<?php declare(strict_types=1);

function http_server_skipif() {

    if (!function_exists('pcntl_fork')) die('skip pcntl_fork() not available');
    if (!function_exists('posix_kill')) die('skip posix_kill() not available');
    if (!stream_socket_server('tcp://localhost:0')) die('skip stream_socket_server() failed');
}

function http_server_init(&$output = null) {
    pcntl_alarm(60);

    $server = stream_socket_server('tcp://localhost:0', $errno, $errstr);
    if (!$server) {
        return false;
    }

    if ($output === null) {
        $output = tmpfile();
        if ($output === false) {
            return false;
        }
    }

    $pid = pcntl_fork();
    if ($pid == -1) {
        die('could not fork');
    } else if ($pid) {
        return [
            'pid' => $pid,
            'uri' => 'http://' . stream_socket_get_name($server, false),
        ];
    }

    return $server;
}

/* Minimal HTTP server with predefined responses.
 *
 * $socket_string is the socket to create and listen on (e.g. tcp://127.0.0.1:1234)
 * $files is an iterable of files or callable generator yielding files.
 *        containing N responses for N expected requests. Server dies after N requests.
 * $output is a stream on which everything sent by clients is written to
 */
function http_server($files, &$output = null) {

    if (!is_resource($server = http_server_init($output))) {
        return $server;
    }

    if (is_callable($files)) {
        $files = $files($server);
    }

    foreach($files as $file) {

        $sock = stream_socket_accept($server);
        if (!$sock) {
            exit(1);
        }

        // read headers

        $content_length = 0;

        stream_set_blocking($sock, false);
        while (!feof($sock)) {

            list($r, $w, $e) = array(array($sock), null, null);
            if (!stream_select($r, $w, $e, 1)) continue;

            $line = stream_get_line($sock, 8192, "\r\n");
            if ($line === '') {
                fwrite($output, "\r\n");
                break;
            } else if ($line !== false) {
                fwrite($output, "$line\r\n");

                if (preg_match('#^Content-Length\s*:\s*([[:digit:]]+)\s*$#i', $line, $matches)) {
                    $content_length = (int) $matches[1];
                }
            }
        }
        stream_set_blocking($sock, true);

        // read content

        if ($content_length > 0) {
            stream_copy_to_stream($sock, $output, $content_length);
        }

        // send response

        $fd = fopen($file, 'rb');
        stream_copy_to_stream($fd, $sock);

        fclose($sock);
    }

    exit(0);
}

function http_server_sleep($micro_seconds = 500000)
{
    if (!is_resource($server = http_server_init($output))) {
        return $server;
    }

    $sock = stream_socket_accept($server);
    if (!$sock) {
        exit(1);
    }

    usleep($micro_seconds);

    fclose($sock);

    exit(0);
}

function http_server_kill(int $pid) {
    posix_kill($pid, SIGTERM);
    pcntl_waitpid($pid, $status);
}