install.sh

#!/usr/bin/env bash

set -eu

# Colors for output
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
BLUE='\033[0;34m'
NC='\033[0m' # No Color

# Global variables
SINGLE_USER_MODE=false

# Logging functions
log_info() {
	echo -e "${BLUE}[INFO]${NC} $1"
}

log_success() {
	echo -e "${GREEN}[SUCCESS]${NC} $1"
}

log_warning() {
	echo -e "${YELLOW}[WARNING]${NC} $1"
}

log_error() {
	echo -e "${RED}[ERROR]${NC} $1"
}

# Detect OS
detect_os() {
	if [[ -f /etc/NIXOS ]]; then
		echo "nixos"
	elif [[ -d /nix/store ]] && command_exists nix; then
		echo "nixos-container"
	elif [[ -f /etc/arch-release ]]; then
		echo "arch"
	elif [[ -f /etc/debian_version ]]; then
		echo "debian"
	elif [[ -f /etc/redhat-release ]]; then
		echo "redhat"
	else
		echo "unknown"
	fi
}

# Check if command exists
command_exists() {
	command -v "$1" >/dev/null 2>&1
}

# Show help information
show_help() {
	echo "Usage: $0 [OPTIONS]"
	echo ""
	echo "OPTIONS:"
	echo "  --single       Install Nix in single-user mode (no daemon)"
	echo "  --uninstall    Completely uninstall Nix and remove dead symlinks"
	echo "  --help, -h     Show this help message"
	echo ""
	echo "Default behavior (no options):"
	echo "  Set up Nix environment for flake-based configurations (multi-user mode)"
	echo ""
	echo "Examples:"
	echo "  $0                 # Setup Nix environment (multi-user)"
	echo "  $0 --single        # Setup Nix environment (single-user)"
	echo "  $0 --uninstall     # Uninstall Nix and cleanup"
	echo "  $0 --help          # Show this help"
	echo ""
	echo "Single-user mode is recommended for:"
	echo "  • Docker containers"
	echo "  • Development environments"
	echo "  • Systems without systemd"
	echo "  • Non-root installations"
}

# Remove dead symlinks
remove_dead_symlinks() {
	local directories=("$@")

	log_info "Removing dead symlinks from home directories..."

	for dir in "${directories[@]}"; do
		if [[ -d "$dir" ]]; then
			log_info "Checking for dead symlinks in: $dir"

			# Find and remove dead symlinks
			local dead_links
			dead_links=$(find "$dir" -type l ! -exec test -e {} \; -print 2>/dev/null || true)

			if [[ -n "$dead_links" ]]; then
				echo "$dead_links" | while IFS= read -r link; do
					if [[ -n "$link" ]]; then
						log_info "Removing dead symlink: $link"
						rm -f "$link"
					fi
				done
				log_success "Dead symlinks removed from $dir"
			else
				log_info "No dead symlinks found in $dir"
			fi
		else
			log_info "Directory does not exist: $dir"
		fi
	done
}

# Uninstall Nix (multi-user)
uninstall_nix_multiuser() {
	log_info "Uninstalling Nix (multi-user mode)..."

	# Try to use nix-installer uninstall if available
	if [[ -x /nix/nix-installer ]]; then
		log_info "Using nix-installer for clean uninstall..."
		if sudo /nix/nix-installer uninstall; then
			log_success "Nix uninstalled successfully using nix-installer"
			return 0
		else
			log_warning "nix-installer failed, falling back to manual method"
		fi
	fi

	# Manual multi-user uninstall
	log_info "Performing manual multi-user uninstall..."

	# Stop daemon
	if systemctl is-active --quiet nix-daemon 2>/dev/null; then
		sudo systemctl stop nix-daemon
		sudo systemctl disable nix-daemon
		log_success "Nix daemon stopped and disabled"
	fi

	# Remove systemd files
	sudo rm -f /etc/systemd/system/nix-daemon.service
	sudo rm -f /etc/systemd/system/nix-daemon.socket
	sudo rm -f /etc/systemd/system/multi-user.target.wants/nix-daemon.service
	sudo systemctl daemon-reload

