import type { SupabaseClient } from '@supabase/supabase-js';

export const SAJU_DAILY_LIMIT = 1;
export const TAROT_DAILY_LIMIT = 3;
export const MUSIC_DAILY_LIMIT = 1;
export type AiService = 'saju' | 'tarot' | 'music';

/** KST(UTC+9) 자정을 UTC ISO로. 오늘 사용량 집계 하한. */
export function kstDayStartISO(now: Date): string {
  const kstMs = now.getTime() + 9 * 60 * 60 * 1000;
  const kst = new Date(kstMs);
  const kstMidnightUtcMs = Date.UTC(kst.getUTCFullYear(), kst.getUTCMonth(), kst.getUTCDate()) - 9 * 60 * 60 * 1000;
  return new Date(kstMidnightUtcMs).toISOString();
}

export async function getTodayUsage(admin: SupabaseClient, userId: string, service: AiService): Promise<number> {
  const since = kstDayStartISO(new Date());
  const { count } = await admin
    .from('ai_usage_log')
    .select('id', { count: 'exact', head: true })
    .eq('user_id', userId)
    .eq('service', service)
    .gte('created_at', since);
  return count ?? 0;
}

export async function recordUsage(admin: SupabaseClient, userId: string, service: AiService): Promise<void> {
  await admin.from('ai_usage_log').insert({ user_id: userId, service });
}