// Circle Suite — Traffic Desk. Places member banner ads on the team's own
// NetworkAdSpace network through the signed bridge API (rmc-api on that host).
//
// Two deliberate constraints:
//  1. Creative comes from the TEAM banner kit only. Members never upload art.
//     That removes moderation risk entirely — every ad on the network carries
//     approved branding — and it means a member can launch in two clicks.
//  2. Allowances scale with contract level and are counted per calendar month
//     against a local ledger, so a member cannot spend more than their level.
'use strict';
const fs = require('fs');
const path = require('path');
const crypto = require('crypto');
const suiteGrants = require('./suite-grants');

let DATA_DIR = null;
function init(opts) { DATA_DIR = opts.dataDir; }
function credsFile() { return path.join(DATA_DIR, 'nas-api.json'); }
function creds() { try { return JSON.parse(fs.readFileSync(credsFile(), 'utf8')); } catch (e) { return null; } }
function configured() { const c = creds(); return !!(c && c.url && c.secret); }

// Monthly impressions by contract level (index = level-1). Marty-approved.
const ALLOWANCE = [2500, 5000, 10000, 20000, 50000, 75000, 100000, 150000];
function allowanceFor(level) {
  const n = Math.max(1, Math.min(8, Number(level) || 1));
  return ALLOWANCE[n - 1];
}

// Team banner kit — every ad uses approved creative, so nothing needs review.
const CREATIVES = {
  '468x60':  [ 'rmc-468x60-v1.png', 'rmc-468x60-v2.png', 'rmc-468x60-v3.png', 'rmc-468x60-v4.png',
               'rmc-468x60-v5.png', 'rmc-468x60-v6.png', 'rmc-468x60-v7.png', 'rmc-growing-468x60-bluegreen.png' ],
  '728x90':  [ 'rmc-728x90-v1.png', 'rmc-728x90-v2.png', 'rmc-728x90-v3.png' ],
  '300x250': [ 'rmc-300x250-v1.png', 'rmc-300x250-v3.png', 'rmc-300x250-v4.png' ],
  '160x600': [ 'rmc-160x600-v1.png', 'rmc-160x600-v2.png', 'rmc-160x600-v3.png' ],
  '120x600': [ 'rmc-120x600-v1.png', 'rmc-120x600-v2.png' ],
  '125x125': [ 'rmc-banner-125x125.png' ]
};
function sizes() { return Object.keys(CREATIVES); }

// ── local ledger: what each position has been granted this month ────────────
function ledgerFile() { return path.join(DATA_DIR, 'traffic-grants.json'); }
function readLedger() { try { return JSON.parse(fs.readFileSync(ledgerFile(), 'utf8')); } catch (e) { return {}; } }
function writeLedger(v) { try { fs.writeFileSync(ledgerFile(), JSON.stringify(v)); } catch (e) {} }
function monthKey() { const d = new Date(); return d.getUTCFullYear() + '-' + String(d.getUTCMonth() + 1).padStart(2, '0'); }

function usage(memberId) {
  const all = readLedger();
  const rows = ((all[monthKey()] || {})[String(memberId)]) || [];
  const used = rows.reduce(function (s, r) { return s + (Number(r.impressions) || 0); }, 0);
  return { used: used, campaigns: rows };
}

function status(memberId, level) {
  const base = allowanceFor(level);
  // Impressions an upline granted this month sit on top of the level allowance.
  let granted = 0;
  try { granted = suiteGrants.receivedBy(memberId, 'traffic') || 0; } catch (e) {}
  const limit = base + granted;
  const u = usage(memberId);
  return {
    limit: limit, base: base, granted: granted,
    used: u.used, remaining: Math.max(0, limit - u.used),
    campaigns: u.campaigns, resets: monthKey(), sizes: sizes(), creatives: CREATIVES
  };
}

function record(memberId, entry) {
  const all = readLedger();
  const mk = monthKey();
  if (!all[mk]) all[mk] = {};
  const id = String(memberId);
  if (!all[mk][id]) all[mk][id] = [];
  all[mk][id].push(entry);
  // keep three months of history; the file stays small forever
  const keep = Object.keys(all).sort().slice(-3);
  const trimmed = {};
  keep.forEach(function (k) { trimmed[k] = all[k]; });
  writeLedger(trimmed);
}

