<?php
/**
 * Small writes and deletes through WP_Filesystem.
 *
 * @package Shiftora\Support
 */

declare(strict_types=1);

namespace Shiftora\Support;

// Prevent direct file access.
if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * Whole-file work inside uploads goes through WP_Filesystem's direct method.
 * Anything that appends or streams (chunked imports, SQL dumps) cannot, because
 * WP_Filesystem has no append or stream API, and keeps its own PHP handles.
 *
 * Credentials are never asked for and the global $wp_filesystem is never set:
 * when WordPress would pick anything but the direct method, the plain PHP call
 * runs instead. Every call names the folder it may touch and refuses paths
 * that resolve outside it, links included.
 */
final class Filesystem {

	/** Writes a whole file inside $boundary. */
	public static function write( string $path, string $contents, string $boundary ): bool {
		if ( ! self::inside( dirname( $path ), $boundary ) ) {
			return false;
		}

		$fs = self::direct( $boundary );
		if ( null !== $fs ) {
			return (bool) $fs->put_contents( $path, $contents );
		}

		return false !== file_put_contents( $path, $contents, LOCK_EX ); // phpcs:ignore WordPress.WP.AlternativeFunctions.file_system_operations_file_put_contents -- the direct method is unavailable here.
	}

	/**
	 * Moves a file, replacing the target; both ends have to sit inside $boundary.
	 *
	 * @param string|null $from_boundary Folder the source has to sit inside when it lives somewhere else than the target.
	 */
	public static function move( string $from, string $to, string $boundary, ?string $from_boundary = null ): bool {
		if ( is_link( $from ) || ! self::inside( dirname( $from ), $from_boundary ?? $boundary ) || ! self::inside( dirname( $to ), $boundary ) ) {
			return false;
		}

		$fs = self::direct( $boundary );
		if ( null !== $fs ) {
			return (bool) $fs->move( $from, $to, true );
		}

		return rename( $from, $to ); // phpcs:ignore WordPress.WP.AlternativeFunctions.rename_rename -- the direct method is unavailable here.
	}

	/**
	 * Removes a folder and everything under it, inside $boundary.
	 * A link is removed itself and never followed, at the top or further down.
	 */
	public static function delete_tree( string $dir, string $boundary ): bool {
		if ( is_link( $dir ) ) {
			wp_delete_file( $dir );

			return ! is_link( $dir );
		}

		if ( ! is_dir( $dir ) ) {
			return true;
		}

		if ( ! self::inside( $dir, $boundary ) ) {
			return false;
		}

		$fs = self::direct( $boundary );
		foreach ( (array) scandir( $dir ) as $name ) {
			if ( '.' === $name || '..' === $name ) {
				continue;
			}

			$path = $dir . '/' . $name;
			if ( is_dir( $path ) && ! is_link( $path ) ) {
				self::delete_tree( $path, $boundary );
			} elseif ( null !== $fs && ! is_link( $path ) ) {
				$fs->delete( $path, false, 'f' );
			} else {
				wp_delete_file( $path );
			}
		}

		if ( null !== $fs ) {
			return (bool) $fs->rmdir( $dir );
		}

		return rmdir( $dir ); // phpcs:ignore WordPress.WP.AlternativeFunctions.file_system_operations_rmdir -- the direct method is unavailable here.
	}

	/** Whether a path resolves to $boundary or somewhere under it. */
	private static function inside( string $path, string $boundary ): bool {
		$real_path     = realpath( $path );
		$real_boundary = realpath( $boundary );
		if ( false === $real_path || false === $real_boundary ) {
			return false;
		}

		return $real_path === $real_boundary || str_starts_with( $real_path, rtrim( $real_boundary, '/\\' ) . DIRECTORY_SEPARATOR );
	}

	/**
	 * A local direct filesystem, or null when WordPress would not choose that method.
	 * It is built here rather than through WP_Filesystem() so no unconnected FTP object is left in the global.
	 */
	private static function direct( string $context ): ?\WP_Filesystem_Base {
		$loader = ABSPATH . 'wp-admin/includes/file.php';
		if ( ! function_exists( 'get_filesystem_method' ) ) {
			if ( ! is_file( $loader ) ) {
				return null;
			}
			require_once $loader;
		}

		if ( 'direct' !== get_filesystem_method( [], $context, true ) ) {
			return null;
		}

		require_once ABSPATH . 'wp-admin/includes/class-wp-filesystem-base.php';
		require_once ABSPATH . 'wp-admin/includes/class-wp-filesystem-direct.php';

		// WP_Filesystem() normally defines these; without them core's chmod()
		// reads an undefined constant and PHP 8 turns that into a fatal.
		if ( ! defined( 'FS_CHMOD_DIR' ) ) {
			define( 'FS_CHMOD_DIR', ( fileperms( ABSPATH ) & 0777 ) | 0755 ); // phpcs:ignore WordPress.NamingConventions.PrefixAllGlobals.NonPrefixedConstantFound -- WordPress core's own constant, defined exactly as WP_Filesystem() defines it.
		}
		if ( ! defined( 'FS_CHMOD_FILE' ) ) {
			define( 'FS_CHMOD_FILE', ( fileperms( ABSPATH . 'index.php' ) & 0777 ) | 0644 ); // phpcs:ignore WordPress.NamingConventions.PrefixAllGlobals.NonPrefixedConstantFound -- WordPress core's own constant, defined exactly as WP_Filesystem() defines it.
		}

		return new \WP_Filesystem_Direct( null );
	}
}