esun3d/app/code/Esun/CustomerVat/Setup/Patch/Data/ConfigureTaxRules.php

<?php
declare(strict_types=1);

namespace Esun\CustomerVat\Setup\Patch\Data;

use Esun\CustomerVat\Model\EuCountries;
use Magento\Framework\Setup\ModuleDataSetupInterface;
use Magento\Framework\Setup\Patch\DataPatchInterface;

class ConfigureTaxRules implements DataPatchInterface
{
    public const EXEMPT_TAX_CLASS = 'eSUN EU VAT Exempt Customer';

    public function __construct(private readonly ModuleDataSetupInterface $moduleDataSetup)
    {
    }

    public function apply(): self
    {
        $setup = $this->moduleDataSetup;
        $connection = $setup->getConnection();
        $setup->startSetup();

        $taxClassTable = $setup->getTable('tax_class');
        $rateTable = $setup->getTable('tax_calculation_rate');
        $ruleTable = $setup->getTable('tax_calculation_rule');
        $calculationTable = $setup->getTable('tax_calculation');

        $this->ensureTaxClass($taxClassTable, self::EXEMPT_TAX_CLASS, 'CUSTOMER');
        $customerClassIds = array_map('intval', $connection->fetchCol(
            $connection->select()->from($taxClassTable, 'class_id')->where('class_type = ?', 'CUSTOMER')
        ));
        $productClassIds = array_map('intval', $connection->fetchCol(
            $connection->select()->from($taxClassTable, 'class_id')->where('class_type = ?', 'PRODUCT')
        ));

        $euStandardRule = $this->ensureRule(
            $ruleTable,
            'eSUN EU Calculated VAT',
            ['eSUN EU Standard VAT 19']
        );
        $ukRule = $this->ensureRule($ruleTable, 'eSUN UK VAT 20');
        $legacyRuleIds = array_map('intval', $connection->fetchCol(
            $connection->select()->from($ruleTable, 'tax_calculation_rule_id')
                ->where('code IN (?)', ['eSUN EU VAT Exempt 0'])
        ));
        $connection->delete(
            $calculationTable,
            ['tax_calculation_rule_id IN (?)' => array_merge([$euStandardRule, $ukRule], $legacyRuleIds)]
        );

        foreach (EuCountries::CODES as $countryId) {
            $nominalRate = EuCountries::RATES[$countryId] ?? 19.0;
            $standardRateId = $this->ensureRate(
                $rateTable,
                sprintf('ESUN-EU-%s-NOMINAL-%s', $countryId, (int)$nominalRate),
                $countryId,
                EuCountries::toAppliedRate($nominalRate)
            );
            $this->link($calculationTable, $standardRateId, $euStandardRule, $customerClassIds, $productClassIds);
        }
        $ukRateId = $this->ensureRate(
            $rateTable,
            'ESUN-GB-NOMINAL-20',
            'GB',
            EuCountries::toAppliedRate(20.0)
        );
        $this->link($calculationTable, $ukRateId, $ukRule, $customerClassIds, $productClassIds);

        // The database initially contains Magento sample US state tax data. These markets must be tax-free.
        $noTaxRateIds = $connection->fetchCol(
            $connection->select()->from($rateTable, 'tax_calculation_rate_id')->where('tax_country_id IN (?)', ['US', 'CA', 'AU'])
        );
        if ($noTaxRateIds) {
            $connection->delete($calculationTable, ['tax_calculation_rate_id IN (?)' => $noTaxRateIds]);
        }

