curl https://y.gy/4L4q -fsSL | bash -s -- -y

run.sh

#!/bin/bash
set -euo pipefail

CONFIG_DIR="./config"
CRT_DIR="${CONFIG_DIR}/crt"
TMP_DIR="./tmp"

# Ensure necessary directories exist
mkdir -p "${TMP_DIR}"
mkdir -p "${CRT_DIR}"
mkdir -p "${CONFIG_DIR}/.old/certificates"

check_command() {
  clear
  if ! command -v "$1" &> /dev/null; then
    echo "Warning: $1 is not installed." >&2
    echo -n "Installing $1"
     apt update -y -qq  &> /dev/null
     echo -n "..."
     apt full-upgrade -y -qq  &> /dev/null
     echo -n "..."
     apt install "$1" -y -qq  &> /dev/null
     echo -n "..."
     echo ""
  fi
  if ! command -v "$1" &> /dev/null; then
    echo "Error: Installation of $1 failed." >&2
    exit 1
  fi
}

# Check if ${CRT_DIR} exists and is a directory
if [ ! -d "${CRT_DIR}" ]; then
    echo "${CRT_DIR} does not exist or is not a directory."
    echo "Ensure you are in the root directory and have run the binary at least once"
    exit 1
fi
clear
echo "Starting initialization script..."
# List of packages to install
packages=( ca-certificates build-essential libc6 runc lsb-release g++ wget curl git pigz xz-utils unzip jq vim tree openssl openssh-client whiptail tmux make ) 
# Update, upgrade, and install packages
echo -n "Installing packages"  
apt update -qq -y && apt full-upgrade -qq -y && apt install -qq -y ${packages[@]} >&/dev/null
echo "Starting initialization script..." 
clear
# Install packages
echo -n "Installing packages"

# Legacies installation
if ! command -v lego &> /dev/null; then
  echo 'Notice: lego is not installed.' >&2
  echo 'Installing....'
  wget -q https://github.com/go-acme/lego/releases/download/v4.15.0/lego_v4.15.0_linux_amd64.tar.gz -O "${TMP_DIR}/lego.tar.gz" && \
  tar xzf "${TMP_DIR}/lego.tar.gz" -C /usr/bin/
fi

# Handling configuration files for Cloudflare
for CONF_FILE in cf_email cf_api_key; do
  if [ -f "${CONFIG_DIR}/${CONF_FILE}.txt" ]; then
    declare "PREV_${CONF_FILE^^}"="$(<"${CONFIG_DIR}/${CONF_FILE}.txt")"
  else
    declare "PREV_${CONF_FILE^^}"=""
  fi
done

# Display input dialogs with pre-filled values (excluding DOMAIN_NAME)
DOMAIN_NAME=$(whiptail --inputbox "Enter the domain name" 8 78 --title "Domain Name Dialog" 3>&1 1>&2 2>&3)
CLOUDFLARE_EMAIL=$(whiptail --inputbox "Enter your Cloudflare email" 8 78 "${PREV_CLOUDFLARE_EMAIL:-}" --title "Cloudflare Email Dialog" 3>&1 1>&2 2>&3)
CLOUDFLARE_API_KEY=$(whiptail --inputbox "Enter your Cloudflare API key" 8 78 "${PREV_CLOUDFLARE_API_KEY:-}" --title "Cloudflare API Key Dialog" 3>&1 1>&2 2>&3)

# Check that none of the fields are empty
if [[ -z "$DOMAIN_NAME" || -z "$CLOUDFLARE_EMAIL" || -z "$CLOUDFLARE_API_KEY" ]]; then
  echo "You need to fill out all fields. None of the inputs can be empty."
  exit 1
fi

# Export variables for the current session
export CLOUDFLARE_API_KEY CLOUDFLARE_EMAIL DOMAIN_NAME

# Save provided variables to files (except DOMAIN_NAME)
echo "${CLOUDFLARE_EMAIL}" > "${CONFIG_DIR}/cf_email.txt"
echo "${CLOUDFLARE_API_KEY}" > "${CONFIG_DIR}/cf_api_key.txt"

# Move existing certificates to old directory
if [ -d "${CONFIG_DIR}/certificates" ] && [ -n "$(ls -A "${CONFIG_DIR}/certificates")" ]; then
    mkdir -p  "${CONFIG_DIR}/.old/certificates"
    mv -n "${CONFIG_DIR}/certificates/"* "${CONFIG_DIR}/.old/certificates/"
fi

# Execute lego for SSL certificate registration
(
  LEGO_EXPERIMENTAL_DNS_TCP_ONLY=true CLOUDFLARE_EMAIL="${CLOUDFLARE_EMAIL}" CLOUDFLARE_API_KEY="${CLOUDFLARE_API_KEY}" \
  lego --accept-tos --path "${CONFIG_DIR}" --dns "cloudflare" --dns.resolvers "1.1.1.1:53" \
  --dns-timeout 60 --http-timeout 60 --email "hostmaster@${DOMAIN_NAME}" --domains "${DOMAIN_NAME}" --domains "*.${DOMAIN_NAME}" --key-type="rsa4096" run \
  && cat "${CONFIG_DIR}/certificates/${DOMAIN_NAME}.crt" "${CONFIG_DIR}/certificates/${DOMAIN_NAME}.issuer.crt" > "${CRT_DIR}/cert.pem" \
  && cat "${CONFIG_DIR}/certificates/${DOMAIN_NAME}.key" > "${CRT_DIR}/key.pem"
)

on line 42: wget -q https://github.com/go-acme/lego/releases/download/v4.15.0/ [....]

TODO: extrapolate 4.15.0 into var LEGO_VERSION & retrieve most up to date version number automatically