<?php
/**
 * Uninstall cleanup, run by uninstall.php without the plugin or its autoloader loaded.
 *
 * Always: the core's options mench_migrate_* and their transients (never an add-on's: mench_migrate_cloud_* and the other
 * prefixes in ADDON_PREFIXES stay for the add-on's own uninstall), every mench_migrate_* cron hook, and this site's import
 * staging and rollback tables (mmtmp_<hash>_*, mmold_<hash>_*). Only the hashes of this site's own jobs count: the job
 * folders under jobs/, the snapshots under rollback/ and the last import, so on a database shared by several sites
 * another site's rollback tables are never dropped (orphans of job folders deleted by hand stay). Only when the setting delete_backups_on_uninstall is true: the storage root with every
 * backup, job and rollback copy in it, removed without following symlinks. Off by default, so backups survive an uninstall.
 *
 * @package Mench_Migrate
 */

defined( 'ABSPATH' ) || exit;

final class Mench_Migrate_Uninstall {

	public static function run(): void {
		// Read before the options go: the folder name and the owner's choice live there.
		$settings = get_option( 'mench_migrate_settings', [] );
		$dir      = (string) get_option( 'mench_migrate_storage_dir', '' );

		self::unschedule();
		self::drop_tables( self::job_hashes( $dir ) );
		if ( is_array( $settings ) && true === ( $settings['delete_backups_on_uninstall'] ?? false ) ) {
			self::delete_root( $dir );
		}
		self::delete_options();
	}

	/** Every scheduled event whose hook starts with mench_migrate_ (add-ons' included), whatever its arguments. */
	private static function unschedule(): void {
		foreach ( (array) _get_cron_array() as $events ) {
			foreach ( array_keys( (array) $events ) as $hook ) {
				if ( is_string( $hook ) && 0 === strpos( $hook, 'mench_migrate_' ) ) {
					wp_unschedule_hook( $hook );
				}
			}
		}
	}

	/**
	 * The 8-hex table hashes of this site's jobs: every job folder, every snapshot (and the job id it records) and the
	 * last import. Empty when the storage folder name is not ours.
	 *
	 * @return string[]
	 */
	private static function job_hashes( string $dir ): array {
		$ids  = [];
		$last = get_option( 'mench_migrate_last_import' );
		if ( is_array( $last ) && is_string( $last['job_id'] ?? null ) ) {
			$ids[] = $last['job_id'];
		}
		if ( 1 === preg_match( '/^mench-migrate-[a-z0-9]{12}$/', $dir ) ) {
			$root = rtrim( WP_CONTENT_DIR, '/\\' ) . '/' . $dir;
			foreach ( [ 'jobs', 'rollback' ] as $sub ) {
				foreach ( (array) @scandir( $root . '/' . $sub ) as $name ) { // phpcs:ignore WordPress.PHP.NoSilencedErrors
					if ( ! is_string( $name ) || '' === $name || '.' === $name[0] || 0 === strpos( $name, 'upl-' ) || ! is_dir( $root . '/' . $sub . '/' . $name ) ) {
						continue;
					}
					$ids[] = $name;
					$snap  = $root . '/' . $sub . '/' . $name . '/snapshot.json';
					if ( 'rollback' === $sub && is_file( $snap ) ) {
						$state = wp_json_file_decode( $snap, [ 'associative' => true ] ); // Small local snapshot.json in the plugin's own storage root.
						if ( is_array( $state ) && is_string( $state['job_id'] ?? null ) ) {
							$ids[] = $state['job_id'];
						}
					}
				}
			}
		}
		$out = [];
		foreach ( array_unique( $ids ) as $id ) {
			if ( 1 === preg_match( '/^[A-Za-z0-9][A-Za-z0-9._-]*$/', $id ) ) {
				$out[] = substr( md5( $id ), 0, 8 );
			}
		}
		return array_values( array_unique( $out ) );
	}

