#!/bin/bash

# GRUB Theme Installer Script (Distro-Agnostic)

# Theme directory
THEME_DIR='/boot/grub/themes'
THEME_NAME=''
DISTRO=''

# Function to detect the Linux distribution
function detect_distro() {
    if [ -f /etc/os-release ]; then
        . /etc/os-release
        DISTRO=$ID
    else
        echo "Unknown distribution. Exiting..."
        exit 1
    fi
}

# Function to display menu and install selected theme
function select_theme() {
    # Get the list of theme directories in THEME_DIR
    themes=($(ls -d "${THEME_DIR}"/*/ | xargs -n 1 basename))
    themes+=("Quit")  # Add a Quit option at the end

    if [ ${#themes[@]} -eq 1 ]; then
        echo "No themes found in ${THEME_DIR}. Please add themes before running the script."
        exit 1
    fi

    PS3='Choose The Theme You Want: '
    select THEME_NAME in "${themes[@]}"; do
        if [ "${THEME_NAME}" == "Quit" ]; then
            echo 'Exiting...'
            exit 0
        elif [[ " ${themes[@]} " =~ " ${THEME_NAME} " ]]; then
            echo "Installing ${THEME_NAME} Theme..."
            break
        else
            echo "Invalid option"
        fi
    done
}

# Function to check for root access
function check_root() {
    if [[ $EUID -ne 0 ]]; then
        echo "This script must be run as root. Please use sudo."
        exit 1
    fi
}

# Function to backup the current GRUB config
function backup_grub() {
    cp -an /etc/default/grub /etc/default/grub.bak
    echo "Backup of GRUB config created at /etc/default/grub.bak"
}

# Function to install the selected theme
function install_theme() {
    # Create the theme directory if it doesn't exist
    if [[ ! -d "${THEME_DIR}/${THEME_NAME}" ]]; then
        echo "Error: Theme ${THEME_NAME} does not exist."
        exit 1
    fi

    # Set the theme in the GRUB config
    sed -i '/GRUB_THEME=/d' /etc/default/grub
    echo "GRUB_THEME=\"${THEME_DIR}/${THEME_NAME}/theme.txt\"" >> /etc/default/grub
    echo "Theme ${THEME_NAME} installed."
}

# Function to configure GRUB
function config_grub() {
    # Enable GRUB menu
    sed -i '/GRUB_TIMEOUT_STYLE=/d' /etc/default/grub
    echo 'GRUB_TIMEOUT_STYLE="menu"' >> /etc/default/grub

    # Set GRUB timeout to 60 seconds
    sed -i '/GRUB_TIMEOUT=/d' /etc/default/grub
    echo 'GRUB_TIMEOUT=60' >> /etc/default/grub

    # Set GRUB graphics mode to auto
    sed -i '/GRUB_GFXMODE=/d' /etc/default/grub
    echo 'GRUB_GFXMODE="auto"' >> /etc/default/grub
}

# Function to update GRUB based on distro
function update_grub() {
    case "$DISTRO" in
        ubuntu|debian)
            update-grub
            ;;
        arch|manjaro)
            grub-mkconfig -o /boot/grub/grub.cfg
            ;;
        fedora|centos)
            grub2-mkconfig -o /boot/grub2/grub.cfg
            ;;
        *)
            echo "Unsupported distribution: $DISTRO"
            exit 1
            ;;
    esac
    echo "GRUB configuration updated."
}

# Main function to run the theme installation process
function main() {
    detect_distro
    check_root
    select_theme
    backup_grub
    install_theme
    config_grub
    update_grub
    echo "GRUB Theme Update Successful!"
}

main