import { drizzle } from "drizzle-orm/node-postgres";
import pg from "pg";
import * as schema from "@shared/schema";

const { Pool } = pg;

let pool: pg.Pool | null = null;
let db: ReturnType<typeof drizzle> | null = null;

function getPool(): pg.Pool {
  if (!pool) {
    if (!process.env.DATABASE_URL) {
      throw new Error(
        "DATABASE_URL must be set. Did you forget to provision a database?",
      );
    }
    pool = new Pool({ 
      connectionString: process.env.DATABASE_URL,
      connectionTimeoutMillis: 10000,
      idleTimeoutMillis: 30000,
      max: 25,
    });
    pool.on('error', (err) => {
      console.error('Unexpected error on idle database client', err);
    });
  }
  return pool;
}

function getDb() {
  if (!db) {
    db = drizzle(getPool(), { schema });
  }
  return db;
}

export { getPool as pool, getDb as db };

export const poolInstance = () => getPool();
export const dbInstance = () => getDb();

export async function verifyDatabaseConnection(): Promise<boolean> {
  try {
    const p = getPool();
    const client = await p.connect();
    try {
      await client.query('SELECT 1');
      console.log("Database connection verified successfully.");
      return true;
    } finally {
      client.release();
    }
  } catch (error) {
    console.error("Database connection failed:", error);
    return false;
  }
}