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

let
  inherit (lib) mkEnableOption mkOption mkIf types;
  format = pkgs.formats.toml { };
  cfg = config.services.hebbot;
  settingsFile = format.generate "config.toml" cfg.settings;
  mkTemplateOption = templateName: mkOption {
    type = types.path;
    description = lib.mdDoc ''
      A path to the Markdown file for the ${templateName}.
    '';
  };
in
  {
    meta.maintainers = [ lib.maintainers.raitobezarius ];
    options.services.hebbot = {
      enable = mkEnableOption "hebbot";
      botPasswordFile = mkOption {
        type = types.path;
        description = lib.mdDoc ''
          A path to the password file for your bot.

          Consider using a path that does not end up in your Nix store
          as it would be world readable.
        '';
      };
      templates = {
        project = mkTemplateOption "project template";
        report = mkTemplateOption "report template";
        section = mkTemplateOption "section template";
      };
      settings = mkOption {
        type = format.type;
        default = { };
        description = lib.mdDoc ''
          Configuration for Hebbot, see, for examples:

          - <https://github.com/matrix-org/twim-config/blob/master/config.toml>
          - <https://gitlab.gnome.org/Teams/Websites/thisweek.gnome.org/-/blob/main/hebbot/config.toml>
        '';
      };
    };

    config = mkIf cfg.enable {
      systemd.services.hebbot = {
        description = "hebbot - a TWIM-style Matrix bot written in Rust";
        after = [ "network.target" ];
        wantedBy = [ "multi-user.target" ];

        preStart = ''
          ln -sf ${cfg.templates.project} ./project_template.md
          ln -sf ${cfg.templates.report} ./report_template.md
          ln -sf ${cfg.templates.section} ./section_template.md
          ln -sf ${settingsFile} ./config.toml
        '';

        script = ''
          export BOT_PASSWORD="$(cat $CREDENTIALS_DIRECTORY/bot-password-file)"
          ${lib.getExe pkgs.hebbot}
        '';

        serviceConfig = {
          DynamicUser = true;
          Restart = "on-failure";
          LoadCredential = "bot-password-file:${cfg.botPasswordFile}";
          RestartSec = "10s";
          StateDirectory = "hebbot";
          WorkingDirectory = "hebbot";
      };
    };
  };
}