{
  config,
  lib,
  pkgs,
  ...
}:
let
  cfg = config.services.renovate-bot;
  inherit (lib)
    mkOption
    mkEnableOption
    types
    ;

  renovateConfig = cfg.settings // {
    platform = cfg.platform;
    endpoint = cfg.endpoint;
  };

  renovateConfigFile = pkgs.writeText "renovate-config.json" (builtins.toJSON renovateConfig);

  renovateWrapper = pkgs.writeShellScript "renovate-wrapper" ''
    export RENOVATE_TOKEN=$(cat "${cfg.tokenFile}")
    exec ${lib.getExe cfg.package} ${lib.concatStringsSep " " cfg.repositories}
  '';
in
{
  options = {
    services.renovate-bot = {
      enable = mkEnableOption "Renovate Bot service";

      package = mkOption {
        type = types.package;
        default = pkgs.renovate;
        defaultText = "pkgs.renovate";
        description = "Renovate Bot package to use";
      };

      platform = mkOption {
        type = types.enum [
          "gitlab"
          "github"
          "bitbucket"
          "azure"
        ];
        default = "gitlab";
        description = "Git platform to use";
      };

      endpoint = mkOption {
        type = types.str;
        default = "https://gitlab.com";
        description = "Git platform endpoint URL";
        example = "https://gitlab.example.com";
      };

      tokenFile = mkOption {
        type = types.str;
        description = "Path to file containing authentication token";
      };

      envFile = mkOption {
        type = types.nullOr types.str;
        default = null;
        description = "Path to file containing environment variables (in .env format)";
      };

      user = mkOption {
        type = types.str;
        default = "renovate-bot";
        description = "User account under which renovate-bot runs";
      };

      group = mkOption {
        type = types.str;
        default = "renovate-bot";
        description = "Group account under which renovate-bot runs";
      };

      homeDirectory = mkOption {
        type = types.str;
        default = "/var/lib/renovate-bot";
        description = "Home directory for the renovate-bot user";
      };

      repositories = mkOption {
        type = types.listOf types.str;
        default = [ ];
        description = "List of repositories to monitor (format: owner/repo)";
        example = [
          "myorg/myrepo"
          "myorg/another-repo"
        ];
      };

      schedule = mkOption {
        type = types.nullOr types.str;
        default = null;
        example = "before 6am";
        description = "Schedule for Renovate runs (systemd timer OnCalendar format)";
      };

      logLevel = mkOption {
        type = types.enum [
          "fatal"
          "error"
          "warn"
          "info"
          "debug"
          "trace"
        ];
        default = "info";
        description = "Log level for Renovate (set via LOG_LEVEL environment variable)";
      };

      extraPackages = mkOption {
        type = types.listOf types.package;
        default = [ ];
        description = "Extra packages to add to PATH for the Renovate Bot service";
        example = "[ pkgs.curl pkgs.jq ]";
      };

      nodeMemoryLimit = mkOption {
        type = types.int;
        default = 4096;
        description = "Node.js memory limit in MB (--max-old-space-size)";
      };

      settings = mkOption {
        default = { };
        type = types.submodule {
          freeformType =
            with types;
            attrsOf (oneOf [
              str
              bool
              int
              float
              (listOf str)
              (attrsOf anything)
            ]);

          options = {
            # Common Renovate configuration options
            # Based on https://docs.renovatebot.com/configuration-options/

            requireConfig = mkOption {
              type = types.bool;
              default = false;
              description = "Require renovate.json config file";
            };

            dryRun = mkOption {
              type = types.bool;
              default = false;
              description = "Run in dry-run mode (no PRs created)";
            };

            printConfig = mkOption {
              type = types.bool;
              default = false;
              description = "Print the resolved config and exit";
            };

            gitAuthor = mkOption {
              type = types.nullOr types.str;
              default = null;
              example = "Renovate Bot <bot@example.com>";
              description = "Git author for commits";
            };

            gitPrivateKey = mkOption {
              type = types.nullOr types.str;
              default = null;
              description = "Private key for git operations";
            };

            includeForks = mkOption {
              type = types.bool;
              default = false;
              description = "Include forked repositories";
            };

            includeMirrors = mkOption {
              type = types.bool;
              default = false;
              description = "Include mirrored repositories";
            };

            autodiscover = mkOption {
              type = types.bool;
              default = false;
              description = "Auto-discover repositories";
            };

            autodiscoverFilter = mkOption {
              type = types.nullOr types.str;
              default = null;
              description = "Filter for auto-discovered repositories";
            };

            timezone = mkOption {
              type = types.nullOr types.str;
              default = null;
              example = "America/Sao_Paulo";
              description = "Timezone for scheduling";
            };

            prConcurrentLimit = mkOption {
              type = types.int;
              default = 10;
              description = "Maximum number of concurrent PRs";
            };

            prHourlyLimit = mkOption {
              type = types.int;
              default = 2;
              description = "Maximum number of PRs per hour (0 = unlimited)";
            };

            branchConcurrentLimit = mkOption {
              type = types.int;
              default = 10;
              description = "Maximum number of concurrent branches (0 = unlimited)";
            };
          };
        };
        description = ''
          Settings for the Renovate configuration.
          See https://docs.renovatebot.com/configuration-options/
          for detailed information about all available settings.
        '';
      };
    };
  };

  config = lib.mkIf cfg.enable {

    warnings = (
      lib.optional (lib.isStorePath cfg.tokenFile) ''
        services.renovate-bot.tokenFile points to a file in the Nix store.
        You should use a quoted absolute path instead.
      ''
    );

    users.users.${cfg.user} = {
      isSystemUser = true;
      group = cfg.group;
      home = cfg.homeDirectory;
      createHome = true;
    };

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

    systemd.services.renovate-bot = {
      description = "Renovate Bot Service";
      after = [ "network.target" ];

      path = [ pkgs.git ] ++ cfg.extraPackages;

      environment = {
        RENOVATE_CONFIG_FILE = renovateConfigFile;
        LOG_LEVEL = cfg.logLevel;
        NODE_OPTIONS = "--max-old-space-size=${toString cfg.nodeMemoryLimit}";
      };

      serviceConfig = {
        Type = "oneshot";
        User = cfg.user;
        Group = cfg.group;
        WorkingDirectory = cfg.homeDirectory;
        ExecStart = "${renovateWrapper}";
      }
      // lib.optionalAttrs (cfg.envFile != null) {
        EnvironmentFile = cfg.envFile;
      };
    };

    systemd.timers.renovate-bot = lib.mkIf (cfg.schedule != null) {
      description = "Renovate Bot Timer";
      wantedBy = [ "timers.target" ];
      timerConfig = {
        OnCalendar = cfg.schedule;
        Persistent = true;
      };
    };
  };
}