import { ActionReducer } from "./StateManager.js";
import { Action } from "./action/DataUnitAction.js";
import StateManager, {StateAction} from "./StateManager.js";

class HistReducerImpl implements ActionReducer {

    public sliceName: string = "";

    public reduce(stateManager: StateManager, _currentState: void, action: StateAction): void {
        
        switch (action.type) {
            case Action.DATA_SAVED:
            case Action.EDITION_CANCELED:
                stateManager.clearUndo();
                break;
            case Action.CHANGE_UNDONE:
                stateManager.undo();
                break;
            case Action.CHANGE_REDONE:
                stateManager.redo();
                break;
        }
    }
}

export const HistReducer = new HistReducerImpl();

export const canUndo = (stateManager: StateManager): boolean => {
    return stateManager.canUndo();
}

export const canRedo = (stateManager: StateManager): boolean =>{
    return stateManager.canRedo();
}