<?php
/**
 * Desktop Mode — Heartbeat-driven nonce refresh.
 *
 * WordPress nonces are valid for `nonce_life` (24 hours by default).
 * The desktop shell is a long-running SPA whose per-window config
 * blobs bake `wp_create_nonce()` values into the page at render
 * time, so any session that stays open past the 24-hour mark hits
 * `rest_cookie_invalid_nonce` ("Cookie check failed") on the next
 * REST call — even though the auth cookie is still valid.
 *
 * Fix: on every Heartbeat tick, return a fresh copy of every nonce
 * action the shell cares about, keyed by action string. The client
 * subscribes via `src/nonce-refresh.ts` and rewrites the cached
 * values in place. `wp_create_nonce()` returns the same value
 * inside a single 12-hour tick window, so the actual nonce string
 * only changes when the tick rolls — well before the 24-hour hard
 * expiry catches the cached value.
 *
 * Default actions covered:
 *
 *   - `wp_rest` — the canonical REST cookie nonce. Used by every
 *      window that stashes a `restNonce` in its config blob, plus
 *      the shell-wide auto-injection in `src/inject-rest-nonce.ts`.
 *   - `desktop-mode-plugins` — admin-ajax nonce for our
 *      browse/install/upload/reviews handlers.
 *   - `updates` — Core's wp.updates nonce used by
 *      `wp_ajax_install_plugin` / `wp_ajax_update_plugin`.
 *
 * Plugin authors who need to extend the set can hook
 * `desktop_mode_nonce_refresh_actions` and add their own nonce
 * action strings. The client side picks the new fields up
 * automatically through the same heartbeat field — feature modules
 * just need to register a target for the field they care about via
 * the JS-side `registerNonceTarget()` helper.
 *
 * @package WPDesktopMode
 * @since   0.8.7
 */

defined( 'ABSPATH' ) || exit;

/**
 * Heartbeat field name. Public — `src/nonce-refresh.ts` subscribes
 * to this string. Keep the value stable across versions or update
 * both ends.
 */
const DESKTOP_MODE_NONCE_REFRESH_FIELD = 'desktop_mode_nonces';

/**
 * Mint a fresh map of `{ action => nonce }` for every action the
 * shell needs to keep alive past `nonce_life`. The set is
 * filterable so other native windows / third-party plugins can
 * extend it; the only requirement is that the action string match
 * whatever was passed to `wp_create_nonce()` at registration.
 *
 * @since 0.8.7
 *
 * @return array<string,string> Map of nonce-action => current nonce value.
 */
function desktop_mode_nonce_refresh_build_payload() {
	$actions = array(
		'wp_rest',
		'desktop-mode-plugins',
		'updates',
	);

	/**
	 * Filter the set of nonce actions refreshed on every Heartbeat tick.
	 *
	 * Each entry must be a literal nonce action string (the same value
	 * passed to `wp_create_nonce()` wherever the original was minted).
	 *
	 * @since 0.8.7
	 *
	 * @param string[] $actions Default nonce actions.
	 */
	$actions = (array) apply_filters( 'desktop_mode_nonce_refresh_actions', $actions );

	$payload = array();
	foreach ( $actions as $action ) {
		if ( ! is_string( $action ) || $action === '' ) {
			continue;
		}
		$payload[ $action ] = wp_create_nonce( $action );
	}
	return $payload;
}

/**
 * Heartbeat handler — attach the fresh nonce map to every tick
 * from a user who has Desktop Mode enabled.
 *
 * Gated on `desktop_mode_is_enabled()` (not just `is_user_logged_in()`)
 * so users on classic admin screens — editors on post-edit pages,
 * subscribers reading the front-end heartbeat — don't carry the
 * payload around. The shell's nonces only need refreshing for
 * users who actually run the shell.
 *
 * The cost is tiny when fired (three `wp_create_nonce()` calls,
 * all hot-cached inside a single request) — the gate is about
 * not shipping irrelevant data to non-shell users on every tick.
 *
 * @since 0.8.7
 *
 * @param array $response Heartbeat response (filter return value).
 * @param array $data     Client-sent payload. Unused here.
 * @return array
 */
function desktop_mode_nonce_refresh_heartbeat_received( $response, $data ) {
	unset( $data );
	if ( ! is_array( $response ) ) {
		$response = array();
	}
	if ( ! function_exists( 'desktop_mode_is_enabled' ) || ! desktop_mode_is_enabled() ) {
		return $response;
	}
	$response[ DESKTOP_MODE_NONCE_REFRESH_FIELD ] = desktop_mode_nonce_refresh_build_payload();
	return $response;
}
add_filter( 'heartbeat_received', 'desktop_mode_nonce_refresh_heartbeat_received', 5, 2 );