	/** This site's import staging (mmtmp_<hash>_) and rollback (mmold_<hash>_) tables. */
	private static function drop_tables( array $hashes ): void {
		global $wpdb;
		foreach ( $hashes as $hash ) {
			foreach ( [ 'mmtmp_', 'mmold_' ] as $kind ) {
				$head   = $kind . $hash . '_';
				$tables = (array) $wpdb->get_col( $wpdb->prepare( 'SHOW TABLES LIKE %s', $wpdb->esc_like( $head ) . '%' ) );
				foreach ( $tables as $table ) {
					if ( is_string( $table ) && 0 === strpos( $table, $head ) && 1 === preg_match( '/^[A-Za-z0-9_]+$/', $table ) ) {
						$wpdb->query( 'DROP TABLE IF EXISTS `' . $table . '`' ); // phpcs:ignore WordPress.DB -- name checked above.
					}
				}
			}
		}
	}

	/**
	 * Option prefixes that belong to add-ons (every catalogue add-on, shipped or planned). The core uninstall never deletes
	 * them: WordPress lets the core be deleted while its add-ons stay installed, and each add-on's own uninstall.php owns
	 * its settings, secrets and open-upload records.
	 */
	private const ADDON_PREFIXES = [
		'mench_migrate_cloud_',
		'mench_migrate_schedules_',
		'mench_migrate_google_drive_',
		'mench_migrate_dropbox_',
		'mench_migrate_sftp_',
		'mench_migrate_site_to_site_',
		'mench_migrate_multisite_',
	];

	/** True for a (transient-stripped) option name that an add-on owns. */
	private static function addon_owned( string $name ): bool {
		$bare = (string) preg_replace( '/^_(?:site_)?transient_(?:timeout_)?/', '', $name );
		foreach ( self::ADDON_PREFIXES as $prefix ) {
			if ( 0 === strpos( $bare, $prefix ) ) {
				return true;
			}
		}
		return false;
	}

	/** The core's own options and transients (mench_migrate_*), never an add-on's (see ADDON_PREFIXES). */
	private static function delete_options(): void {
		global $wpdb;
		$names = (array) $wpdb->get_col(
			$wpdb->prepare(
				"SELECT option_name FROM {$wpdb->options} WHERE option_name LIKE %s OR option_name LIKE %s OR option_name LIKE %s OR option_name LIKE %s OR option_name LIKE %s",
				$wpdb->esc_like( 'mench_migrate_' ) . '%',
				$wpdb->esc_like( '_transient_mench_migrate_' ) . '%',
				$wpdb->esc_like( '_transient_timeout_mench_migrate_' ) . '%',
				$wpdb->esc_like( '_site_transient_mench_migrate_' ) . '%',
				$wpdb->esc_like( '_site_transient_timeout_mench_migrate_' ) . '%'
			)
		);
		foreach ( $names as $name ) {
			if ( self::addon_owned( (string) $name ) ) {
				continue;
			}
			delete_option( (string) $name );
		}
	}

	/** The storage root wp-content/mench-migrate-<12 [a-z0-9]>/, only when the stored name has exactly that shape. */
	private static function delete_root( string $dir ): void {
		if ( 1 !== preg_match( '/^mench-migrate-[a-z0-9]{12}$/', $dir ) ) {
			return;
		}
		$root = rtrim( WP_CONTENT_DIR, '/\\' ) . '/' . $dir;
		if ( is_link( $root ) || ! is_dir( $root ) ) {
			return;
		}
		self::remove_tree( $root );
	}

	/** Removes $dir and everything in it; a symlink is unlinked, never followed. */
	private static function remove_tree( string $dir ): void {
		$items = @scandir( $dir ); // phpcs:ignore WordPress.PHP.NoSilencedErrors
		foreach ( false === $items ? [] : $items as $name ) {
			if ( '.' === $name || '..' === $name ) {
				continue;
			}
			$path = $dir . '/' . $name;
			if ( is_link( $path ) || ! is_dir( $path ) ) {
				wp_delete_file( $path );
			} else {
				self::remove_tree( $path );
			}
		}
		@rmdir( $dir ); // phpcs:ignore WordPress.PHP.NoSilencedErrors, WordPress.WP.AlternativeFunctions.file_system_operations_rmdir -- removes an emptied folder of the plugin's own storage root during uninstall, where WP_Filesystem cannot prompt for credentials; a failure leaves the folder.
	}
}