{
  description = "xonotic-exporter dev shell";

  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
    flake-utils.url = "github:numtide/flake-utils";
  };

  outputs =
    {
      self,
      nixpkgs,
      flake-utils,
    }:
    flake-utils.lib.eachDefaultSystem (
      system:
      let
        pkgs = import nixpkgs { inherit system; };

        # Python env with all runtime + dev deps
        pythonEnv = pkgs.python313.withPackages (
          ps: with ps; [
            (ps.buildPythonPackage rec {
              pname = "xrcon";
              version = "0.2";
              format = "setuptools";

              src = ps.fetchPypi {
                inherit pname version;
                sha256 = "sha256-xRuZXgf09zrQUpneR2DTBYr7W08GYOc2TmaVp71rcqs=";
              };

              build-system = [ ps.setuptools ];
              dependencies = [ ps.six ];
            })

            prometheus-client
            pytest
            pytest-asyncio
            mypy
            black
            isort
            ruff
            pip
          ]
        );

        # Convenience script: start a local Xonotic dedicated server
        startXonotic = pkgs.writeShellScriptBin "start-xonotic-server" ''
          set -euo pipefail

          PORT=''${XONOTIC_PORT:-26010}
          RCON_PW=''${XONOTIC_RCON_PASSWORD:-devpassword}
          DATADIR=''${XONOTIC_DATADIR:-$PWD/.xonotic-data}
          CFGDIR="$DATADIR/data"

          mkdir -p "$CFGDIR"

          cat > "$CFGDIR/config.cfg" <<EOF
          hostname "xonotic-dev-server"
          sv_public -1
          rcon_password "$RCON_PW"
          rcon_secure 0
          EOF

          cat > "$CFGDIR/server.cfg" <<EOF
          gametype dm
          minplayers 0
          bot_number 2
          timelimit 20
          fraglimit 30
          EOF

          echo "Starting Xonotic dedicated server on UDP :$PORT  (rcon pw: $RCON_PW)"
          exec ${pkgs.xonotic-dedicated}/bin/xonotic-dedicated \
          -userdir "$DATADIR" \
          -port "$PORT" \
          "$@"
        '';

        # Convenience script: query the local test server
        queryServer = pkgs.writeShellScriptBin "query-xonotic" ''
          set -euo pipefail
          PORT=''${XONOTIC_PORT:-26010}
          PW=''${XONOTIC_RCON_PASSWORD:-devpassword}
          exec xonotic-exporter query \
            --host localhost \
            --port "$PORT" \
            --password "$PW" \
            --mode 0 \
            "$@"
        '';

        # Generate a minimal dev config for the exporter
        genConfig = pkgs.writeShellScriptBin "gen-exporter-config" ''
          PORT=''${XONOTIC_PORT:-26010}
          PW=''${XONOTIC_RCON_PASSWORD:-devpassword}
          OUT=''${1:-dev-config.toml}
          cat > "$OUT" <<EOF
          [exporter]
          host = "0.0.0.0"
          port = 9260

          [[servers]]
          name          = "dev"
          host          = "localhost"
          port          = $PORT
          rcon_password = "$PW"
          rcon_mode     = 0
          EOF
          echo "Wrote exporter config to $OUT"
        '';

      in
      {
        devShells.default = pkgs.mkShell {
          name = "xonotic-exporter";

          packages = [
            pythonEnv

            # Xonotic dedicated server
            pkgs.xonotic-dedicated

            # The project itself (editable install via pip in shellHook)

            # Network / protocol debugging
            pkgs.netcat-gnu # nc — poke UDP ports
            pkgs.tcpdump # capture RCON UDP traffic
            pkgs.wireshark-cli # tshark for scripted captures
            pkgs.socat # relay / inspect UDP
            pkgs.nmap # port scanning / service detection

            # Metrics & observability
            pkgs.prometheus # run a local prometheus instance
            pkgs.grafana # dashboard for scraped metrics
            pkgs.curl # hit the /metrics endpoint

            # Dev tools
            pkgs.git
            pkgs.gnumake
            pkgs.jq # inspect JSON / TOML-adjacent debugging
            pkgs.ripgrep
            pkgs.fd
            pkgs.watchexec # re-run tests on file change
            pkgs.just # task runner (justfile)
            pkgs.entr # alternative file watcher

            # Convenience scripts defined above
            startXonotic
            queryServer
            genConfig
          ];

          shellHook = ''
            echo ""
            echo "  ╔══════════════════════════════════════════╗"
            echo "  ║       xonotic-exporter dev shell         ║"
            echo "  ╚══════════════════════════════════════════╝"
            echo ""

            export PYTHONPATH="$PWD/.dev-packages:$PYTHONPATH"
            export PYTHONDONTWRITEBYTECODE=1
            export PYTHONUNBUFFERED=1

            DEV_PKG="$PWD/.dev-packages"
            PTH="$DEV_PKG/__editable__.xonotic_exporter-1.0.0.pth"
            export PATH="$PWD/.dev-packages/bin:$PATH"

            if [ ! -f "$PTH" ]; then
              echo "  Installing xonotic-exporter (editable)..."
              pip install -e . --target "$DEV_PKG" --quiet || echo "  ⚠ pip install failed — check pyproject.toml"
            else
              echo "  xonotic-exporter already installed, skipping pip."
            fi

            echo ""
            echo "  Commands:"
            echo "    start-xonotic-server   — spin up a local Xonotic dedicated server"
            echo "    query-xonotic          — one-shot RCON query against the dev server"
            echo "    gen-exporter-config    — write a dev config.toml"
            echo "    xonotic-exporter serve dev-config.toml  — start the HTTP exporter"
            echo ""
            echo "  Env overrides:"
            echo "    XONOTIC_PORT            (default 26010)"
            echo "    XONOTIC_RCON_PASSWORD   (default devpassword)"
            echo "    XONOTIC_DATADIR         (default .xonotic-data/)"
            echo ""
          '';
        };
      }
    );
}