/**
 * Conexão MongoDB usando Mongoose
 * Singleton pattern para reutilizar conexão
 */

import mongoose from "mongoose";

function getMongoUrl(): string {
  const url = process.env.MONGO_URL;
  if (!url) {
    throw new Error("MONGO_URL não está definida nas variáveis de ambiente");
  }
  return url;
}

interface MongooseCache {
  conn: typeof mongoose | null;
  promise: Promise<typeof mongoose> | null;
}

// Cache global para Next.js (evita múltiplas conexões em hot reload)
declare global {
  // eslint-disable-next-line no-var
  var mongoose: MongooseCache | undefined;
}

const cached: MongooseCache = global.mongoose || { conn: null, promise: null };

if (!global.mongoose) {
  global.mongoose = cached;
}

/**
 * Conecta ao MongoDB ou retorna conexão existente
 */
export async function connectMongoDB(): Promise<typeof mongoose> {
  if (cached.conn) {
    return cached.conn;
  }

  if (!cached.promise) {
    const opts = {
      bufferCommands: false,
      maxPoolSize: 10,
      serverSelectionTimeoutMS: 5000,
      socketTimeoutMS: 45000,
    };

    cached.promise = mongoose
      .connect(getMongoUrl(), opts)
      .then((mongoose) => {
        // Conexão MongoDB estabelecida (log desabilitado)
        return mongoose;
      })
      .catch((error) => {
        console.error("❌ Erro ao conectar MongoDB:", error);
        cached.promise = null;
        throw error;
      });
  }

  try {
    cached.conn = await cached.promise;
  } catch (e) {
    cached.promise = null;
    throw e;
  }

  return cached.conn;
}

/**
 * Desconecta do MongoDB (útil para testes)
 */
export async function disconnectMongoDB(): Promise<void> {
  if (cached.conn) {
    await mongoose.disconnect();
    cached.conn = null;
    cached.promise = null;
  }
}