#!/usr/bin/env bash
set -euo pipefail

# Display information about the required options
usage() {
  cat <<'EOF'
Usage: $(basename "$0") -i <interface>

Options:
  -i, --iface  Network interface name (e.g., wlan1, eth1). Required.
  -h, --help   Show this help and exit.

Example:
  $(basename "$0") -i wlan1
EOF
}

iface="wlan1"

# Check if script is run as root
if [[ $EUID -ne 0 ]]; then
    echo "[!] This script requires root permissions." >&2
    exit 1
fi

# Translate long options to short for getopts
# Keeping the script POSIX-friendly without relying on GNU getopt
if [[ $# -gt 0 ]]; then
  args=()
  while [[ $# -gt 0 ]]; do
    case "$1" in
      --iface) args+=("-i"); shift ;;
      --help)  args+=("-h"); shift ;;
      *)       args+=("$1"); shift ;;
    esac
  done
  set -- "${args[@]}"
fi

# Parse short options
while getopts ":i:h" opt; do
  case "$opt" in
    i) iface="$OPTARG" ;;
    h) usage; exit 0 ;;
    \?) echo "Error: Invalid option -$OPTARG" >&2; usage; exit 1 ;;
    :)  echo "Error: Option -$OPTARG requires an argument." >&2; usage; exit 1 ;;
  esac
done

# Require -i/--iface
if [[ -z "${iface}" ]]; then
  echo "Error: A network interface must be pecified with -i/--iface." >&2
  echo "Example: $(basename "$0") -i wlan1" >&2
  exit 1
fi

# Validate the interface exists on the system
if ! ip link show "$iface" &>/dev/null; then
  echo "Error: Interface '$iface' does not exist on this system." >&2
  exit 1
fi

# Check if airodump-ng is installed
if ! command -v airodump-ng &>/dev/null; then
    read -r -p "[!] airodump-ng is not installed. Install it now? (Y/n): " choice
    choice=${choice:-Y}
    if [[ $choice =~ ^[Yy]$ ]]; then
        if ! apt update || ! apt install -y aircrack-ng; then
    echo "[!] Installation failed. Exiting."
    exit 1
fi
    else
        echo "[!] airodump-ng is required. Exiting."
        exit 1
    fi
fi

echo "[+] Preparing $iface for monitor mode..."
nmcli device set "$iface" managed no
ip link set "$iface" down
iw dev "$iface" set type monitor
ip link set "$iface" up

# Check for hostapd-wpe.conf in the current directory
# For monitoring only used for using the same channel as the ap
if [[ -f "hostapd-wpe.conf" ]]; then
    echo "[+] Found hostapd-wpe.conf in the current directory. Using it."
    # Import channel variable only
    source <(grep -E '^[[:space:]]*channel[[:space:]]*=' hostapd-wpe.conf)
else
    echo "[!] hostapd-wpe.conf not found in the current directory. Using the default: /etc/hostapd-wpe/hostapd-wpe.conf"
    source <(grep -E '^[[:space:]]*channel[[:space:]]*=' /etc/hostapd-wpe/hostapd-wpe.conf)
fi

TIMESTAMP="$(date '+%Y-%m-%d_%H-%M-%S')"

# Start monitoring
if ! airodump-ng --channel $channel -w wpa-${TIMESTAMP} "$iface"; then
    echo "[!] Failed to start airodump-ng. Exiting."
    exit 1
fi