{ config, pkgs, lib, ...}:
with lib;
let
  cfg = config.services.seafile-server;
  seafileConfigFile = pkgs.writeText "seafile.conf"
    (generators.toINI {} cfg.seafileSettings);
  # fix permissions at start
in
  {
    options.services.seafile-server = {
      enable = mkEnableOption "Seafile server";
      storagePath = mkOption {
        type = types.path;
        default = "/srv/seafile";
        description = "where to store uploaded file data";
      };
      seafileSettings = mkOption {
        type = with types; attrsOf (attrsOf (oneOf [ bool int str ]));
        default = {};
        description = ''
          all possible seafile.conf settings
          '';
        };
      autorun = mkOption {
        type = types.bool;
        default = true;
        description = "enable the seafile-server service to get started automatically";
      };
      db = {
        type = mkOption {
          type = types.enum ["sqlite" "mysql"];
          default = "sqlite";
          description = "database backend type";
        };
        user = mkOption {
          type = types.nullOr types.str;
          default = "seafile";
          description = "Database user name. Not required for sqlite.";
        };
        dbnameSeafile = mkOption {
          type = types.nullOr types.str;
          default = "seafile";
          description = "Database name for Seafile server. Not required for sqlite.";
        };
        dbnameCcnet = mkOption {
          type = types.nullOr types.str;
          default = "seafile";
          description = "Database name for Ccnet server. Not required for sqlite.";
        };
        dbnameSeahub = mkOption {
          type = types.nullOr types.str;
          default = "seafile";
          description = "Database name for Seahub web interface. Not required for sqlite.";
        };
        passwordFile = mkOption {
            type = types.nullOr types.str;
            default = null;
            description = ''
              The full path to a file that contains the database password.
              Not required for sqlite.
            '';
          };
          host = mkOption {
            type = types.nullOr types.str;
            default = "localhost";
            description = "Database host.";
          };
          dbport = mkOption {
            type = with types; nullOr (either int str);
            default = 3306;
            description = "Database port. Not required for sqlite.";
          };
        };

        user = mkOption {
          type = types.str;
          default = "seafile";
          description = "User account under which the Seafile server runs.";
        };

        group = mkOption {
          type = types.str;
          default = "seafile";
          description = "Group account under which the Seafile server runs.";
        };

        name = mkOption {
          type = types.str;
          default = "Seafile";
          description = "name of the Seafile instance, will show up in client and web interface";
        };

        domainName = mkOption {
          type = types.str;
          description = "full domain name of the seafile instance";
        };

#        ccnetPort = mkOption {
#          type = types.int;
#          default = 10001;
#          description = "listening port for ccnet server";
#        };

        seafilePort = mkOption {
          type = types.int;
          default = 12001;
          description = "listening port for Seafile server";
        };

        fileserverPort = mkOption {
          type = types.int;
          default = 8082;
          description = "listening port for Seafile's fileserver component";
        };

        seahubPort = mkOption {
          type = types.int;
          default = 443;
          description = "listening http port for Seahub web interface";
        };

        externalPort = mkOption {
          type = types.int;
          default = 443;
          description = "external port under which Seahub is reachable from the outside. Possibly the external port of a reverse proxy like nginx.";
        };

        enableTLS = mkEnableOption {
          default = true;
          description = "whether to use TLS and HTTPS for communication";
        };

        openFirewall = mkEnableOption {
          default = true;
          description = "whether to open up the firewall ports for ccnet, seafile-server and seahub";
        };

        defaultQuota = mkOption {
          type = types.nullOr types.int;
          default = null;
          description = "default quota to be set per user, in GB";
        };

        trashExpirationTime = mkOption {
          type = types.int;
          default = 30;
          description = "default time for automatic library trash cleanup";
        };

        fileRevisionHistoryDays = mkOption {
          type = types.nullOr types.int;
          default = null;
          description = "default history length of file revisions to keep in days. <literal>null</literal> means keeping all revisions.";
        };

        fileserverBindAddress = mkOption {
          type = types.str;
          default = "0.0.0.0";
          description = "bind address for fileserver, binds to all addresses by default";
        };

        fileserverWorkers = mkOption {
          type = types.int;
          default = 10;
          description = "number of worker threads to server http requests";
        };

        fileserverIndexers = mkOption {
          type = types.int;
          default = 1;
          description = "number of threads used to sequentially divide uploaded files into blocks for storage";
        };

