nix-config/rebuild.sh

#!/usr/bin/env bash

# Get current branch and git status for branch-aware behavior
current_branch=$(git branch --show-current 2>/dev/null || echo "unknown")
git_status=$(git status --porcelain 2>/dev/null || echo "")

# Default values
default_target=$(hostname)
default_user="$USER"
default_host=$(hostname)
default_mode=$(if [[ "$current_branch" != "main" ]]; then echo "test"; else echo "switch"; fi)

if [ -d "result" ];
then
  preserve_result=true
else
  preserve_result=false
fi

show_trace=false
clean_vm=false

while [ $# -gt 0 ]; do
  case "$1" in
    --target*|-t*)
      if [[ "$1" != *=* ]]; then shift; fi # Value is next arg if no `=`
      target="${1#*=}"
      ;;
    --flake*|-f*)
      if [[ "$1" != *=* ]]; then shift; fi
      flake="${1#*=}"
      ;;
    --mode*|-m*)
      if [[ "$1" != *=* ]]; then shift; fi
      mode="${1#*=}"
      ;;
    --user*|-u*)
      if [[ "$1" != *=* ]]; then shift; fi
      user="${1#*=}"
      ;;
    --host*)
      if [[ "$1" != *=* ]]; then shift; fi
      host="${1#*=}"
      ;;
    --preserve-result)
      preserve_result=true
      ;;
    --no-preserve-result)
      preserve_result=false
      ;;
    --show-trace)
      show_trace=true
      ;;
    --clean-vm)
      clean_vm=true
      ;;
    --help|-h)
      echo "--help -h: print this message"
      echo "--target -t: defaults to the current system"
      echo "    currently: $default_target"
      echo "--flake -f: defaults to same as target"
      echo "    currently: ${target:-$default_target}"
      echo "--mode -m: defaults to 'switch', but 'test' on non-main branches"
      echo "    currently would be: $default_mode"
      echo "    Available modes: switch, test, build, boot, vm"
      echo "    'vm' mode builds and starts a virtual machine"
      echo "--user -u: defaults to the current user"
      echo "    currently: $default_user"
      echo "--host: defaults to building on the current machine"
      echo "    currently: $default_host"
      echo "--preserve-result: do not remove the generated result folder after building"
      echo "--no-preserve-result: remove any result folder after building"
      echo "--show-trace: show trace on builds"
      echo "--clean-vm: remove existing VM disk (nixos.qcow2) before building"
      echo ""
      echo "Branch-aware behavior:"
      echo "  - On non-main branches: defaults to test mode with warning"
      echo "  - On main with uncommitted changes: shows warning about creating a branch"
      echo "  - Current branch: $current_branch"
      if [[ -n "$git_status" ]]; then
        echo "  - Git status: uncommitted changes detected"
      else
        echo "  - Git status: clean working tree"
      fi
      exit 0
      ;;
    *)
      echo "Error: Invalid argument $1"
      exit 1
      ;;
  esac
  shift
done

target=${target:-$default_target}
flake=${flake:-$target}
mode=${mode:-$default_mode}
user=${user:-$default_user}

# Validate mode
valid_modes="switch test build boot vm"
if [[ ! " $valid_modes " =~ " $mode " ]]; then
    echo "Error: Invalid mode '$mode'"
    echo "Valid modes are: $valid_modes"
    exit 1
fi

# Clean VM disk if requested
if [[ "$clean_vm" = true ]] && [[ -f "nixos.qcow2" ]]; then
    echo "Removing existing VM disk: nixos.qcow2"
    rm nixos.qcow2
fi

# Branch-aware warnings and behavior
if [[ "$current_branch" != "main" ]] && [[ "$mode" == "test" ]]; then
    echo "⚠️  WARNING: You are on branch '$current_branch' (not main)"
    echo "   Defaulting to test mode to prevent accidental system changes"
    echo "   Specify --mode=switch explicitly if you want to apply changes"
elif [[ "$current_branch" == "main" ]] && [[ -n "$git_status" ]] && [[ "$mode" != "test" ]]; then
    echo "⚠️  WARNING: You are on main branch with uncommitted changes"
    echo "   Consider creating a feature branch for development:"
    echo "   git checkout -b feature/your-feature-name"
fi

if [[ "$mode" == "vm" ]]; then
    command="nix build .#nixosConfigurations.$flake.config.system.build.vm"
    
    if [[ "$show_trace" = true ]]; then
        command="$command --show-trace"
    fi
    
    echo $command
    $command
    
    if [[ $? -eq 0 ]] && [[ -d "result" ]]; then
        echo "Starting VM..."
        QEMU_KERNEL_PARAMS=console=ttyS0 ./result/bin/run-nixos-vm -nographic; reset
    fi
else
    command="nixos-rebuild $mode --sudo --ask-sudo-password --flake .#$flake"
    
    if [[ $host ]]; then
        command="$command --build-host $host"
    fi

    if [[ "$target" != "$(hostname)" ]]; then
        command="$command --target-host $user@$target"
    fi

    if [[ "$show_trace" = true ]]; then
        command="$command --show-trace"
    fi
    
    echo $command
    $command
fi

if [ -d "result" ];
then
  if [[ "$preserve_result" == "false" ]];
  then
    rm -r result
  fi
fi