<?php

namespace App\Services;

use App\Models\Setting;
use Illuminate\Support\Facades\Schema;
use InvalidArgumentException;

class DhlProductResolver
{
    public const DOMESTIC_COUNTRY = 'DE';

    public const DOMESTIC_PRODUCT_CODES = ['V01PAK', 'V62KP'];

    public const INTERNATIONAL_PRODUCT_CODE = 'V53PAK';

    public const DEFAULT_INTERNATIONAL_COUNTRIES = ['AT', 'ES', 'CH', 'NL', 'BE', 'FR'];

    public const DHL_COUNTRY_CODES = [
        'DE' => 'DEU',
        'AT' => 'AUT',
        'ES' => 'ESP',
        'CH' => 'CHE',
        'US' => 'USA',
        'GB' => 'GBR',
        'FR' => 'FRA',
        'IT' => 'ITA',
        'NL' => 'NLD',
        'BE' => 'BEL',
        'PL' => 'POL',
        'CZ' => 'CZE',
        'DK' => 'DNK',
        'SE' => 'SWE',
        'NO' => 'NOR',
    ];

    /**
     * @return array{country_code: string, dhl_country_code: string, product_code: string}
     */
    public function resolveForShipment(string $destinationCountryCode, ?string $requestedProductCode = null, ?string $defaultProductCode = null): array
    {
        $countryCode = $this->normalizeCountryCode($destinationCountryCode);
        $productCode = $this->resolveProductCode($countryCode, $requestedProductCode, $defaultProductCode);

        return [
            'country_code' => $countryCode,
            'dhl_country_code' => $this->toDhlCountryCode($countryCode),
            'product_code' => $productCode,
        ];
    }

    public function resolveProductCode(string $destinationCountryCode, ?string $requestedProductCode = null, ?string $defaultProductCode = null): string
    {
        $countryCode = $this->normalizeCountryCode($destinationCountryCode);
        $hasRequestedProduct = $requestedProductCode !== null && trim($requestedProductCode) !== '';
        $productCode = $this->normalizeProductCode($requestedProductCode ?: $defaultProductCode);

        if ($countryCode === self::DOMESTIC_COUNTRY) {
            $productCode = $productCode ?: 'V01PAK';

            if (! in_array($productCode, self::DOMESTIC_PRODUCT_CODES, true)) {
                throw new InvalidArgumentException("Produkt {$productCode} ist fuer DHL-Versand nach Deutschland nicht erlaubt.");
            }

            return $productCode;
        }

        if (! in_array($countryCode, $this->getSupportedInternationalCountries(), true)) {
            throw new InvalidArgumentException("DHL-Versand in das Zielland {$countryCode} ist aktuell nicht freigegeben.");
        }

        if (! $productCode || (! $hasRequestedProduct && in_array($productCode, self::DOMESTIC_PRODUCT_CODES, true))) {
            return self::INTERNATIONAL_PRODUCT_CODE;
        }

        if ($productCode !== self::INTERNATIONAL_PRODUCT_CODE) {
            throw new InvalidArgumentException("Produkt {$productCode} ist fuer DHL-Versand in das Zielland {$countryCode} nicht erlaubt.");
        }

        return $productCode;
    }

    /**
     * @return array<string, string>
     */
    public function getProductSuggestionsByCountry(): array
    {
        return array_fill_keys($this->getSupportedInternationalCountries(), self::INTERNATIONAL_PRODUCT_CODE)
            + [self::DOMESTIC_COUNTRY => 'V01PAK'];
    }

    /**
     * @return string[]
     */
    public function getAllowedProductCodesForCountry(string $destinationCountryCode): array
    {
        $countryCode = $this->normalizeCountryCode($destinationCountryCode);

        if ($countryCode === self::DOMESTIC_COUNTRY) {
            return self::DOMESTIC_PRODUCT_CODES;
        }

        if (in_array($countryCode, $this->getSupportedInternationalCountries(), true)) {
            return [self::INTERNATIONAL_PRODUCT_CODE];
        }

        return [];
    }

    public function toDhlCountryCode(string $countryCode): string
    {
        $countryCode = $this->normalizeCountryCode($countryCode);

        return self::DHL_COUNTRY_CODES[$countryCode];
    }

    public function assertBillingNumber(string $productCode, ?string $billingNumber): string
    {
        if ($billingNumber === null || trim($billingNumber) === '') {
            throw new InvalidArgumentException("Keine DHL-Abrechnungsnummer fuer Produkt {$productCode} konfiguriert.");
        }

        return $billingNumber;
    }

    public function getProductScope(string $productCode): string
    {
        $productCode = $this->normalizeProductCode($productCode);

        return $productCode === self::INTERNATIONAL_PRODUCT_CODE ? 'international' : 'national';
    }

    public function getProductScopeLabel(string $productCode): string
    {
        return $this->getProductScope($productCode) === 'international'
            ? 'DHL Paket International'
            : 'DHL Paket National';
    }

    public function normalizeCountryCode(string $countryCode): string
    {
        $countryCode = strtoupper(trim($countryCode));

        if ($countryCode === '') {
            throw new InvalidArgumentException('DHL-Zielland fehlt.');
        }

        if (strlen($countryCode) === 3) {
            $countryCode = array_search($countryCode, self::DHL_COUNTRY_CODES, true) ?: $countryCode;
        }

        if (! array_key_exists($countryCode, self::DHL_COUNTRY_CODES)) {
            throw new InvalidArgumentException("DHL-Laendercode {$countryCode} wird nicht unterstuetzt.");
        }

        return $countryCode;
    }

    public function normalizeProductCode(?string $productCode): ?string
    {
        if ($productCode === null || trim($productCode) === '') {
            return null;
        }

        return strtoupper(trim($productCode));
    }

    /**
     * @return string[]
     */
    public function getSupportedInternationalCountries(): array
    {
        $useEnvPriority = config('dhl.config_source') === 'env';
        $configCountries = config('dhl.international_countries', self::DEFAULT_INTERNATIONAL_COUNTRIES);
        $countries = $configCountries;
        $storedCountries = Schema::hasTable('settings')
            ? Setting::getContentBySlug('dhl_international_countries')
            : false;

        if (is_array($storedCountries)) {
            $countries = $storedCountries;
        } elseif (! $useEnvPriority) {
            $countries = $storedCountries ?: $configCountries;
        }

        return self::normalizeCountryCodeList(is_array($countries) ? $countries : []);
    }

    /**
     * @return string[]
     */
    public static function normalizeCountryCodeList(array $countryCodes): array
    {
        $countryCodes = array_map(
            static fn ($countryCode): string => strtoupper(trim((string) $countryCode)),
            $countryCodes
        );

        return array_values(array_filter(array_unique($countryCodes), static function (string $countryCode): bool {
            return $countryCode !== ''
                && $countryCode !== self::DOMESTIC_COUNTRY
                && array_key_exists($countryCode, self::DHL_COUNTRY_CODES);
        }));
    }
}