apps/whatsapp-worker/src/services/usage.ts

import Redis from 'ioredis';
import { logger } from '../logger';
import { getCachedOrganization } from './organization';

export class UsageService {
    /**
     * Checks if an organization has exceeded its daily message limit.
     * Increments the count if within limits.
     */
    static async checkAndIncrement(organizationId: string, redis: Redis, amount: number = 1): Promise<{ allowed: boolean; current: number; limit: number }> {
        const org = await getCachedOrganization(organizationId);
        if (!org) return { allowed: false, current: 0, limit: 0 };

        const limit = org.dailyMessageLimit || 250;
        const today = new Date().toISOString().split('T')[0];
        const key = `usage:${organizationId}:${today}`;

        // Atomic increment by amount
        const current = await redis.incrby(key, amount);
        
        if (current <= amount) {
            // Set expiry for 24h on first use of the day
            await redis.expire(key, 86400);
        }

        if (current > limit) {
            logger.warn(`[USAGE] Org ${organizationId} reached limit: ${current}/${limit}`);
            return { allowed: false, current, limit };
        }

        return { allowed: true, current, limit };
    }

    static async getCurrentUsage(organizationId: string, redis: Redis): Promise<number> {
        const today = new Date().toISOString().split('T')[0];
        const key = `usage:${organizationId}:${today}`;
        const val = await redis.get(key);
        return val ? parseInt(val) : 0;
    }
}