#!/bin/bash
set -euo pipefail

##########################
# Color helpers (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

color_red()    { printf '%b' "$RED"; }
color_green()  { printf '%b' "$GREEN"; }
color_yellow() { printf '%b' "$YELLOW"; }
color_cyan()   { printf '%b' "$CYAN"; }
color_gray()   { printf '%b' "$GRAY"; }
color_reset()  { printf '%b' "$RESET"; }

##########################
# Optional logging
##########################
LOGFILE="${LOGFILE:-/tmp/debian-xfce.log}"
exec > >(tee -a "$LOGFILE") 2>&1

##########################
# Paths and variables
##########################
SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"

OS="${DETECTED_OS:-debian}"
DDE="${DETECTED_DE:-}"
DE="${SELECTED_DE:-none}"
TWM="${SELECTED_TWM:-none}"
INSTALL_LEVEL="${INSTALL_LEVEL:-minimal}"

##########################
# Helper functions
##########################
install_packages() {
    local packages=("$@")
    sudo apt update
    sudo apt install -y --no-install-recommends "${packages[@]}"
}

is_package_installed() {
    dpkg -s "$1" &>/dev/null
}

detect_de() {
    if command -v xfce4-session >/dev/null 2>&1; then
        echo "xfce"
    else
        echo ""
    fi
}

detect_display_manager() {
    if [ -f /etc/X11/default-display-manager ]; then
        basename "$(cat /etc/X11/default-display-manager)"
    else
        echo ""
    fi
}

enable_graphical_target() {
    sudo systemctl enable sddm
    sudo systemctl set-default graphical.target
}

##########################
# Start installation
##########################
color_yellow
echo "Starting XFCE installation..."
color_reset

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

if [[ -z "$CURRENT_DE" ]]; then
    color_cyan
    echo "No Desktop Environment detected. Installing XFCE (light setup with SDDM)..."
    color_reset

    install_packages sddm xfce4 xfce4-goodies

    enable_graphical_target

    color_green
    echo "XFCE with SDDM installed successfully. You can reboot now to start XFCE."
    color_reset
else
    color_cyan
    echo "Detected existing Desktop Environment: $CURRENT_DE"
    color_reset

    if [[ "$CURRENT_DM" == "lightdm" ]]; then
        color_yellow
        echo "LightDM is currently active. Replacing with SDDM..."
        color_reset

        sudo systemctl disable lightdm
        sudo apt purge -y lightdm lightdm-gtk-greeter

        install_packages sddm

        enable_graphical_target

        color_green
        echo "LightDM removed and replaced with SDDM."
        color_reset
    else
        color_cyan
        echo "Current display manager: ${CURRENT_DM:-none}. Leaving unchanged."
        color_reset
    fi
fi

# Force XFCE X11 session for SDDM
sudo mkdir -p /etc/sddm.conf.d
sudo tee /etc/sddm.conf.d/override.conf > /dev/null <<'EOF'
[Autologin]
#User=$USER
#Session=xfce.desktop

[General]
DefaultSession=xfce.desktop
EOF

# End of script
color_green; echo "XFCE / SDDM setup completed."; color_reset