label', t(s.muted ? 'unmute' : 'mute'));
    btnSound.setAttribute('aria-pressed', String(s.muted));
    const fs = isFullscreen();
    btnFull.classList.toggle('is-full', fs);
    btnFull.setAttribute('aria-label', t(fs ? 'exitFullscreen' : 'fullscreen'));
  }

  settings.subscribe((s, patch) => {
    if ('lang' in patch) {
      setLang(s.lang || detectLang());
      applyTranslations();
    }
    syncSheet();
  });

  applyTranslations();
  syncSheet();
  if (debug && new URLSearchParams(location.search).get('open') === 'settings') openSheet();

  // ---- overlay messages ----

  function modeSummary(s) {
    let out = t(`mode.${s.mode}`);
    if (s.mode === 'pickN') out += ` · ${s.pickN}`;
    if (s.mode === 'teams') out += ` · ${s.teams}`;
    const stake = stakeText(s);
    if (stake && s.mode !== 'teams') out += ` · “${stake}”`;
    return out;
  }

  function resultMessage(game, s) {
    const stake = stakeText(s);
    switch (game.plan?.mode) {
      case 'teams':
        return t('teamsReady');
      case 'order':
        return stake ? `#1: ${t('youStake', { stake })}` : t('orderDone');
      case 'elimination':
        return stake ? t('youStake', { stake }) : t('lastStanding');
      default:
        return stake ? t('youStake', { stake }) : t('youreIt');
    }
  }

  function messages(game, now) {
    const s = settings.get();
    const count = game.activeRings().length;
    switch (game.phase) {
      case 'idle':
        if (count === 0) {
          if (showDesktopHint) return [t('hint'), t('desktopHint'), 'hint'];
          // Browsers only allow sound after a tap (a finger *lift*), so ask for one.
          const soundHint = !s.muted && !audioUnlocked() ? `
${t('tapForSound')}` : '';
          return [t('hint'), modeSummary(s) + soundHint, 'hint'];
        }
        return [t('needMore'), modeSummary(s), 'hint'];
      case 'gathering':
        return [t('holdStill'), '', 'soft'];
      case 'countdown':
        return [String(TIMING.beats - Math.max(0, game.beat)), '', 'count'];
      case 'chicken':
        return [chickenMsg, '', 'alert'];
      case 'elimPause': {
        const out = game.lastOut;
        const ring = out && game.rings.get(out.id);
        if (!out) return ['', '', ''];
        return [t(out.chickened ? 'chickenOut' : 'eliminated'), ring?.down ? t('liftFinger') : '', 'alert'];
      }
      case 'result': {
        const sub = game.canRestart(now) ? t('tapRestart') : '';
        return [resultMessage(game, s), sub, 'result'];
      }
      default:
        return ['', '', ''];
    }
  }

  return {
    onEvent(type) {
      if (type === 'chicken') chickenMsg = pick(t('chicken'));
    },

    update(game, now) {
      const [main, sub, cls] = messages(game, now);
      if (main !== shownMain || cls !== shownClass) {
        msgMain.textContent = main;
        msgMain.className = `msg ${cls}`;
        // restart the entrance animation
        void msgMain.offsetWidth;
        msgMain.classList.add('in');
        shownMain = main;
        shownClass = cls;
      }
      if (sub !== shownSub) {
        msgSub.textContent = sub;
        shownSub = sub;
      }

      const showTools = (game.phase === 'idle' && !game.anyDown()) || (game.phase === 'result' && !game.anyDown());
      if (showTools !== toolbarShown) {
        toolbar.classList.toggle('hidden', !showTools);
        toolbar.inert = !showTools;
        toolbarShown = showTools;
      }

      if (debug) {
        const fps = this._fps(now);
        hud.textContent = `${game.phase} · ${game.activeRings().length} fingers · ${fps} fps`;
      }
    },

    _last: 0,
    _frames: 0,
    _fpsVal: 0,
    _fps(now) {
      this._frames++;
      if (now - this._last > 500) {
        this._fpsVal = Math.round((this._frames * 1000) / (now - this._last));
        this._frames = 0;
        this._last = now;
      }
      return this._fpsVal;
    },
  };
}