<?php
/**
 * Versioned schema migrations.
 *
 * @package Consentfold
 */

declare(strict_types=1);

namespace Consentfold\Install;

use RuntimeException;
use Consentfold\Settings\Repository;

/**
 * Brings a site up to {@see Schema::VERSION}: runs every migration newer than the site's stored
 * `schema_version`, recording each one as it completes. Migrations must be idempotent, because two
 * requests can race and a failed run is retried from the last recorded version.
 */
final class Upgrader {

	/**
	 * Settings repository holding the stored `schema_version`.
	 *
	 * @var Repository
	 */
	private Repository $settings;

	/**
	 * Constructor.
	 *
	 * @param Repository $settings Settings repository.
	 */
	public function __construct( Repository $settings ) {
		$this->settings = $settings;
	}

	/**
	 * Run the pending migrations of the current site.
	 *
	 * @throws RuntimeException When a migration fails; the version stays at the last completed one.
	 */
	public function run(): void {
		$current = $this->settings->schema_version();

		foreach ( self::migrations() as $version => $migration ) {
			if ( $version <= $current ) {
				continue;
			}

			$migration();
			$this->settings->set_schema_version( $version );
		}
	}

	/**
	 * Request-time entry point: upgrade after a plugin update and never break the request when that fails.
	 */
	public function maybe_run(): void {
		if ( $this->settings->schema_version() >= Schema::VERSION ) {
			return;
		}

		try {
			$this->run();
		} catch ( RuntimeException $e ) {
			wp_trigger_error( __METHOD__, $e->getMessage() );
		}
	}

	/**
	 * Migrations by the schema version they produce.
	 *
	 * @return array<int, callable(): mixed>
	 */
	private static function migrations(): array {
		return array(
			1 => array( Schema::class, 'install' ),
		);
	}
}