	# Remove nixbld users
	for i in $(seq 1 32); do
		if id "nixbld$i" &>/dev/null; then
			sudo userdel "nixbld$i"
			log_info "Removed user nixbld$i"
		fi
	done

	if getent group nixbld &>/dev/null; then
		sudo groupdel nixbld
		log_success "Removed group nixbld"
	fi

	# Remove Nix store
	sudo rm -rf /nix
	log_success "Nix store removed"

	# Clean system profiles
	local system_profiles=(
		"/etc/bashrc"
		"/etc/profile.d/nix.sh"
		"/etc/zshrc"
		"/etc/bash.bashrc"
		"/etc/zsh/zshrc"
	)

	for profile in "${system_profiles[@]}"; do
		if [[ -f "$profile" ]]; then
			sudo sed -i.bak-before-nix-removal '/nix/d' "$profile" 2>/dev/null || true
			log_info "Cleaned $profile"
		fi
	done

	# Remove backup files
	sudo rm -f /etc/bash.bashrc.backup-before-nix
	sudo rm -f /etc/bashrc.backup-before-nix
	sudo rm -f /etc/profile.backup-before-nix
	sudo rm -f /etc/zsh/zshrc.backup-before-nix
	sudo rm -f /etc/zshrc.backup-before-nix
}

# Uninstall Nix (single-user)
uninstall_nix_singleuser() {
	log_info "Uninstalling Nix (single-user mode)..."

	# Remove Nix store (user-owned)
	rm -rf /nix 2>/dev/null || {
		log_warning "Could not remove /nix (may need sudo for some files)"
		sudo rm -rf /nix
	}
	log_success "Nix store removed"
}

# Common user cleanup for both modes
cleanup_user_files() {
	log_info "Cleaning up user-specific Nix files..."

	# User profiles
	local user_profiles=(
		"$HOME/.bash_profile"
		"$HOME/.bashrc"
		"$HOME/.profile"
		"$HOME/.zshrc"
	)

	for profile in "${user_profiles[@]}"; do
		if [[ -f "$profile" ]]; then
			sed -i.bak-before-nix-removal '/nix/d' "$profile" 2>/dev/null || true
			log_info "Cleaned $profile"
		fi
	done

	# User Nix files
	rm -rf "$HOME/.nix-channels" 2>/dev/null || true
	rm -rf "$HOME/.nix-defexpr" 2>/dev/null || true
	rm -rf "$HOME/.nix-profile" 2>/dev/null || true
	rm -rf "$HOME/.config/nix" 2>/dev/null || true
	rm -rf "$HOME/.config/nixpkgs" 2>/dev/null || true
	rm -rf "$HOME/.cache/nix" 2>/dev/null || true
	rm -rf "$HOME/.local/state/nix" 2>/dev/null || true

	log_success "User Nix files removed"
}

# Complete uninstall
complete_uninstall() {
	log_info "Starting complete Nix uninstallation and cleanup..."

	# Detect installation mode
	if [[ -f /nix/var/nix/profiles/default/etc/profile.d/nix-daemon.sh ]] || systemctl list-unit-files | grep -q nix-daemon; then
		log_info "Detected multi-user Nix installation"
		uninstall_nix_multiuser
	elif [[ -d /nix ]] && [[ -O /nix ]] 2>/dev/null; then
		log_info "Detected single-user Nix installation"
		uninstall_nix_singleuser
	elif [[ -d /nix ]]; then
		log_warning "Nix installation detected but mode unclear, trying both methods"
		uninstall_nix_multiuser 2>/dev/null || uninstall_nix_singleuser
	else
		log_info "No Nix installation detected"
	fi

	# Common cleanup
	cleanup_user_files

	# Remove dead symlinks
	log_info "Cleaning up dead symlinks..."
	remove_dead_symlinks "$HOME" "$HOME/.config"

	log_success "Complete uninstallation finished!"
	log_info "All Nix components and dead symlinks have been removed."
	log_info "You may want to restart your shell or logout/login to complete the cleanup."
}

# Clean install of Nix (multi-user)
clean_install_nix_multiuser() {
	log_info "Performing clean Nix installation (multi-user mode)..."

