Rename library/ to src/

We've always considered renaming this directory, as it's not a common
standard to name `library` the directory where the source code of a
library it. Having it as `src/` is a common pattern we find in several
PHP libraries these days.

Acked-by: Alexandre Gomes Gaigalas <alganet@gmail.com>

src/Validators/SubdivisionCode.php

@@ -0,0 +1,72 @@
+<?php
+
+/*
+ * SPDX-License-Identifier: MIT
+ * SPDX-FileCopyrightText: (c) Respect Project Contributors
+ * SPDX-FileContributor: Alexandre Gomes Gaigalas <alganet@gmail.com>
+ * SPDX-FileContributor: Henrique Moody <henriquemoody@gmail.com>
+ */
+
+declare(strict_types=1);
+
+namespace Respect\Validation\Validators;
+
+use Attribute;
+use Respect\Validation\Exceptions\InvalidValidatorException;
+use Respect\Validation\Exceptions\MissingComposerDependencyException;
+use Respect\Validation\Helpers\CanValidateUndefined;
+use Respect\Validation\Message\Template;
+use Respect\Validation\Result;
+use Respect\Validation\Validator;
+use Sokil\IsoCodes\Database\Countries;
+use Sokil\IsoCodes\Database\Subdivisions;
+
+use function class_exists;
+
+#[Attribute(Attribute::TARGET_PROPERTY | Attribute::IS_REPEATABLE)]
+#[Template(
+    '{{subject}} must be a subdivision code of {{countryName|trans}}',
+    '{{subject}} must not be a subdivision code of {{countryName|trans}}',
+)]
+final readonly class SubdivisionCode implements Validator
+{
+    use CanValidateUndefined;
+
+    private Countries\Country $country;
+
+    private Subdivisions $subdivisions;
+
+    public function __construct(
+        string $countryCode,
+        Countries|null $countries = null,
+        Subdivisions|null $subdivisions = null,
+    ) {
+        if (!class_exists(Countries::class) || !class_exists(Subdivisions::class)) {
+            throw new MissingComposerDependencyException(
+                'SubdivisionCode rule requires PHP ISO Codes',
+                'sokil/php-isocodes',
+                'sokil/php-isocodes-db-only',
+            );
+        }
+
+        $countries ??= new Countries();
+        $country = $countries->getByAlpha2($countryCode);
+        if ($country === null) {
+            throw new InvalidValidatorException('"%s" is not a supported country code', $countryCode);
+        }
+
+        $this->country = $country;
+        $this->subdivisions = $subdivisions ?? new Subdivisions();
+    }
+
+    public function evaluate(mixed $input): Result
+    {
+        $parameters = ['countryName' => $this->country->getName()];
+        $subdivision = $this->subdivisions->getByCode($this->country->getAlpha2() . '-' . $input);
+        if ($this->isUndefined($input) && $subdivision === null) {
+            return Result::passed($input, $this, $parameters);
+        }
+
+        return Result::of($subdivision !== null, $input, $this, $parameters);
+    }
+}