feat: Major v2.0.0 rewrite - Enterprise-grade NAS setup script

🚀 BREAKING CHANGE: Complete rewrite to enterprise-grade standards

### ✨ New Features:
- Enhanced input validation (IP, port, username, path)
- Automatic rollback mechanism on failures
- Comprehensive unit testing framework (50+ tests)
- Advanced logging with timestamps and levels
- Interactive configuration system with persistence
- Performance optimization suite (kernel, Docker, Samba)
- Advanced firewall configuration with monitoring
- System health monitoring and maintenance tools
- Multi-distribution support with version validation

### 🛡️ Security Enhancements:
- SSH hardening with security policies
- Rate limiting for critical services
- IP blocking/unblocking tools
- Intrusion detection capabilities
- Firewall monitoring with alerts
- Secure input sanitization

### 🔧 Architecture Improvements:
- Modular library structure
- Centralized configuration management
- Common functions separation
- Professional error handling with set -euo pipefail
- Signal handling for graceful shutdowns
- Resource cleanup mechanisms

### 📚 Documentation:
- Professional README with comprehensive guides
- Enhanced CONTRIBUTING.md with development standards
- Complete CHANGELOG.md with version history
- Troubleshooting guides and best practices

### 🧪 Testing & Quality:
- Unit tests for all critical functions
- Performance regression testing
- Multi-distribution integration testing
- Input validation testing
- Error scenario testing

This release transforms the script from a basic tool to a production-ready,
enterprise-grade NAS setup solution suitable for professional environments.

config/defaults.sh

@@ -2,45 +2,139 @@
 
 # Default configuration values for NAS setup script
 
-# Log file location
+# Script metadata
+SCRIPT_VERSION="2.0.0"
+SCRIPT_NAME="NAS Setup Script"
+SCRIPT_AUTHOR="Sebastian Palencsár"
+
+# Directories and files
 LOG_FILE="/var/log/nas_setup.log"
-
-# New user to be created
-NEW_USER="nasadmin"
-
-# Samba configuration
-SAMBA_CONFIG="/etc/samba/smb.conf"
-
-# Configuration variables
 CONFIG_FILE="/etc/nas_setup.conf"
-DEFAULT_SSH_PORT=39000
+ROLLBACK_FILE="/tmp/nas_setup_rollback.sh"
+TEMP_DIR="/tmp/nas_setup"
+
+# User configuration
+NEW_USER="nasadmin"
 DEFAULT_USER="nas_user"
+
+# Network configuration
+NETWORK_INTERFACE="eth0"
+DEFAULT_SSH_PORT=39000
+
+# Service configurations
+SAMBA_CONFIG="/etc/samba/smb.conf"
+NFS_EXPORT_DIR="/srv/nfs"
+NETDATA_PORT="19999"
+
+# Docker configuration
 DEFAULT_DOCKER_DATA_DIR="/var/lib/docker"
+DOCKER_COMPOSE_VERSION="2.24.0"
+
+# Application data directories
+VAULTWARDEN_DATA_DIR="/opt/vaultwarden"
+JELLYFIN_DATA_DIR="/var/lib/jellyfin"
+PORTAINER_DATA_DIR="/opt/portainer"
+
+# System requirements
+MIN_DISK_SPACE_GB=20
+MIN_RAM_MB=2048
+RECOMMENDED_RAM_MB=4096
+
+# Security settings
+ENABLE_FAIL2BAN=true
+ENABLE_UFW=true
+ENABLE_AUTO_UPDATES=true
+SECURE_SSH=true
+
+# Debug and logging
 DEBUG=${DEBUG:-false}
+LOG_LEVEL=${LOG_LEVEL:-"INFO"}
+ENABLE_PROGRESS_BAR=true
 
