#!/usr/bin/env bash
#
# I believe there are a few ways to do this:
#
#    1. My current way, using a minimal /etc/nixos/configuration.nix that just imports my config from my home directory (see it in the gist)
#    2. Symlinking to your own configuration.nix in your home directory (I think I tried and abandoned this and links made relative paths weird)
#    3. My new favourite way: as @clot27 says, you can provide nixos-rebuild with a path to the config, allowing it to be entirely inside your dotfies, with zero bootstrapping of files required.
#       `nixos-rebuild switch -I nixos-config=path/to/configuration.nix`
#    4. If you uses a flake as your primary config, you can specify a path to `configuration.nix` in it and then `nixos-rebuild switch —flake` path/to/directory
# As I hope was clear from the video, I am new to nixos, and there may be other, better, options, in which case I'd love to know them! (I'll update the gist if so)

DIR=$HOME/nixos
OPT=$1

FORCE=false
[ "$1" = "-f" ] && FORCE=true

# A rebuild script that commits on a successful build
set -e pipefail

# cd to your config dir
pushd $DIR

# Early return if no changes were detected (thanks @singiamtel!)
if $FORCE; then
	echo Forcing rebuild
else
    if git diff --quiet '*'; then
        echo "No changes detected, exiting."
        popd
        exit 0
    fi
fi

# Autoformat your nix files
# alejandra . &>/dev/null \
#  || ( alejandra . ; echo "formatting failed!" && exit 1)

# Shows your changes
git diff -U0 '*'

echo "NixOS Rebuilding..."

# Rebuild, output simplified errors, log trackebacks
sudo nixos-rebuild switch --flake $DIR 2>&1 | tee nixos-switch.log
cat nixos-switch.log | grep --color error && exit 1

# Get current generation metadata
current=$(nixos-rebuild list-generations | grep current)

# Commit all changes witih the generation metadata
if $FORCE; then
    exit 0
fi
git commit -am "$(hostname): $current"

# Back to where you were
popd

# Notify all OK!
notify-send -e "NixOS Rebuilt OK!" --icon=software-update-available