<?php

use Symfony\Component\Mailer\Exception\TransportExceptionInterface;
use Symfony\Component\Mailer\Transport;
use Symfony\Component\Mime\Address;
use Symfony\Component\Mime\Email;

session_start();

function missing_field(string $name): never {
    http_response_code(400);
    echo "Missing or malformed field '$name'\n";
    exit;
}

function getenv_or_fail(string $key): ?string {
    $value = getenv($key);
    if ($value !== false)
        return $value;
    http_response_code(500);
    echo "Missing environment variable '$key'\n";
    exit;
}

function quote(string $message): string {
    return implode("\n", array_map(fn($ln) => "> $ln", preg_split('~(*BSR_ANYCRLF)\R~', trim($message))));
}

if ($_SERVER["REQUEST_METHOD"] !== "POST") {
    http_response_code(405);
    echo "Invalid request method!\n";
    exit;
}

$name = $_POST["name"] ?? missing_field("name");
if (empty($name) || strlen($name) > 128)
    missing_field("name");

$email = $_POST["email"] ?? missing_field("email");
if (empty($email) || strlen($email) > 128 || !str_contains($email, "@"))
    missing_field("email");

$subject = $_POST["subject"] ?? missing_field("subject");
if (empty($email) || strlen($subject) > 256)
    missing_field("subject");

$message = $_POST["message"] ?? missing_field("message");
if (empty($email) || strlen($message) > 16384)
    missing_field("message");

$captcha = $_POST["captcha"] ?? missing_field("captcha");
if (empty($email) || strlen($captcha) > 7)
    missing_field("captcha");

$expected_captcha = $_SESSION["captcha_phrase"] ?? null;

if ($captcha !== $expected_captcha) {
    http_response_code(400);
    echo "Ung&uuml;ltiges CAPTCHA!";
    exit;
}

require_once __DIR__ . "/../vendor/autoload.php";

$mailer_dsn = getenv_or_fail("MAILER_DSN");

$transport = Transport::fromDsn($mailer_dsn);

$time = (new DateTimeImmutable("now", new DateTimeZone("Europe/Berlin")))->format("d.m.y \\u\\m H:i");

$serviceAddress = "mystic-contactform+no-reply@jonaskohl.de";
$sender = new Address($email, $name);

$body = "Guten Tag $name,\n\nIhre Kontaktanfrage vom $time ist erfolgreich bei uns eingegangen!\nUntenstehend finden Sie eine Kopie Ihrer Nachricht.\n\nMit freundlichen Grüßen\nDas Mystic House Corner Team\n\n---\n\n" . quote($message) . "\n";

try {
    $transport->send((new Email())
        ->from(new Address($serviceAddress, "Mystic House Corner"))
        ->to($sender)
        ->subject("Ihre Kontaktanfrage ist bei uns eingegangen")
        ->text($body)
    );

    $body = "Am $time schrieb $name via Kontaktformular:\n" . quote($message) . "\n";

    $transport->send((new Email())
        ->from(new Address($serviceAddress, $name))
        ->to("mystic@jonaskohl.de")
        ->replyTo($sender)
        ->subject("[Mystic House Corner] $subject")
        ->text($body)
    );
    header("Location: /pages/sent.php");
} catch (TransportExceptionInterface $ex) {
    header("Location: /pages/sent-error.php");
}