	# Install Nix with daemon
	log_info "Running Nix installer with daemon..."
	if sh <(curl -L https://nixos.org/nix/install) --daemon; then
		log_success "Nix installed successfully (multi-user)"

		# Source the profile for current session
		if [[ -f /nix/var/nix/profiles/default/etc/profile.d/nix-daemon.sh ]]; then
			source /nix/var/nix/profiles/default/etc/profile.d/nix-daemon.sh
			log_info "Nix profile sourced for current session"
		fi

		# Verify installation
		if command_exists nix; then
			nix --version
			log_success "Nix installation verified"
		else
			log_error "Nix installation completed but nix command not found"
			log_info "You may need to restart your shell"
			return 1
		fi
	else
		log_error "Nix installation failed"
		return 1
	fi
}

# Clean install of Nix (single-user)
clean_install_nix_singleuser() {
	log_info "Performing clean Nix installation (single-user mode)..."

	# Install Nix without daemon
	log_info "Running Nix installer without daemon..."
	if sh <(curl -L https://nixos.org/nix/install) --no-daemon; then
		log_success "Nix installed successfully (single-user)"

		# Create initial profile if it doesn't exist
		if [[ ! -e "$HOME/.nix-profile" ]]; then
			log_info "Creating initial Nix profile..."
			/nix/var/nix/profiles/default/bin/nix-env -i
			log_info "Initial profile created"
		fi

		# Source the profile for current session
		if [[ -f "$HOME/.nix-profile/etc/profile.d/nix.sh" ]]; then
			source "$HOME/.nix-profile/etc/profile.d/nix.sh"
			log_info "Nix profile sourced for current session"
		else
			log_error "Nix profile not found at $HOME/.nix-profile/etc/profile.d/nix.sh"
			log_error "Initial profile creation may have failed"
			return 1
		fi

		# Add to shell profiles if not already there
		local shell_profiles=("$HOME/.bashrc" "$HOME/.zshrc" "$HOME/.profile")
		local nix_source_line='if [ -e ~/.nix-profile/etc/profile.d/nix.sh ]; then . ~/.nix-profile/etc/profile.d/nix.sh; fi'

		for profile in "${shell_profiles[@]}"; do
			if [[ -f "$profile" ]] && ! grep -q "nix-profile/etc/profile.d/nix.sh" "$profile"; then
				echo "$nix_source_line" >>"$profile"
				log_info "Added Nix sourcing to $profile"
			fi
		done

		# Verify installation
		if command_exists nix; then
			nix --version
			log_success "Nix installation verified"
		else
			log_error "Nix installation completed but nix command not found"
			log_info "You may need to restart your shell or run: source ~/.nix-profile/etc/profile.d/nix.sh"
			return 1
		fi
	else
		log_error "Nix installation failed"
		return 1
	fi
}

# Install Nix (for non-NixOS systems)
install_nix() {
	log_info "Setting up Nix..."

	# Check if Nix is already installed
	if command_exists nix; then
		log_info "Nix is already installed ($(nix --version))"

		# Ask user if they want to reinstall
		if [[ -t 0 ]]; then
			read -p "Would you like to reinstall Nix for a clean setup? (y/N): " -n 1 -r
			echo
		else
			log_info "Non-interactive session detected; keeping existing Nix installation"
			REPLY="n"
		fi
		if [[ $REPLY =~ ^[Yy]$ ]]; then
			complete_uninstall
			if [[ "$SINGLE_USER_MODE" == "true" ]]; then
				clean_install_nix_singleuser
			else
				clean_install_nix_multiuser
			fi
		else
			log_info "Using existing Nix installation"

			if [[ "$SINGLE_USER_MODE" == "false" ]]; then
				# For multi-user, ensure daemon is running
				if ! systemctl is-active --quiet nix-daemon 2>/dev/null; then
					log_info "Starting nix-daemon..."
					sudo systemctl start nix-daemon 2>/dev/null || true
				fi

