/**
 * External dependencies
 */
import { isEqual } from 'lodash';
import type { AnyAction } from '@nab/types';

/**
 * Internal dependencies
 */
import { INIT_STATE } from './config';
import type { State } from './types';
import type { Action } from './actions';

export function reducer( state = INIT_STATE, action: AnyAction ): State {
	return actualReducer( state, action as Action ) ?? state;
}

function actualReducer( state: State, action: Action ): State {
	switch ( action.type ) {
		case 'SET_FIELD_VALUE': {
			const value = state.values[ action.field ];
			if ( isEqual( value, action.value ) ) {
				return state;
			}

			return {
				...state,
				values: {
					...state.values,
					[ action.field ]: action.value,
				},
			};
		}

		case 'SET_FIELD_ATTRIBUTES': {
			const attributes = state.attributes[ action.field ];
			const newAttributes = {
				...attributes,
				...action.attributes,
			};
			if ( isEqual( attributes, newAttributes ) ) {
				return state;
			}
			return {
				...state,
				attributes: {
					...state.attributes,
					[ action.field ]: newAttributes,
				},
			};
		}
	}
}