#!/bin/bash
set -euo pipefail

##########################
# Color helpers (printf-safe, no tput)
##########################
RED="\033[0;31m"
GREEN="\033[0;32m"
YELLOW="\033[0;33m"
CYAN="\033[0;36m"
GRAY="\033[0;37m"
BOLD="\033[1m"
RESET="\033[0m"

# Disable colors if output is not a terminal
if [ ! -t 1 ]; then
    RED="" GREEN="" YELLOW="" CYAN="" GRAY="" BOLD="" RESET=""
fi

say_red()    { printf "\n"; printf "%b%s%b\n" "$RED" "$*" "$RESET"; }
say_green()    { printf "\n"; printf "%b%s%b\n" "$GREEN" "$*" "$RESET"; }
say_yellow()   { printf "\n"; printf "%b%s%b\n" "$YELLOW" "$*" "$RESET"; }
say_cyan()     { printf "\n"; printf "%b%s%b\n" "$CYAN" "$*" "$RESET"; }
say_gray()     { printf "\n"; printf "%b%s%b\n" "$GRAY" "$*" "$RESET"; }
say_bold()     { printf "\n"; printf "%b%s%b\n" "$BOLD" "$*" "$RESET"; }

##########################
# Use exported variables from main detection script
##########################
OS="${DETECTED_OS:-debian}"
DDE="${DETECTED_DE:-}"
DE="${SELECTED_DE:-none}"
TWM="${SELECTED_TWM:-none}"
INSTALL_LEVEL="${INSTALL_LEVEL:-minimal}"
SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"

##########################
# Helper functions
##########################
install_packages() { sudo apt update; sudo apt install -y --no-install-recommends "$@"; }
is_package_installed() { dpkg -s "$1" &>/dev/null; }
detect_de() { command -v gnome-session >/dev/null 2>&1 && echo "gnome" || echo ""; }
detect_display_manager() { [ -f /etc/X11/default-display-manager ] && basename "$(cat /etc/X11/default-display-manager)" || echo ""; }
enable_graphical_target() { sudo systemctl enable sddm; sudo systemctl set-default graphical.target; }

say_yellow "Starting Gnome installation..."

CURRENT_DE="$(detect_de)"
CURRENT_DM="$(detect_display_manager)"

if [[ -z "$CURRENT_DE" ]]; then
    say_cyan "No DE detected. Installing Gnome with SDDM..."
    install_packages sddm gnome-shell gnome-terminal nautilus gnome-control-center gnome-system-monitor gnome-tweaks network-manager-gnome gnome-keyring gnome-session
    enable_graphical_target
    say_green "Gnome with SDDM installed successfully."
else
    say_cyan "Detected existing DE: $CURRENT_DE"
    if [[ "$CURRENT_DM" == "lightdm" ]]; then
        say_yellow "Replacing LightDM with SDDM..."
        sudo systemctl disable lightdm
        sudo apt purge -y lightdm lightdm-gtk-greeter
        install_packages sddm
        enable_graphical_target
        say_green "LightDM replaced with SDDM."
    else
        say_cyan "Current DM: ${CURRENT_DM:-none}, leaving unchanged."
    fi
fi