<?php
/**
 * brverify-v1 manifest builder.
 *
 * @package BRVerify
 */

declare(strict_types=1);

namespace BRVerify\Backup;

/**
 * Manifest — builds and encodes manifest.json.
 */
final class Manifest {

	public const FORMAT = 'brverify-v1';

	/** Format ids written by pre-release builds; still accepted when reading/restoring. */
	public const LEGACY_FORMATS = array( 'restoreproof-v1' );

	/**
	 * Whether a manifest format id is one this plugin can read.
	 *
	 * @param string $format Format id.
	 */
	public static function is_supported_format( string $format ): bool {
		return self::FORMAT === $format || in_array( $format, self::LEGACY_FORMATS, true );
	}

	/**
	 * Build manifest array.
	 *
	 * @param array<string,mixed> $args Arguments.
	 * @return array<string,mixed>
	 */
	public static function build( array $args ): array {
		global $wpdb;

		$components = isset( $args['components'] ) && is_array( $args['components'] )
			? $args['components']
			: array(
				'database' => true,
				'plugins'  => true,
				'themes'   => true,
				'uploads'  => true,
			);

		$exclusions = isset( $args['exclusions'] ) && is_array( $args['exclusions'] )
			? array_values( $args['exclusions'] )
			: array();

		$payload_hash = isset( $args['payload_hash'] ) ? (string) $args['payload_hash'] : '';

		$created = wp_date( 'c' );
		if ( ! is_string( $created ) || '' === $created ) {
			$created = gmdate( 'c' );
		}

		$manifest = array(
			'format'         => self::FORMAT,
			'created_at'     => $created,
			'plugin_version' => defined( 'BRVERIFY_VERSION' ) ? BRVERIFY_VERSION : '',
			'wp_version'     => get_bloginfo( 'version' ),
			'php_version'    => PHP_VERSION,
			'siteurl'        => site_url( '/' ),
			'home'           => home_url( '/' ),
			'table_prefix'   => $wpdb->prefix,
			'source'         => self::source_info(),
			'blog_charset'   => get_bloginfo( 'charset' ),
			'locale'         => get_locale(),
			'components'     => array(
				'database' => ! empty( $components['database'] ),
				'plugins'  => ! empty( $components['plugins'] ),
				'themes'   => ! empty( $components['themes'] ),
				'uploads'  => ! empty( $components['uploads'] ),
			),
			'exclusions'     => $exclusions,
			'encryption'     => ( isset( $args['encryption'] ) && is_array( $args['encryption'] ) ) ? $args['encryption'] : null, // Non-secret descriptor only (supplied by an add-on).
			'integrity'      => array(
				'algo'                          => 'sha256',
				'manifest_hash_of_payload_list' => $payload_hash,
			),
			'parts'          => array(),
			'generator'      => 'brverify',
			// Free always full; extended edition may attach chain metadata via filter.
			'chain'          => array(
				'mode'             => 'full',
				'backup_id'        => isset( $args['backup_id'] ) ? (string) $args['backup_id'] : '',
				'parent_backup_id' => null,
				'base_full_id'     => isset( $args['backup_id'] ) ? (string) $args['backup_id'] : '',
				'sequence'         => 0,
				'db_policy'        => 'full_every_run',
			),
		);

		// Phase K: trigger metadata (additive; validators ignore unknown keys).
		$manifest['trigger'] = isset( $args['trigger'] ) && '' !== (string) $args['trigger'] ? (string) $args['trigger'] : 'manual';
		if ( 'pre_update' === $manifest['trigger'] && isset( $args['pre_update'] ) && is_array( $args['pre_update'] ) ) {
			$manifest['pre_update'] = $args['pre_update'];
		}

		/**
		 * Filter brverify-v1 manifest before encode.
		 *
		 * @param array<string,mixed> $manifest Manifest.
		 * @param array<string,mixed> $args     Build args.
		 */
		$filtered = apply_filters( 'brverify_manifest', $manifest, $args );
		return is_array( $filtered ) ? $filtered : $manifest;
	}

	/**
	 * Phase L: facts about the source site (informational, additive; validators ignore it).
	 *
	 * Lets a migration tool know the old URLs, filesystem paths and table prefix without
	 * guessing. Older backups simply lack this block.
	 *
	 * @return array<string,mixed>
	 */
	public static function source_info(): array {
		global $wpdb;

		$upload = function_exists( 'wp_upload_dir' ) ? wp_upload_dir( null, false ) : array();
		return array(
			'siteurl'         => site_url(),
			'home'            => home_url(),
			'abspath'         => rtrim( str_replace( '\\', '/', ABSPATH ), '/' ),
			'content_dir'     => rtrim( str_replace( '\\', '/', dirname( \BRVerify\Support\Working_Dir::plugins_root() ) ), '/' ),
			'content_url'     => content_url(),
			'plugin_dir'      => rtrim( str_replace( '\\', '/', \BRVerify\Support\Working_Dir::plugins_root() ), '/' ),
			'uploads_basedir' => isset( $upload['basedir'] ) ? rtrim( str_replace( '\\', '/', (string) $upload['basedir'] ), '/' ) : '',
			'uploads_baseurl' => isset( $upload['baseurl'] ) ? (string) $upload['baseurl'] : '',
			'table_prefix'    => $wpdb->prefix,
			'multisite'       => is_multisite(),
		);
	}

	/**
	 * Encode pretty JSON.
	 *
	 * @param array<string,mixed> $manifest Manifest.
	 */
	public static function encode( array $manifest ): string {
		$json = wp_json_encode( $manifest, JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES );
		return is_string( $json ) ? $json . "\n" : "{}\n";
	}
}