src/lib/db.ts

// This file should only be imported on the client side.
'use client';

import { openDB, type IDBPDatabase } from 'idb';
import type { PostWithUIState } from './types';

const DB_NAME = 'AIWorldDB';
const DB_VERSION = 1;
const POSTS_STORE_NAME = 'posts';

interface AIWorldDB {
  posts: {
    key: string;
    value: PostWithUIState;
    indexes: { createdAt: string };
  };
}

let dbPromise: Promise<IDBPDatabase<AIWorldDB>> | null = null;

function getDb(): Promise<IDBPDatabase<AIWorldDB>> {
  if (typeof window === 'undefined') {
    return Promise.reject(new Error('IndexedDB cannot be used on the server.'));
  }
  if (!dbPromise) {
    dbPromise = openDB<AIWorldDB>(DB_NAME, DB_VERSION, {
      upgrade(db) {
        if (!db.objectStoreNames.contains(POSTS_STORE_NAME)) {
          const store = db.createObjectStore(POSTS_STORE_NAME, {
            keyPath: 'id',
          });
          store.createIndex('createdAt', 'createdAt');
        }
      },
    });
  }
  return dbPromise;
}