import { getDb, hashIp } from "./db";
import { lookupCountry } from "./geo";

// Patterns we don't want polluting analytics
const BOT_UA = /bot|crawl|spider|slurp|curl|wget|httpclient|python-requests|axios|node-fetch|monitor|uptime|pingdom|datadog|prometheus|scanner|fetch|preview|whatsapp|telegrambot|facebookexternalhit|linkedinbot|twitterbot|discordbot|skypeuripreview|mastodon|matrix-bot|preconnect|dnsperf|sentry|newrelic|gtmetrix|lighthouse|headlesschrome|phantomjs|puppeteer|playwright|chrome-lighthouse/i;
const SKIP_PATHS = /^\/(favicon\.ico|robots\.txt|sitemap\.xml|apple-touch-icon[\w-]*\.png|browserconfig\.xml|\.well-known\/|ads\.txt)/i;

export function shouldRecord(method: string, path: string | null, userAgent: string | null): boolean {
  const m = (method || "GET").toUpperCase();
  if (m === "HEAD" || m === "OPTIONS") return false;
  if (path && SKIP_PATHS.test(path)) return false;
  if (userAgent && BOT_UA.test(userAgent)) return false;
  return true;
}

type PendingHit = {
  domain_id: number;
  ts: number;
  ip_hash: string;
  country: string | null;
  user_agent: string | null;
  referer: string | null;
  path: string | null;
};

const buffer: PendingHit[] = [];
let flushTimer: NodeJS.Timeout | null = null;

function flush() {
  if (buffer.length === 0) return;
  const batch = buffer.splice(0, buffer.length);
  try {
    const db = getDb();
    const stmt = db.prepare(
      "INSERT INTO hits (domain_id, ts, ip_hash, country, user_agent, referer, path) VALUES (?, ?, ?, ?, ?, ?, ?)"
    );
    db.transaction(() => {
      for (const h of batch) {
        stmt.run(h.domain_id, h.ts, h.ip_hash, h.country, h.user_agent, h.referer, h.path);
      }
    })();
  } catch (e) {
    console.error("[hits] flush failed", e);
  }
}

function scheduleFlush() {
  if (flushTimer) return;
  flushTimer = setTimeout(() => {
    flushTimer = null;
    flush();
  }, 5000);
}

export async function recordHit(input: {
  domain_id: number;
  ip: string;
  user_agent: string | null;
  referer: string | null;
  path: string | null;
}) {
  const country = await lookupCountry(input.ip).catch(() => null);
  buffer.push({
    domain_id: input.domain_id,
    ts: Date.now(),
    ip_hash: hashIp(input.ip),
    country,
    user_agent: input.user_agent ? input.user_agent.slice(0, 500) : null,
    referer: input.referer ? input.referer.slice(0, 500) : null,
    path: input.path ? input.path.slice(0, 500) : null,
  });
  if (buffer.length >= 100) flush();
  else scheduleFlush();
}

export function flushHitsSync() {
  flush();
}