				# Source profile
				if [[ -f /nix/var/nix/profiles/default/etc/profile.d/nix-daemon.sh ]]; then
					source /nix/var/nix/profiles/default/etc/profile.d/nix-daemon.sh
					log_info "Nix profile sourced for current session"
				fi
			else
				# For single-user, just source profile
				if [[ -f "$HOME/.nix-profile/etc/profile.d/nix.sh" ]]; then
					source "$HOME/.nix-profile/etc/profile.d/nix.sh"
					log_info "Nix profile sourced for current session"
				fi
			fi
		fi
	else
		# Fresh installation
		if [[ "$SINGLE_USER_MODE" == "true" ]]; then
			clean_install_nix_singleuser
		else
			clean_install_nix_multiuser
		fi
	fi
}

# Enable Nix flakes
enable_flakes() {
	log_info "Enabling Nix flakes..."

	# Create config directory
	mkdir -p ~/.config/nix

	# Enable experimental features
	if ! grep -q "experimental-features" ~/.config/nix/nix.conf 2>/dev/null; then
		echo "experimental-features = nix-command flakes" >>~/.config/nix/nix.conf
		log_success "Flakes enabled in user config"
	else
		log_warning "Flakes already enabled in user config"
	fi

	# For multi-user mode, also enable system-wide if possible
	if [[ "$SINGLE_USER_MODE" == "false" ]] && ([[ -w /etc/nix ]] || sudo -n true 2>/dev/null); then
		sudo mkdir -p /etc/nix
		if ! sudo grep -q "experimental-features" /etc/nix/nix.conf 2>/dev/null; then
			echo "experimental-features = nix-command flakes" | sudo tee -a /etc/nix/nix.conf >/dev/null
			log_success "Flakes enabled system-wide"
		else
			log_warning "Flakes already enabled system-wide"
		fi
	fi
}

# Install Home Manager (standalone)
install_home_manager_standalone() {
	log_info "Installing Home Manager (standalone)..."

	# Check if Home Manager is already installed
	if command_exists home-manager; then
		log_warning "Home Manager is already installed"
		home-manager --version

		# Update channels anyway
		log_info "Updating existing Home Manager channels..."
		nix-channel --update home-manager 2>/dev/null || true
		return 0
	fi

	# Add Home Manager channel if not exists
	if ! nix-channel --list | grep -q home-manager; then
		log_info "Adding Home Manager channel..."
		nix-channel --add https://github.com/nix-community/home-manager/archive/master.tar.gz home-manager
		log_success "Home Manager channel added"
	else
		log_warning "Home Manager channel already exists"
	fi

	# Update channels
	log_info "Updating Nix channels..."
	nix-channel --update

	# Install Home Manager
	log_info "Installing Home Manager..."
	if nix-shell '<home-manager>' -A install; then
		log_success "Home Manager installed successfully"

		# Verify installation
		if command_exists home-manager; then
			home-manager --version
			log_success "Home Manager installation verified"
		else
			log_warning "Home Manager installation completed but command not found"
			log_info "You may need to restart your shell or source the profile"
		fi
	else
		log_error "Home Manager installation failed"
		return 1
	fi
}

# Setup for NixOS
setup_nixos() {
	log_info "Setting up Nix environment for NixOS..."

	if [[ "$SINGLE_USER_MODE" == "true" ]]; then
		log_warning "Single-user mode is not typical for NixOS systems"
		log_info "NixOS usually uses multi-user Nix installation"
	fi

	# Enable flakes
	enable_flakes

	# Check if flake.nix is valid
	log_info "Validating flake configuration..."
	if nix flake check --no-build 2>/dev/null; then
		log_success "Flake configuration is valid"
	else
		log_warning "Flake configuration has issues (this might be normal)"
	fi

	# Show available configurations
	log_info "Available NixOS configurations:"
	nix flake show 2>/dev/null | grep -E "nixosConfigurations" -A 10 || log_warning "Could not display configurations"

	log_success "NixOS environment setup complete!"
}

# Setup for NixOS container (nixos/nix Docker image)
setup_nixos_container() {
	log_info "Setting up Nix environment for NixOS container..."

