{ config, pkgs, lib, ... }: {

  options = {
    caddyRoutes = lib.mkOption {
      type = lib.types.listOf lib.types.attrs;
      description = "Caddy JSON routes for http servers";
    };
  };

  config = {

    services.caddy = {
      enable = true;
      adapter = "''"; # Required to enable JSON
      configFile = pkgs.writeText "Caddyfile" (builtins.toJSON {
        apps.http.servers.main = {
          listen = [ ":443" ];
          routes = config.caddyRoutes;
          errors.routes = [{
            match = [{
              not = [{
                remote_ip.ranges = [

                  # Cloudflare IPv4: https://www.cloudflare.com/ips-v4
                  "173.245.48.0/20"
                  "103.21.244.0/22"
                  "103.22.200.0/22"
                  "103.31.4.0/22"
                  "141.101.64.0/18"
                  "108.162.192.0/18"
                  "190.93.240.0/20"
                  "188.114.96.0/20"
                  "197.234.240.0/22"
                  "198.41.128.0/17"
                  "162.158.0.0/15"
                  "104.16.0.0/13"
                  "104.24.0.0/14"
                  "172.64.0.0/13"
                  "131.0.72.0/22"

                  # Cloudflare IPv6: https://www.cloudflare.com/ips-v6
                  "2400:cb00::/32"
                  "2606:4700::/32"
                  "2803:f800::/32"
                  "2405:b500::/32"
                  "2405:8100::/32"
                  "2a06:98c0::/29"
                  "2c0f:f248::/32"

                ];
              }];
            }];
            handle = [{
              handler = "static_response";
              abort = true;
            }];
          }];
        };
      });

    };

    networking.firewall.allowedTCPPorts = [ 80 443 ];
    networking.firewall.allowedUDPPorts = [ 443 ];

  };

}