/**
 * Browse pages — category index and per-listing detail.
 *
 * Everything here is rendered server-side from the SQLite listings table. No
 * client JS, so Googlebot sees the real page, Theseus sees the real page, and
 * the s3 snapshot (future milestone #12) is just the same HTML written to disk.
 *
 * These pages are also where the "0 listings" messaging on the home page and
 * /browse flips to real counts — `countsByCategory()` is exported here and
 * imported by pages.js so the two render surfaces agree on what is live.
 */

import {
  listingsByCategory,
  getListing,
  countByCategory as countByCategoryDb,
} from './db.js';
import { escapeHtml } from './layout.js';
import { notFound } from './pages.js';

/* ------------------------------- categories ------------------------------- */

/**
 * The authoritative metadata for the eight categories — icon, title, and the
 * blurb that shows on the home grid and at the top of the category page. One
 * table so a copy change is a one-liner rather than scattered across templates.
 *
 * Adding a new category means adding a row here AND adding the slug to the
 * allow-list in listings.js. The browse grid picks up the new row
 * automatically.
 */
export const CATEGORIES = [
  { slug: 'communication', icon: '💬', title: 'Communication',
    blurb: `Messengers, voice, boards, group chats. Clients that route through peers rather than someone else's server.` },
  { slug: 'privacy',       icon: '🛡️', title: 'Privacy & security',
    blurb: `Tor and mix-net tooling, key and vault managers, disk crypto. The things a conventional store delists first when a government writes.` },
  { slug: 'wallets',       icon: '💸', title: 'Wallets & payments',
    blurb: `BCH wallets, cross-chain bridges, point-of-sale terminals. The chain publishes the listing and the chain settles the payment.` },
  { slug: 'games',         icon: '🎮', title: 'Games',
    blurb: `Standalone titles, on-chain leaderboards, in-app purchases that reach the publisher instead of a 30% toll.` },
  { slug: 'devtools',      icon: '🧰', title: 'Developer tools',
    blurb: `SDKs, libraries, indexers, faucets, protocol utilities. The pieces other apps on this list are built out of.` },
  { slug: 'media',         icon: '🎧', title: 'Media & publishing',
    blurb: `Readers, players, one-file blogs, podcast hosts. Clients that find their audience without going through an aggregator.` },
  { slug: 'utilities',     icon: '⚙️', title: 'Utilities',
    blurb: `File tools, format converters, backup, calculators. The small sharp things that solve one problem and do not ask for an account first.` },
  { slug: 'other',         icon: '✨', title: 'Everything else',
    blurb: `Anything that does not fit above. New categories are proposed in-band — any listing can declare one and clients will offer to add it.` },
];

const CATEGORY_BY_SLUG = Object.fromEntries(CATEGORIES.map((c) => [c.slug, c]));

/**
 * {slug: count} for every category — categories with 0 listings are present
 * with the value 0, so templates can read them unconditionally.
 */
export function countsByCategory() {
  const raw = countByCategoryDb();
  const out = {};
  for (const c of CATEGORIES) out[c.slug] = raw[c.slug] || 0;
  return out;
}

/**
 * Shared category grid, used on the home page and on /browse.
 *
 * `verbose` controls whether each card carries its blurb. Home page wants it;
 * the dedicated browse page already has the blurb at the top and does not
 * need to repeat it on every card.
 */
export function renderCategoriesGrid({ verbose = true } = {}) {
  const counts = countsByCategory();
  return `<div class="categories">
    ${CATEGORIES.map((c) => {
      const n = counts[c.slug];
      const emptyCls = n === 0 ? ' empty' : '';
      const countLabel = `${n} ${n === 1 ? 'listing' : 'listings'}`;
      return `<a class="cat${emptyCls}" href="/c/${c.slug}">
        <div class="ico">${c.icon}</div>
        <h3>${escapeHtml(c.title)}</h3>
        ${verbose ? `<p>${escapeHtml(c.blurb)}</p>` : ''}
        <span class="count">${countLabel}</span>
      </a>`;
    }).join('\n    ')}
  </div>`;
}

