#!/bin/bash

# =============================================
# Static IP Configuration Script
# Configures static IP for active interface (eth0 or wlan0)
# Must be run with sudo!
#
# Usage:
#   IP_ADDRESS=192.168.1.100 GATEWAY=192.168.1.1 ./set_static_ip.sh
# =============================================

# --- Configuration ---
DEFAULT_GATEWAY="${GATEWAY_ENV:-10.10.0.1}"  # Use GATEWAY_ENV if provided, otherwise default
DNS_SERVERS="8.8.8.8 8.8.4.4"
LOG_FILE="/var/log/set_static_ip.log"
NETPLAN_DIR="/etc/netplan"
MAX_LOG_SIZE_KB=1024  # 1MB

# --- Funções Auxiliares ---

# Função de Log (modificada para usar logger)
log() {
    local message="$1"
    local timestamp=$(date '+%Y-%m-%d %H:%M:%S')

    # Escreve no ficheiro de log
    echo "$timestamp: $message" | tee -a "$LOG_FILE"

    # Envia para o syslog (opcional)
    logger -t "set_static_ip" "$message"
}

# Função para limitar o tamanho do log
limit_log_size() {
    local log_file="$1"
    local max_size_kb="$2"
    local max_size_bytes=$((max_size_kb * 1024))

    if [ -f "$log_file" ]; then
        local current_size=$(stat -c %s "$log_file" 2>/dev/null || wc -c < "$log_file" 2>/dev/null)

        if [ "$current_size" -gt "$max_size_bytes" ]; then
            log "Aviso: Ficheiro de log $log_file excedeu $max_size_kb KB. A truncar..."
            tail -n 500 "$log_file" > "${log_file}.tmp" && mv "${log_file}.tmp" "$log_file"
            log "Ficheiro de log truncado. As últimas 500 linhas foram mantidas."
        fi
    fi
}

# Function to fix netplan permissions
fix_netplan_permissions() {
    log "Fixing netplan permissions..."

    # Fix permissions for all netplan files
    find "$NETPLAN_DIR" -type f -name "*.yaml" -exec chmod 600 {} \;
    find /lib/netplan -type f -name "*.yaml" -exec chmod 600 {} \;
    find /run/netplan -type f -name "*.yaml" -exec chmod 600 {} \;

    # Fix ownership
    chown root:root "$NETPLAN_DIR"/*.yaml 2>/dev/null
    chown root:root /lib/netplan/*.yaml 2>/dev/null
    chown root:root /run/netplan/*.yaml 2>/dev/null

    log "Netplan permissions fixed"
}

# Function to check if interface is up
is_interface_up() {
    local interface="$1"
    if ip link show "$interface" | grep -q "state UP"; then
        return 0
    else
        return 1
    fi
}

# Function to get active interface
get_active_interface() {
    # Check eth0 first
    if is_interface_up "eth0"; then
        echo "eth0"
        return 0
    fi

    # Then check wlan0
    if is_interface_up "wlan0"; then
        echo "wlan0"
        return 0
    fi

    # No active interface found
    return 1
}

# Function to check if system uses dhcpcd
uses_dhcpcd() {
    if [ -f /etc/dhcpcd.conf ] && systemctl list-unit-files | grep -q dhcpcd; then
        return 0
    else
        return 1
    fi
}

# Function to check if system uses netplan
uses_netplan() {
    if [ -d "$NETPLAN_DIR" ] && command -v netplan >/dev/null; then
        return 0
    else
        return 1
    fi
}

# Function to check if system uses NetworkManager
uses_network_manager() {
    if systemctl list-unit-files | grep -q NetworkManager && command -v nmcli >/dev/null; then
        return 0
    else
        return 1
    fi
}

# Function to configure static IP using dhcpcd
configure_static_ip_dhcpcd() {
    local interface="$1"
    local ip_address="$2"
    local gateway="$3"
    local dns="$4"

    log "Configuring static IP for $interface using dhcpcd..."

    # Backup original dhcpcd.conf
    if [ ! -f /etc/dhcpcd.conf.bak ]; then
        cp /etc/dhcpcd.conf /etc/dhcpcd.conf.bak
        log "Created backup of /etc/dhcpcd.conf"
    fi

    # Remove any existing configuration for this interface
    sed -i "/^interface $interface$/,/^$/d" /etc/dhcpcd.conf

    # Add new configuration
    {
        echo ""
        echo "# Static IP configuration for $interface"
        echo "interface $interface"
        echo "static ip_address=$ip_address"
        echo "static routers=$gateway"
        echo "static domain_name_servers=$dns"
    } >> /etc/dhcpcd.conf

    log "Static IP configuration added to /etc/dhcpcd.conf"
    log "Restarting networking..."