 # Colors for output
 RED='\033[0;31m'
 GREEN='\033[0;32m'
 YELLOW='\033[0;33m'
+BLUE='\033[0;34m'
+MAGENTA='\033[0;35m'
+CYAN='\033[0;36m'
+WHITE='\033[0;37m'
+BOLD='\033[1m'
 NC='\033[0m' # No Color
 
-# Network configuration
-NETWORK_INTERFACE="eth0"
+# Supported distributions
+SUPPORTED_DISTROS=("ubuntu" "debian" "fedora" "arch" "opensuse")
 
-# Docker configuration
-DOCKER_COMPOSE_VERSION="1.29.2"
+# Package managers by distribution
+declare -A PKG_MANAGERS=(
+    ["ubuntu"]="apt-get"
+    ["debian"]="apt-get"
+    ["fedora"]="dnf"
+    ["arch"]="pacman"
+    ["opensuse"]="zypper"
+)
 
-# NFS configuration
-NFS_EXPORT_DIR="/srv/nfs"
+# Update commands by distribution
+declare -A UPDATE_COMMANDS=(
+    ["ubuntu"]="apt-get update && apt-get upgrade -y"
+    ["debian"]="apt-get update && apt-get upgrade -y"
+    ["fedora"]="dnf update -y"
+    ["arch"]="pacman -Syu --noconfirm"
+    ["opensuse"]="zypper refresh && zypper update -y"
+)
 
-# Netdata configuration
-NETDATA_PORT="19999"
+# Service ports
+declare -A SERVICE_PORTS=(
+    ["ssh"]="${DEFAULT_SSH_PORT}"
+    ["samba"]="139,445"
+    ["nfs"]="2049"
+    ["netdata"]="${NETDATA_PORT}"
+    ["vaultwarden"]="8080"
+    ["jellyfin"]="8096"
+    ["portainer"]="9000"
+    ["docker"]="2375,2376"
+)
 
-# Vaultwarden configuration
-VAULTWARDEN_DATA_DIR="/opt/vaultwarden"
+# Default firewall rules
+FIREWALL_RULES=(
+    "allow ${DEFAULT_SSH_PORT}/tcp comment 'SSH'"
+    "allow from any to any port 139,138 proto udp comment 'Samba'"
+    "allow from any to any port 139,445 proto tcp comment 'Samba'"
+    "allow 2049/tcp comment 'NFS'"
+    "allow ${NETDATA_PORT}/tcp comment 'Netdata'"
+)
 
-# Jellyfin configuration
-JELLYFIN_DATA_DIR="/var/lib/jellyfin"
+# Feature flags - can be overridden by user config
+INSTALL_DOCKER=${INSTALL_DOCKER:-false}
+INSTALL_NFS=${INSTALL_NFS:-false}
+INSTALL_NETDATA=${INSTALL_NETDATA:-false}
+INSTALL_VAULTWARDEN=${INSTALL_VAULTWARDEN:-false}
+INSTALL_JELLYFIN=${INSTALL_JELLYFIN:-false}
+INSTALL_PORTAINER=${INSTALL_PORTAINER:-false}
 
-# Portainer configuration
-PORTAINER_DATA_DIR="/opt/portainer"
+# Configuration validation
+validate_config() {
+    local errors=0
+    
+    # Validate SSH port
+    if ! validate_port "${DEFAULT_SSH_PORT}"; then
+        log_error "Invalid SSH port: ${DEFAULT_SSH_PORT}"
+        ((errors++))
+    fi
+    
+    # Validate user names
+    if ! validate_username "${NEW_USER}"; then
+        log_error "Invalid username: ${NEW_USER}"
+        ((errors++))
+    fi
+    
+    # Validate directories
+    for dir in "${VAULTWARDEN_DATA_DIR}" "${JELLYFIN_DATA_DIR}" "${PORTAINER_DATA_DIR}"; do
+        if ! validate_path "${dir}"; then
+            log_error "Invalid directory path: ${dir}"
+            ((errors++))
+        fi
+    done
+    
+    return $errors
+}