// Follow-up email sequence for new free members ("the lead came in the door
// with their email"). A row is queued when an account is created; a ticker
// sends each step when it comes due; a signed unsubscribe link stops it.
// Sequence copy lives in DATA_DIR/drip.json (admin-editable) with the
// defaults below. Dual-mode storage like the rest of the site (MySQL / JSON).
const fs = require('fs');
const path = require('path');
const crypto = require('crypto');
const db = require('./db');

let DATA_DIR = null, mailer = null, accounts = null, SITE = 'https://instantadpay.com';

// hours = time after the account was created
const DEFAULT_SEQUENCE = [
  { hours: 24, subject: 'Your first five minutes on InstantAdPay',
    body: 'Yesterday you created a free InstantAdPay account. Here is the shortest useful thing you can do with it today.\n\n'
      + '1. Pick a username. It becomes your invite link, and it is how your sponsor and your line see you.\n'
      + '2. Take the welcome tour. It is three short stops on your upline\'s pages, and it unlocks your welcome credits. Those credits spend on real ads.\n'
      + '3. Copy your invite link and put it somewhere: a bio, a group, a text to one person.\n\n'
      + 'Your link right now: {{link}}\n\n'
      + 'That is the whole first day. Nothing to buy, nothing to connect.\n\n'
      + 'Sign in: {{site}}/my\n\n{{footer}}' },
  { hours: 48, subject: 'Where the money actually goes',
    body: 'Most programs ask you to trust a back office. Here is what happens instead, in plain terms.\n\n'
      + 'When anyone buys an ad package, a verified smart contract on Polygon splits that payment in the same transaction: 50 percent to their direct sponsor, 20 percent to level two, 10 percent to level three, 20 percent to the platform. It lands in real wallets in seconds. Nothing is held, so there is nothing to withdraw.\n\n'
      + 'Every one of those payments is public. Open the live ledger and read it yourself:\n{{site}}/ledger\n\n'
      + 'You do not need a wallet to look. You only need one when you buy a package or switch on payouts, and the site walks you through it.\n\n'
      + 'Your invite link: {{link}}\n\n{{footer}}' },
  { hours: 96, subject: 'The five dollar test',
    body: 'If you want to see the whole machine work without much at stake, the $5 package is the test.\n\n'
      + 'It mints 500 ad credits. One credit is one cent of delivery, and you spend them on seven formats: banners, text ads, login ads, solo ads into member inboxes, video ads, featured links and verified visits. Every view is dwell-timed on the server, so a real person saw it.\n\n'
      + 'The packages: $5 = 500 credits, $20 = 2,000, $50 = 5,500, $100 = 12,000, $250 = 32,500.\n\n'
      + 'Prefer to spend nothing? Keep viewing ads in Earn credits and run your first campaign on those. Both paths are real.\n\n'
      + 'Buy packages: {{site}}/my#buy\n\n{{footer}}' },
  { hours: 168, subject: 'Two buyers open level two',
    body: 'One week in. Here is the referral side, with the numbers exactly as the contract has them.\n\n'
      + 'Every person who joins through your link and buys a package pays you 50 percent of that package, from their very first purchase, in the same transaction.\n\n'
      + 'Two qualifying buyers ($20 or more) open level two: 20 percent of everything their people buy. Five open level three: 10 percent of the level after that.\n\n'
      + 'Promo tools in your dashboard has posts, texts, email swipes and banners already carrying your link, plus honest answers to the objections you will hear. Your sponsor {{sponsor}} can be messaged from the dashboard any time.\n\n'
      + 'Your invite link: {{link}}\n\n'
      + 'No income is promised. Results depend on your effort, and crypto carries risk of loss.\n\n{{footer}}' }
];

