let
  certs = import ./snakeoil-certs.nix;
in
{ pkgs, ... }:
{
  name = "nginx-proxyprotocol";

  meta = {
    maintainers = with pkgs.lib.maintainers; [ raitobezarius ];
  };

  nodes = {
    webserver =
      { pkgs, lib, ... }:
      {
        environment.systemPackages = [ pkgs.netcat ];
        security.pki.certificateFiles = [
          certs.ca.cert
        ];

        networking.extraHosts = ''
          127.0.0.5 proxy.test.nix
          127.0.0.5 noproxy.test.nix
          127.0.0.3 direct-nossl.test.nix
          127.0.0.4 unsecure-nossl.test.nix
          127.0.0.2 direct-noproxy.test.nix
          127.0.0.1 direct-proxy.test.nix
        '';
        services.nginx = {
          enable = true;
          defaultListen = [
            {
              addr = "127.0.0.1";
              proxyProtocol = true;
              ssl = true;
            }
            { addr = "127.0.0.2"; }
            {
              addr = "127.0.0.3";
              ssl = false;
            }
            {
              addr = "127.0.0.4";
              ssl = false;
              proxyProtocol = true;
            }
          ];
          commonHttpConfig = ''
            log_format pcombined '(proxy_protocol=$proxy_protocol_addr) - (remote_addr=$remote_addr) - (realip=$realip_remote_addr) - (upstream=) - (remote_user=$remote_user) [$time_local] '
                          '"$request" $status $body_bytes_sent '
                          '"$http_referer" "$http_user_agent"';
            access_log /var/log/nginx/access.log pcombined;
            error_log /var/log/nginx/error.log;
          '';
          virtualHosts =
            let
              commonConfig = {
                locations."/".return = "200 '$remote_addr'";
                extraConfig = ''
                  set_real_ip_from 127.0.0.5/32;
                  real_ip_header proxy_protocol;
                '';
              };
            in
            {
              "*.test.nix" = commonConfig // {
                sslCertificate = certs."*.test.nix".cert;
                sslCertificateKey = certs."*.test.nix".key;
                forceSSL = true;
              };
              "direct-nossl.test.nix" = commonConfig;
              "unsecure-nossl.test.nix" = commonConfig // {
                extraConfig = ''
                  real_ip_header proxy_protocol;
                '';
              };
            };
        };

        services.sniproxy = {
          enable = true;
          config = ''
            error_log {
              syslog daemon
            }
            access_log {
              syslog daemon
            }
            listener 127.0.0.5:443 {
              protocol tls
              source 127.0.0.5
            }
            table {
              ^proxy\.test\.nix$   127.0.0.1 proxy_protocol
              ^noproxy\.test\.nix$ 127.0.0.2
            }
          '';
        };
      };
  };

  testScript = ''
    def check_origin_ip(src_ip: str, dst_url: str, failure: bool = False, proxy_protocol: bool = False, expected_ip: str | None = None):
      check = webserver.fail if failure else webserver.succeed
      if expected_ip is None:
        expected_ip = src_ip

      return check(f"curl {'--haproxy-protocol' if proxy_protocol else '''} --interface {src_ip} --fail -L {dst_url} | grep '{expected_ip}'")

    webserver.wait_for_unit("nginx")
    webserver.wait_for_unit("sniproxy")
    # This should be closed by virtue of ssl = true;
    webserver.wait_for_closed_port(80, "127.0.0.1")
    # This should be open by virtue of no explicit ssl
    webserver.wait_for_open_port(80, "127.0.0.2")
    # This should be open by virtue of ssl = true;
    webserver.wait_for_open_port(443, "127.0.0.1")
    # This should be open by virtue of no explicit ssl
    webserver.wait_for_open_port(443, "127.0.0.2")
    # This should be open by sniproxy
    webserver.wait_for_open_port(443, "127.0.0.5")
    # This should be closed by sniproxy
    webserver.wait_for_closed_port(80, "127.0.0.5")

    # Sanity checks for the NGINX module
    # direct-HTTP connection to NGINX without TLS, this checks that ssl = false; works well.
    check_origin_ip("127.0.0.10", "http://direct-nossl.test.nix/")
    # webserver.execute("openssl s_client -showcerts -connect direct-noproxy.test.nix:443")
    # direct-HTTP connection to NGINX with TLS
    check_origin_ip("127.0.0.10", "http://direct-noproxy.test.nix/")
    check_origin_ip("127.0.0.10", "https://direct-noproxy.test.nix/")
    # Well, sniproxy is not listening on 80 and cannot redirect
    check_origin_ip("127.0.0.10", "http://proxy.test.nix/", failure=True)
    check_origin_ip("127.0.0.10", "http://noproxy.test.nix/", failure=True)

    # Actual PROXY protocol related tests
    # Connecting through sniproxy should passthrough the originating IP address.
    check_origin_ip("127.0.0.10", "https://proxy.test.nix/")
    # Connecting through sniproxy to a non-PROXY protocol enabled listener should not pass the originating IP address.
    check_origin_ip("127.0.0.10", "https://noproxy.test.nix/", expected_ip="127.0.0.5")

    # Attack tests against spoofing
    # Let's try to spoof our IP address by connecting direct-y to the PROXY protocol listener.
    # FIXME(RaitoBezarius): rewrite it using Python + (Scapy|something else) as this is too much broken unfortunately.
    # Or wait for upstream curl patch.
    # def generate_attacker_request(original_ip: str, target_ip: str, dst_url: str):
    #     return f"""PROXY TCP4 {original_ip} {target_ip} 80 80
    #     GET / HTTP/1.1
    #     Host: {dst_url}

    #     """
    # def spoof(original_ip: str, target_ip: str, dst_url: str, tls: bool = False, expect_failure: bool = True):
    #   method = webserver.fail if expect_failure else webserver.succeed
    #   port = 443 if tls else 80
    #   print(webserver.execute(f"cat <<EOF | nc {target_ip} {port}\n{generate_attacker_request(original_ip, target_ip, dst_url)}\nEOF"))
    #   return method(f"cat <<EOF | nc {target_ip} {port} | grep {original_ip}\n{generate_attacker_request(original_ip, target_ip, dst_url)}\nEOF")

    # check_origin_ip("127.0.0.10", "http://unsecure-nossl.test.nix", proxy_protocol=True)
    # spoof("1.1.1.1", "127.0.0.4", "direct-nossl.test.nix")
    # spoof("1.1.1.1", "127.0.0.4", "unsecure-nossl.test.nix", expect_failure=False)
  '';
}