<?php
/**
 * Bundle: a ZIP with a manifest, one JSON file per object and the media files.
 *
 * @package WonderfulSync
 */

namespace WonderfulPlugins\WonderfulSync;

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

/**
 * Writes and reads bundles.
 *
 * manifest.json            format, created, source {home, siteurl, origin, wp, divi, plugin, code[]}, objects[]
 *   object                 key, kind, class, subtype, title, op (upsert|delete), base (baseline hash), hash,
 *                          source (ID on staging), file (path of the data inside the ZIP, '' for deletions)
 * objects/<n>.json         the object data
 * files/<upload path>      media files of attachments in the bundle
 *
 * Object data lives in separate entries, so neither side ever holds the whole bundle in memory.
 */
class Bundle {

	const FORMAT = 2;

	/**
	 * Default limits a bundle must stay within.
	 *
	 * @return array{manifest_bytes: int, object_bytes: int, total_bytes: int, objects: int}
	 */
	public static function limits(): array {
		/**
		 * Filters the limits a bundle must stay within.
		 *
		 * @param array $limits manifest_bytes, object_bytes, total_bytes (unpacked), objects.
		 */
		return array_map(
			'intval',
			(array) apply_filters(
				'wonderful_sync_bundle_limits',
				array(
					'manifest_bytes' => 64 * MB_IN_BYTES,
					'object_bytes'   => 64 * MB_IN_BYTES,
					'total_bytes'    => 4 * GB_IN_BYTES,
					'objects'        => 50000,
					'entries'        => 250000,
				)
			)
		);
	}

	/**
	 * Builds a bundle file from selected changeset keys.
	 *
	 * @param Exporter $exporter Exporter of this site.
	 * @param array    $changes  Changeset from Changeset::compute().
	 * @param string[] $keys     Keys to include.
	 * @param string   $file     Target path of the ZIP.
	 * @param array    $source_extra Extra manifest source fields (direction of the package).
	 * @return array Manifest (summary).
	 */
	public static function build( Exporter $exporter, array $changes, array $keys, string $file, array $source_extra = array() ): array {
		if ( ! class_exists( '\ZipArchive' ) ) {
			throw new \RuntimeException( esc_html__( 'The PHP extension zip is missing.', 'wonderful-sync' ) );
		}

		$tmp = Storage::scratch() . Storage::new_id() . '/';
		wp_mkdir_p( $tmp );
		$zip = new \ZipArchive();
		if ( true !== $zip->open( $file, \ZipArchive::CREATE | \ZipArchive::OVERWRITE ) ) {
			throw new \RuntimeException( esc_html__( 'The package file could not be created.', 'wonderful-sync' ) );
		}

		$objects = array();
		$files   = array();
		$n       = 0;
		foreach ( $keys as $key ) {
			if ( ! isset( $changes[ $key ] ) ) {
				continue;
			}
			$change = $changes[ $key ];
			if ( 'deleted' === $change['status'] ) {
				$objects[] = array(
					'key'     => $key,
					'kind'    => $change['kind'],
					'class'   => $change['class'],
					'subtype' => '',
					'title'   => $change['title'],
					'op'      => 'delete',
					'base'    => $change['base'],
					'hash'    => '',
					'source'  => 0,
					'file'    => '',
				);
				continue;
			}
			$object = $exporter->export_key( $key );
			if ( ! $object ) {
				continue;
			}
			// Data goes to a temporary file that the ZIP reads on close: memory stays flat.
			$entry = sprintf( 'objects/%06d.json', ++$n );
			// phpcs:ignore WordPress.WP.AlternativeFunctions.file_system_operations_file_put_contents -- temporary bundle part.
			file_put_contents( $tmp . basename( $entry ), (string) wp_json_encode( $object['data'], JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE ) );
			$zip->addFile( $tmp . basename( $entry ), $entry );

			$objects[] = array(
				'key'     => $key,
				'kind'    => $object['kind'],
				'class'   => $object['class'],
				'subtype' => Exporter::subtype_of( $object ),
				'title'   => $exporter->title_of( $object ),
				'op'      => 'upsert',
				'base'    => $change['base'],
				'hash'    => Normalizer::hash( $object['data'] ),
				'source'  => $object['id'],
				'file'    => $entry,
			);
			foreach ( (array) ( $object['data']['files']['all'] ?? array() ) as $rel ) {
				$files[] = $rel;
			}
			unset( $object );
		}

