cacheService.ts

import { createClient, type RedisClientType } from "redis";

let client: RedisClientType | null = null;

async function getClient(): Promise<RedisClientType | null> {
  if (!process.env.REDIS_URL) return null;
  if (client) return client;

  client = createClient({ url: process.env.REDIS_URL }) as RedisClientType;
  client.on("error", (err) => {
    console.error("[cache] Redis error:", err);
    client = null;
  });
  await client.connect();
  return client;
}

const DEFAULT_TTL = 60; // seconds

export async function cacheGet(key: string): Promise<string | null> {
  try {
    const c = await getClient();
    if (!c) return null;
    return c.get(key);
  } catch {
    return null;
  }
}

export async function cacheSet(
  key: string,
  value: string,
  ttlSeconds = DEFAULT_TTL,
): Promise<void> {
  try {
    const c = await getClient();
    if (!c) return;
    await c.set(key, value, { EX: ttlSeconds });
  } catch {
    // cache miss is non-fatal
  }
}

export async function cacheDel(...keys: string[]): Promise<void> {
  try {
    const c = await getClient();
    if (!c) return;
    await c.del(keys);
  } catch {
    // non-fatal
  }
}

export async function cacheDelPattern(pattern: string): Promise<void> {
  try {
    const c = await getClient();
    if (!c) return;
    const keys = await c.keys(pattern);
    if (keys.length) await c.del(keys);
  } catch {
    // non-fatal
  }
}

export const CACHE_KEYS = {
  promptList: (query: string) => `prompts:list:${query}`,
  promptDetail: (id: string) => `prompts:detail:${id}`,
};