#!/bin/bash
set -euo pipefail

# Map the exported variables to your local names with fallbacks to satisfy set -u
OS="${DETECTED_OS:-fedora}"
DE="${SELECTED_DE:-xfce}"
TWM="${SELECTED_TWM:-none}"
INSTALL_LEVEL="${INSTALL_LEVEL:-minimal}"
SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"

echo
color_cyan "Starting Fedora XFCE setup..."
echo

#------------------------------------------
# Helper functions
#------------------------------------------
install_packages() { sudo dnf install -y "$@"; }
is_package_installed() { rpm -q "$@" &>/dev/null; }

detect_de() {
    echo "${XDG_CURRENT_DESKTOP:-${DESKTOP_SESSION:-}}"
}

detect_display_manager() {
    if systemctl is-active --quiet sddm; then
        echo "sddm"
    elif systemctl is-active --quiet lightdm; then
        echo "lightdm"
    elif systemctl is-active --quiet gdm; then
        echo "gdm"
    else
        echo "none"
    fi
}

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

#------------------------------------------
# Main Execution Flow
#------------------------------------------
echo
color_yellow "Starting XFCE installation..."

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

if [[ -z "$CURRENT_DE" || "$CURRENT_DE" == "none" ]]; then
    color_cyan "No Desktop Environment detected. Installing XFCE (light setup with SDDM)..."

    # 1. Install core XFCE desktop components + SDDM
    install_packages sddm xfce4-session xfce4-settings xfwm4 xfce4-panel xfdesktop Thunar xorg-x11-xinit xorg-x11-server-Xorg xhost
    
    # 2. Install the XFCE core plugins safely via DNF group/virtual syntax
    install_packages @xfce-extra-plugins

    enable_graphical_target
    sudo systemctl enable sddm

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

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

        sudo systemctl disable lightdm
        sudo dnf remove -y lightdm lightdm-gtk-greeter

        install_packages sddm
        sudo systemctl enable sddm
        enable_graphical_target

        color_green "LightDM removed and replaced with SDDM."
    else
        color_cyan "Current display manager: ${CURRENT_DM}. Leaving unchanged."
    fi
fi

pause_if_debug

#------------------------------------------
# XFCE-specific configuration
#------------------------------------------
if [[ "${DE}" == "xfce" || "${DDE}" == "xfce" ]]; then
    echo
    color_cyan "Applying XFCE defaults: fonts, browser, and terminal..."

    # Ensure xfconf-query exists (for XFCE settings)
    if ! command -v xfconf-query >/dev/null 2>&1; then
        color_yellow "xfconf-query not found — installing xfce4-settings..."
        install_packages xfce4-settings
    fi

    pause_if_debug

    # Set fonts via xfconf-query
    if command -v xfconf-query >/dev/null 2>&1; then
        # Interface font (UI)
        xfconf-query -c xsettings -p /Gtk/FontName -s "RobotoMono Nerd Font Regular 10" || true
        # Monospace font (terminals, editors)
        xfconf-query -c xsettings -p /Gtk/MonospaceFontName -s "RobotoMono Nerd Font Mono Regular 10" || true

        color_green "XFCE fonts updated successfully!"
    else
        color_yellow "xfconf-query not found — skipping XFCE font config (will apply at first login)."
    fi

    pause_if_debug

    # Set default terminal to Alacritty
    if command -v alacritty >/dev/null 2>&1; then
        # 1. Update the traditional XFCE helpers file
        mkdir -p "$HOME/.config/xfce4"
        HELPERS_FILE="$HOME/.config/xfce4/helpers.rc"
        touch "$HELPERS_FILE"

        for entry in TerminalEmulator TerminalEmulatorCommand; do
            if grep -q "^${entry}=" "$HELPERS_FILE"; then
                sed -i "s|^${entry}=.*|${entry}=alacritty|" "$HELPERS_FILE"
            else
                echo "${entry}=alacritty" >> "$HELPERS_FILE"
            fi
        done

        # 2. Update XFCE's internal configuration database (Xfconf)
        # This tells the panel applets and shortcut keys exactly what engine binary to execute
        if command -v xfconf-query >/dev/null 2>&1; then
            # Create the channel property if it doesn't exist, and force set it to alacritty
            xfconf-query -c xfce4-session -p /general/TerminalEmulator -s "alacritty" --create 2>/dev/null || \
            xfconf-query -c xfce4-session -p /general/TerminalEmulator -s "alacritty"
        fi

        # 3. Set standard XDG MIME Association for terminal execution
        # This prevents XFCE's exo-helper from prompting you on first launch
        mkdir -p "$HOME/.config"
        MIME_FILE="$HOME/.config/mimeapps.list"
        touch "$MIME_FILE"
        
        # Ensure the [Default Applications] header exists
        if ! grep -q '\[Default Applications\]' "$MIME_FILE"; then
            echo "[Default Applications]" >> "$MIME_FILE"
        fi
        
        # Associate terminal/x-terminal-emulator scheme with alacritty
        if ! grep -q 'x-terminal-emulator=' "$MIME_FILE"; then
            sed -i '/\[Default Applications\]/a x-scheme-handler/terminal=alacritty.desktop\nuser-extension/x-terminal-emulator=alacritty.desktop' "$MIME_FILE"
        fi

        color_green "XFCE default terminal set to alacritty across helpers, xfconf, and XDG handlers!"
    fi

pause_if_debug

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