// ---- storage ----
const J = {
  db: null,
  FILE: () => path.join(DATA_DIR, 'drips.json'),
  load() { try { this.db = JSON.parse(fs.readFileSync(this.FILE(), 'utf8')); } catch (e) { this.db = {}; } },
  save() { try { fs.writeFileSync(this.FILE(), JSON.stringify(this.db)); } catch (e) {} },
  async enqueue(rec) { if (!this.db) this.load(); if (this.db[rec.email]) return false; this.db[rec.email] = rec; this.save(); return true; },
  async due(now, limit) { if (!this.db) this.load(); return Object.values(this.db).filter(r => !r.stopped && r.nextAt <= now).sort((a, b) => a.nextAt - b.nextAt).slice(0, limit); },
  async update(email, fields) { if (!this.db) this.load(); if (this.db[email]) { Object.assign(this.db[email], fields); this.save(); } },
  async stats() { if (!this.db) this.load(); const v = Object.values(this.db); return { active: v.filter(r => !r.stopped).length, unsubscribed: v.filter(r => r.stopped === 2).length, done: v.filter(r => r.stopped === 1).length, total: v.length }; },
  async get(email) { if (!this.db) this.load(); return this.db[email] || null; }
};
const rowR = r => ({ email: r.email, step: r.step, nextAt: Number(r.next_at), started: Number(r.started), stopped: r.stopped, ref: r.ref, angle: r.angle });
const D = {
  async enqueue(rec) {
    try {
      await db.q('INSERT INTO drips (email,step,next_at,started,stopped,ref,angle) VALUES (?,?,?,?,0,?,?)',
        [rec.email, rec.step, rec.nextAt, rec.started, rec.ref || null, rec.angle || null]);
      return true;
    } catch (e) { if (e.code === 'ER_DUP_ENTRY') return false; throw e; }
  },
  async due(now, limit) { return (await db.q('SELECT * FROM drips WHERE stopped=0 AND next_at<=? ORDER BY next_at LIMIT ?', [now, limit])).map(rowR); },
  async update(email, fields) {
    const sets = [], vals = [];
    if ('step' in fields) { sets.push('step=?'); vals.push(fields.step); }
    if ('nextAt' in fields) { sets.push('next_at=?'); vals.push(fields.nextAt); }
    if ('stopped' in fields) { sets.push('stopped=?'); vals.push(fields.stopped); }
    if (!sets.length) return;
    vals.push(email);
    await db.q('UPDATE drips SET ' + sets.join(',') + ' WHERE email=?', vals);
  },
  async stats() {
    const r = await db.q('SELECT SUM(stopped=0) active, SUM(stopped=2) unsubscribed, SUM(stopped=1) done, COUNT(*) total FROM drips');
    return { active: Number(r[0].active || 0), unsubscribed: Number(r[0].unsubscribed || 0), done: Number(r[0].done || 0), total: Number(r[0].total || 0) };
  },
  async get(email) { const r = await db.q('SELECT * FROM drips WHERE email=?', [email]); return r.length ? rowR(r[0]) : null; }
};
const impl = () => db.enabled() ? D : J;

// ---- sequence config ----
function seqFile() { return path.join(DATA_DIR, 'drip.json'); }
function sequence() {
  try {
    const saved = JSON.parse(fs.readFileSync(seqFile(), 'utf8'));
    if (Array.isArray(saved) && saved.length) return saved.map(normStep).filter(Boolean);
  } catch (e) {}
  return DEFAULT_SEQUENCE;
}
function normStep(s) {
  if (!s || typeof s !== 'object') return null;
  const hours = Number(s.hours);
  const subject = String(s.subject || '').trim().slice(0, 150);
  const body = String(s.body || '').trim().slice(0, 8000);
  if (!(hours >= 1) || !subject || !body) return null;
  return { hours, subject, body };
}
function setSequence(arr) {
  if (!Array.isArray(arr)) return { error: 'Send a list of steps.' };
  const steps = arr.map(normStep);
  if (steps.some(s => !s)) return { error: 'Every step needs hours (>= 1), a subject and a body.' };
  if (steps.length > 20) return { error: 'Keep it to 20 steps or fewer.' };
  for (let i = 1; i < steps.length; i++) if (steps[i].hours <= steps[i - 1].hours) return { error: 'Steps must be in increasing hours.' };
  fs.writeFileSync(seqFile(), JSON.stringify(steps, null, 2));
  return { ok: true, sequence: steps };
}
function resetSequence() { try { fs.unlinkSync(seqFile()); } catch (e) {} return { ok: true, sequence: DEFAULT_SEQUENCE }; }

