// server/utils/prisma.ts - Prisma 客户端初始化：使用 MariaDB adapter 并在开发热更新中复用连接池。
import { PrismaMariaDb } from "@prisma/adapter-mariadb";
import { PrismaClient } from "~~/app/generated/prisma/client";

const globalForPrisma = globalThis as unknown as {
  prisma?: PrismaClient;
};

const databaseUrl = process.env.DATABASE_URL;

if (!databaseUrl) {
  throw new Error("DATABASE_URL is required to initialize PrismaClient");
}

type MariaDbPoolConfig = Exclude<
  ConstructorParameters<typeof PrismaMariaDb>[0],
  string
>;

/** 从 DATABASE_URL 查询参数读取连接池配置，非法值回退到默认值 */
function getNumberParam(url: URL, name: string, fallback: number) {
  const value = url.searchParams.get(name);
  if (!value) {
    return fallback;
  }

  const parsed = Number(value);
  return Number.isFinite(parsed) && parsed > 0 ? parsed : fallback;
}

/** 将 DATABASE_URL 拆成 Prisma MariaDB adapter 需要的连接池配置 */
function createMariaDbConfig(urlString: string): MariaDbPoolConfig {
  const url = new URL(urlString);
  const database = decodeURIComponent(url.pathname.replace(/^\//, ""));

  if (!url.hostname || !url.username || !database) {
    throw new Error("DATABASE_URL must include host, user and database");
  }

  const port = url.port ? Number(url.port) : 3306;

  if (!Number.isInteger(port) || port <= 0) {
    throw new Error("DATABASE_URL port is invalid");
  }

  return {
    host: url.hostname,
    port,
    user: decodeURIComponent(url.username),
    password: decodeURIComponent(url.password),
    database,
    connectionLimit: getNumberParam(url, "connection_limit", 5),
    acquireTimeout: getNumberParam(url, "pool_timeout", 30) * 1000,
    connectTimeout: getNumberParam(url, "connect_timeout", 10) * 1000
  };
}

const mariaDbConfig = createMariaDbConfig(databaseUrl);
const adapter = new PrismaMariaDb(mariaDbConfig, {
  database: mariaDbConfig.database
});

/** Reuse PrismaClient during dev hot reloads so Nuxt does not create duplicate pools. */
export const prisma =
  globalForPrisma.prisma ??
  new PrismaClient({
    adapter,
    log: ["warn", "error"]
  });

if (process.env.NODE_ENV !== "production") {
  globalForPrisma.prisma = prisma;
}