		$source           = self::site_info();
		$baseline         = Changeset::meta();
		$source['origin'] = (string) ( $baseline['origin'] ?? '' );
		// When the staging copy was cloned: edits on the target before that are no conflict reason.
		$source['baseline'] = (int) ( $baseline['created'] ?? 0 );
		// Live → staging: the live site says where the package goes back to.
		$source = array_merge( $source, $source_extra );
		$manifest         = array(
			'format'  => self::FORMAT,
			'created' => time(),
			'source'  => $source,
			'objects' => $objects,
		);

		$zip->addFromString( 'manifest.json', (string) wp_json_encode( $manifest, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE ) );
		$uploads = wp_upload_dir( null, false );
		$base    = trailingslashit( $uploads['basedir'] );
		foreach ( array_unique( $files ) as $rel ) {
			if ( is_file( $base . $rel ) ) {
				$zip->addFile( $base . $rel, 'files/' . $rel );
			}
		}
		$ok = $zip->close();
		foreach ( (array) glob( $tmp . '*.json' ) as $part ) {
			wp_delete_file( $part );
		}
		rmdir( $tmp ); // phpcs:ignore WordPress.WP.AlternativeFunctions.file_system_operations_rmdir -- own temporary directory.
		if ( ! $ok ) {
			throw new \RuntimeException( esc_html__( 'The package file could not be written.', 'wonderful-sync' ) );
		}

		return $manifest;
	}

	/**
	 * Reads and checks the manifest of a bundle (without object data).
	 *
	 * @param string $file ZIP path.
	 * @return array
	 */
	public static function read_manifest( string $file ): array {
		$zip = new \ZipArchive();
		if ( true !== $zip->open( $file ) ) {
			throw new \RuntimeException( esc_html__( 'The package could not be opened.', 'wonderful-sync' ) );
		}
		$limits = self::limits();
		$total  = 0;
		$count  = $zip->count();
		$names  = array();
		if ( $count > $limits['entries'] ) {
			$zip->close();
			throw new \RuntimeException( esc_html__( 'The package contains more files than this site accepts.', 'wonderful-sync' ) );
		}
		for ( $i = 0; $i < $count; $i++ ) {
			$stat = $zip->statIndex( $i );
			$name = (string) ( $stat['name'] ?? '' );
			// Every entry must be unique and below manifest.json, objects/ or files/, without traversal.
			if ( isset( $names[ $name ] ) || false !== strpos( $name, '..' ) || ( 'manifest.json' !== $name && 0 !== strpos( $name, 'objects/' ) && 0 !== strpos( $name, 'files/' ) ) ) {
				$zip->close();
				throw new \RuntimeException( esc_html__( 'The package contains unexpected files and is rejected.', 'wonderful-sync' ) );
			}
			$names[ $name ] = true;
			$total         += (int) ( $stat['size'] ?? 0 );
		}
		$stat = $zip->statName( 'manifest.json' );
		if ( $total > $limits['total_bytes'] || ! $stat || (int) $stat['size'] > $limits['manifest_bytes'] ) {
			$zip->close();
			throw new \RuntimeException( esc_html__( 'The package is larger than this site accepts.', 'wonderful-sync' ) );
		}
		$raw = $zip->getFromName( 'manifest.json' );
		$zip->close();

		$manifest = is_string( $raw ) ? json_decode( $raw, true ) : null;
		if ( ! is_array( $manifest ) || self::FORMAT !== (int) ( $manifest['format'] ?? 0 ) || ! is_array( $manifest['objects'] ?? null ) ) {
			throw new \RuntimeException( esc_html__( 'The package has an unknown format. Update Wonderful Sync on both sites.', 'wonderful-sync' ) );
		}
		if ( count( $manifest['objects'] ) > $limits['objects'] ) {
			throw new \RuntimeException( esc_html__( 'The package contains more objects than this site accepts.', 'wonderful-sync' ) );
		}
		$seen = array();
		foreach ( $manifest['objects'] as $object ) {
			if ( ! is_array( $object ) || ! isset( $object['key'], $object['kind'], $object['op'] ) || ! is_string( $object['key'] ) ) {
				throw new \RuntimeException( esc_html__( 'The package contains a malformed object.', 'wonderful-sync' ) );
			}
			$entry = (string) ( $object['file'] ?? '' );
			if ( '' !== $entry && ! preg_match( '#^objects/\d{6}\.json$#', $entry ) ) {
				throw new \RuntimeException( esc_html__( 'The package contains a malformed object.', 'wonderful-sync' ) );
			}
			if ( isset( $seen[ $object['key'] ] ) ) {
				/* translators: %s: object key. */
				throw new \RuntimeException( esc_html( sprintf( __( 'The package contains %s twice and is rejected.', 'wonderful-sync' ), $object['key'] ) ) );
			}
			$seen[ $object['key'] ] = true;
		}