	# In containers, Nix is already installed and configured
	# We just need to enable flakes and validate configuration

	# Enable flakes
	enable_flakes

	# Skip Home Manager installation in container mode - not needed for testing
	log_info "Skipping Home Manager installation in container mode"

	# Check if flake.nix is valid
	log_info "Validating flake configuration..."
	if nix flake check --no-build 2>/dev/null; then
		log_success "Flake configuration is valid"
	else
		log_warning "Flake configuration has issues (this might be normal)"
	fi

	# Show available configurations
	log_info "Available configurations:"
	nix flake show 2>/dev/null || log_warning "Could not display configurations"
	install_home_manager_standalone

	log_success "NixOS container environment setup complete!"
}

# Setup for non-NixOS systems
setup_standalone() {
	local os_type="$1"

	if [[ "$SINGLE_USER_MODE" == "true" ]]; then
		log_info "Setting up Nix environment for $os_type (single-user mode)..."
	else
		log_info "Setting up Nix environment for $os_type (multi-user mode)..."
	fi

	# Install Nix if not present
	install_nix

	# Enable flakes
	enable_flakes

	# Install Home Manager
	install_home_manager_standalone

	# Check if flake.nix is valid
	log_info "Validating flake configuration..."
	if nix flake check --no-build 2>/dev/null; then
		log_success "Flake configuration is valid"
	else
		log_warning "Flake configuration has issues (this might be normal)"
	fi

	# Show available configurations
	log_info "Available Home Manager configurations:"
	nix flake show 2>/dev/null | grep -E "homeConfigurations" -A 10 || log_warning "Could not display configurations"

	if [[ "$SINGLE_USER_MODE" == "true" ]]; then
		log_success "Standalone Nix environment setup complete (single-user mode)!"
	else
		log_success "Standalone Nix environment setup complete (multi-user mode)!"
	fi
}

# Display usage instructions
show_usage_instructions() {
	local os_type="$1"
	local hostname=${HOSTNAME}

	log_info ""
	log_info "=== Next Steps ==="

	case "$os_type" in
	"nixos")
		log_info "For NixOS system configuration:"
		log_info "  sudo nixos-rebuild switch --flake .#$hostname"
		log_info ""
		log_info "To link dotfiles (first run; afterwards just 'mise dotfiles apply'):"
		log_info "  mise trust .config/mise/config.toml"
		log_info "  MISE_GLOBAL_CONFIG_FILE=\$PWD/.config/mise/config.toml mise dotfiles apply"
		log_info ""
		log_info "To install CLI tools and zsh completions:"
		log_info "  mise install"
		log_info "  mise run zsh-completions-sync"
		log_info ""
		log_info "To see available configurations:"
		log_info "  nix flake show"
		log_info ""
		log_info "To update flake inputs:"
		log_info "  nix flake update"
		;;
	*)
		log_info "For Home Manager configuration:"
		log_info "  # Default user:"
		log_info "  home-manager switch --flake .#$hostname"
		log_info ""
		log_info "  # Custom username:"
		log_info "  NIX_USERNAME=your_username home-manager switch --impure --flake .#$hostname"
		log_info ""
		log_info "To link dotfiles (first run; afterwards just 'mise dotfiles apply'):"
		log_info "  mise trust .config/mise/config.toml"
		log_info "  MISE_GLOBAL_CONFIG_FILE=\$PWD/.config/mise/config.toml mise dotfiles apply"
		log_info ""
		log_info "To install CLI tools and zsh completions:"
		log_info "  mise install"
		log_info "  mise run zsh-completions-sync"
		log_info ""
		log_info "To see available configurations:"
		log_info "  nix flake show"
		log_info ""
		log_info "To update flake inputs:"
		log_info "  nix flake update"
		log_info ""
		log_info "Useful commands:"
		log_info "  home-manager generations           # Show previous generations"
		log_info "  nix-collect-garbage -d             # Clean up old packages"
		;;
	esac

