<?php

declare(strict_types=1);

namespace App\Rules;

use Closure;
use Illuminate\Contracts\Validation\ValidationRule;

/**
 * Validates a translatable field submitted either as a plain string (meaning
 * "the current locale") or as a locale => value object.
 *
 * Unknown locale keys are rejected rather than ignored, so a typo like "gb"
 * fails loudly instead of silently writing a translation nobody will ever read.
 */
class Translatable implements ValidationRule
{
    public function __construct(
        protected bool $requireDefaultLocale = false,
        protected ?int $max = null,
    ) {}

    public function validate(string $attribute, mixed $value, Closure $fail): void
    {
        $supported = array_keys(config('locales.supported'));
        $default = (string) config('locales.default');

        if (is_string($value)) {
            $value = [app()->getLocale() => $value];
        }

        if (! is_array($value)) {
            $fail(__('rules.translatable.type', ['attribute' => $attribute]));

            return;
        }

        foreach ($value as $locale => $translation) {
            if (! in_array((string) $locale, $supported, true)) {
                $fail(__('rules.translatable.unsupported_locale', [
                    'attribute' => $attribute,
                    'locale' => (string) $locale,
                    'supported' => implode(', ', $supported),
                ]));

                return;
            }

            if ($translation !== null && ! is_string($translation)) {
                $fail(__('rules.translatable.type', ['attribute' => $attribute]));

                return;
            }

            if ($this->max !== null && is_string($translation) && mb_strlen($translation) > $this->max) {
                $fail(__('rules.translatable.max', [
                    'attribute' => $attribute,
                    'locale' => (string) $locale,
                    'max' => $this->max,
                ]));

                return;
            }
        }

        // The default locale is the fallback every other language borrows from
        // when it has no translation, so a record without it can render blank.
        if ($this->requireDefaultLocale && blank($value[$default] ?? null)) {
            $fail(__('rules.translatable.default_required', [
                'attribute' => $attribute,
                'locale' => $default,
            ]));
        }
    }
}