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

let
  dcrdEnabled = config.services.dcrd.enable or false;
  cfg = config.services.vspd;
in {
  options.services.vspd = with lib; {
    enable = mkEnableOption "Voting Service Provider Daemon";

    package = mkOption {
      type = types.package;
      default = pkgs.vspd;
      description = "vspd package to use";
    };

    user = mkOption {
      type = types.str;
      default = "vspd";
      description = "User to run vspd as";
    };

    group = mkOption {
      type = types.str;
      default = cfg.user;
      description = "Group to run vspd as";
    };

    dataDir = mkOption {
      type = types.path;
      default = "/var/lib/vspd";
      description = "State directory for vspd";
    };

    configFile = mkOption {
      type = types.path;
      description = "Path to vspd.conf";
    };
  };

  config = lib.mkIf cfg.enable {
    users.users.${cfg.user} = {
      group = cfg.group;
      home = cfg.dataDir;
      isSystemUser = true;
      description = "vspd user";
      # vspd needs read access to the dcrd RPC certificate
      extraGroups = lib.optional (dcrdEnabled && config.services.dcrd.group != cfg.group) config.services.dcrd.group;
    };

    users.groups.${cfg.group} = {};

    systemd.services.vspd = {
      description = "Voting Service Provider Daemon";
      wantedBy = [ "multi-user.target" ];
      after = [ "network-online.target" ];
      wants = [ "network-online.target" ];

      serviceConfig = {
        User = cfg.user;
        Group = cfg.group;
        StateDirectory = "vspd";
        StateDirectoryMode = "0750";
        WorkingDirectory = cfg.dataDir;
        # Link the provided config file to the expected location in homedir
        ExecStartPre = "${pkgs.writeShellScript "vspd-pre-start" ''
          set -e
          ln -sf ${cfg.configFile} ${cfg.dataDir}/vspd.conf
          mkdir -p ${cfg.dataDir}/internal/webapi
          if [ ! -e "${cfg.dataDir}/internal/webapi/public" ]; then
            ln -sfn "${cfg.package}/share/vspd/internal/webapi/public" "${cfg.dataDir}/internal/webapi/public"
          fi
          if [ ! -e "${cfg.dataDir}/internal/webapi/templates" ]; then
            ln -sfn "${cfg.package}/share/vspd/internal/webapi/templates" "${cfg.dataDir}/internal/webapi/templates"
          fi
        ''}";
        ExecStart = "${lib.getExe cfg.package} --homedir=${cfg.dataDir}";
        Restart = "on-failure";
        RestartSec = "10s";
      };
    };
  };
}