// ── signed call to the NAS bridge ───────────────────────────────────────────
function callNas(payload) {
  return new Promise(function (resolve, reject) {
    const c = creds();
    if (!c) return reject(new Error('The ad network bridge is not configured yet.'));
    const body = JSON.stringify(payload);
    const ts = String(Math.floor(Date.now() / 1000));
    const sig = crypto.createHmac('sha256', c.secret).update(ts + '.' + body).digest('hex');
    const u = new URL(c.url);
    const lib = u.protocol === 'https:' ? require('https') : require('http');
    const req = lib.request({
      hostname: u.hostname, port: u.port || (u.protocol === 'https:' ? 443 : 80),
      path: u.pathname + (u.search || ''), method: 'POST',
      headers: {
        'Content-Type': 'application/json',
        'Content-Length': Buffer.byteLength(body),
        'X-RMC-Signature': sig,
        'X-RMC-Timestamp': ts,
        'User-Agent': 'RMCircleSuite/1.0'
      }
    }, function (res) {
      let data = '';
      res.on('data', function (d) { data += d; });
      res.on('end', function () {
        let j = null;
        try { j = JSON.parse(data); } catch (e) { return reject(new Error('The ad network returned something unexpected.')); }
        if (!j.ok) return reject(new Error(j.error || 'The ad network rejected that.'));
        resolve(j);
      });
    });
    req.on('error', function (e) { reject(new Error('Could not reach the ad network: ' + e.message)); });
    req.setTimeout(45000, function () { req.destroy(new Error('The ad network took too long.')); });
    req.write(body); req.end();
  });
}

async function launch(opts) {
  const level = Number(opts.level) || 1;
  const isText = opts.kind === 'text';
  let size = '', file = '', subject = '', lines = [];

  if (isText) {
    // Limits measured from live network inventory — see suite-textads.js.
    subject = String(opts.subject || '').trim();
    lines = (Array.isArray(opts.lines) ? opts.lines : []).slice(0, 3)
      .map(function (l) { return String(l || '').replace(/[<>]/g, '').trim(); });
    while (lines.length < 3) lines.push('');
    if (!subject || !lines[0]) throw new Error('That text ad is missing its headline or first line.');
    if (Array.from(subject).length > 20) throw new Error('The headline is longer than the network allows.');
    if (lines.some(function (l) { return Array.from(l).length > 24; })) {
      throw new Error('One of those lines is longer than the network allows.');
    }
  } else {
    size = String(opts.size || '');
    if (!CREATIVES[size]) throw new Error('Pick one of the available banner sizes.');
    file = String(opts.creative || '');
    if (CREATIVES[size].indexOf(file) === -1) throw new Error('Pick one of the team banner designs.');
  }

  const st = status(opts.id, level);
  const impressions = Math.max(100, Math.min(st.limit, Number(opts.impressions) || 0));
  if (impressions > st.remaining) {
    throw new Error('That is more than your remaining ' + st.remaining.toLocaleString() + ' impressions this month.');
  }

