import db from "../../db.server";

/**
 * Periodic TTL cleanup for the `ProcessedWebhook` idempotency table.
 *
 * The table grows by one row per Shopify webhook delivery and is never read
 * after the retry window closes, so without pruning it grows unbounded —
 * eventually a disk/space DoS. We only need rows for as long as Shopify might
 * retry a delivery (hours), so a generous retention window of a few days is
 * ample while keeping the table small.
 */
const RETENTION_MS = 7 * 24 * 60 * 60 * 1000; // 7 days
const INTERVAL_MS = 60 * 60 * 1000; // hourly

export interface CleanupDeps {
  db: {
    processedWebhook: {
      deleteMany: (args: {
        where: { receivedAt: { lt: Date } };
      }) => Promise<{ count: number }>;
    };
  };
}

let scheduled = false;

async function runCleanup(deps: CleanupDeps): Promise<void> {
  try {
    const cutoff = new Date(Date.now() - RETENTION_MS);
    const { count } = await deps.db.processedWebhook.deleteMany({
      where: { receivedAt: { lt: cutoff } },
    });
    if (count > 0) {
      console.log(`webhook-cleanup: removed ${count} ProcessedWebhook row(s) older than 7d`);
    }
  } catch (err) {
    // Best-effort housekeeping — never throw into the caller.
    console.warn("webhook-cleanup: prune failed:", err);
  }
}

/**
 * Idempotently schedule the hourly cleanup. Safe to call on every webhook —
 * the first call starts a single unref'd interval and runs an immediate
 * sweep; subsequent calls are no-ops.
 *
 * Because this is only ever invoked while handling a live webhook request, it
 * never runs during `prisma generate` / `react-router build` or other CLI
 * contexts. The interval is `unref`'d so it can never keep the process alive.
 */
export function ensureWebhookCleanupScheduled(deps: CleanupDeps = { db }): void {
  if (scheduled) return;
  scheduled = true;

  const timer = setInterval(() => {
    void runCleanup(deps);
  }, INTERVAL_MS);
  // Don't let the housekeeping interval keep the event loop alive on shutdown.
  if (typeof timer.unref === "function") timer.unref();

  // Kick off an immediate sweep so a long-lived process prunes promptly.
  void runCleanup(deps);
}