'use strict';
/* Shared helpers for all pages. Plain scripts, no build step. */

function $(sel, root) { return (root || document).querySelector(sel); }

// h('a', { href, class, onclick }, 'text', childNode, [more]) -> element. Strings always become text, never HTML.
function h(tag, props, ...kids) {
  const el = document.createElement(tag);
  for (const k in props || {}) {
    const v = props[k];
    if (v == null || v === false) continue;
    if (k === 'class') el.className = v;
    else if (k.slice(0, 2) === 'on') el.addEventListener(k.slice(2), v);
    else el.setAttribute(k, v === true ? '' : v);
  }
  for (const c of kids.flat(9)) if (c != null && c !== false) el.append(c instanceof Node ? c : String(c));
  return el;
}

// Only for the constant SVG icons below.
function icon(svg) { const t = document.createElement('template'); t.innerHTML = svg.trim(); return t.content.firstChild; }
const ICONS = {
  bell: '<svg viewBox="0 0 24 24" width="20" height="20" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M6 8a6 6 0 0 1 12 0c0 7 3 9 3 9H3s3-2 3-9"/><path d="M10.3 21a1.94 1.94 0 0 0 3.4 0"/></svg>',
};

async function api(path, body) {
  const opt = body === undefined ? {} : { method: 'POST', headers: { 'Content-Type': 'application/json' }, body: JSON.stringify(body) };
  const r = await fetch(path, opt);
  if (r.status === 401 && !/login\.html$/.test(location.pathname)) {
    location.href = 'login.html?next=' + encodeURIComponent(location.pathname + location.search);
    throw new Error('Please log in');
  }
  const data = await r.json().catch(() => ({}));
  if (!r.ok) throw new Error(data.error || r.statusText);
  return data;
}

const store = {
  get(k) { try { return localStorage.getItem('mc.' + k); } catch (e) { return null; } },
  set(k, v) { try { localStorage.setItem('mc.' + k, v); } catch (e) { /* private mode */ } },
};
// One id per browser tab (it survives navigation and reloads in that tab): progress saves carry it, so
// a reader can tell its own saves from those of another tab or device.
const tabId = (() => {
  let id = null;
  return () => {
    if (id) return id;
    try { id = sessionStorage.getItem('mc.tab'); } catch (e) { /* storage blocked */ }
    if (!/^[a-zA-Z0-9_-]{8,40}$/.test(id || '')) {
      id = Array.from(crypto.getRandomValues(new Uint8Array(12)), b => b.toString(16).padStart(2, '0')).join('');
      try { sessionStorage.setItem('mc.tab', id); } catch (e) { /* this page keeps it in memory */ }
    }
    return id;
  };
})();

function ago(t) {
  const s = (Date.now() - t) / 1000;
  if (s < 90) return 'just now';
  if (s < 5400) return Math.round(s / 60) + ' min ago';
  if (s < 129600) return Math.round(s / 3600) + ' h ago';
  if (s < 3e6) return Math.round(s / 86400) + ' days ago';
  return new Date(t).toLocaleDateString();
}

function readingDuration(ms, compact = false) {
  const seconds = Math.max(0, Math.round((+ms || 0) / 1000));
  if (!seconds) return 'Not timed';
  if (seconds < 60) return compact ? '<1 min' : 'Under a minute';
  const minutes = Math.max(1, Math.round(seconds / 60));
  if (minutes < 60) return `${minutes} min`;
  const hours = Math.floor(minutes / 60), rest = minutes % 60;
  return rest ? `${hours} h ${rest} min` : `${hours} h`;
}

const qsa = obj => { const p = new URLSearchParams(); for (const k in obj) if (obj[k] != null && obj[k] !== '') p.set(k, obj[k]); return p.toString(); };
// `at`: the manga's latest progress time the linking page knew, so the reader can tell it opened from a stale page.
const readUrl = (m, c, v, at) => 'read.html?' + qsa({ m, c, v, at: at || null });
const mangaUrl = m => 'manga.html?' + qsa({ m });
const libraryUrlForTags = tags => {
  const p = new URLSearchParams();
  for (const tag of tags || []) if (tag) p.append('tag', tag);
  const query = p.toString();
  return './' + (query ? '?' + query : '');
};
const safeHref = u => (/^https?:\/\//i.test(u || '') ? u : null);

// Top navigation with the notification bell.
function topNav(me) {
  const count = h('span', { class: 'count', hidden: !me.unread }, me.unread);
  const panel = h('div', { class: 'panel', hidden: true });
  const setCount = n => { count.textContent = n; count.hidden = !n; };
  async function open() {
    panel.hidden = !panel.hidden;
    if (panel.hidden) return;
    panel.textContent = 'Loading…';
    const { items } = await api('api/notifications');
    panel.textContent = '';
    if (!items.length) {
      panel.append(h('p', { class: 'muted' }, 'Nothing yet. Press "Notify me" on a manga to hear about its new chapters.'));
      return;
    }
    panel.append(h('div', { class: 'panel-head' }, h('b', {}, 'New chapters'),
      h('button', { class: 'btn small', onclick: async () => { setCount((await api('api/notifications/read', { all: true })).unread); panel.querySelectorAll('.unread').forEach(e => e.classList.remove('unread')); } }, 'Mark all read')));
    for (const n of items) {
      panel.append(h('a', { class: 'note' + (n.read ? '' : ' unread'), href: readUrl(n.m, n.c) }, h('div', {}, n.text), h('div', { class: 'muted small' }, ago(n.t))));
    }
  }
  const bell = h('button', { class: 'btn icon bell', title: 'Notifications', 'aria-label': 'Notifications', onclick: e => { e.stopPropagation(); open(); } }, icon(ICONS.bell), count);
  panel.addEventListener('click', e => e.stopPropagation());
  document.addEventListener('click', () => { panel.hidden = true; });
  const settingsLink = h('a', { class: 'btn', href: 'settings.html' }, 'Settings');
  const nav = h('header', { class: 'nav' },
    h('a', { class: 'brand', href: './' }, 'MangaCircus'),
    h('a', { class: 'btn nav-greatest', href: 'greatest.html', title: 'Shijō Saikō no Manga · Greatest of All Time', 'aria-label': 'Shijō Saikō no Manga' }, 'Shijō Saikō no Manga'),
    h('a', { class: 'btn', href: 'discover.html' }, 'Discover'),
    h('div', { class: 'grow' }),
    h('div', { class: 'bell-wrap' }, bell, panel),
    settingsLink,
    h('button', { class: 'btn', onclick: async () => { await api('api/logout', {}); location.href = 'login.html'; } }, 'Log out'));
  document.body.prepend(nav);
  if (me.admin) {
    api('api/admin/peering').then(state => {
      if (state.peers?.length && nav.isConnected) {
        nav.insertBefore(h('a', { class: 'btn', href: 'peer-catalog.html' }, 'Peer catalogs'), settingsLink);
      }
    }).catch(() => {}).finally(() => { nav.dataset.peerCatalogResolved = 'true'; });
  } else nav.dataset.peerCatalogResolved = 'true';
}

function showError(e) {
  const main = $('main') || document.body;
  main.textContent = '';
  main.append(h('p', { class: 'error' }, e.message || String(e)), h('a', { class: 'btn', href: './' }, 'Back to the library'));
}