#!/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="${DETECTED_OS}"
DDE="${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 pacman -S --noconfirm --needed "$@"; }
is_package_installed() { pacman -Qi "$@" &>/dev/null; }
remove_packages() {
    local packages_to_remove=()
    
    # 1. Identify which packages are actually installed
    for pkg in "$@"; do
        if is_package_installed "$pkg"; then
            packages_to_remove+=("$pkg")
        else
            say_gray "Package '$pkg' not found. Skipping removal."
        fi
    done

    # 2. Only run pacman if there are packages to remove
    if [ ${#packages_to_remove[@]} -gt 0 ]; then
        say_cyan "Removing packages: ${packages_to_remove[*]}"
        sudo pacman -Rs --noconfirm "${packages_to_remove[@]}" || true
    else
        say_gray "No packages to remove from the list."
    fi
}

detect_de() {
    if command -v plasmashell >/dev/null 2>&1; then
        echo "kde"
    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
##########################
say_yellow -e "Starting KDE Plasma installation..."

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

if [[ -z "$CURRENT_DE" || "$CURRENT_DE" != "kde" ]]; then
    say_cyan -e "KDE Plasma not detected. Installing KDE Plasma (light setup with SDDM)..."

    install_packages sddm plasma
    enable_graphical_target

    say_green -e "KDE Plasma with SDDM installed successfully. You can reboot now to start XFCE."
else
    say_cyan -e "Detected existing Desktop Environment: $CURRENT_DE. Checking Display Manager..."

    # Check and replace other Display Managers if they conflict with the preferred SDDM setup
    if [[ "$CURRENT_DM" != "sddm" ]]; then
        say_yellow -e "Display manager **$CURRENT_DM** is currently active. Replacing with **SDDM**, the default for KDE Plasma..."

        # Attempt to disable the old DM if detected
        if [ ! -z "$CURRENT_DM" ]; then
            sudo systemctl disable "$CURRENT_DM" || true
        fi
        
        # Remove common alternative DMs if they exist to prevent conflicts
        if is_package_installed lightdm; then
            say_gray -e "Removing lightdm..."
            remove_packages lightdm lightdm-gtk-greeter || true
        fi
        if is_package_installed gdm; then
            say_gray -e "Removing gdm..."
            remove_packages gdm || true
        fi

        # Ensure SDDM is installed and enabled
        install_packages sddm gst-libav qt5-graphicaleffects qt5-quickcontrols qt5-quickcontrols2
        enable_graphical_target

        say_green -e "Old display manager removed and replaced with SDDM."
    else
        say_cyan -e "Current display manager is already **SDDM**. Leaving unchanged."
    fi
fi


###### TODO
### from paru install pamac-tray-icon-plasma
### let autostart pamac-tray-plasma


# End of script
say_green -e "KDE Plasma / SDDM setup completed."