/**
 * apps/worker — per-workspace automation email daily cap (TASK-0112 §8).
 *
 * Redis counter `auto:email:{wsId}:{utc-date}` (shared `emailCapKey`). The
 * SEND_EMAIL executor INCRs before enqueueing; if the result exceeds the cap
 * (AUTOMATION_EMAIL_DAILY_CAP = 500) the email is NOT sent and the executor
 * throws the FATAL EMAIL_DAILY_CAP (no retry — the quota won't change by
 * retrying). The counter has a 24 h TTL so it rolls over on its own.
 */
import { AUTOMATION_EMAIL_DAILY_CAP, emailCapKey } from "@factory/shared";
import type { Redis } from "ioredis";
import { FatalError } from "./classify.js";

/**
 * Reserve one email slot for the workspace today. Throws FatalError
 * EMAIL_DAILY_CAP when the cap is exceeded. Returns the new counter value.
 */
export async function reserveEmailSlot(redis: Redis, workspaceId: string): Promise<number> {
  const key = emailCapKey(workspaceId);
  const n = await redis.incr(key);
  if (n === 1) {
    // First send today: arm the 24 h TTL.
    await redis.expire(key, 24 * 60 * 60);
  }
  if (n > AUTOMATION_EMAIL_DAILY_CAP) {
    throw new FatalError("EMAIL_DAILY_CAP", `workspace ${workspaceId} exceeded ${AUTOMATION_EMAIL_DAILY_CAP} automation emails today`);
  }
  return n;
}