import {
  db,
  hydrateFromServer,
  startSync,
  setCompletion,
  onChange,
  getMeta,
  setMeta,
} from './db.js';
import { initTheme, cycleTheme, currentTheme } from './theme.js';
import { renderCalendar } from './calendar.js';
import {
  todayISO,
  daysRemaining,
  completedSet,
  currentStreak,
  longestStreak,
  totalCompleted,
} from './stats.js';

const VALID_USERS = new Set(['ray', 'cer']);
const app = document.getElementById('app');

/* ---------- PWA install prompt ---------- */

let deferredInstallPrompt = null;
const isIOS = /iphone|ipad|ipod/i.test(navigator.userAgent);
const isStandalone =
  window.matchMedia('(display-mode: standalone)').matches ||
  ('standalone' in navigator && navigator.standalone === true);

window.addEventListener('beforeinstallprompt', (e) => {
  e.preventDefault();
  deferredInstallPrompt = e;
  const btn = document.querySelector('[data-install-wrap]');
  if (btn) btn.hidden = false;
});

window.addEventListener('appinstalled', () => {
  deferredInstallPrompt = null;
  const wrap = document.querySelector('[data-install-wrap]');
  if (wrap) wrap.hidden = true;
});

const state = {
  route: '/',
  user: '',
  goals: [],
  completions: [],
  view: { year: new Date().getFullYear(), month: new Date().getMonth() },
};

/* ---------- Router ---------- */

function parseRoute(pathname) {
  if (pathname === '/' || pathname === '') return { route: '/', user: '' };
  if (pathname === '/ray') return { route: '/ray', user: 'ray' };
  if (pathname === '/cer') return { route: '/cer', user: 'cer' };
  return { route: '/', user: '' };
}

function navigate(path, { replace = false } = {}) {
  if (replace) history.replaceState({}, '', path);
  else history.pushState({}, '', path);
  handleRoute();
}

function handleRoute() {
  const { route, user } = parseRoute(location.pathname);
  state.route = route;
  state.user = user;
  document.body.dataset.route = route;
  document.body.dataset.user = user || '';
  if (user) setMeta('last_route', route).catch(() => {});
  render();
}

window.addEventListener('popstate', handleRoute);

document.addEventListener('click', (e) => {
  const link = e.target.closest('a[data-link]');
  if (!link) return;
  const href = link.getAttribute('href');
  if (!href || href.startsWith('http') || link.target === '_blank') return;
  e.preventDefault();
  navigate(href);
});

/* ---------- Data load ---------- */

async function loadFromDexie() {
  const [goals, completions] = await Promise.all([
    db.goals.orderBy('start_date').toArray(),
    db.completions.toArray(),
  ]);
  state.goals = goals;
  state.completions = completions;
}

/* ---------- Templates ---------- */

function tpl(id) {
  const t = document.getElementById(id);
  return t.content.cloneNode(true);
}

/* ---------- Render: landing ---------- */

function renderLanding() {
  app.innerHTML = '';
  app.appendChild(tpl('tpl-landing'));

  if (isStandalone) return;

  const wrap = app.querySelector('[data-install-wrap]');
  const btn = app.querySelector('[data-install-btn]');
  const hint = app.querySelector('[data-install-hint]');

  // Show immediately if we already have the prompt or are on iOS
  if (deferredInstallPrompt || isIOS) wrap.hidden = false;

  // Always attach handler — check state at click time (handles async beforeinstallprompt)
  btn.addEventListener('click', async () => {
    if (deferredInstallPrompt) {
      deferredInstallPrompt.prompt();
      const { outcome } = await deferredInstallPrompt.userChoice;
      if (outcome === 'accepted') {
        deferredInstallPrompt = null;
        wrap.hidden = true;
      }
    } else if (isIOS) {
      hint.hidden = !hint.hidden;
    }
  });
}

/* ---------- Render: route page ---------- */

async function renderRoute() {
  app.innerHTML = '';
  app.appendChild(tpl('tpl-route'));

  // Topbar
  const themeBtn = app.querySelector('[data-theme-toggle]');
  const themeIcon = app.querySelector('[data-theme-icon]');
  themeIcon.textContent = await currentTheme();
  themeBtn.addEventListener('click', async () => {
    themeIcon.textContent = await cycleTheme();
  });

