<?php
namespace Patchwork\Split;

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

/**
 * Creating child orders and changing the parent's status fires WooCommerce's
 * status-transition emails ("New order", "Processing", "Cancelled"…), which
 * would confuse customers and admins. While a split runs, every WooCommerce
 * email is switched off; the splitter sends its own customer note afterwards.
 */
class Email_Guard {

    private static $depth = 0;

    public static function suspend(): void {
        if ( self::$depth++ > 0 ) return;
        // Deferred emails are sent at shutdown, after resume() — so don't defer.
        add_filter( 'woocommerce_defer_transactional_emails', '__return_false', 999 );
        foreach ( self::email_ids() as $id ) {
            add_filter( 'woocommerce_email_enabled_' . $id, '__return_false', 999 );
        }
    }

    public static function resume(): void {
        if ( self::$depth === 0 || --self::$depth > 0 ) return;
        foreach ( self::email_ids() as $id ) {
            remove_filter( 'woocommerce_email_enabled_' . $id, '__return_false', 999 );
        }
        remove_filter( 'woocommerce_defer_transactional_emails', '__return_false', 999 );
    }

    private static function email_ids(): array {
        $ids = [];
        foreach ( WC()->mailer()->get_emails() as $email ) {
            if ( ! empty( $email->id ) ) $ids[] = $email->id;
        }
        return $ids;
    }
}