// NAS syndication — pushes IAP campaigns out to Network Ad Space (Marty's own
// EvolutionScript platform; no source, so its MySQL DB IS the API). Mirrors the
// CTB Rewards direct-write pattern: INSERT payments then sponsorads with
// approved:1 (bypasses NAS moderation), and reads `remaining` back to reconcile
// spend into IAP's unified credit pool.
//
// KNOWN NAS TRUTHS (measured across RM Circle + CTB, 1600+ ads):
//  - sponsorads.remaining counts DOWN: served = assigned - remaining.
//  - pid 1 = text, pid 2 = banner ONLY; banner size lives in width/height.
//  - hits = clicks (not impressions). catid 5 = Cryptocurrencies.
//  - NAS drifts its own counters upward post-insert → clamp served to assigned.
//
// FEATURE-FLAGGED: inert unless NAS_DB_HOST/USER/PASSWORD/NAME are all set.
// Nothing here runs (no connection, no writes) when the flag is off.
const crypto = require('crypto');

let pool = null;
function enabled() {
  return !!(process.env.NAS_DB_HOST && process.env.NAS_DB_USER
    && process.env.NAS_DB_PASSWORD && process.env.NAS_DB_NAME);
}
function nasPool() {
  if (pool) return pool;
  const mysql = require('mysql2/promise');
  pool = mysql.createPool({
    host: process.env.NAS_DB_HOST,
    port: Number(process.env.NAS_DB_PORT || 3306),
    user: process.env.NAS_DB_USER,
    password: process.env.NAS_DB_PASSWORD,
    database: process.env.NAS_DB_NAME,
    charset: 'latin1', // EvolutionScript is latin1
    connectionLimit: 3,
    connectTimeout: 10000
  });
  return pool;
}
async function q(sql, args) { const [r] = await nasPool().query(sql, args); return r; }

const CATID_CRYPTO = Number(process.env.NAS_CATID || 5);
// how many NAS impressions one IAP credit buys, per format. IAP charges credits
// on its own surfaces at these same rates, so NAS delivery draws the same pool.
function impressionsPerCredit(type) {
  return type === 'banner' ? 5 : type === 'text' ? 10 : type === 'video' ? 0 : 0;
}
function nasKind(type) {
  // pid encodes text(1)/banner(2); adtype is a separate small int — 1 is the
  // value the overwhelming majority of live NAS rows use for both formats.
  const adtype = Number(process.env.NAS_ADTYPE || 1);
  if (type === 'banner') return { pid: 2, adtype };
  if (type === 'text') return { pid: 1, adtype };
  return null; // only banner/text syndicate to NAS in v1 (login/solo/video are IAP-native)
}

// push one IAP campaign into NAS. `c` is a pubC-shaped campaign. Returns
// { nasAdId, assigned } or { skipped } / throws on a real DB error.
async function pushCampaign(c, opts = {}) {
  if (!enabled()) return { skipped: 'flag-off' };
  const kind = nasKind(c.type);
  if (!kind) return { skipped: 'type' };
  const budgetLeft = c.budget - (c.spent || 0);
  const window = c.dailyCap ? Math.min(c.dailyCap, budgetLeft) : budgetLeft; // capped campaigns start with one day's allowance
  const assigned = Math.max(1, Math.floor(window * impressionsPerCredit(c.type)));
  const token = 'iap_' + crypto.randomBytes(8).toString('hex'); // manage token = Username
  const now = new Date();
  const days = Number(opts.days || 30);
  const edate = new Date(now.getTime() + days * 86400000);
  const payref = 'iap_campaign:' + c.id;
  // payments first (MyISAM, no txn) — hand-rollback the row if sponsorads fails
  const pay = await q(
    'INSERT INTO payments (Username, Amount, Currency_code, status, Date, pay_address) VALUES (?,?,?,1,?,?)',
    [token, 0, 'IAP_CREDIT', now, payref]);
  try {
    const ad = await q(
      `INSERT INTO sponsorads
        (Username, Subject, Body, WebsiteURL, assigned, remaining, hits, approved, Date, adtype,
         Name, Email, PaymentDetails, EDate, sp, width, height, BannerURL, pid, ref_by, catid)
       VALUES (?,?,?,?,?,?,0,1,?,?,?,?,?,?,'',?,?,?,?,0,?)`,
      // clicks route through our redirect so they count and carry the network site as the referrer
      [token, c.title || null, c.type === 'text' ? (c.body || null) : null, 'https://linkspin-test.saasy.top/api/ads/click/' + c.id,
        assigned, assigned, now, kind.adtype,
        opts.name || 'LinkSpin member', opts.email || 'ads@linkspin-test.saasy.top',
        'LinkSpin campaign #' + c.id, edate,
        c.width || '', c.height || '', c.type === 'banner' ? c.imageUrl : null, kind.pid, CATID_CRYPTO]);
    return { nasAdId: ad.insertId, manageToken: token, assigned };
  } catch (e) {
    try { await q('DELETE FROM payments WHERE ID=?', [pay.insertId]); } catch (e2) {}
    throw e;
  }
}

// read served count for a syndicated ad (assigned - remaining, clamped ≥0 and
// ≤ assigned because NAS drifts counters upward post-insert).
async function readServed(nasAdId) {
  if (!enabled()) return null;
  const rows = await q('SELECT assigned, remaining, hits FROM sponsorads WHERE ID=?', [Number(nasAdId)]);
  if (!rows.length) return null;
  const assigned = Number(rows[0].assigned) || 0;
  const remaining = Number(rows[0].remaining) || 0;
  const served = Math.max(0, Math.min(assigned, assigned - remaining));
  return { assigned, remaining, served, clicks: Number(rows[0].hits) || 0 };
}

// stop a syndicated ad (budget spent, paused, or expired) — remaining:0 halts serving.
async function deactivate(nasAdId) {
  if (!enabled()) return { skipped: 'flag-off' };
  await q('UPDATE sponsorads SET remaining=0, EDate=NOW() WHERE ID=?', [Number(nasAdId)]);
  return { ok: true };
}

// top up a syndicated ad with more impressions (buy-more-views / reactivate).
// point an existing NAS ad at our click redirect (migration for rows pushed before 2026-09-10)
async function setClickUrl(nasAdId, campaignId) {
  if (!enabled()) return { skipped: 'flag-off' };
  await q('UPDATE sponsorads SET WebsiteURL=? WHERE ID=?', ['https://linkspin-test.saasy.top/api/ads/click/' + Number(campaignId), Number(nasAdId)]);
  return { ok: true };
}
async function topUp(nasAdId, addImpressions, days) {
  if (!enabled()) return { skipped: 'flag-off' };
  await q(`UPDATE sponsorads SET assigned=assigned+?, remaining=remaining+?, approved=1,
    EDate=DATE_ADD(NOW(), INTERVAL ? DAY) WHERE ID=?`,
    [Number(addImpressions), Number(addImpressions), Number(days || 30), Number(nasAdId)]);
  return { ok: true };
}

module.exports = { setClickUrl, enabled, pushCampaign, readServed, deactivate, topUp, impressionsPerCredit, nasKind };