    # Try different methods to restart networking
    if systemctl restart dhcpcd 2>/dev/null; then
        log "dhcpcd service restarted successfully"
        return 0
    elif systemctl restart networking 2>/dev/null; then
        log "networking service restarted successfully"
        return 0
    elif systemctl restart systemd-networkd 2>/dev/null; then
        log "systemd-networkd service restarted successfully"
        return 0
    else
        log "Could not restart networking service automatically"
        log "Please reboot the system for changes to take effect"
        return 0
    fi
}

# Function to configure static IP using netplan
configure_static_ip_netplan() {
    local interface="$1"
    local ip_address="$2"
    local gateway="$3"
    local dns="$4"

    log "Configuring static IP for $interface using netplan..."

    # Fix netplan permissions first
    fix_netplan_permissions

    # Find netplan config file
    local netplan_file=$(ls "$NETPLAN_DIR"/*.yaml 2>/dev/null | head -n 1)

    if [ -z "$netplan_file" ]; then
        # Create default netplan file if none exists
        netplan_file="$NETPLAN_DIR/01-static-ip.yaml"
        log "Creating new netplan configuration file: $netplan_file"
    else
        # Backup original netplan config
        if [ ! -f "$netplan_file.bak" ]; then
            cp "$netplan_file" "$netplan_file.bak"
            log "Created backup of $netplan_file"
        fi
    fi

    # Create new netplan configuration
    cat > "$netplan_file" <<EOF
network:
  version: 2
  renderer: networkd
  ethernets:
    $interface:
      addresses: [$ip_address]
      routes:
        - to: default
          via: $gateway
      nameservers:
        addresses: [$(echo $dns | sed 's/ /, /g')]
EOF

    # Set correct permissions
    chmod 600 "$netplan_file"
    chown root:root "$netplan_file"

    log "Static IP configuration added to $netplan_file"
    log "Applying netplan configuration..."

    # Apply netplan configuration
    if netplan apply; then
        log "Netplan configuration applied successfully"
        return 0
    else
        log "Failed to apply netplan configuration"
        return 1
    fi
}

# Function to configure static IP using NetworkManager
configure_static_ip_network_manager() {
    local interface="$1"
    local ip_address="$2"
    local gateway="$3"
    local dns="$4"

    log "Configuring static IP for $interface using NetworkManager..."

    # Set static IP
    if nmcli con show "$interface" >/dev/null 2>&1; then
        nmcli con mod "$interface" ipv4.method manual ipv4.addresses "$ip_address" ipv4.gateway "$gateway" ipv4.dns "$dns"
    else
        nmcli con add type ethernet ifname "$interface" con-name "$interface" ipv4.method manual ipv4.addresses "$ip_address" ipv4.gateway "$gateway" ipv4.dns "$dns"
    fi

    # Restart connection
    nmcli con down "$interface" && nmcli con up "$interface"

    log "NetworkManager configuration applied successfully"
    return 0
}

# Function to configure static IP
configure_static_ip() {
    local ip_address="${IP_ADDRESS_ENV:-$1}"
    local gateway="${GATEWAY_ENV:-$DEFAULT_GATEWAY}"
    local interface
    local dns="$DNS_SERVERS"

    mkdir -p "$(dirname "$LOG_FILE")"
    limit_log_size "$LOG_FILE" "$MAX_LOG_SIZE_KB"  # Verifica o tamanho do log no início

    # Get active interface
    if ! interface=$(get_active_interface); then
        log "No active network interface found (eth0 or wlan0)"
        return 1
    fi

    log "Active interface: $interface"
    log "Configuring static IP: $ip_address"
    log "Gateway: $gateway"
    log "DNS Servers: $dns"

    # Check which network management system is in use
    if uses_dhcpcd; then
        configure_static_ip_dhcpcd "$interface" "$ip_address" "$gateway" "$dns"
    elif uses_netplan; then
        configure_static_ip_netplan "$interface" "$ip_address" "$gateway" "$dns"
    elif uses_network_manager; then
        configure_static_ip_network_manager "$interface" "$ip_address" "$gateway" "$dns"
    else
        log "Could not determine network configuration method"
        log "Please configure your network manually:"
        log "Interface: $interface"
        log "IP Address: $ip_address"
        log "Gateway: $gateway"
        log "DNS Servers: $dns"
        return 1
    fi
}

# --- Main Execution ---

# Configure static IP
configure_static_ip