import _ from 'lodash';
import * as yup from 'yup';

const listenerSchema = yup.mixed().test('function', 'Invalid function', (value) => {
  return _.isFunction(value);
});

type IListener = (value: unknown) => void;
interface ILocalStorage {
  get: (key: string) => unknown | null;
  set: (key: string, value: unknown) => unknown | null;
  watch: (key: string, callback: IListener) => void;
  unwatch: (key: string, callback?: IListener) => void;
}

class LocalStorage implements ILocalStorage {
  #listeners: Array<{ key: string; callback: IListener }> = [];

  #canAccessLocalStorage(): boolean {
    return typeof window !== 'undefined';
  }

  get(key: string): unknown | null {
    yup.string().required().validateSync(key);
    if (!this.#canAccessLocalStorage()) {
      return null;
    } else {
      const value = localStorage.getItem(key);
      return _.isNil(value) ? null : JSON.parse(value);
    }
  }

  set(key: string, value: unknown): unknown | null {
    yup.string().required().validateSync(key);
    if (this.#canAccessLocalStorage()) {
      localStorage.setItem(key, JSON.stringify(value));
      return value;
    } else {
      return null;
    }
  }

  watch(key: string, callback: IListener): void {
    yup.string().required().validateSync(key);
    listenerSchema.validateSync(callback);
    if (this.#canAccessLocalStorage()) {
      this.#listeners.push({ key: key, callback: callback });
      window.addEventListener('storage', (e) => {
        if (e.storageArea === localStorage && e.key === key) {
          callback(this.get(key));
        }
      });
    }
  }

  unwatch(key: string, callback?: IListener | undefined): void {
    yup.string().required().validateSync(key);
    listenerSchema.optional().default(_.identity).validateSync(callback);
    if (this.#canAccessLocalStorage()) {
      if (callback !== undefined) {
        this.#listeners = _.reject(this.#listeners, (listener) => {
          return listener.key === key && listener.callback === callback;
        });
      } else {
        this.#listeners = _.reject(this.#listeners, (listener) => {
          return listener.key === key;
        });
      }
    }
  }
}

export { LocalStorage };