/**
 * 玩值电竞 - MongoDB 连接（单例）
 * 库名：wanzhi_esports
 */

import { config } from "dotenv"
import { resolve } from "path"
config({ path: resolve(process.cwd(), ".env.local") })

import { MongoClient, Db } from "mongodb"

const DB_NAME = "wanzhi_esports"
/** 本地开发回退：未设置 MONGODB_URI 时使用（与 00_账号与API索引 一致） */
const DEFAULT_URI = "mongodb://admin:admin123@localhost:27017?authSource=admin"
function getUri(): string {
  if (typeof process === "undefined" || !process.env) return DEFAULT_URI
  if (process.env.MONGODB_URI) return process.env.MONGODB_URI
  // Next 等环境下模块加载时 env 可能尚未注入，请求时再尝试加载一次
  try {
    config({ path: resolve(process.cwd(), ".env.local") })
    if (process.env.MONGODB_URI) return process.env.MONGODB_URI
  } catch {
    /* ignore */
  }
  return DEFAULT_URI
}

let client: MongoClient | null = null
let db: Db | null = null

export async function getMongoClient(): Promise<MongoClient> {
  // 开发模式下每次新建连接，避免 Next 热重载后连接失效
  if (process.env.NODE_ENV === "development" && client) {
    try {
      await client.close()
    } catch {
      /* ignore */
    }
    client = null
    db = null
  }
  if (client) return client
  const uri = getUri()
  client = new MongoClient(uri, { serverSelectionTimeoutMS: 10000, connectTimeoutMS: 10000 })
  await client.connect()
  return client
}

export async function getDb(): Promise<Db> {
  if (db) return db
  const c = await getMongoClient()
  db = c.db(DB_NAME)
  return db
}

/** 关闭连接（用于脚本结束或 serverless 冷启动回收） */
export async function closeMongo(): Promise<void> {
  if (client) {
    await client.close()
    client = null
    db = null
  }
}

export { DB_NAME }
export const MONGODB_URI = getUri()