  // Countdown - use earliest end_date among active goals
  const cdEl = app.querySelector('[data-countdown]');
  const today = todayISO();
  const activeGoals = state.goals.filter((g) => g.end_date >= today);
  if (activeGoals.length) {
    const minEnd = activeGoals
      .map((g) => g.end_date)
      .sort()[0];
    const remain = daysRemaining(minEnd);
    cdEl.textContent = remain === 0 ? 'last day' : `${remain}d left`;
  } else {
    cdEl.textContent = 'window closed';
  }

  renderStats();
  renderActionbar();
  renderCalendarRoot();
}

/* ---------- Render: stats row ---------- */

function renderStats() {
  const root = app.querySelector('[data-stats]');
  if (!root) return;
  root.innerHTML = '';

  const today = todayISO();
  const orderedGoals = [...state.goals].sort((a, b) =>
    a.start_date === b.start_date ? a.id.localeCompare(b.id) : a.start_date.localeCompare(b.start_date)
  );

  for (const g of orderedGoals) {
    const card = document.createElement('div');
    card.className = 'stat';

    const label = document.createElement('div');
    label.className = 'stat__label';
    label.textContent = g.name;
    card.appendChild(label);

    for (const user of ['ray', 'cer']) {
      const set = completedSet(state.completions, user, g.id);
      const cur = currentStreak(set, g, today);
      const long = longestStreak(set, g, today);
      const total = totalCompleted(set, g, today);
      const row = document.createElement('div');
      row.className = 'stat__row';
      row.innerHTML = `
        <span class="stat__user stat__user--${user}">
          <span class="stat__user-tag">${user}</span>
          <span class="stat__num">${cur}</span>
          <span class="stat__num-sub">streak / ${long} best / ${total} total</span>
        </span>
      `;
      card.appendChild(row);
    }

    root.appendChild(card);
  }
}

/* ---------- Render: action bar ---------- */

function renderActionbar() {
  const root = app.querySelector('[data-actionbar]');
  if (!root) return;
  root.innerHTML = '';
  const today = todayISO();

  const orderedGoals = [...state.goals].sort((a, b) =>
    a.start_date === b.start_date ? a.id.localeCompare(b.id) : a.start_date.localeCompare(b.start_date)
  );

  for (const g of orderedGoals) {
    const inWindow = today >= g.start_date && today <= g.end_date;
    const existing = state.completions.find(
      (c) => c.user === state.user && c.goal_id === g.id && c.date === today
    );
    const done = !!existing?.completed;

    const btn = document.createElement('button');
    btn.type = 'button';
    btn.className = 'action' + (done ? ' action--done' : '');
    btn.disabled = !inWindow;
    btn.innerHTML = `
      <span class="action__label">${state.user} • today</span>
      <span class="action__title">${g.name}</span>
      <span class="action__state">${done ? 'completed — tap to undo' : inWindow ? 'tap to mark done' : 'outside goal window'}</span>
    `;
    btn.addEventListener('click', async () => {
      await setCompletion(state.user, g.id, today, !done);
      // optimistic UI update via subscription, but also re-render now
      await loadFromDexie();
      renderStats();
      renderActionbar();
      renderCalendarRoot();
    });
    root.appendChild(btn);
  }
}

/* ---------- Render: calendar ---------- */

function renderCalendarRoot() {
  const root = app.querySelector('[data-calendar]');
  if (!root) return;

  renderCalendar(root, {
    year: state.view.year,
    month: state.view.month,
    goals: state.goals,
    completions: state.completions,
    activeUser: state.user,
    onPrev: () => {
      const m = state.view.month - 1;
      if (m < 0) {
        state.view.month = 11;
        state.view.year -= 1;
      } else {
        state.view.month = m;
      }
      renderCalendarRoot();
    },
    onNext: () => {
      const m = state.view.month + 1;
      if (m > 11) {
        state.view.month = 0;
        state.view.year += 1;
      } else {
        state.view.month = m;
      }
      renderCalendarRoot();
    },
    onJumpToday: (y, m) => {
      state.view.year = y;
      state.view.month = m;
      renderCalendarRoot();
    },
    onDayClick: ({ iso }) => openDayPopover(iso),
  });
}

