<?php
// define variables and set to empty values
$errors = 0;

$nameErr = $firstNameErr = $emailErr = $messageErr = $subjectErr = $phoneErr = "";
$name = $firstName = $email = $message = $subject = $phone = "";

if ($_SERVER["REQUEST_METHOD"] == "POST") {
    if (empty($_POST["user_name"])) {
        $nameErr = "Name is required";
        $errors++;
    } else {
        $name = test_input($_POST["user_name"]);
    }

    if (empty($_POST["user_firstName"])) {
        $firstNameErr = "Name is required";
        $errors++;
    } else {
        $firstName = test_input($_POST["user_firstName"]);
    }

    if (empty($_POST["user_email"])) {
        $emailErr = "Email is required";
        $errors++;
    } else {
        $email = test_input($_POST["user_email"]);
    }

    if (empty($_POST["user_telephone"])) {
        $phoneErr = "Phone is required";
        $errors++;
    } else {
        $phone = test_input($_POST["user_telephone"]);
    }

    if (empty($_POST["subject"])) {
        $subjectErr = "Field is required";
        $errors++;
    } else {
        $subject = test_input($_POST["subject"]);
    }

    if (empty($_POST["user_message"])) {
        $messageErr = "Message is required";
        $errors++;
    } else {
        $message = test_input($_POST["user_message"]);
    }

    if ($errors == 0) {
        header("Location: success.php");
    }

}

function test_input($data) {
    $data = trim($data);
    $data = stripslashes($data);
    $data = htmlspecialchars($data);
    return $data;
}
?>

<form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>">
    <div>
        <label  for="nom">Nom :</label>
        <input  type="text"  id="nom"  name="user_name">
        <span><?= $nameErr; ?></span>
    </div>
    <div>
        <label  for="prenom">Prénom :</label>
        <input  type="text"  id="prenom"  name="user_firstName">
        <span><?= $firstNameErr; ?></span>
    </div>
    <div>
        <label  for="courriel">Email :</label>
        <input  type="email"  id="courriel"  name="user_email">
        <span><?= $emailErr; ?></span>
    </div>
    <div>
        <label  for="telephone">Telephone :</label>
        <input  type="tel"  id="tel"  name="user_telephone">
        <span><?= $phoneErr; ?></span>
    </div>
    <div>
        <label  for="SUJET">Sujet :</label>
        <span><?= $subjectErr; ?></span>
        <select id="sujet" name="subject">
            <option>WTF</option>
            <option>DTF</option>
            <option>BTW</option>
        </select>
    </div>
    <div>
        <label  for="message">Message :</label>
        <span><?= $messageErr; ?></span>
        <textarea  id="message"  name="user_message"></textarea>
    </div>
    <div  class="button">
        <button  type="submit">VOILA</button>
    </div>
</form>