#!/bin/sh

set -eo pipefail

if [ -z "$HOST" ]
then
    HOST=$(hostname)
fi
DIR=$(realpath "$(dirname "$0")")
OUT=$(mktemp -du)
ROOT="$DIR/roots/$HOST.nix"

echo Active tree: "$ROOT"

## Build the libkookie tree
function build {  
    NIXPKGS_ALLOW_UNFREE=1 \
            nix build -f '<nixpkgs/nixos>' system \
            -I nixos-config="$ROOT" \
            -I "nixpkgs=$DIR/nixpkgs/unstable" \
            -I "nixpkgs-overlays=$DIR/overlays" \
            -I "home-manager=$DIR/home-manager" \
            -I "modules=$DIR/modules" \
            -I "shells=$DIR/shells" \
            -I "configuration=$DIR/configuration" \
            --out-link "$OUT" "$@"
}

## Build and output build path for debugging
function debug {
    build "$@"
    echo "Build path: $OUT"
    exec build "$@"
}

## Build and switch to the new configuration (requires root)
function switch {
    build "$@"
    nix-env -p /nix/var/nix/profiles/system --set "$OUT"
    "$OUT"/bin/switch-to-configuration switch
}

function vmimage {
    RUN="$1"; shift

    NIXPKGS_ALLOW_UNFREE=1 \
              nix build -f '<nixpkgs/nixos>' vm \
              -I nixos-config="$ROOT" \
              -I "nixpkgs=$DIR" \
              -I "nixpkgs-overlays=$DIR/overlays" \
              -I "home-manager=$DIR/home-manager" \
              -I "modules=$DIR/modules" \
              -I "shells=$DIR/shells" \
              -I "configuration=$DIR/configuration" \
              --argstr system x86_64-linux "$@"

    if [ "$RUN" -eq "1" ]; then
        echo "Running VM image..."
        ./result/bin/run-$HOST-vm
    fi

    exit 0
}

case "$1" in
    -s* | --switch*) shift; switch "$@" ;;
    -d* | --debug*)  shift; debug "$@" ;;
    -vr*)  shift; vmimage "1" "$@" ;;
    -v*)  shift; vmimage "0" "$@" ;;
    *)               build "$@" ;;
esac

rm -rf "$OUT"*