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

let
  reportDir = "/var/lib/lidarr-mb-gap/reports";
  envFile = "/var/lib/lidarr-mb-gap/.env";
in
{
  options.services.lidarr-mb-gap = {
    enable = lib.mkEnableOption "Lidarr MusicBrainz Gap Reporter";
    
    package = lib.mkOption {
      type = lib.types.nullOr lib.types.package;
      default = null;
      description = "The lidarr-mb-gap package to use. If null, will be built from src.";
    };
    
    src = lib.mkOption {
      type = lib.types.nullOr lib.types.path;
      default = null;
      description = "Source path for building the package. Required if package is not explicitly set.";
    };
    
    reportDir = lib.mkOption {
      type = lib.types.str;
      default = reportDir;
      description = "Directory where reports will be generated";
    };
    
    envFile = lib.mkOption {
      type = lib.types.str;
      default = envFile;
      description = "Path to .env file with LIDARR_URL and LIDARR_API_KEY";
    };
    
    runInterval = lib.mkOption {
      type = lib.types.str;
      default = "daily";
      description = "systemd timer interval (e.g., 'daily', 'hourly', '*-*-* 02:00:00')";
    };
    
    syncToVPS = lib.mkOption {
      type = lib.types.bool;
      default = false;
      description = "Whether to sync reports to VPS via rsync";
    };
    
    vpsHost = lib.mkOption {
      type = lib.types.nullOr lib.types.str;
      default = null;
      description = "VPS hostname or IP for rsync (e.g., 'vps' or 'user@vps.example.com')";
    };
    
    vpsPath = lib.mkOption {
      type = lib.types.str;
      default = "/var/www/html";
      description = "Path on VPS where reports should be synced";
    };
  };

  config = lib.mkIf config.services.lidarr-mb-gap.enable {
    systemd.tmpfiles.rules = [
      "d ${config.services.lidarr-mb-gap.reportDir} 0755 lidarr-mb-gap lidarr-mb-gap -"
    ];

    users.users.lidarr-mb-gap = {
      isSystemUser = true;
      group = "lidarr-mb-gap";
      home = "/var/lib/lidarr-mb-gap";
      createHome = true;
    };

    users.groups.lidarr-mb-gap = {};

    systemd.services.lidarr-mb-gap = {
      description = "Generate Lidarr MusicBrainz Gap Report";
      after = [ "network.target" ];
      wantedBy = [ "multi-user.target" ];
      
      serviceConfig = {
        Type = "oneshot";
        User = "lidarr-mb-gap";
        Group = "lidarr-mb-gap";
        WorkingDirectory = config.services.lidarr-mb-gap.reportDir;
        EnvironmentFile = config.services.lidarr-mb-gap.envFile;
        ExecStart = pkgs.writeShellScript "lidarr-mb-gap-run" ''
          set -euo pipefail
          
          # Export OUTPUT_DIR to environment
          export OUTPUT_DIR=${config.services.lidarr-mb-gap.reportDir}
          
          # Run the binary
          ${lib.getExe lidarrMbGapPackage} || {
            echo "Failed to generate report"
            exit 1
          }
          
          # Sync to VPS if enabled
          ${lib.optionalString (config.services.lidarr-mb-gap.syncToVPS && config.services.lidarr-mb-gap.vpsHost != null) ''
            ${pkgs.rsync}/bin/rsync -avz --delete \
              ${config.services.lidarr-mb-gap.reportDir}/ \
              ${config.services.lidarr-mb-gap.vpsHost}:${config.services.lidarr-mb-gap.vpsPath}/
          ''}
        '';
        StandardOutput = "journal";
        StandardError = "journal";
      };
    };

    systemd.timers.lidarr-mb-gap = {
      description = "Timer for Lidarr MusicBrainz Gap Report";
      wantedBy = [ "timers.target" ];
      timerConfig = {
        OnCalendar = config.services.lidarr-mb-gap.runInterval;
        Persistent = true;
      };
    };
  };
}