<?php
declare(strict_types=1);

namespace Esun\OrderNumber\Model;

use Magento\Framework\App\ResourceConnection;
use Magento\Framework\DB\Sequence\SequenceInterface;

class WebsiteSequence implements SequenceInterface
{
    private const TABLE_NAME = 'esun_order_number_sequence';

    private ?int $lastValue = null;

    public function __construct(
        private readonly ResourceConnection $resource,
        private readonly Config $config,
        private readonly int $websiteId
    ) {
    }

    public function getCurrentValue(): ?string
    {
        if ($this->lastValue === null) {
            return null;
        }

        return $this->config->getSiteName($this->websiteId) . $this->lastValue;
    }

    public function getNextValue(): string
    {
        $connection = $this->resource->getConnection('sales');
        $table = $this->resource->getTableName(self::TABLE_NAME, 'sales');
        $initialLastValue = $this->config->getStartNumber($this->websiteId) - 1;

        $connection->beginTransaction();
        try {
            // The no-op duplicate update safely creates one counter per Website under concurrency.
            $connection->insertOnDuplicate(
                $table,
                ['website_id' => $this->websiteId, 'last_value' => $initialLastValue],
                ['website_id']
            );
            $lastValue = (int)$connection->fetchOne(
                $connection->select()
                    ->from($table, ['last_value'])
                    ->where('website_id = ?', $this->websiteId)
                    ->forUpdate(true)
            );
            $this->lastValue = $lastValue + 1;
            $connection->update(
                $table,
                ['last_value' => $this->lastValue],
                ['website_id = ?' => $this->websiteId]
            );
            $connection->commit();
        } catch (\Throwable $exception) {
            $connection->rollBack();
            throw $exception;
        }

        return (string)$this->getCurrentValue();
    }
}