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

with lib;

let
  cfg = config.services.netbox;
  pythonFmt = pkgs.formats.pythonVars {};
  staticDir = cfg.dataDir + "/static";

  settingsFile = pythonFmt.generate "netbox-settings.py" cfg.settings;
  extraConfigFile = pkgs.writeTextFile {
    name = "netbox-extraConfig.py";
    text = cfg.extraConfig;
  };
  configFile = pkgs.concatText "configuration.py" [ settingsFile extraConfigFile ];

  pkg = (cfg.package.overrideAttrs (old: {
    installPhase = old.installPhase + ''
      ln -s ${configFile} $out/opt/netbox/netbox/netbox/configuration.py
    '' + optionalString cfg.enableLdap ''
      ln -s ${cfg.ldapConfigPath} $out/opt/netbox/netbox/netbox/ldap_config.py
    '';
  })).override {
    inherit (cfg) plugins;
  };
  netboxManageScript = with pkgs; (writeScriptBin "netbox-manage" ''
    #!${stdenv.shell}
    export PYTHONPATH=${pkg.pythonPath}
    sudo -u netbox ${pkg}/bin/netbox "$@"
  '');

in {
  options.services.netbox = {
    enable = mkOption {
      type = lib.types.bool;
      default = false;
      description = lib.mdDoc ''
        Enable Netbox.

        This module requires a reverse proxy that serves `/static` separately.
        See this [example](https://github.com/netbox-community/netbox/blob/develop/contrib/nginx.conf/) on how to configure this.
      '';
    };

    settings = lib.mkOption {
      description = lib.mdDoc ''
        Configuration options to set in `configuration.py`.
        See the [documentation](https://docs.netbox.dev/en/stable/configuration/) for more possible options.
      '';

      default = { };

      type = lib.types.submodule {
        freeformType = pythonFmt.type;

        options = {
          ALLOWED_HOSTS = lib.mkOption {
            type = with lib.types; listOf str;
            default = ["*"];
            description = lib.mdDoc ''
              A list of valid fully-qualified domain names (FQDNs) and/or IP
              addresses that can be used to reach the NetBox service.
            '';
          };
        };
      };
    };

    listenAddress = mkOption {
      type = types.str;
      default = "[::1]";
      description = lib.mdDoc ''
        Address the server will listen on.
      '';
    };

    package = mkOption {
      type = types.package;
      default = if versionAtLeast config.system.stateVersion "23.05" then pkgs.netbox else pkgs.netbox_3_3;
      defaultText = literalExpression ''
        if versionAtLeast config.system.stateVersion "23.05" then pkgs.netbox else pkgs.netbox_3_3;
      '';
      description = lib.mdDoc ''
        NetBox package to use.
      '';
    };

    port = mkOption {
      type = types.port;
      default = 8001;
      description = lib.mdDoc ''
        Port the server will listen on.
      '';
    };

    plugins = mkOption {
      type = types.functionTo (types.listOf types.package);
      default = _: [];
      defaultText = literalExpression ''
        python3Packages: with python3Packages; [];
      '';
      description = lib.mdDoc ''
        List of plugin packages to install.
      '';
    };

    dataDir = mkOption {
      type = types.str;
      default = "/var/lib/netbox";
      description = lib.mdDoc ''
        Storage path of netbox.
      '';
    };

    secretKeyFile = mkOption {
      type = types.path;
      description = lib.mdDoc ''
        Path to a file containing the secret key.
      '';
    };

    extraConfig = mkOption {
      type = types.lines;
      default = "";
      description = lib.mdDoc ''
        Additional lines of configuration appended to the `configuration.py`.
        See the [documentation](https://docs.netbox.dev/en/stable/configuration/) for more possible options.
      '';
    };

    enableLdap = mkOption {
      type = types.bool;
      default = false;
      description = lib.mdDoc ''
        Enable LDAP-Authentication for Netbox.

        This requires a configuration file being pass through `ldapConfigPath`.
      '';
    };

    ldapConfigPath = mkOption {
      type = types.path;
      default = "";
      description = lib.mdDoc ''
        Path to the Configuration-File for LDAP-Authentication, will be loaded as `ldap_config.py`.
        See the [documentation](https://netbox.readthedocs.io/en/stable/installation/6-ldap/#configuration) for possible options.
      '';
      example = ''
        import ldap
        from django_auth_ldap.config import LDAPSearch, PosixGroupType

        AUTH_LDAP_SERVER_URI = "ldaps://ldap.example.com/"

        AUTH_LDAP_USER_SEARCH = LDAPSearch(
            "ou=accounts,ou=posix,dc=example,dc=com",
            ldap.SCOPE_SUBTREE,
            "(uid=%(user)s)",
        )

        AUTH_LDAP_GROUP_SEARCH = LDAPSearch(
            "ou=groups,ou=posix,dc=example,dc=com",
            ldap.SCOPE_SUBTREE,
            "(objectClass=posixGroup)",
        )
        AUTH_LDAP_GROUP_TYPE = PosixGroupType()