        fileserverBlockSize = mkOption {
          type = types.int;
          default = 1;
          description = "size of blocks that uploaded files are divided into, in MB";
        };
      };


      config = let
        directoriesToManage = [ cfg.storagePath ];
      in
      mkIf cfg.enable {
        services.seafile-server.seafileSettings = {
          library_trash.expire_days = cfg.trashExpirationTime;
          fileserver = {
            host = cfg.fileserverBindAddress;
            port = cfg.fileserverPort;
            worker_threads = cfg.fileserverWorkers;
            max_indexing_threads = cfg.fileserverIndexers;
            fixed_block_size = cfg.fileserverBlockSize;
          };
          quota = mkIf (! isNull cfg.defaultQuota) {
            default = cfg.defaultQuota;
          };
          history = mkIf (! isNull cfg.fileRevisionHistoryDays) {
            keep_days = cfg.fileRevisionHistoryDays;
          };
          database = mkMerge [
            {
              type = cfg.db.type;
            }
            # while just using the cfg.db set directly might be possible and
            # save lines of code, I prefer hand-picking options
            (mkIf (cfg.db.type == "mysql") {
              host = cfg.db.host;
              port = cfg.db.port;
              user = cfg.db.user;
              connection_charset = "utf8";
              db_name = cfg.db.dbname;
              max_connections = 100;
              password = "#dbpass#";
            })
          ];
        };

        systemd = {
          # state directory permissions managed by systemd
          tmpfiles.rules = [
            "d ${cfg.storagePath} 0750 ${cfg.user} ${cfg.group} -"
            "d ${cfg.storagePath}/conf 0750 ${cfg.user} ${cfg.group} -"
            "d ${cfg.storagePath}/home 0710 ${cfg.user} ${cfg.group} -"
          ];
          services.seafile-server = {

          path = with pkgs; [ seafile-server.seafile-server-core ];
          script = ''
            ./seafile-server/seafile-server-latest/bin/seafile-admin start
            '';
          serviceConfig = {
            ExecStartPre = [
              ("+${pkgs.writeScript "seafile-server-preStart-privileged" ''
                #!${pkgs.runtimeShell}
                #  stuff run as root
              ''}")
              ("${pkgs.writeShellScript "seafile-server-preStart-unprivileged" ''
                # stuff run as seafile user
                set -x

                # outside URL
                SERVICE_URL="http${if cfg.enableTLS then "s" else ""}://${cfg.domainName}:${toString cfg.externalPort}"

                # seafile.conf generation

                # move seafile.conf template from nix store
                cp ${seafileConfigFile} ./conf/seafile.conf
                # replace placeholder secrets with real secret read from file
                ${if (isNull cfg.db.passwordFile) then ''
                  DBPASS="$(head -n1 ${toString cfg.db.passwordFile})"
                  sed -e "s,#dbpass#,$DBPASS,g" -i ./conf/seafile.conf
                  ''
                  else ""
                }

                
                pwd
                ln -sf ${pkgs.seafile-server} seafile-server
                ${pkgs.seafile-server.pythonEnv}/bin/python seafile-server/setup-seafile-mysql.py auto \
                  -n "${cfg.name}" \
                  -i "${cfg.domainName}" \
                  -p "${toString cfg.fileserverPort}" \
                  -d "${cfg.storagePath}" \
                  -o "${cfg.db.host}" \
                  -t "${toString cfg.db.dbport}" \
                  -u "${cfg.db.user}" \
                  -w "$DBPASS" \
                  -c "${cfg.db.dbnameCcnet}" \
                  -s "${cfg.db.dbnameSeafile}" \
                  -b "${cfg.db.dbnameSeahub}"
              ''}")
            ];
            User = cfg.user;
            Group = cfg.group;
            Type = "oneshot";
            WorkingDirectory = cfg.storagePath;
          };
          enable = cfg.autorun;
          wantedBy = [ "multi-user.target" ];
        };
      };

        users.users.${cfg.user} = {
          home = "${cfg.storagePath}/home";
          group = cfg.group;
          # don't make NixOS create the home directory as otherwise the permissions for /srv might be 0700,
          # making it impossible to cd into the storagePath
          createHome = false;
          isNormalUser = false;
        };
        users.groups.${cfg.group}.members = [ cfg.user ];

        # ToDo: make sure ccnet is reachable
        networking.firewall.allowedTCPPorts = with cfg; if openFirewall then [ seafilePort fileserverPort ] else [];
      };
    }