<?php

declare(strict_types=1);

namespace TFGraphics\SmartImport\Domain;

final class IdentifierMetadata
{
    public function resolve(string $identifierType, string $normalizedValue): array
    {
        $countryPrefix = null;
        $gs1Prefix = null;
        $notes = [];
        $expectedDomains = $this->getExpectedDomains($identifierType, $normalizedValue);

        if ($this->usesGs1Prefix($identifierType) && preg_match('/^\d{3}/', $normalizedValue, $matches) === 1) {
            $gs1Prefix = $matches[0];
            [$countryPrefix, $prefixNote] = $this->resolveGs1Prefix((int) $gs1Prefix);
            if ($prefixNote !== null) {
                $notes[] = $prefixNote;
            }
        }

        if ($identifierType === DomainIdentifier::ISBN13 && str_starts_with($normalizedValue, '978')) {
            $countryPrefix = $this->resolveIsbnRegistrationGroup($normalizedValue);
            $notes[] = '978 is the GS1 Bookland prefix.';
        }

        if ($identifierType === DomainIdentifier::ISBN13 && str_starts_with($normalizedValue, '979')) {
            $notes[] = '979 is a GS1 Bookland prefix also used by music publications.';
        }

        return [
            'country_prefix' => $countryPrefix,
            'gs1_prefix' => $gs1Prefix,
            'expected_domains' => $expectedDomains,
            'notes' => $notes,
        ];
    }

    private function getExpectedDomains(string $identifierType, string $value): array
    {
        if ($identifierType === DomainIdentifier::ISBN13 && str_starts_with($value, '979')) {
            return [DomainRegistry::BOOKS, DomainRegistry::MUSIC];
        }

        $map = [
            DomainIdentifier::ISBN10 => [DomainRegistry::BOOKS],
            DomainIdentifier::ISBN13 => [DomainRegistry::BOOKS],
            DomainIdentifier::ISSN => [DomainRegistry::BOOKS],
            DomainIdentifier::ISMN => [DomainRegistry::MUSIC],
            DomainIdentifier::ASIN => [DomainRegistry::GENERIC_PRODUCTS],
            DomainIdentifier::AIC6 => [DomainRegistry::MEDICAL],
            DomainIdentifier::AIC9 => [DomainRegistry::MEDICAL],
            DomainIdentifier::AIC => [DomainRegistry::MEDICAL],
            DomainIdentifier::ATC => [DomainRegistry::MEDICAL],
        ];

        return $map[$identifierType] ?? [DomainRegistry::GENERIC_PRODUCTS];
    }

    private function usesGs1Prefix(string $identifierType): bool
    {
        return in_array($identifierType, [
            DomainIdentifier::ISBN13,
            DomainIdentifier::EAN13,
            DomainIdentifier::UPC_A,
            DomainIdentifier::GTIN,
            DomainIdentifier::ISMN,
            DomainIdentifier::JAN,
        ], true);
    }

    private function resolveGs1Prefix(int $prefix): array
    {
        if ($prefix >= 0 && $prefix <= 19) {
            return ['United States / Canada', 'GS1 prefix assigned to United States / Canada.'];
        }
        if ($prefix >= 400 && $prefix <= 440) {
            return ['Germany', 'GS1 prefix assigned to Germany.'];
        }
        if ($prefix >= 450 && $prefix <= 459 || $prefix >= 490 && $prefix <= 499) {
            return ['Japan', 'GS1 prefix assigned to Japan.'];
        }
        if ($prefix >= 500 && $prefix <= 509) {
            return ['United Kingdom', 'GS1 prefix assigned to the United Kingdom.'];
        }
        if ($prefix >= 800 && $prefix <= 839) {
            return ['Italy', 'GS1 prefix assigned to Italy.'];
        }
        if ($prefix === 978 || $prefix === 979) {
            return ['Bookland', 'GS1 prefix assigned to Bookland.'];
        }

        return [null, 'Unknown prefix.'];
    }

    private function resolveIsbnRegistrationGroup(string $value): string
    {
        $group = substr($value, 3, 2);
        if ($group === '88') {
            return 'Italy';
        }
        if ($value[3] === '3') {
            return 'Germany';
        }
        if (in_array($value[3], ['0', '1'], true)) {
            return 'English language area';
        }

        return 'Bookland';
    }
}