import Dexie, { type Table } from 'dexie';

export interface PendingRequest {
  clientRequestId: string; // primary key
  workstationId: string;
  description: string;
  photoBlob?: Blob;
  queuedAt: number;
  retries: number;
  lastError?: string;
}

export interface DeadLetter {
  clientRequestId: string;
  error: string;
  failedAt: number;
}

class MaiCallDb extends Dexie {
  pending!: Table<PendingRequest, string>;
  deadLetters!: Table<DeadLetter, string>;

  constructor() {
    super('mai-call-v1');
    this.version(1).stores({
      pending: 'clientRequestId, queuedAt',
      deadLetters: 'clientRequestId',
    });
  }
}

// Single browser-side instance. Guards against SSR import.
function makeDb(): MaiCallDb {
  if (typeof window === 'undefined') {
    return null as unknown as MaiCallDb; // never called server-side
  }
  return new MaiCallDb();
}

export const db = makeDb();