/* ------------------------------- category page ------------------------------- */

export function categoryPage(req, slug) {
  const cat = CATEGORY_BY_SLUG[slug];
  if (!cat) return notFound(req);

  const rows = listingsByCategory(slug);
  const title = cat.title;
  const here = `/c/${slug}`;

  return {
    title,
    description: `${cat.title} apps on Prometheus — ${cat.blurb}`,
    here,
    body: `
<header class="hero compact">
  <div class="mark" style="font-size:40px">${cat.icon}</div>
  <h1>${escapeHtml(title)}</h1>
  <p class="tag">${escapeHtml(cat.blurb)}</p>
</header>

<div class="wrap">

<section class="plain">
  <p class="lede">
    ${rows.length === 0
      ? `No listings in this category yet. <a href="/submit">Be the first</a>.`
      : `${rows.length} ${rows.length === 1 ? 'listing' : 'listings'}, newest first.`}
  </p>

  ${rows.length === 0 ? emptyCategory(cat) : renderListingList(rows)}

  <p style="margin-top:1.8rem;color:var(--dim);font-size:13px">
    <a href="/browse">← All categories</a>
  </p>
</section>

</div>`,
  };
}

/* ------------------------------- app detail page ------------------------------- */

export function appPage(req, publisher, slug) {
  const id = `${String(publisher).toLowerCase()}/${String(slug).toLowerCase()}`;
  const row = getListing(id);
  if (!row || row.withdrawn_at) return notFound(req);

  const cat = CATEGORY_BY_SLUG[row.category];
  const catChip = cat
    ? `<a href="/c/${cat.slug}" class="pill p-upcoming" style="text-decoration:none">${cat.icon} ${escapeHtml(cat.title)}</a>`
    : '';

  const scanReport = safeParse(row.scan_report);
  const scanPayload = scanReport?.payload ? safeParse(fromBase64Url(scanReport.payload)) : null;
  const verdict = scanPayload?.scan?.verdict || 'unknown';
  const scanBadge = renderScanBadge(verdict, scanPayload);

  const iconHtml = row.icon
    ? `<img src="${escapeAttr(row.icon)}" alt="" width="80" height="80"
         style="width:80px;height:80px;border-radius:16px;border:1px solid var(--line);background:var(--panel);object-fit:cover">`
    : `<div style="width:80px;height:80px;border-radius:16px;border:1px solid var(--line);background:var(--panel);display:grid;place-items:center;font-size:36px">${cat?.icon || '📦'}</div>`;

  return {
    title: `${row.name} by ${row.publisher}`,
    description: row.description.slice(0, 200),
    here: `/app/${row.publisher}/${row.slug}`,
    body: `
<header class="hero compact" style="padding-bottom:1rem">
  <div style="display:flex;gap:18px;align-items:center;justify-content:center;flex-wrap:wrap;margin-bottom:.8rem">
    ${iconHtml}
    <div style="text-align:left">
      <h1 style="margin:0;font-size:1.8rem">${escapeHtml(row.name)}</h1>
      <div style="color:var(--mut);font-size:14px;margin-top:.3rem">
        by <b style="color:var(--ink)">${escapeHtml(row.publisher)}</b> ·
        v${escapeHtml(row.version)} ·
        ${catChip}
      </div>
    </div>
  </div>
</header>

<div class="wrap">

<section class="plain">
  <div class="card" style="padding:22px 26px">
    <div style="display:flex;gap:1rem;align-items:center;justify-content:space-between;flex-wrap:wrap">
      <div>
        <h3 style="margin:0 0 .3rem;font-size:1.05rem">Download</h3>
        <p style="margin:0;color:var(--mut);font-size:13px">
          ${formatBytes(row.download_size)} ·
          <code class="inline" title="SHA-256">${shortSha(row.download_sha256)}</code>
          ${scanBadge}
        </p>
      </div>
      <a class="btn acid" href="${escapeAttr(row.download_url)}" rel="noopener">Download</a>
    </div>
    <details style="margin-top:1rem">
      <summary style="color:var(--dim);font-size:13px;cursor:pointer">Full hash + source URL</summary>
      <div style="margin-top:.6rem;font-size:13px;color:var(--mut)">
        <div><b style="color:var(--ink)">URL</b> <a href="${escapeAttr(row.download_url)}" rel="noopener">${escapeHtml(row.download_url)}</a></div>
        <div style="margin-top:.4rem"><b style="color:var(--ink)">SHA-256</b> <code class="inline">${row.download_sha256}</code></div>
      </div>
    </details>
  </div>
</section>