		return $manifest;
	}

	/**
	 * Reads the data of one object, or null (deletions, missing or oversized entry).
	 *
	 * @param string $file   ZIP path.
	 * @param array  $object Manifest object.
	 * @return array|null
	 */
	public static function object_data( string $file, array $object ): ?array {
		$entry = (string) ( $object['file'] ?? '' );
		if ( '' === $entry || ! preg_match( '#^objects/\d{6}\.json$#', $entry ) ) {
			return null;
		}
		$zip = self::reader( $file );
		if ( ! $zip ) {
			return null;
		}
		$stat = $zip->statName( $entry );
		$raw  = ( $stat && (int) $stat['size'] <= self::limits()['object_bytes'] ) ? $zip->getFromName( $entry ) : false;
		$data = is_string( $raw ) ? json_decode( $raw, true ) : null;

		return is_array( $data ) ? $data : null;
	}

	/**
	 * Open ZIP readers, one per bundle file, kept for the request.
	 *
	 * @var array<string, \ZipArchive>
	 */
	private static $readers = array();

	/**
	 * A ZIP reader for a bundle, opened once per request.
	 *
	 * @param string $file ZIP path.
	 */
	private static function reader( string $file ): ?\ZipArchive {
		if ( ! isset( self::$readers[ $file ] ) ) {
			$zip = new \ZipArchive();
			if ( true !== $zip->open( $file, \ZipArchive::RDONLY ) ) {
				return null;
			}
			self::$readers[ $file ] = $zip;
		}

		return self::$readers[ $file ];
	}

	/**
	 * Closes the reader of a bundle (before it is deleted).
	 *
	 * @param string $file ZIP path.
	 */
	public static function close( string $file ): void {
		if ( isset( self::$readers[ $file ] ) ) {
			self::$readers[ $file ]->close();
			unset( self::$readers[ $file ] );
		}
	}

	/**
	 * Extracts one media file of the bundle to a target path.
	 *
	 * @param string $file   ZIP path.
	 * @param string $rel    Upload path inside the bundle.
	 * @param string $target Absolute target path.
	 */
	public static function extract_file( string $file, string $rel, string $target ): bool {
		if ( false !== strpos( $rel, '..' ) ) {
			return false;
		}
		$zip = self::reader( $file );
		if ( ! $zip ) {
			return false;
		}
		$stream = $zip->getStream( 'files/' . $rel );
		if ( ! $stream ) {
			return false;
		}
		wp_mkdir_p( dirname( $target ) );
		$out = fopen( $target, 'wb' ); // phpcs:ignore WordPress.WP.AlternativeFunctions.file_system_operations_fopen -- streaming copy of a media file.
		$ok  = $out && false !== stream_copy_to_stream( $stream, $out );
		fclose( $stream ); // phpcs:ignore WordPress.WP.AlternativeFunctions.file_system_operations_fclose
		if ( $out ) {
			fclose( $out ); // phpcs:ignore WordPress.WP.AlternativeFunctions.file_system_operations_fclose
		}

		return $ok;
	}

	/**
	 * Information about this site sent with every bundle and returned by /info.
	 *
	 * @return array
	 */
	public static function site_info(): array {
		if ( ! function_exists( 'get_plugins' ) ) {
			require_once ABSPATH . 'wp-admin/includes/plugin.php';
		}
		$code = array();
		foreach ( get_plugins() as $file => $data ) {
			$code[] = array(
				'type'    => 'plugin',
				'slug'    => dirname( $file ) === '.' ? basename( $file, '.php' ) : dirname( $file ),
				'name'    => $data['Name'],
				'version' => $data['Version'],
				'active'  => is_plugin_active( $file ),
			);
		}
		foreach ( wp_get_themes() as $slug => $theme ) {
			$code[] = array(
				'type'    => 'theme',
				'slug'    => (string) $slug,
				'name'    => $theme->get( 'Name' ),
				'version' => $theme->get( 'Version' ),
				'active'  => get_stylesheet() === $slug || get_template() === $slug,
			);
		}
		$divi = wp_get_theme( 'Divi' );

		return array(
			'home'    => home_url(),
			'siteurl' => site_url(),
			'wp'      => get_bloginfo( 'version' ),
			'divi'    => $divi->exists() ? (string) $divi->get( 'Version' ) : '',
			'plugin'  => WONDERFUL_SYNC_VERSION,
			'hashes'  => Normalizer::VERSION,
			'code'    => $code,
		);
	}
}