	log_info ""
	if [[ "$SINGLE_USER_MODE" == "true" ]]; then
		log_info "If you encounter 'command not found' errors, try:"
		log_info "  source ~/.nix-profile/etc/profile.d/nix.sh"
	else
		log_info "If you encounter 'command not found' errors, try:"
		log_info "  source ~/.nix-profile/etc/profile.d/hm-session-vars.sh"
	fi
	log_info "Or restart your terminal session."
}

# Main function
main() {
	# Parse command line arguments
	case "${1:-}" in
	--single)
		SINGLE_USER_MODE=true
		log_info "Single-user mode selected"
		;;
	--uninstall)
		log_info "Uninstall mode selected"

		# Show what will be uninstalled
		log_info ""
		log_info "=== UNINSTALL CONFIRMATION ==="
		log_info "This will completely remove:"
		log_info "• Nix package manager and all its components"
		log_info "• All Nix store contents (/nix directory)"
		log_info "• Nix daemon and systemd services (if multi-user)"
		log_info "• nixbld users and group (if multi-user)"
		log_info "• Nix-related shell profile modifications"
		log_info "• User-specific Nix files and caches"
		log_info "• Dead symlinks in ~ and ~/.config directories"
		log_info ""
		log_warning "This action cannot be undone!"
		log_info ""

		# Confirm uninstallation
		if [[ -t 0 ]]; then
			read -p "Do you really want to proceed with complete Nix uninstallation? (y/N): " -n 1 -r
			echo
		else
			log_warning "Non-interactive session detected; run interactively to confirm uninstallation"
			REPLY="n"
		fi
		if [[ $REPLY =~ ^[Yy]$ ]]; then
			log_info "Proceeding with uninstallation..."
			complete_uninstall
		else
			log_info "Uninstallation cancelled by user"
			log_info "No changes were made to your system"
		fi
		exit 0
		;;
	--help | -h)
		show_help
		exit 0
		;;
	"")
		# Default behavior - setup (multi-user)
		;;
	*)
		log_error "Unknown option: $1"
		show_help
		exit 1
		;;
	esac

	log_info "Starting Nix environment setup..."

	# Detect OS
	local os_type
	os_type="$(detect_os)"
	log_info "Detected OS: $os_type"

	# Change to script directory
	cd "$(dirname "$0")"

	# Check if flake.nix exists
	if [[ ! -f "flake.nix" ]]; then
		log_error "flake.nix not found in current directory"
		exit 1
	fi

	case "$os_type" in
	"nixos")
		if setup_nixos; then
			show_usage_instructions "$os_type"
			log_success "Nix environment setup completed successfully!"
			log_info "You can now apply your configurations using the commands shown above."
		else
			log_error "NixOS setup failed"
			exit 1
		fi
		;;
	"nixos-container")
		if setup_nixos_container; then
			show_usage_instructions "nixos"
			log_success "Nix environment setup completed successfully!"
			log_info "Container setup complete - ready for testing."
		else
			log_error "NixOS container setup failed"
			exit 1
		fi
		;;
	"arch" | "debian" | "redhat" | "unknown")
		if setup_standalone "$os_type"; then
			show_usage_instructions "$os_type"
			log_success "Nix environment setup completed successfully!"
			log_info "You can now apply your configurations using the commands shown above."
		else
			log_error "Standalone setup failed"
			exit 1
		fi
		;;
	*)
		log_error "Unsupported OS: $os_type"
		exit 1
		;;
	esac
}

# Run main function
main "$@"