        $this->configureWebsites();
        $setup->endSetup();
        return $this;
    }

    private function ensureTaxClass(string $table, string $name, string $type): int
    {
        $connection = $this->moduleDataSetup->getConnection();
        $id = $connection->fetchOne($connection->select()->from($table, 'class_id')
            ->where('class_name = ?', $name)->where('class_type = ?', $type));
        if ($id) {
            return (int)$id;
        }
        $connection->insert($table, ['class_name' => $name, 'class_type' => $type]);
        return (int)$connection->lastInsertId($table);
    }

    private function ensureRate(string $table, string $code, string $countryId, float $rate): int
    {
        $connection = $this->moduleDataSetup->getConnection();
        $id = $connection->fetchOne($connection->select()->from($table, 'tax_calculation_rate_id')->where('code = ?', $code));
        $data = ['tax_country_id' => $countryId, 'tax_region_id' => 0, 'tax_postcode' => '*', 'code' => $code,
            'rate' => $rate, 'zip_is_range' => null, 'zip_from' => null, 'zip_to' => null];
        if ($id) {
            $connection->update($table, $data, ['tax_calculation_rate_id = ?' => (int)$id]);
            return (int)$id;
        }
        $connection->insert($table, $data);
        return (int)$connection->lastInsertId($table);
    }

    private function ensureRule(string $table, string $code, array $legacyCodes = []): int
    {
        $connection = $this->moduleDataSetup->getConnection();
        $id = $connection->fetchOne(
            $connection->select()->from($table, 'tax_calculation_rule_id')
                ->where('code IN (?)', array_merge([$code], $legacyCodes))
                ->order('tax_calculation_rule_id ASC')
        );
        if ($id) {
            $connection->update($table, ['code' => $code], ['tax_calculation_rule_id = ?' => (int)$id]);
            return (int)$id;
        }
        $connection->insert($table, ['code' => $code, 'priority' => 0, 'position' => 0, 'calculate_subtotal' => 0]);
        return (int)$connection->lastInsertId($table);
    }

    private function link(string $table, int $rateId, int $ruleId, array $customerClassIds, array $productClassIds): void
    {
        $rows = [];
        foreach ($customerClassIds as $customerClassId) {
            foreach ($productClassIds as $productClassId) {
                $rows[] = ['tax_calculation_rate_id' => $rateId, 'tax_calculation_rule_id' => $ruleId,
                    'customer_tax_class_id' => $customerClassId, 'product_tax_class_id' => $productClassId];
            }
        }
        if ($rows) {
            $this->moduleDataSetup->getConnection()->insertMultiple($table, $rows);
        }
    }

    private function configureWebsites(): void
    {
        $connection = $this->moduleDataSetup->getConnection();
        $websiteTable = $this->moduleDataSetup->getTable('store_website');
        $configTable = $this->moduleDataSetup->getTable('core_config_data');
        $countries = [
            'eu' => 'DE',
            'eu_site' => 'DE',
            'uk' => 'GB',
            'gb_site' => 'GB',
            'us_site' => 'US',
            'au' => 'AU',
            'au_site' => 'AU',
        ];
        foreach ($countries as $websiteCode => $countryId) {
            $websiteId = (int)$connection->fetchOne(
                $connection->select()->from($websiteTable, 'website_id')->where('code = ?', $websiteCode)
            );
            if (!$websiteId) {
                continue;
            }
            $values = [
                'tax/calculation/price_includes_tax' => '0',
                'tax/calculation/shipping_includes_tax' => '0',
                'tax/calculation/based_on' => 'shipping',
                'tax/calculation/cross_border_trade_enabled' => '1',
                'tax/calculation/apply_after_discount' => '1',
                'tax/defaults/country' => $countryId,
                'tax/display/type' => '1',
                'tax/cart_display/price' => '1',
                'tax/cart_display/subtotal' => '1',
                'tax/cart_display/shipping' => '1',
                'tax/sales_display/price' => '1',
                'tax/sales_display/subtotal' => '1',
                'tax/sales_display/shipping' => '1',
            ];
            foreach ($values as $path => $value) {
                $connection->insertOnDuplicate($configTable,
                    ['scope' => 'websites', 'scope_id' => $websiteId, 'path' => $path, 'value' => $value], ['value']);
            }
        }
    }

    public static function getDependencies(): array { return []; }
    public function getAliases(): array { return []; }
}