import type { Plan } from '@bmm/llm';
import { getRedis } from './redis.js';

const DAY_SEC = 24 * 60 * 60;

function todayKey(): string {
  return new Date().toISOString().slice(0, 10);
}

export interface RateLimitResult {
  ok: boolean;
  remaining: number;
  resetIn: number;
}

/**
 * Daily counter via Redis INCR. Atomic — no race window between read & write.
 * First INCR (count === 1) sets the TTL so the key auto-rolls at midnight UTC.
 */
export async function checkDailyLimit(
  scope: string,
  userId: string,
  max: number,
): Promise<RateLimitResult> {
  const key = `ratelimit:${scope}:${userId}:${todayKey()}`;
  const redis = getRedis();
  const count = await redis.incr(key);
  if (count === 1) await redis.expire(key, DAY_SEC);
  const ttl = await redis.ttl(key);
  return {
    ok: count <= max,
    remaining: Math.max(0, max - count),
    resetIn: ttl > 0 ? ttl : DAY_SEC,
  };
}

// Per-tier daily limits on the two LLM-priced actions.
// Preview = ~€0.002-0.015/call · Build = ~€0.005-0.22/call.
export const PREVIEW_DAILY_LIMIT: Record<Plan, number> = {
  hobby: 5,
  pro: 40,
  team: 150,
  enterprise: 1000,
};

export const BUILD_DAILY_LIMIT: Record<Plan, number> = {
  hobby: 3,
  pro: 20,
  team: 100,
  enterprise: 500,
};