enbock / Time-Tracker

import {IObserverAdapter, IOnChangeCallback} from '../Observer/Observer';

import StorageAdapter from './StorageAdapter';

export interface IAdapterDictionary {

  [index: string]: StorageAdapter<any>

}

export default class DataStorage {

  protected domain: string;

  protected storage: Storage;

  protected adapters: IAdapterDictionary;

  constructor(domain: string, storage: Storage) {

    this.domain = domain;

    this.storage = storage;

    this.adapters = {};

  }

  attach<T>(key: string, adapter: IObserverAdapter<T>): StorageAdapter<T> {

    const callback: IOnChangeCallback<T> = (oldValue: T, newValue: T) => this.updateStorage(key, newValue);

    const storageAdapter: StorageAdapter<T> = new StorageAdapter<T>(adapter, callback);

    this.adapters[key] = storageAdapter;

    return storageAdapter;

  }

  loadData<T>(key: string, initialValue: T): T {

    const initJSON: string | null = this.storage.getItem(this.domain + '::' + key);

    let data: T = initialValue;

    if (initJSON != null) {

      data = JSON.parse(initJSON) as T;

    }

    return data;

  }

  protected updateStorage<T>(key: string, newValue: T) {

    this.storage.setItem(this.domain + '::' + key, JSON.stringify(newValue));

  }

}