<?php
/**
 * Save handler for form help blocks (student-facing explanatory text shown
 * in the /partage share-link submission form).
 */
require_once __DIR__ . '/../../../bootstrap.php';
require_once __DIR__ . '/../../../src/AdminAuth.php';
AdminAuth::requireLogin();

if (!isset($_POST['csrf_token'], $_SESSION['csrf_token'])
    || !hash_equals($_SESSION['csrf_token'], $_POST['csrf_token'])) {
    App::flash('error', 'Erreur de sécurité : token invalide.');
    header('Location: /admin/contenus.php');
    exit;
}

$key     = $_POST['form_help_key'] ?? '';
$content = $_POST['content']       ?? '';

require_once APP_ROOT . '/src/Database.php';
require_once APP_ROOT . '/src/AdminLogger.php';
require_once APP_ROOT . '/src/ErrorHandler.php';
$db = new Database();

if (!in_array($key, Database::FORM_HELP_KEYS, true)) {
    App::flash('error', 'Clé de bloc invalide.');
    header('Location: /admin/contenus.php');
    exit;
}

try {
    $db->setFormHelpBlock($key, $content);
    AdminLogger::make()->logFormStructureEdit($key);
    App::flash('success', 'Bloc « ' . htmlspecialchars($key) . ' » mis à jour.');
} catch (Exception $e) {
    ErrorHandler::log('form_help', $e);
    App::flash('error', 'Erreur lors de la sauvegarde : ' . ErrorHandler::userMessage($e));
}

$_SESSION['csrf_token'] = bin2hex(random_bytes(32));
header('Location: /admin/contenus.php#form-help-blocks');
exit;
