Establish baseline

terminal-environment/genv/default.nix

@@ -0,0 +1,67 @@
+{ pkgs, lib, ... }:
+
+let
+  genv = pkgs.writeShellScriptBin "genv" ''
+    #!/usr/bin/env bash
+    set -e
+
+    DISTRO="$1"
+    PRESET="$2"
+
+    if [ -z "$DISTRO" ] || [ -z "$PRESET" ]; then
+      echo "Usage: genv <distro> <preset>"
+      exit 1
+    fi
+
+    PROJECT=$(basename "$PWD")
+    BOX="genv-$PROJECT"
+
+    # distro mapping
+    case "$DISTRO" in
+      ubuntu) IMAGE="docker.io/library/ubuntu:24.04" ;;
+      arch) IMAGE="docker.io/library/archlinux:latest" ;;
+      alpine) IMAGE="docker.io/library/alpine:latest" ;;
+      *) IMAGE="$DISTRO" ;;
+    esac
+
+    echo "[genv] image: $IMAGE"
+
+    # container nur erstellen wenn nötig
+    if ! distrobox list | grep -q "$BOX"; then
+      distrobox create --name "$BOX" --image "$IMAGE"
+    fi
+
+    mkdir -p .genv
+
+    # preset kopieren
+    cp ${./presets}/$PRESET.sh .genv/setup.sh
+    chmod +x .genv/setup.sh
+
+    # envrc generieren
+    cat > .envrc <<EOF
+export GENV_BOX="$BOX"
+
+# container starten
+distrobox start "$GENV_BOX" >/dev/null 2>&1 || true
+
+# setup einmalig
+if [ ! -f .genv/.init ]; then
+  echo "[genv] setup läuft"
+  distrobox enter "$GENV_BOX" -- bash .genv/setup.sh
+  touch .genv/.init
+fi
+
+# tmux workflow
+if [ -z "$TMUX" ]; then
+  tmux new-session -A -s "$GENV_BOX" \
+    \; new-window -n editor "nvim" \
+    \; new-window -n dev "distrobox enter $GENV_BOX"
+fi
+EOF
+
+    echo "[genv] fertig → direnv allow"
+  '';
+in
+{
+  home.packages = [ genv ];
+}