import R from 'remeda';
import u from 'updeep';

const localMutation = (mutations) => (action) => (state) => {
    const mutation = mutations[action.type];

    if (!mutation) return state;

    return mutation(action.payload, action)(state);
};

const subMutations = (subduxes) => (action) => (state) => {
    const subReducers =
        Object.keys(subduxes).length > 0
            ? R.mapValues(subduxes, R.prop('upreducer'))
            : null;

    if (!subReducers) return state;

    if (subReducers['*']) {
        return u.updateIn('*', subReducers['*'](action), state);
    }

    const update = R.mapValues(subReducers, (upReducer) => upReducer(action));

    return u(update, state);
};

export function buildUpreducer(mutations, subduxes) {
    return (action) => (state) => {
        if( ! mutations[action.type]?.terminal )
            state = subMutations(subduxes)(action)(state);

        return localMutation(mutations)(action)(state);
    };
}