import { Observable, of } from 'rxjs';
import { map } from 'rxjs/operators';

import { IRxIDB } from './rxidb.interfaces';
import { RxIDBStore } from './rxidb-store';

export class RxIDB implements IRxIDB {
  private _storeCache: {[key: string]: RxIDBStore} = {};

  constructor (
    public readonly idb: IDBDatabase
  ) {}

  /**
   * Close db
   */
  public close(): void {
    this.idb.close();
  }

  /**
   * Get store
   */
  public get(key: string): RxIDBStore {
    if (this._storeCache[key]) {
      return this._storeCache[key];
    }

    return this._storeCache[key] = new RxIDBStore(key, this);
  }

  /**
   * Stream: IDBTransaction
   */
  public tx(
    store: string | string[],
    mode: 'readonly' | 'readwrite' = 'readonly'
  ): Observable<IDBTransaction> {
    return of(null).pipe(
      map(() => this.idb.transaction(store, mode))
    );
  }

  /**
   * Open IDBTransaction
   */
  public transaction(
    store: string|string[],
    mode: 'readonly'|'readwrite' = 'readonly'
  ): IDBTransaction {
    return this.idb.transaction(store, mode);
  }
}