/* ---------- Popover ---------- */

function openDayPopover(iso) {
  const root = app.querySelector('[data-popover]');
  if (!root) return;
  root.hidden = false;
  root.innerHTML = '';

  const card = document.createElement('div');
  card.className = 'popover';

  const head = document.createElement('div');
  head.className = 'popover__head';
  head.innerHTML = `
    <div class="popover__title">${iso} • ${state.user}</div>
    <button class="popover__close" data-close aria-label="Close">close</button>
  `;
  card.appendChild(head);

  const list = document.createElement('div');
  list.className = 'popover__list';
  const orderedGoals = [...state.goals].sort((a, b) =>
    a.start_date === b.start_date ? a.id.localeCompare(b.id) : a.start_date.localeCompare(b.start_date)
  );
  for (const g of orderedGoals) {
    const inWindow = iso >= g.start_date && iso <= g.end_date;
    if (!inWindow) continue;
    const existing = state.completions.find(
      (c) => c.user === state.user && c.goal_id === g.id && c.date === iso
    );
    const done = !!existing?.completed;
    const row = document.createElement('button');
    row.type = 'button';
    row.className = 'popover__row' + (done ? ' popover__row--on' : '');
    row.innerHTML = `
      <span class="popover__row__name">${g.name}</span>
      <span class="popover__row__state">${done ? 'done • tap to undo' : 'tap to mark done'}</span>
    `;
    row.addEventListener('click', async () => {
      await setCompletion(state.user, g.id, iso, !done);
      await loadFromDexie();
      renderStats();
      renderActionbar();
      renderCalendarRoot();
      openDayPopover(iso); // refresh popover state
    });
    list.appendChild(row);
  }

  if (!list.children.length) {
    const empty = document.createElement('div');
    empty.className = 'popover__hint';
    empty.textContent = 'no goals active on this date';
    list.appendChild(empty);
  }

  card.appendChild(list);

  const hint = document.createElement('div');
  hint.className = 'popover__hint';
  hint.textContent = 'changes only affect the active user';
  card.appendChild(hint);

  root.appendChild(card);

  const close = () => {
    root.hidden = true;
    root.innerHTML = '';
  };
  head.querySelector('[data-close]').addEventListener('click', close);
  root.addEventListener('click', (e) => {
    if (e.target === root) close();
  });
  document.addEventListener(
    'keydown',
    function onKey(e) {
      if (e.key === 'Escape') {
        close();
        document.removeEventListener('keydown', onKey);
      }
    },
    { once: true }
  );
}

/* ---------- Top-level render ---------- */

function render() {
  if (state.route === '/' || !VALID_USERS.has(state.user)) {
    renderLanding();
  } else {
    renderRoute();
  }
}

/* ---------- Boot ---------- */

async function boot() {
  await initTheme();
  await loadFromDexie();

  // Restore last visited user route if opening at root
  const curPath = location.pathname;
  if (curPath === '/' || curPath === '') {
    const saved = await getMeta('last_route', null);
    if (saved && VALID_USERS.has(saved.slice(1))) {
      history.replaceState({}, '', saved);
    }
  }

  handleRoute();

  // Hydrate from server (non-blocking) and start sync
  hydrateFromServer().then(async () => {
    await loadFromDexie();
    if (state.route !== '/') render();
    else if (state.goals.length) {
      // landing has no data dependency, but we still re-render to no-op safely
    }
  });
  startSync();

  onChange(async () => {
    await loadFromDexie();
    if (state.route !== '/') {
      renderStats();
      renderActionbar();
      renderCalendarRoot();
    }
  });

  // Register service worker
  if ('serviceWorker' in navigator) {
    try {
      await navigator.serviceWorker.register('/sw.js');
    } catch (e) {
      console.warn('[sw] register failed:', e);
    }
  }
}

boot().catch((e) => {
  console.error('[boot] failed:', e);
  app.innerHTML = `<pre style="padding:24px;color:var(--fg)">boot failed: ${e?.message || e}</pre>`;
});