        # Mirror LDAP group assignments.
        AUTH_LDAP_MIRROR_GROUPS = True

        # For more granular permissions, we can map LDAP groups to Django groups.
        AUTH_LDAP_FIND_GROUP_PERMS = True
      '';
    };
  };

  config = mkIf cfg.enable {
    services.netbox = {
      plugins = mkIf cfg.enableLdap (ps: [ ps.django-auth-ldap ]);
      settings = {
        STATIC_ROOT = staticDir;
        MEDIA_ROOT = "${cfg.dataDir}/media";
        REPORTS_ROOT = "${cfg.dataDir}/reports";
        SCRIPTS_ROOT = "${cfg.dataDir}/scripts";

        DATABASE = {
          NAME = "netbox";
          USER = "netbox";
          HOST = "/run/postgresql";
        };

        # Redis database settings. Redis is used for caching and for queuing
        # background tasks such as webhook events. A separate configuration
        # exists for each. Full connection details are required in both
        # sections, and it is strongly recommended to use two separate database
        # IDs.
        REDIS = {
            tasks = {
                URL = "unix://${config.services.redis.servers.netbox.unixSocket}?db=0";
                SSL = false;
            };
            caching =  {
                URL = "unix://${config.services.redis.servers.netbox.unixSocket}?db=1";
                SSL = false;
            };
        };

        REMOTE_AUTH_BACKEND = lib.mkIf cfg.enableLdap "netbox.authentication.LDAPBackend";

        LOGGING = lib.mkDefault {
          version = 1;

          formatters.precise.format = "[%(levelname)s@%(name)s] %(message)s";

          handlers.console = {
            class = "logging.StreamHandler";
            formatter = "precise";
          };

          # log to console/systemd instead of file
          root = {
            level = "INFO";
            handlers = [ "console" ];
          };
        };
      };

      extraConfig = ''
        with open("${cfg.secretKeyFile}", "r") as file:
            SECRET_KEY = file.readline()
      '';
    };

    services.redis.servers.netbox.enable = true;

    services.postgresql = {
      enable = true;
      ensureDatabases = [ "netbox" ];
      ensureUsers = [
        {
          name = "netbox";
          ensurePermissions = {
            "DATABASE netbox" = "ALL PRIVILEGES";
          };
        }
      ];
    };

    environment.systemPackages = [ netboxManageScript ];

    systemd.targets.netbox = {
      description = "Target for all NetBox services";
      wantedBy = [ "multi-user.target" ];
      after = [ "network-online.target" "redis-netbox.service" ];
    };

    systemd.services = let
      defaultServiceConfig = {
        WorkingDirectory = "${cfg.dataDir}";
        User = "netbox";
        Group = "netbox";
        StateDirectory = "netbox";
        StateDirectoryMode = "0750";
        Restart = "on-failure";
      };
    in {
      netbox-migration = {
        description = "NetBox migrations";
        wantedBy = [ "netbox.target" ];

        environment = {
          PYTHONPATH = pkg.pythonPath;
        };

        serviceConfig = defaultServiceConfig // {
          Type = "oneshot";
          ExecStart = ''
            ${pkg}/bin/netbox migrate
          '';
        };
      };

      netbox = {
        description = "NetBox WSGI Service";
        wantedBy = [ "netbox.target" ];
        after = [ "netbox-migration.service" ];

        preStart = ''
          ${pkg}/bin/netbox trace_paths --no-input
          ${pkg}/bin/netbox collectstatic --no-input
          ${pkg}/bin/netbox remove_stale_contenttypes --no-input
        '';

        environment = {
          PYTHONPATH = pkg.pythonPath;
        };

        serviceConfig = defaultServiceConfig // {
          ExecStart = ''
            ${pkgs.python3Packages.gunicorn}/bin/gunicorn netbox.wsgi \
              --bind ${cfg.listenAddress}:${toString cfg.port} \
              --pythonpath ${pkg}/opt/netbox/netbox
          '';
        };
      };

      netbox-rq = {
        description = "NetBox Request Queue Worker";
        wantedBy = [ "netbox.target" ];
        after = [ "netbox.service" ];

        environment = {
          PYTHONPATH = pkg.pythonPath;
        };

        serviceConfig = defaultServiceConfig // {
          ExecStart = ''
            ${pkg}/bin/netbox rqworker high default low
          '';
        };
      };

      netbox-housekeeping = {
        description = "NetBox housekeeping job";
        after = [ "netbox.service" ];

        environment = {
          PYTHONPATH = pkg.pythonPath;
        };

        serviceConfig = defaultServiceConfig // {
          Type = "oneshot";
          ExecStart = ''
            ${pkg}/bin/netbox housekeeping
          '';
        };
      };
    };

    systemd.timers.netbox-housekeeping = {
      description = "Run NetBox housekeeping job";
      wantedBy = [ "timers.target" ];

      timerConfig = {
        OnCalendar = "daily";
      };
    };

    users.users.netbox = {
      home = "${cfg.dataDir}";
      isSystemUser = true;
      group = "netbox";
    };
    users.groups.netbox = {};
    users.groups."${config.services.redis.servers.netbox.user}".members = [ "netbox" ];
  };
}