import session from "express-session";
import { createClient } from "redis";


export async function createRedisSession({
redisUrl = process.env.REDIS_URL,
cookieName = process.env.SESSION_COOKIE_NAME || "sc.sid",
secret = process.env.SESSION_SECRET,
trustProxy = process.env.TRUST_PROXY === "1",
ttlSeconds = 60 * 60 * 12, // 12h
} = {}) {
if (!redisUrl) throw new Error("REDIS_URL no definido");
if (!secret) throw new Error("SESSION_SECRET no definido");


const redis = createClient({ url: redisUrl });
redis.on("error", (err) => console.error("[Redis]", err));
await redis.connect();
console.log("[Redis] conectado");


// Resolver RedisStore (v5 / v6 / v7)
async function resolveRedisStore() {
const mod = await import("connect-redis");
// v6/v7: named export class
if (typeof mod.RedisStore === "function") return mod.RedisStore;
// v5: default factory connectRedis(session)
if (typeof mod.default === "function") {
const maybe = mod.default;
if (maybe.prototype && (maybe.prototype.get || maybe.prototype.set)) return maybe; // clase
const factory = mod.default(session);
return factory;
}
throw new Error("No se pudo resolver RedisStore de connect-redis");
}


const RedisStore = await resolveRedisStore();
const store = new RedisStore({ client: redis, prefix: "sc:sess:", ttl: ttlSeconds });


const sessionMw = session({
name: cookieName,
secret,
resave: false,
saveUninitialized: false,
store,
cookie: {
httpOnly: true,
sameSite: "lax",
secure: process.env.NODE_ENV === "production", // requiere https
maxAge: ttlSeconds * 1000,
},
});


return { sessionMw, redis, store, trustProxy };
}