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

with lib;

let

  cfg = config.services.strojnadzor;

  hsts = ''
    add_header Strict-Transport-Security "max-age=31536000; includeSubDomains; preload";
  '';

  static = pkgs.runCommand "static" {} ''
    export STROJNADZOR_STATIC_ROOT="$out"
    ${cfg.package}/bin/strojnadzor-admin collectstatic
  '';

in

{

  options = {
    services.strojnadzor = {
      enable = mkOption {
        default = false;
        description = "
          Whether to enable Strojnadzor
        ";
      };
      package = mkOption {
        type = types.path;
        default = pkgs.strojnadzor;
        description = "The Strojnadzor package.";
      };
      hostName = mkOption {
        default = "golovizin.ru";
        type = types.str;
        description = "Main hostname.";
      };
      hostNameAliases = mkOption {
        default = [ "www.golovizin.ru" "xn--b1abndboscb.xn--p1ai" "www.xn--b1abndboscb.xn--p1ai" ];
        type = types.listOf types.str;
        description = "Additional hostnames.";
      };
      stateDir = mkOption {
        default = "/var/lib/strojnadzor";
        type = types.str;
        description = "Data directory.";
      };
      backupDir = mkOption {
        default = "/var/backup/strojnadzor";
        type = types.str;
        description = "Backup directory.";
      };
      socketPath = mkOption {
        default = "/run/strojnadzor.sock";
        type = types.str;
        description = "UNIX socket path.";
      };
      borgbackup = {
        enable = mkEnableOption "backup via borgbackup";
      };
    };
  };

  config = mkIf cfg.enable {
    users.users.strojnadzor = {
      description = "Strojnadzor user";
      isSystemUser = true;
      group = "strojnadzor";
      home = cfg.stateDir;
    };

    users.groups.strojnadzor = {};

    systemd.tmpfiles.rules = [
      "d '${cfg.stateDir}/db' 0700 strojnadzor strojnadzor - -"
      "d '${cfg.stateDir}/media' 0755 strojnadzor strojnadzor - -"
      "d '${cfg.backupDir}/borg' 0700 strojnadzor strojnadzor - -"
    ];

    systemd.sockets.strojnadzor = {
      description = "Strojnadzor HTTP socket.";
      wantedBy = [ "sockets.target" ];
      socketConfig = {
        SocketUser = "nginx";
        SocketGroup = "nginx";
        SocketMode = 0660;
        ListenStream = "${cfg.socketPath}";
      };
    };

    systemd.services.strojnadzor = {
      description = "Strojnadzor HTTP server.";
      after = [ "network.target" ];
      wantedBy = [ "multi-user.target" ];
      requires = [ "strojnadzor.socket" ];
      serviceConfig = {
        Type = "notify";
        User = "strojnadzor";
        Group = "strojnadzor";
        ExecStartPre = "${cfg.package}/bin/strojnadzor-admin migrate";
        ExecStart = "${cfg.package}/bin/strojnadzor-admin runserver-gunicorn";
        StateDirectory = "strojnadzor";
        CapabilityBoundingSet = "";
        LockPersonality = true;
        NoNewPrivileges = true;
        PrivateDevices = true;
        # PrivateNetwork = true;
        PrivateTmp = true;
        PrivateUsers = true;
        ProtectControlGroups = true;
        ProtectHome = true;
        ProtectKernelModules = true;
        ProtectKernelTunables = true;
        ProtectSystem = "strict";
        RestrictAddressFamilies = [ "AF_UNIX" "AF_INET" "AF_INET6" ];
        RestrictNamespaces = true;
        RestrictSUIDSGID = true;
        SystemCallErrorNumber = "EPERM";
        SystemCallFilter = "@system-service";
      };
      environment.STROJNADZOR_DATA_DIR = "${cfg.stateDir}";
    };

    services.nginx = {
      enable = true;
      virtualHosts = {
        "${cfg.hostName}" = {
          serverAliases = cfg.hostNameAliases;
          forceSSL = true;
          enableACME = true;
          extraConfig = hsts;
          locations."/static/".alias = "${static}/";
          locations."/media/".alias = "${cfg.stateDir}/media/";
          locations."= /favicon.ico".return = "404";
          locations."/" = {
            proxyPass = "http://unix:${cfg.socketPath}";
            extraConfig = ''
              proxy_set_header Host $host;
              proxy_set_header X-Forwarded-For $remote_addr;
              gzip off;
            '';
          };
        };
      };
    };

    services.borgbackup.jobs.strojnadzor = mkIf cfg.borgbackup.enable {
      paths = [ cfg.stateDir ];
      exclude = [ "${cfg.stateDir}/.cache" "${cfg.stateDir}/.config" ];
      repo = "${cfg.backupDir}/borg";
      compression = "auto,lzma";
      encryption.mode = "none";
      startAt = "hourly";
      user = "strojnadzor";
      group = "strojnadzor";
    };
  };
}