php<?php
namespace App\Service;

class Validator
{
    private array $errors = [];

    public function validate(array $data, array $rules): bool
    {
        $this->errors = [];

        foreach ($rules as $field => $fieldRules) {
            $value = $data[$field] ?? null;

            foreach ($fieldRules as $rule) {
                $error = $this->checkRule($field, $value, $rule);
                if ($error !== null) {
                    $this->errors[$field][] = $error;
                }
            }
        }

        return empty($this->errors);
    }

    private function checkRule(string $field, mixed $value,
        string $rule): ?string
    {
        // required
        if ($rule === 'required' && (is_null($value)
            || trim((string)$value) === '')) {
            return "Le champ $field est obligatoire.";
        }

        // email
        if ($rule === 'email' && $value !== null
            && !filter_var($value, FILTER_VALIDATE_EMAIL)) {
            return "Le champ $field doit etre un email valide.";
        }

        // min:N
        if (str_starts_with($rule, 'min:')) {
            $min = (int) substr($rule, 4);
            if ($value !== null && strlen((string)$value) < $min) {
                return "Le champ $field doit faire au moins $min caracteres.";
            }
        }

        // max:N
        if (str_starts_with($rule, 'max:')) {
            $max = (int) substr($rule, 4);
            if ($value !== null && strlen((string)$value) > $max) {
                return "Le champ $field ne doit pas depasser $max caracteres.";
            }
        }

        // numeric
        if ($rule === 'numeric' && $value !== null
            && !is_numeric($value)) {
            return "Le champ $field doit etre un nombre.";
        }

        return null;
    }

    public function getErrors(): array
    {
        return $this->errors;
    }

    public function getFirstError(string $field): ?string
    {
        return $this->errors[$field][0] ?? null;
    }
}

php<?php
session_start();

$validator = new Validator();
$errors = [];
$old = [];

if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    $old = $_POST;  // Garder les valeurs pour re-remplir le formulaire

    $isValid = $validator->validate($_POST, [
        'nom'      => ['required', 'min:2', 'max:100'],
        'email'    => ['required', 'email'],
        'password' => ['required', 'min:8'],
        'confirm'  => ['required'],
    ]);

    // Validation supplementaire
    if ($_POST['password'] !== $_POST['confirm']) {
        $errors['confirm'] = 'Les mots de passe ne correspondent pas.';
        $isValid = false;
    }

    if ($isValid && empty($errors)) {
        // Nettoyer les donnees
        $nom = htmlspecialchars(trim($_POST['nom']));
        $email = filter_var($_POST['email'], FILTER_SANITIZE_EMAIL);
        $password = password_hash($_POST['password'], PASSWORD_DEFAULT);

        // Verifier que l'email n'existe pas deja
        $stmt = $pdo->prepare(
            "SELECT id FROM users WHERE email = :email"
        );
        $stmt->execute(['email' => $email]);
        if ($stmt->fetch()) {
            $errors['email'] = 'Cet email est deja utilise.';
        } else {
            // Inserer en BDD
            $stmt = $pdo->prepare(
                "INSERT INTO users (nom, email, password)
                 VALUES (:nom, :email, :password)"
            );
            $stmt->execute([
                'nom' => $nom,
                'email' => $email,
                'password' => $password,
            ]);

            $_SESSION['success'] = 'Inscription reussie !';
            header('Location: login.php');
            exit;
        }
    } else {
        $errors = array_merge($errors, $validator->getErrors());
    }
}
?>

<form method="POST" novalidate>
    <div>
        <label for="nom">Nom</label>
        <input type="text" name="nom" id="nom"
               value="<?= htmlspecialchars($old['nom'] ?? '') ?>"
               required minlength="2">
        <?php if (isset($errors['nom'])): ?>
            <p class="error">
                <?= htmlspecialchars(
                    is_array($errors['nom'])
                        ? $errors['nom'][0]
                        : $errors['nom']
                ) ?>
            </p>
        <?php endif; ?>
    </div>

    <div>
        <label for="email">Email</label>
        <input type="email" name="email" id="email"
               value="<?= htmlspecialchars($old['email'] ?? '') ?>"
               required>
        <?php if (isset($errors['email'])): ?>
            <p class="error">
                <?= htmlspecialchars(
                    is_array($errors['email'])
                        ? $errors['email'][0]
                        : $errors['email']
                ) ?>
            </p>
        <?php endif; ?>
    </div>

    <div>
        <label for="password">Mot de passe</label>
        <input type="password" name="password" id="password"
               required minlength="8">
    </div>

    <div>
        <label for="confirm">Confirmer le mot de passe</label>
        <input type="password" name="confirm" id="confirm" required>
        <?php if (isset($errors['confirm'])): ?>
            <p class="error">
                <?= htmlspecialchars($errors['confirm']) ?>
            </p>
        <?php endif; ?>
    </div>

    <button type="submit">S'inscrire</button>
</form>