// ---- unsubscribe signing ----
function secret() {
  const f = path.join(DATA_DIR, 'drip.secret');
  try { return fs.readFileSync(f, 'utf8').trim(); } catch (e) {}
  const s = crypto.randomBytes(24).toString('hex');
  try { fs.writeFileSync(f, s, { mode: 0o600 }); } catch (e) {}
  return s;
}
function token(email) { return crypto.createHmac('sha256', secret()).update(String(email).toLowerCase()).digest('hex').slice(0, 32); }
function unsubUrl(email) { return SITE + '/unsubscribe?e=' + encodeURIComponent(email) + '&t=' + token(email); }
async function unsubscribe(email, t) {
  const e = String(email || '').trim().toLowerCase();
  if (!e || !t || t !== token(e)) return { error: 'That link is not valid.' };
  const cur = await impl().get(e);
  if (!cur) return { ok: true, already: true };
  await impl().update(e, { stopped: 2 });
  return { ok: true };
}

// ---- rendering ----
async function vars(email) {
  const a = accounts ? await accounts.byEmail(email) : null;
  const tok = a ? (a.username || a.code || (a.memberId ? String(a.memberId) : '')) : '';
  let sponsor = 'your sponsor';
  try {
    const sp = accounts && await accounts.sponsorOf(email);
    if (sp) sponsor = sp.username ? '@' + sp.username : (sp.memberId ? 'member #' + sp.memberId : 'your sponsor');
  } catch (e) {}
  return {
    link: tok ? SITE + '/join/' + tok : SITE + '/my',
    sponsor, site: SITE, email,
    footer: 'You are getting these follow-ups because you created a free InstantAdPay account. Stop them here: ' + unsubUrl(email)
      + '\n\nInstantAdPay · Advertising, not investing. No income is guaranteed; results depend on your effort. Crypto carries risk of loss.'
  };
}
function render(text, v) { return String(text).replace(/\{\{(\w+)\}\}/g, (m, k) => (k in v ? v[k] : m)); }

// ---- lifecycle ----
function init(opts) {
  DATA_DIR = opts.dataDir; mailer = opts.mailer; accounts = opts.accounts;
  if (opts.site) SITE = opts.site;
}
// queue a fresh account; step 0 of the sequence is due `hours` after creation
async function enqueue(email, ref, angle) {
  const e = String(email || '').trim().toLowerCase();
  if (!e) return false;
  const seq = sequence();
  const now = Date.now();
  return impl().enqueue({ email: e, step: 0, nextAt: now + seq[0].hours * 3600000, started: now, stopped: 0,
    ref: String(ref || '').slice(0, 40) || null, angle: String(angle || '').slice(0, 20) || null });
}
async function sendStep(email, stepIdx, to) {
  const seq = sequence();
  const s = seq[stepIdx];
  if (!s) return { error: 'No such step.' };
  const v = await vars(email);
  await mailer.send(to || email, render(s.subject, v), render(s.body, v));
  return { ok: true };
}
let ticking = false;
async function tick() {
  if (ticking || !mailer || !mailer.hasKey()) return 0;
  ticking = true;
  let sent = 0;
  try {
    const seq = sequence();
    const now = Date.now();
    const rows = await impl().due(now, 50);
    for (const r of rows) {
      try {
        if (r.step >= seq.length) { await impl().update(r.email, { stopped: 1 }); continue; }
        await sendStep(r.email, r.step);
        sent += 1;
        const next = r.step + 1;
        if (next >= seq.length) await impl().update(r.email, { step: next, stopped: 1 });
        else await impl().update(r.email, { step: next, nextAt: Math.max(now + 60000, r.started + seq[next].hours * 3600000) });
      } catch (e) {
        console.error('drip send', r.email, e.message);
        await impl().update(r.email, { nextAt: now + 6 * 3600000 }); // retry later, do not spin
      }
    }
  } finally { ticking = false; }
  return sent;
}
async function stats() { return impl().stats(); }

module.exports = { init, enqueue, tick, stats, sequence, setSequence, resetSequence, sendStep, unsubscribe, unsubUrl, DEFAULT_SEQUENCE };