/*
 This file is part of TALER
 (C) 2016 Inria

 TALER is free software; you can redistribute it and/or modify it under the
 terms of the GNU General Public License as published by the Free Software
 Foundation; either version 3, or (at your option) any later version.

 TALER is distributed in the hope that it will be useful, but WITHOUT ANY
 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
 A PARTICULAR PURPOSE.  See the GNU General Public License for more details.

 You should have received a copy of the GNU General Public License along with
 TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
 */


/**
 * General helper components
 * 
 * @author Florian Dold
 */

export interface StateHolder<T> {
  (): T;
  (newState: T): void;
}

/**
 * Component that doesn't hold its state in one object,
 * but has multiple state holders.
 */
export abstract class ImplicitStateComponent<PropType> extends preact.Component<PropType, any> {
  makeState<StateType>(initial: StateType): StateHolder<StateType> {
    let state: StateType = initial;
    return (s?: StateType): StateType => {
      if (s !== undefined) {
        state = s;
        // In preact, this will always schedule a (debounced) redraw
        this.setState({} as any);
      }
      return state;
    };
  }
}