/**
 * Reducer: Defines store structure and state updates for this module.
 *
 * Manages both transient (temporary) and persistent (saved) state.
 * The initial state must define all properties, as dynamic additions are not supported.
 *
 * @file
 */

import { createReducer, createReducerSetters } from '../utils';
import ACTION_TYPES from './action-types';

// Store structure.

/**
 * Transient: Values that are _not_ saved to the DB (like app lifecycle-flags).
 * These reset on page reload.
 */
const defaultTransient = Object.freeze( {
	isReady: false,
} );

/**
 * Persistent: Values that are loaded from and saved to the DB.
 * These represent the core PayPal payment settings configuration.
 */
const defaultPersistent = Object.freeze( {
	// String values.
	invoicePrefix: '', // Prefix for PayPal invoice IDs
	brandName: '', // Merchant brand name for PayPal
	softDescriptor: '', // Payment descriptor on statements

	// Limited value strings.
	subtotalAdjustment: 'no_details', // [correction|no_details] Handling for subtotal mismatches
	landingPage: 'any', // [any|login|guest_checkout] PayPal checkout landing page
	buttonLanguage: '', // Language for PayPal buttons

	// Boolean flags.
	authorizeOnly: false, // Whether to only authorize payments initially
	captureVirtualOrders: false, // Auto-capture virtual-only orders
	savePaypalAndVenmo: false, // Enable PayPal & Venmo vaulting
	saveCardDetails: false, // Enable card vaulting
	enablePayNow: false, // Enable Pay Now experience
	enableLogging: false, // Enable debug logging

	// String arrays.
	disabledCards: [], // Disabled credit card types
} );

// Reducer logic.

const [ changeTransient, changePersistent ] = createReducerSetters(
	defaultTransient,
	defaultPersistent
);

/**
 * Reducer implementation mapping actions to state updates.
 */
const reducer = createReducer( defaultTransient, defaultPersistent, {
	/**
	 * Updates temporary state values
	 *
	 * @param {Object} state   Current state
	 * @param {Object} payload Update payload
	 * @return {Object} Updated state
	 */
	[ ACTION_TYPES.SET_TRANSIENT ]: ( state, payload ) => {
		return changeTransient( state, payload );
	},

	/**
	 * Updates persistent configuration values
	 *
	 * @param {Object} state   Current state
	 * @param {Object} payload Update payload
	 * @return {Object} Updated state
	 */
	[ ACTION_TYPES.SET_PERSISTENT ]: ( state, payload ) =>
		changePersistent( state, payload ),

	/**
	 * Resets state to defaults while maintaining initialization status
	 *
	 * @param {Object} state Current state
	 * @return {Object} Reset state
	 */
	[ ACTION_TYPES.RESET ]: ( state ) => {
		const cleanState = changeTransient(
			changePersistent( state, defaultPersistent ),
			defaultTransient
		);
		cleanState.isReady = true; // Keep initialization flag
		return cleanState;
	},

	/**
	 * Initializes persistent state with data from the server
	 *
	 * @param {Object} state        Current state
	 * @param {Object} payload      Hydration payload containing server data
	 * @param {Object} payload.data The settings data to hydrate
	 * @return {Object} Hydrated state
	 */
	[ ACTION_TYPES.HYDRATE ]: ( state, payload ) =>
		changePersistent( state, payload.data ),
} );

export default reducer;