<?php
$config = yaml_parse_file("../config.yaml");
$remoteIp = $_SERVER["REMOTE_ADDR"];
$reverseDns = gethostbyaddr($remoteIp);
$match = false;
foreach ($config["allowed_sender"] as $host) {
    if (fnmatch($host, $remoteIp)) {
        echo "match $host, $remoteIp\n";
        $match = true;
        break;
    }
    $forwardResolve = gethostbyname($reverseDns);
    if ($forwardResolve != $remoteIp) {
        header(
            "X-Auth: reverse dns of $remoteIp ($reverseDns) does not resolve to $remoteIp ($forwardResolve)"
        );
        continue;
    }
    if (fnmatch($host, $reverseDns)) {
        echo "match $host, $reverseDns\n";
        $match = true;
        break;
    }
}
if (!$match) {
    header("HTTP/1.0 403 Forbidden");
    die("403 Forbidden");
}
send("$reverseDns: " . file_get_contents("php://input"), $config);

function send($message, $config)
{
    $target = $config["matrix"]["target"];
    $token = $config["matrix"]["token"];
    $ch = curl_init();
    curl_setopt(
        $ch,
        CURLOPT_URL,
        "https://matrix.c3re.de/_matrix/client/r0/rooms/$target/send/m.room.message/123?access_token=$token"
    );
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    curl_setopt(
        $ch,
        CURLOPT_POSTFIELDS,
        json_encode(["msgtype" => "m.text", "body" => $message])
    );
    curl_setopt($ch, CURLOPT_POST, 1);
    curl_setopt($ch, CURLOPT_CUSTOMREQUEST, "PUT");
    curl_exec($ch);
}