  // Server-side guard: only allow the personal page as a destination when one
  // actually exists. /p/<id> also redirects to /join/<id> when empty, so a live
  // banner can never dead-end — but we shouldn't create that situation at all.
  let target = 'https://rmcircle.team/join/' + opts.id + (opts.angle ? '?v=' + opts.angle : '');
  if (opts.target === 'page') {
    if (!opts.hasPage) throw new Error('Build your personal page first, then you can point ads at it.');
    target = 'https://rmcircle.team/p/' + opts.id;
  }

  const idem = 'rmc-' + opts.id + '-' + monthKey() + '-' + crypto.randomBytes(6).toString('hex');
  const payload = {
    action: 'create', member_id: Number(opts.id), idem_key: idem,
    kind: isText ? 'text' : 'banner',
    impressions: impressions, days: 365, target_url: target,
    advertiser_name: (opts.name || 'RM Circle member #' + opts.id).slice(0, 60),
    advertiser_email: '', catid: 5
  };
  if (isText) {
    payload.subject = subject;
    payload.lines = lines;
  } else {
    payload.size = size;
    payload.banner_url = 'https://rmcircle.team/banners/' + file;
  }
  const res = await callNas(payload);

  const entry = {
    adId: res.ad_id, impressions: impressions,
    size: isText ? 'text' : size, creative: isText ? '' : file,
    kind: isText ? 'text' : 'banner',
    subject: isText ? subject : undefined,
    lines: isText ? lines : undefined,
    target: target, at: new Date().toISOString()
  };
  record(opts.id, entry);
  return entry;
}

// Stop a running banner and return the UNSERVED impressions to the member's
// monthly balance. Order matters: read the counters BEFORE deactivating,
// because deactivation zeroes `remaining` and would make it look fully served.
async function stop(memberId, adId) {
  const all = readLedger();
  const mk = monthKey();
  const rows = ((all[mk] || {})[String(memberId)]) || [];
  const pre = rows.find(function (r) { return Number(r.adId) === Number(adId); });
  if (!pre) throw new Error('That banner is not one of yours from this month.');
  if (pre.stopped) throw new Error('That banner is already stopped.');

  let served = 0, unserved = 0;
  try {
    const s = await callNas({ action: 'stats', ad_ids: [Number(adId)] });
    const st = (s.stats || [])[0];
    if (st) {
      served = Math.max(0, Number(st.served) || 0);
      unserved = Math.max(0, Number(st.remaining) || 0);
    }
  } catch (e) { /* if stats are unavailable, refund nothing rather than guess */ }

  await callNas({ action: 'deactivate', ad_id: Number(adId) });

  // RE-READ before writing. Everything above this point took two network round
  // trips to the ad network, and the ledger object read at the top of this
  // function is now seconds stale. Writing it back would silently discard any
  // campaign another member launched in the meantime — impressions spent on the
  // network with no record that they were. Node's single thread makes the block
  // below atomic; the danger was only ever the await gap.
  const fresh = readLedger();
  const freshRows = ((fresh[mk] || {})[String(memberId)]) || [];
  const row2 = freshRows.find(function (r) { return Number(r.adId) === Number(adId); });
  if (!row2) throw new Error('That banner is no longer in this month\'s ledger.');
  if (row2.stopped) return { adId: Number(adId), served: row2.served || 0, refunded: row2.refunded || 0 };

  const all2 = fresh;
  const row = row2;

  // Charge only what actually served; the rest returns to the allowance.
  // `bought` preserves the original order size so the member's history still
  // shows what they launched, not just what it ended up costing them.
  if (row.bought == null) row.bought = row.impressions;

  // A handful of rows on the network carry a `remaining` larger than their
  // `assigned` (a pre-existing counter quirk). Clamp, or a member sees
  // "1,002 returned" on an ad they bought 1,000 impressions for.
  unserved = Math.min(unserved, row.bought);
  served = row.bought - unserved;
  row.stopped = true;
  row.stoppedAt = new Date().toISOString();
  row.served = served;
  row.refunded = unserved;
  row.impressions = served;   // what this campaign counts against the month
  writeLedger(all2);
  return { adId: Number(adId), served: served, refunded: unserved };
}

async function stats(adIds) {
  if (!adIds || !adIds.length) return [];
  const r = await callNas({ action: 'stats', ad_ids: adIds.slice(0, 200) });
  return r.stats || [];
}

module.exports = { init, configured, status, launch, stop, stats, allowanceFor, sizes, CREATIVES, ALLOWANCE };