// dbConnect.js
import mongoose from "mongoose";

const MONGODB_URI = process.env.MONGODB_URI;
const DB_NAME = process.env.MONGODB_DB_NAME || "mydatabase"; // 添加数据库名称

if (!MONGODB_URI) {
  throw new Error(
    "Please define the MONGODB_URI environment variable inside .env.local"
  );
}

let cached = global.mongoose;

if (!cached) {
  cached = global.mongoose = { conn: null, promise: null };
}

async function dbConnect() {
  if (cached.conn) {
    return cached.conn;
  }

  if (!cached.promise) {
    const opts = {
      bufferCommands: false,
      dbName: DB_NAME, // 明确指定数据库名称
      useNewUrlParser: true,
      useUnifiedTopology: true,
    };

    cached.promise = mongoose.connect(MONGODB_URI, opts).then((mongoose) => {
      console.log(`Connected to MongoDB database: ${DB_NAME}`);
      return mongoose;
    });
  }

  try {
    cached.conn = await cached.promise;
  } catch (e) {
    cached.promise = null;
    console.error("Failed to connect to MongoDB:", e);
    throw e;
  }

  return cached.conn;
}

export default dbConnect;