Building Modern
Scalable Systems

// Distributed Cache Decorator with Redis & Graceful Degradation
import { redisClient } from "@/lib/redis";
import { logger } from "@/lib/logger";

export function AutoCache(ttlSeconds: number = 300) {
  return function (
    target: any,
    propertyKey: string,
    descriptor: PropertyDescriptor
  ) {
    const originalMethod = descriptor.value;

    descriptor.value = async function (...args: any[]) {
      const cacheKey = `cache:${target.constructor.name}:${propertyKey}:${JSON.stringify(args)}`;

      try {
        const cachedResult = await redisClient.get(cacheKey);
        if (cachedResult) {
          logger.debug({ key: cacheKey }, "⚡ Cache Hit");
          return JSON.parse(cachedResult);
        }
      } catch (err) {
        logger.warn({ err }, "Redis unavailable, skipping cache read");
      }

      // Execute original method
      const result = await originalMethod.apply(this, args);

      try {
        if (result !== undefined && result !== null) {
          await redisClient.setex(cacheKey, ttlSeconds, JSON.stringify(result));
          logger.debug({ key: cacheKey, ttl: ttlSeconds }, "📦 Cache Populated");
        }
      } catch (err) {
        logger.warn({ err }, "Failed to write to Redis cache");
      }

      return result;
    };

    return descriptor;
  };
}