#!/bin/bash

# Constants
CONFIG_DIR="/etc/pve/lxc"
TMP_DIR="/tmp"

# Function to display log messages
log() {
    echo -e "$1"
}

# Function to display error and exit
function display_error_and_exit() {
    log "Error: $1 Exiting."
    exit 1
}

# Function to display information
function display_info {
    clear
    log "This script is used to configure prerequisites to run Synology Virtual DSM"
    log "in a Docker container inside an unprivileged Proxmox LXC container."
    log "Please run this script on the Proxmox host, not inside the LXC container.\n"
}

# Check for root privileges
if [ "$EUID" -ne 0 ]; then
    display_error_and_exit "Please run this script as root."
fi

display_info

read -p "Do you want to continue? (y/n): " choice

if [[ $choice == "y" || $choice == "Y" ]]; then
    read -p "Enter the LXC Container ID (CT ID): " ct_id

    # Check if ct_id is a non-empty numeric value
    if [[ ! $ct_id =~ ^[0-9]+$ ]]; then
        display_error_and_exit "Invalid LXC Container ID. Please enter a numeric value."
    fi

    # Check if the configuration file exists
    config_file="$CONFIG_DIR/$ct_id.conf"
    if [[ ! -f "$config_file" ]]; then
        display_error_and_exit "Configuration file $config_file does not exist."
    fi

    # Check if the LXC container is running
    container_status=$(pct status $ct_id 2>&1)
    if [[ "$container_status" == *"running"* ]]; then
        log "Stopping running LXC container $ct_id..."
        pct stop $ct_id || display_error_and_exit "Failed to stop LXC container $ct_id."
    fi

    # Remove existing dev folder and tun, kvm, and vhost-net devices
    if [[ -d "/dev-$ct_id" ]]; then
        log "Removing existing /dev-$ct_id folder..."
        rm -r "/dev-$ct_id" || display_error_and_exit "Failed to remove existing /dev-$ct_id folder."
    fi

    # Function to configure devices
    function configure_device() {
        device=$1
        module=$2
        major=$3
        minor=$4

        log "Configuring $device..."
        mkdir -p "/dev-$ct_id/net" || display_error_and_exit "Failed to create /dev-$ct_id/net"
        mknod "/dev-$ct_id/$device" c $major $minor || display_error_and_exit "Failed to mknod /dev-$ct_id/$device"
        chown 100000:100000 "/dev-$ct_id/$device" || display_error_and_exit "Failed to chown /dev-$ct_id/$device"

        #log "Checking if /dev-$ct_id/$device exists..."
        if ! [[ -e "/dev-$ct_id/$device" ]]; then
            display_error_and_exit "/dev-$ct_id/$device should have been created but does not exist."
        fi
    }

    # Configure devices
    configure_device "net/tun" "tun" 10 200
    configure_device "kvm" "kvm" 10 232
    configure_device "vhost-net" "vhost-net" 10 238

    # Check and add configuration lines to /et/pve/lxc/<CT ID>.conf
    log "Checking and adding configuration to $config_file..."
    lines_to_add=(
        "lxc.mount.entry: /dev-$ct_id/net/tun dev/net/tun none bind,create=file 0 0"
        "lxc.mount.entry: /dev-$ct_id/kvm dev/kvm none bind,create=file 0 0"
        "lxc.mount.entry: /dev-$ct_id/vhost-net dev/vhost-net none bind,create=file 0 0"
    )

    # Error handling for config file changes
    for line in "${lines_to_add[@]}"; do
        if ! grep -qF "$line" "$config_file"; then
            echo "$line" >> "$config_file" || display_error_and_exit "Failed to add line '$line' to $config_file."
        fi
    done

    log "Configuration completed successfully.\n\nStart the docker image (vdsm/virtual-dsm:latest) inside the LXC container."

else
    clear
    log "\nScript aborted. No changes were made."
fi