<?php
/**
 * Activation, deactivation and schema migration.
 *
 * @package R2Clouder
 */

namespace R2Clouder;

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

/**
 * Owns everything that has to happen once, rather than on every request.
 */
final class Installer {

	/**
	 * Schema version, bumped whenever the jobs table changes.
	 */
	const DB_VERSION = 1;

	/**
	 * Cron hook that drives the queue worker.
	 */
	const CRON_HOOK = 'r2clouder_run_queue';

	/**
	 * Name of the custom cron interval registered by the plugin.
	 */
	const CRON_SCHEDULE = 'r2clouder_minute';

	/**
	 * Runs on plugin activation.
	 *
	 * @param bool $network_wide True when activated across a multisite network.
	 * @return void
	 */
	public static function activate( $network_wide = false ): void {
		if ( $network_wide && is_multisite() ) {
			foreach ( self::site_ids() as $site_id ) {
				switch_to_blog( $site_id );
				self::activate_single_site();
				restore_current_blog();
			}

			return;
		}

		self::activate_single_site();
	}

	/**
	 * Runs on plugin deactivation.
	 *
	 * Touches no data - it only stops scheduled work.
	 *
	 * @param bool $network_wide True when deactivated across a multisite network.
	 * @return void
	 */
	public static function deactivate( $network_wide = false ): void {
		if ( $network_wide && is_multisite() ) {
			foreach ( self::site_ids() as $site_id ) {
				switch_to_blog( $site_id );
				self::unschedule();
				restore_current_blog();
			}

			return;
		}

		self::unschedule();
	}

	/**
	 * Brings a single site up to date.
	 *
	 * @return void
	 */
	private static function activate_single_site(): void {
		self::create_tables();
		self::schedule();
		update_option( Options::VERSION, R2CLOUDER_VERSION, false );
	}

	/**
	 * Re-runs migrations when the plugin files are updated without reactivation.
	 *
	 * @return void
	 */
	public static function maybe_upgrade(): void {
		$installed = get_option( Options::VERSION, '' );

		if ( R2CLOUDER_VERSION === $installed ) {
			return;
		}

		self::create_tables();
		self::schedule();
		update_option( Options::VERSION, R2CLOUDER_VERSION, false );
	}

	/**
	 * Fully qualified name of the jobs table for the current site.
	 *
	 * @return string
	 */
	public static function jobs_table(): string {
		global $wpdb;

		return $wpdb->prefix . 'r2clouder_jobs';
	}

	/**
	 * Creates or updates the jobs table.
	 *
	 * The schema deliberately avoids FULLTEXT indexes and any MySQL-only
	 * construct, so it works on the SQLite backend as well.
	 *
	 * @return void
	 */
	public static function create_tables(): void {
		global $wpdb;

		require_once ABSPATH . 'wp-admin/includes/upgrade.php';

		$table   = self::jobs_table();
		$collate = $wpdb->get_charset_collate();

		$sql = "CREATE TABLE {$table} (
			id bigint(20) unsigned NOT NULL AUTO_INCREMENT,
			attachment_id bigint(20) unsigned NOT NULL DEFAULT 0,
			job_type varchar(32) NOT NULL DEFAULT '',
			status varchar(16) NOT NULL DEFAULT 'pending',
			priority smallint(6) NOT NULL DEFAULT 10,
			attempts smallint(6) NOT NULL DEFAULT 0,
			available_at datetime NOT NULL DEFAULT '0000-00-00 00:00:00',
			claimed_at datetime DEFAULT NULL,
			finished_at datetime DEFAULT NULL,
			last_error text NULL,
			payload longtext NULL,
			created_at datetime NOT NULL DEFAULT '0000-00-00 00:00:00',
			PRIMARY KEY  (id),
			KEY status_available (status, available_at),
			KEY attachment (attachment_id, job_type)
		) {$collate};";

		dbDelta( $sql );

		update_option( 'r2clouder_db_version', self::DB_VERSION, false );
	}

	/**
	 * Registers the queue cron event when it is not already scheduled.
	 *
	 * @return void
	 */
	public static function schedule(): void {
		if ( ! wp_next_scheduled( self::CRON_HOOK ) ) {
			wp_schedule_event( time() + MINUTE_IN_SECONDS, self::CRON_SCHEDULE, self::CRON_HOOK );
		}
	}

	/**
	 * Removes the queue cron event.
	 *
	 * @return void
	 */
	public static function unschedule(): void {
		wp_clear_scheduled_hook( self::CRON_HOOK );
	}

	/**
	 * Returns every site id on the network, capped to keep activation bounded.
	 *
	 * @return int[]
	 */
	private static function site_ids(): array {
		if ( ! is_multisite() ) {
			return array( get_current_blog_id() );
		}

		return get_sites(
			array(
				'fields'                 => 'ids',
				'number'                 => 0,
				'update_site_meta_cache' => false,
			)
		);
	}
}