<?php
declare( strict_types = 1 );

namespace Automattic\WooCommerce\Internal\Utilities;

use Automattic\Jetpack\Constants;
use Exception;
use WP_Filesystem_Base;

/**
 * FilesystemUtil class.
 */
class FilesystemUtil {
	/**
	 * Wrapper to retrieve the class instance contained in the $wp_filesystem global, after initializing if necessary.
	 *
	 * @return WP_Filesystem_Base
	 * @throws Exception Thrown when the filesystem fails to initialize.
	 */
	public static function get_wp_filesystem(): WP_Filesystem_Base {
		global $wp_filesystem;

		if ( ! $wp_filesystem instanceof WP_Filesystem_Base ) {
			$initialized = self::initialize_wp_filesystem();

			if ( false === $initialized ) {
				throw new Exception( 'The WordPress filesystem could not be initialized.' );
			}
		}

		return $wp_filesystem;
	}

	/**
	 * Wrapper to initialize the WP filesystem with defined credentials if they are available.
	 *
	 * @return bool True if the $wp_filesystem global was successfully initialized.
	 */
	protected static function initialize_wp_filesystem(): bool {
		global $wp_filesystem;

		if ( $wp_filesystem instanceof WP_Filesystem_Base ) {
			return true;
		}

		require_once ABSPATH . 'wp-admin/includes/file.php';

		$method      = get_filesystem_method();
		$initialized = false;

		if ( 'direct' === $method ) {
			$initialized = WP_Filesystem();
		} elseif ( false !== $method ) {
			// See https://core.trac.wordpress.org/changeset/56341.
			ob_start();
			$credentials = request_filesystem_credentials( '' );
			ob_end_clean();

			$initialized = $credentials && WP_Filesystem( $credentials );
		}

		return is_null( $initialized ) ? false : $initialized;
	}
}