<section>
  <h2>About</h2>
  <p style="white-space:pre-wrap">${escapeHtml(row.description)}</p>
  ${row.homepage ? `<p style="margin-top:1rem"><a href="${escapeAttr(row.homepage)}" rel="noopener">Project homepage →</a></p>` : ''}
</section>

<section>
  <h2>Who published this</h2>
  <p>Signed by <b>${escapeHtml(row.publisher)}</b> — a BNS name owned by
    <code class="inline">${escapeHtml(row.signer_address)}</code>. Any installer
    the chain says belongs to that key is trusted by your client; any client
    that follows a different trust list will not see it as trusted.</p>
</section>

<section>
  <h2>Endorsements</h2>
  <div class="note"><b>No endorsements yet.</b> An endorsement is a signed
    on-chain statement from any BNS name saying "I vouch for this app." Readers
    whose trust list includes the endorser see the endorsement; those who do
    not, do not. The endorsement protocol lands with APS1.</div>
</section>

<p style="margin-top:1.8rem;color:var(--dim);font-size:13px">
  ${cat ? `<a href="/c/${cat.slug}">← Back to ${escapeHtml(cat.title)}</a>` : `<a href="/browse">← Browse</a>`}
</p>

</div>`,
  };
}

/* ------------------------------- helpers ------------------------------- */

function renderListingList(rows) {
  return `<div class="grid" style="margin-top:1.2rem">
    ${rows.map(renderListingCard).join('\n')}
  </div>`;
}

function renderListingCard(row) {
  const href = `/app/${encodeURIComponent(row.publisher)}/${encodeURIComponent(row.slug)}`;
  return `<a class="card" href="${href}"
    style="text-decoration:none;color:inherit;display:flex;flex-direction:column;gap:.5rem">
    <h3 style="margin:0">${escapeHtml(row.name)}</h3>
    <p style="margin:0;color:var(--mut);font-size:13.5px;line-height:1.5">
      ${escapeHtml(truncate(row.description, 160))}
    </p>
    <div style="color:var(--dim);font-size:12px;margin-top:auto;padding-top:.5rem">
      by ${escapeHtml(row.publisher)} · v${escapeHtml(row.version)} · ${formatBytes(row.download_size)}
    </div>
  </a>`;
}

function emptyCategory(cat) {
  return `<div class="note">
    <b>Nothing here yet.</b> If you ship software that fits "${escapeHtml(cat.title)}",
    the <a href="/submit">submit flow</a> is live — upload, scan, sign, your listing
    appears in this view.
  </div>`;
}

function renderScanBadge(verdict, payload) {
  const engine = payload?.scan?.engine || '';
  const sigs = payload?.scan?.signatures || [];
  switch (verdict) {
    case 'clean':
      return `<span class="pill p-live" style="margin-left:.4rem">scan ✓ clean${engine ? ` (${escapeHtml(engine)})` : ''}</span>`;
    case 'infected':
      return `<span class="pill" style="background:rgba(246,118,138,.14);color:var(--taken);margin-left:.4rem" title="${escapeAttr(sigs.join(', '))}">scan ⚠ infected</span>`;
    default:
      return `<span class="pill p-upcoming" style="margin-left:.4rem">scan ? ${escapeHtml(verdict)}</span>`;
  }
}

function formatBytes(n) {
  const num = Number(n) || 0;
  if (num < 1024) return `${num} B`;
  if (num < 1024 * 1024) return `${(num / 1024).toFixed(1)} KiB`;
  if (num < 1024 * 1024 * 1024) return `${(num / 1024 / 1024).toFixed(1)} MiB`;
  return `${(num / 1024 / 1024 / 1024).toFixed(2)} GiB`;
}

function shortSha(sha) {
  if (!sha) return '';
  const s = String(sha);
  if (s.length <= 16) return s;
  return `${s.slice(0, 8)}…${s.slice(-6)}`;
}

function truncate(s, max) {
  const str = String(s || '');
  if (str.length <= max) return str;
  return str.slice(0, max - 1) + '…';
}

function escapeAttr(s) {
  // Same as text escape; attributes are also always wrapped in double-quotes.
  return escapeHtml(s);
}

function safeParse(s) {
  if (!s) return null;
  if (typeof s === 'object') return s;
  try { return JSON.parse(s); } catch { return null; }
}

function fromBase64Url(s) {
  try { return Buffer.from(String(s), 'base64url').toString('utf8'); }
  catch { return ''; }
}