<?php
namespace Rafgrid;

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * Full-list snapshots (posts + meta + terms as JSON) in the private
 * uploads/rafgrid/snapshots/ folder. See Storage for the access protection.
 */
class Snapshot {

	/**
	 * Allowed snapshot file name: snapshot-{type}-{date}-{time}-{token}.json.
	 */
	public const string FILE_PATTERN = '/^snapshot-[a-z0-9_\-]+-\d{8}-\d{6}-[a-z0-9]{24}\.json$/';

	private static function dir(): string {
		return Storage::dir( 'snapshots' );
	}

	/**
	 * @param string $post_type Post type.
	 * @return array|\WP_Error {file, count}
	 */
	public static function create( string $post_type ) {
		$posts = get_posts( array( 'post_type' => $post_type, 'posts_per_page' => 5000, 'post_status' => 'any' ) );
		$data  = array();
		foreach ( $posts as $p ) {
			$terms = array();
			foreach ( get_object_taxonomies( $post_type ) as $tax ) {
				$ids = wp_get_post_terms( $p->ID, $tax, array( 'fields' => 'ids' ) );
				if ( ! is_wp_error( $ids ) ) {
					$terms[ $tax ] = $ids;
				}
			}
			$data[] = array(
				'ID' => $p->ID, 'post_title' => $p->post_title, 'post_name' => $p->post_name, 'post_status' => $p->post_status,
				'post_content' => $p->post_content, 'post_excerpt' => $p->post_excerpt, 'post_author' => (int) $p->post_author,
				'post_date' => $p->post_date, 'menu_order' => $p->menu_order, 'post_parent' => $p->post_parent,
				'meta' => get_post_meta( $p->ID ), 'terms' => $terms,
			);
		}
		$file = 'snapshot-' . sanitize_key( $post_type ) . '-' . gmdate( 'Ymd-His' ) . '-' . Storage::token() . '.json';
		$ok   = file_put_contents( self::dir() . $file, wp_json_encode( array( 'post_type' => $post_type, 'created' => gmdate( 'c' ), 'items' => $data ) ) ); // phpcs:ignore WordPress.WP.AlternativeFunctions.file_system_operations_file_put_contents
		if ( false === $ok ) {
			return new \WP_Error( 'rafgrid_snapshot_failed', __( 'Cannot write snapshot file.', 'rafgrid' ) );
		}
		return array( 'file' => $file, 'count' => count( $data ) );
	}

	/**
	 * @return array list of {file, size, post_type}
	 */
	public static function listing(): array {
		$out = array();
		foreach ( glob( self::dir() . 'snapshot-*.json' ) ?: array() as $f ) {
			if ( ! preg_match( self::FILE_PATTERN, basename( $f ) ) ) {
				continue;
			}
			$out[] = array( 'file' => basename( $f ), 'size' => filesize( $f ), 'mtime' => filemtime( $f ) );
		}
		usort( $out, static fn( $a, $b ) => $b['mtime'] <=> $a['mtime'] );
		return array_slice( $out, 0, 20 );
	}

	/**
	 * Restore existing posts from a snapshot (updates by ID, skips deleted).
	 *
	 * @param string $file File name.
	 * @return array {restored, skipped}
	 */
	public static function restore( string $file ) {
		$path = Storage::path( 'snapshots', $file, self::FILE_PATTERN );
		if ( null === $path ) {
			return array( 'restored' => 0, 'skipped' => 0 );
		}
		$raw  = json_decode( (string) file_get_contents( $path ), true ); // phpcs:ignore WordPress.WP.AlternativeFunctions.file_system_operations_file_get_contents
		$restored = 0;
		$skipped  = 0;
		foreach ( (array) ( $raw['items'] ?? array() ) as $item ) {
			$post = get_post( (int) ( $item['ID'] ?? 0 ) );
			if ( ! $post || ! Access::can_edit_post( $post->ID ) ) {
				++$skipped;
				continue;
			}
			wp_update_post( array(
				'ID' => $post->ID, 'post_title' => $item['post_title'], 'post_status' => $item['post_status'],
				'post_content' => $item['post_content'], 'post_excerpt' => $item['post_excerpt'],
			) );
			foreach ( (array) ( $item['meta'] ?? array() ) as $k => $vals ) {
				delete_post_meta( $post->ID, $k );
				foreach ( (array) $vals as $v ) {
					add_post_meta( $post->ID, $k, maybe_unserialize( $v ) );
				}
			}
			foreach ( (array) ( $item['terms'] ?? array() ) as $tax => $ids ) {
				wp_set_post_terms( $post->ID, array_map( 'intval', (array) $ids ), $tax, false );
			}
			++$restored;
		}
		return array( 'restored' => $restored, 'skipped' => $skipped );
	}
}