#!/bin/bash

set -e

echo "Installing Nix package manager..."

# Check if running as root
if [ "$EUID" -ne 0 ]; then
    echo "Error: This script must be run as root" >&2
    exit 1
fi

# Install xz-utils if not present (required for decompressing Nix tarball)
if ! command -v xz &> /dev/null; then
    echo "Installing xz-utils..."
    if command -v apt-get &> /dev/null; then
        sudo apt-get update && sudo apt-get install -y xz-utils
    elif command -v dnf &> /dev/null; then
        sudo dnf install -y xz
    elif command -v yum &> /dev/null; then
        sudo yum install -y xz
    elif command -v pacman &> /dev/null; then
        sudo pacman -S --noconfirm xz
    else
        echo "Please install xz-utils manually for your distribution"
        exit 1
    fi
fi

# Download and run the Nix installer (multi-user mode with daemon)
curl --proto '=https' --tlsv1.2 -L https://nixos.org/nix/install | sh -s -- --daemon

# Source Nix profile
if [ -f /nix/var/nix/profiles/default/etc/profile.d/nix-daemon.sh ]; then
    . /nix/var/nix/profiles/default/etc/profile.d/nix-daemon.sh
fi

echo "Nix installation complete!"
echo "Restart your shell or run: source /nix/var/nix/profiles/default/etc/profile.d/nix-daemon.sh"