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

RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
CYAN='\033[0;36m'
NC='\033[0m'

info()   { echo -e "${GREEN}[+]${NC} $*"; }
warn()   { echo -e "${YELLOW}[!]${NC} $*"; }
die()    { echo -e "${RED}[ERROR]${NC} $*" >&2; exit 1; }
header() { echo -e "\n${CYAN}══════════════════════════════════════════${NC}"; echo -e "${CYAN}  $*${NC}"; echo -e "${CYAN}══════════════════════════════════════════${NC}"; }

[ "$(id -u)" -eq 0 ] || die "Run as root"

header "TinyBoard Network Setup"

info "Available interfaces:"
ip -o link show | awk -F': ' 'NR>1 {print "  " $2}'
echo ""

read -rp "Enter interface name to configure (e.g. wlan0, eth0, end0): " IFACE
[ -n "$IFACE" ] || die "Interface name cannot be empty"
ip link show "$IFACE" >/dev/null 2>&1 || die "Interface $IFACE not found"

IS_WIFI=false
if [[ "$IFACE" == wl* ]]; then
    IS_WIFI=true
    info "Wireless interface detected."
else
    info "Wired interface detected — skipping WiFi credential setup."
fi

CURRENT_IP=$(ip -o -4 addr show "$IFACE" 2>/dev/null | awk '{print $4}' | head -1)
CURRENT_GW=$(ip route show default 2>/dev/null | awk '/default/ {print $3}' | head -1)

echo ""
info "Current IP:      ${CURRENT_IP:-none}"
info "Current gateway: ${CURRENT_GW:-none}"
echo ""

read -rp "Set a static IP for this spoke? [Y/n]: " SET_STATIC
SET_STATIC="${SET_STATIC:-y}"

if [[ "${SET_STATIC,,}" != "y" ]]; then
    info "Keeping DHCP. No changes made."
    exit 0
fi

header "Static IP Configuration"

read -rp "Enter static IP with prefix (e.g. 192.168.1.69/24): " STATIC_IP
[ -n "$STATIC_IP" ] || die "IP address cannot be empty"

DEFAULT_GW="${CURRENT_GW:-192.168.1.1}"
read -rp "Gateway [${DEFAULT_GW}]: " GATEWAY
GATEWAY="${GATEWAY:-$DEFAULT_GW}"

read -rp "DNS servers (comma-separated) [${GATEWAY},8.8.8.8]: " DNS_INPUT
DNS_INPUT="${DNS_INPUT:-${GATEWAY},8.8.8.8}"

DNS_YAML=""
IFS=',' read -ra DNS_LIST <<< "$DNS_INPUT"
for DNS in "${DNS_LIST[@]}"; do
    DNS=$(echo "$DNS" | tr -d ' ')
    DNS_YAML="${DNS_YAML}          - ${DNS}\n"
done

info "Current netplan configs:"
ls /etc/netplan/ | sed 's/^/  /'
echo ""

NETPLAN_FILE=$(ls /etc/netplan/*.yaml 2>/dev/null | head -1)
read -rp "Netplan file to update [${NETPLAN_FILE}]: " INPUT_FILE
NETPLAN_FILE="${INPUT_FILE:-$INPUT_FILE}"
NETPLAN_FILE="${NETPLAN_FILE:-$(ls /etc/netplan/*.yaml 2>/dev/null | head -1)}"
[ -n "$NETPLAN_FILE" ] || die "No netplan file specified"

if $IS_WIFI; then
    header "WiFi Credentials"
    CURRENT_SSID=""
    if [ -f "$NETPLAN_FILE" ]; then
        CURRENT_SSID=$(grep -A1 'access-points:' "$NETPLAN_FILE" 2>/dev/null | tail -1 | tr -d ' "' | sed 's/:$//' || true)
    fi

    KEEP_WIFI="n"
    if [ -n "$CURRENT_SSID" ]; then
        warn "Existing WiFi config found for: $CURRENT_SSID"
        read -rp "Keep existing WiFi credentials? [Y/n]: " KEEP_WIFI
        KEEP_WIFI="${KEEP_WIFI:-y}"
    fi

    if [[ "${KEEP_WIFI,,}" != "y" ]]; then
        read -rp "WiFi SSID: " WIFI_SSID
        [ -n "$WIFI_SSID" ] || die "SSID cannot be empty"
        read -rsp "WiFi password: " WIFI_PASS
        echo ""
        [ -n "$WIFI_PASS" ] || die "Password cannot be empty"
    else
        WIFI_SSID="$CURRENT_SSID"
        WIFI_PASS=$(grep -A2 "\"${WIFI_SSID}\"" "$NETPLAN_FILE" 2>/dev/null | grep password | awk -F': ' '{print $2}' | tr -d '"' || true)
    fi
fi

header "Writing Netplan Config"
if [ -f "$NETPLAN_FILE" ]; then
    cp "$NETPLAN_FILE" "${NETPLAN_FILE}.bak"
    info "Backup saved to ${NETPLAN_FILE}.bak"
fi

if $IS_WIFI; then
    cat > "$NETPLAN_FILE" <<NETEOF
network:
  version: 2
  wifis:
    ${IFACE}:
      dhcp4: no
      addresses:
        - ${STATIC_IP}
      routes:
        - to: default
          via: ${GATEWAY}
      nameservers:
        addresses:
$(printf '%b' "$DNS_YAML")      access-points:
        "${WIFI_SSID}":
          password: "${WIFI_PASS}"
NETEOF
else
    cat > "$NETPLAN_FILE" <<NETEOF
network:
  version: 2
  ethernets:
    ${IFACE}:
      dhcp4: no
      addresses:
        - ${STATIC_IP}
      routes:
        - to: default
          via: ${GATEWAY}
      nameservers:
        addresses:
$(printf '%b' "$DNS_YAML")NETEOF
fi

info "Netplan config written to $NETPLAN_FILE"

header "Applying Configuration"
warn "Testing netplan config..."
if netplan try --timeout 10 2>/dev/null; then
    info "Netplan config applied successfully."
else
    warn "netplan try timed out or failed — applying anyway..."
    netplan apply
fi

STATIC_ADDR="${STATIC_IP%%/*}"
echo ""
echo -e "${YELLOW}══════════════════════════════════════════${NC}"
echo -e "${YELLOW}  Network reconfigured.${NC}"
echo -e "${YELLOW}  If you are connected via SSH, your session${NC}"
echo -e "${YELLOW}  may drop. Reconnect to: ${STATIC_ADDR}${NC}"
echo -e "${YELLOW}  Then run: sudo ./setup-spoke.sh${NC}"
echo -e "${YELLOW}══════════════════════════════════════════${NC}"
echo ""