// admin-ka — Analytics first-party : visiteurs uniques par site KA.
// Un beacon (1px) sur chaque site envoie GET /collect?site=..&vid=..&p=..
// On stocke les hits (SQLite), on compte les uniques (vid distincts) en live,
// et on fige un rollup quotidien pour l'historique long terme.
import fs from 'node:fs';
import path from 'node:path';
import { fileURLToPath } from 'node:url';
import { DatabaseSync } from 'node:sqlite';

const __dirname = path.dirname(fileURLToPath(import.meta.url));
const DATA_DIR = path.join(__dirname, '..', 'data');
const DB_PATH = path.join(DATA_DIR, 'analytics.sqlite');

let db = null;
const RETENTION_DAYS = 45;

// GIF transparent 1x1 renvoyé au beacon
export const PIXEL = Buffer.from('R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7', 'base64');

function dayKey(ts) {
  // jour local (Amérique/Montréal ~ heure du serveur)
  const d = new Date(ts);
  return d.getFullYear() + '-' + String(d.getMonth() + 1).padStart(2, '0') + '-' + String(d.getDate()).padStart(2, '0');
}

export function initAnalytics() {
  fs.mkdirSync(DATA_DIR, { recursive: true });
  db = new DatabaseSync(DB_PATH);
  db.exec(`
    CREATE TABLE IF NOT EXISTS hits (site TEXT, vid TEXT, ts INTEGER, path TEXT);
    CREATE INDEX IF NOT EXISTS idx_hits_site_ts ON hits(site, ts);
    CREATE TABLE IF NOT EXISTS daily (site TEXT, day TEXT, uniques INTEGER, pv INTEGER, PRIMARY KEY(site, day));
  `);
  rollup();
  setInterval(rollup, 10 * 60 * 1000);       // fige les stats quotidiennes
  setInterval(purge, 6 * 60 * 60 * 1000);    // purge le brut ancien
  purge();
}

// enregistre un hit (appelé par /collect)
export function recordHit(site, vid, p) {
  if (!db || !site || !vid) return;
  site = String(site).slice(0, 40);
  vid = String(vid).slice(0, 64);
  p = String(p || '/').slice(0, 200);
  try { db.prepare('INSERT INTO hits (site,vid,ts,path) VALUES (?,?,?,?)').run(site, vid, Date.now(), p); } catch {}
}

function purge() {
  if (!db) return;
  const cutoff = Date.now() - RETENTION_DAYS * 864e5;
  try { db.prepare('DELETE FROM hits WHERE ts < ?').run(cutoff); } catch {}
}

// fige les uniques/pv par jour dans `daily` (sauvegarde long terme)
function rollup() {
  if (!db) return;
  try {
    const rows = db.prepare(`
      SELECT site, ts, vid FROM hits WHERE ts >= ?`).all(Date.now() - 3 * 864e5);
    const agg = {}; // site|day -> {set, pv}
    for (const r of rows) {
      const k = r.site + '|' + dayKey(r.ts);
      if (!agg[k]) agg[k] = { set: new Set(), pv: 0 };
      agg[k].set.add(r.vid); agg[k].pv++;
    }
    const up = db.prepare('INSERT OR REPLACE INTO daily (site,day,uniques,pv) VALUES (?,?,?,?)');
    for (const k in agg) { const [site, day] = k.split('|'); up.run(site, day, agg[k].set.size, agg[k].pv); }
  } catch {}
}

function uniquesSince(site, sinceTs) {
  try { return db.prepare('SELECT COUNT(DISTINCT vid) c FROM hits WHERE site=? AND ts>=?').get(site, sinceTs).c; } catch { return 0; }
}
function pvSince(site, sinceTs) {
  try { return db.prepare('SELECT COUNT(*) c FROM hits WHERE site=? AND ts>=?').get(site, sinceTs).c; } catch { return 0; }
}

export function analyticsSummary(sites) {
  const now = Date.now();
  const startToday = new Date(); startToday.setHours(0, 0, 0, 0);
  const t0 = startToday.getTime();
  const out = [];
  let g = { online: 0, today: 0, d7: 0, pv_today: 0 };
  for (const s of sites) {
    const site = s.app || s;
    const row = {
      site, label: s.label || site, domain: s.domain || '',
      online: uniquesSince(site, now - 5 * 60 * 1000),      // uniques dans les 5 dernières min
      today: uniquesSince(site, t0),
      d7: uniquesSince(site, now - 7 * 864e5),
      d30: uniquesSince(site, now - 30 * 864e5),
      pv_today: pvSince(site, t0),
      pv_total: pvSince(site, now - RETENTION_DAYS * 864e5),
    };
    out.push(row);
    g.online += row.online; g.today += row.today; g.d7 += row.d7; g.pv_today += row.pv_today;
  }
  out.sort((a, b) => b.online - a.online || b.today - a.today);
  return { sites: out, global: g, updated: now };
}

// série quotidienne (uniques) des N derniers jours pour un site
export function analyticsSeries(site, days = 30) {
  const out = [];
  for (let i = days - 1; i >= 0; i--) {
    const d = new Date(); d.setHours(0, 0, 0, 0); d.setDate(d.getDate() - i);
    const key = dayKey(d.getTime());
    let u = 0;
    try { const r = db.prepare('SELECT uniques FROM daily WHERE site=? AND day=?').get(site, key); if (r) u = r.uniques; } catch {}
    // aujourd'hui : recalcule en direct (le rollup peut être en retard)
    if (i === 0) u = Math.max(u, uniquesSince(site, d.getTime()));
    out.push({ day: key, uniques: u });
  }
  return out;
}