<?php

declare(strict_types=1);

namespace Aivie\WooCommerce\Support;

class ClientItemFieldMappingConfiguration
{
    /**
     * @return array<string, array{source_key: string, target: string, transform: string, enabled: bool}>
     */
    public static function requiredMappings(string $clientIdAlias = 'client_id', string $clientRegionAlias = 'client_region'): array
    {
        return [
            'aiv_client_id' => [
                'source_key' => 'aiv_client_id',
                'target'     => 'meta_data:' . $clientIdAlias,
                'transform'  => 'text',
                'enabled'    => true,
            ],
            'aiv_client_region' => [
                'source_key' => 'aiv_client_region',
                'target'     => 'meta_data:' . $clientRegionAlias,
                'transform'  => 'text',
                'enabled'    => true,
            ],
        ];
    }

    /**
     * @param array<int, array<string, mixed>> $existing
     *
     * @return array<int, array<string, mixed>>
     */
    public static function merge(array $existing, string $clientIdAlias = 'client_id', string $clientRegionAlias = 'client_region'): array
    {
        $required = self::requiredMappings($clientIdAlias, $clientRegionAlias);
        $result   = [];

        foreach ($existing as $row) {
            if (!is_array($row)) {
                continue;
            }

            $sourceKey = trim((string) ($row['source_key'] ?? ''));
            if (isset($required[$sourceKey])) {
                if (!isset($result[$sourceKey])) {
                    $result[$sourceKey] = $required[$sourceKey];
                }
                continue;
            }

            $result[] = $row;
        }

        foreach ($required as $sourceKey => $mapping) {
            $result[$sourceKey] = $mapping;
        }

        return array_values($result);
    }

    /**
     * @param array<int, mixed> $fields
     * @param string[]          $requiredAliases
     *
     * @return string[]
     */
    public static function missingCustomAliases(array $fields, array $requiredAliases): array
    {
        $available = [];
        foreach ($fields as $field) {
            if (!is_array($field) || 'custom' !== ($field['source'] ?? null)) {
                continue;
            }

            $alias = trim((string) ($field['alias'] ?? ''));
            if ('' !== $alias) {
                $available[$alias] = true;
            }
        }

        return array_values(array_filter(
            $requiredAliases,
            static fn (string $alias): bool => !isset($available[$alias])
        ));
    }
}