<?php
/**
 * V2-Plattform — Request-Validierung
 *
 * Schmal — kein vollausgebautes JSON-Schema, sondern feldweise Asserts.
 */

declare(strict_types=1);

function v2_validate_required(array $body, array $fields): void {
    $missing = [];
    foreach ($fields as $f) {
        if (!array_key_exists($f, $body) || $body[$f] === null || $body[$f] === '') {
            $missing[] = $f;
        }
    }
    if ($missing) {
        v2_response_error(400, 'missing_fields', 'Pflichtfelder fehlen.', [
            'missing' => $missing,
        ]);
    }
}

function v2_validate_enum(string $value, array $allowed, string $fieldName): void {
    if (!in_array($value, $allowed, true)) {
        v2_response_error(400, 'invalid_value', "Ungültiger Wert für '$fieldName'.", [
            'allowed' => $allowed,
            'got' => $value,
        ]);
    }
}

function v2_validate_int_range(int $value, int $min, int $max, string $fieldName): void {
    if ($value < $min || $value > $max) {
        v2_response_error(400, 'out_of_range', "Wert für '$fieldName' außerhalb [$min,$max].");
    }
}

function v2_validate_method(string $expected): void {
    $actual = $_SERVER['REQUEST_METHOD'] ?? '';
    if ($actual !== $expected) {
        v2_response_error(405, 'method_not_allowed', "Methode $actual nicht erlaubt, erwartet $expected.");
    }
}

function v2_validate_method_in(array $expected): string {
    $actual = $_SERVER['REQUEST_METHOD'] ?? '';
    if (!in_array($actual, $expected, true)) {
        v2_response_error(405, 'method_not_allowed', "Methode $actual nicht erlaubt.");
    }
    return $actual;
}