#!/bin/bash
# ================================================
# STA+AP 异频设置脚本
# STA: 5GHz 连接上游WiFi（wld0）
# AP:  2.4GHz 发出热点（ap0）
# ================================================

set -e

# ========== 配置区域（按需修改）==========
AP_SSID="K20P-AP"               # AP热点名称
AP_PASS="12345678"               # AP密码（至少8位）
AP_CHANNEL="6"                   # AP信道（2.4GHz: 1/6/11）
AP_IP="192.168.50.1"             # AP网关IP
AP_DHCP_START="192.168.50.100"   # DHCP起始IP
AP_DHCP_END="192.168.50.200"     # DHCP结束IP
STA_IFACE="wld0"                 # STA接口名
AP_IFACE="ap0"                   # AP接口名
# =========================================

echo "================================================"
echo " STA+AP 异频设置"
echo " STA: $STA_IFACE (5GHz) → 连接上游WiFi"
echo " AP:  $AP_IFACE (2.4GHz) → 发出 $AP_SSID"
echo "================================================"
echo ""

# 检查root权限
if [ "$(id -u)" != "0" ]; then
  echo "[错误] 请用root权限运行此脚本"
  exit 1
fi

# 检查STA接口是否存在
if ! ip link show $STA_IFACE &>/dev/null; then
  echo "[错误] STA接口 $STA_IFACE 不存在"
  echo "当前接口列表："
  iw dev
  exit 1
fi

# 检查STA是否已连接
STA_STATUS=$(iw dev $STA_IFACE link 2>/dev/null | grep -c "Connected" || true)
if [ "$STA_STATUS" -eq 0 ]; then
  echo "[警告] $STA_IFACE 当前未连接WiFi，AP仍会创建但无法上网"
fi

echo "[1/7] 安装依赖..."
apt install -y hostapd dnsmasq iptables 2>/dev/null | tail -1

echo "[2/7] 创建AP虚拟接口 $AP_IFACE..."
# 如果已存在则先删除
if ip link show $AP_IFACE &>/dev/null; then
  echo "      $AP_IFACE 已存在，先删除..."
  ip link set $AP_IFACE down 2>/dev/null || true
  iw dev $AP_IFACE del 2>/dev/null || true
fi

# 获取phy设备
PHY=$(iw dev $STA_IFACE info | grep wiphy | awk '{print "phy"$2}')
echo "      使用物理设备: $PHY"
iw phy $PHY interface add $AP_IFACE type __ap

echo "[3/7] 配置AP接口..."
# 生成MAC地址（修改第一个字节为02表示本地管理）
STA_MAC=$(cat /sys/class/net/$STA_IFACE/address)
AP_MAC="02:$(echo $STA_MAC | cut -d: -f2-)"
ip link set $AP_IFACE address $AP_MAC
ip link set $AP_IFACE up
ip addr flush dev $AP_IFACE
ip addr add ${AP_IP}/24 dev $AP_IFACE
echo "      AP MAC: $AP_MAC"
echo "      AP IP:  $AP_IP"

echo "[4/7] 配置 hostapd..."
cat > /etc/hostapd/hostapd.conf << EOF
# AP接口
interface=$AP_IFACE
driver=nl80211

# 热点信息
ssid=$AP_SSID
hw_mode=g
channel=$AP_CHANNEL

# 802.11n支持
ieee80211n=1
wmm_enabled=1
ht_capab=[HT40+][SHORT-GI-40][DSSS_CCK-40]

# 加密设置
auth_algs=1
wpa=2
wpa_passphrase=$AP_PASS
wpa_key_mgmt=WPA-PSK
rsn_pairwise=CCMP

# 其他
ignore_broadcast_ssid=0
EOF

# 指定配置文件
sed -i 's|#DAEMON_CONF=.*|DAEMON_CONF="/etc/hostapd/hostapd.conf"|' \
  /etc/default/hostapd 2>/dev/null || \
  echo 'DAEMON_CONF="/etc/hostapd/hostapd.conf"' >> /etc/default/hostapd

echo "[5/7] 配置 dnsmasq DHCP..."
# 备份原配置
[ -f /etc/dnsmasq.conf ] && cp /etc/dnsmasq.conf /etc/dnsmasq.conf.bak

cat > /etc/dnsmasq.d/ap0.conf << EOF
# AP热点 DHCP配置
interface=$AP_IFACE
bind-interfaces
dhcp-range=$AP_DHCP_START,$AP_DHCP_END,255.255.255.0,24h
dhcp-option=3,$AP_IP
dhcp-option=6,8.8.8.8,8.8.4.4
EOF

echo "[6/7] 配置 NAT 转发..."
# 开启IP转发
echo 1 > /proc/sys/net/ipv4/ip_forward
# 永久生效
if ! grep -q "net.ipv4.ip_forward=1" /etc/sysctl.conf; then
  echo "net.ipv4.ip_forward=1" >> /etc/sysctl.conf
fi

# 清理旧规则
iptables -t nat -D POSTROUTING -o $STA_IFACE -j MASQUERADE 2>/dev/null || true
# 添加NAT规则
iptables -t nat -A POSTROUTING -o $STA_IFACE -j MASQUERADE
iptables -A FORWARD -i $AP_IFACE -o $STA_IFACE -j ACCEPT
iptables -A FORWARD -i $STA_IFACE -o $AP_IFACE -m state \
  --state RELATED,ESTABLISHED -j ACCEPT

# 保存iptables规则
apt install -y iptables-persistent 2>/dev/null | tail -1
netfilter-persistent save 2>/dev/null || true

echo "[7/7] 启动服务..."
systemctl restart dnsmasq
systemctl unmask hostapd 2>/dev/null || true
systemctl enable hostapd
systemctl restart hostapd

# 等待hostapd启动
sleep 2

echo ""
echo "================================================"
echo " 设置完成，当前状态："
echo "================================================"
echo ""

# 显示STA状态
STA_SSID=$(iw dev $STA_IFACE link 2>/dev/null | grep SSID | awk '{print $2}')
STA_FREQ=$(iw dev $STA_IFACE link 2>/dev/null | grep freq | awk '{print $2}')
echo "STA ($STA_IFACE):"
echo "  连接: ${STA_SSID:-未连接}"
echo "  频率: ${STA_FREQ:-N/A} MHz"

echo ""
echo "AP ($AP_IFACE):"
echo "  SSID:    $AP_SSID"
echo "  密码:    $AP_PASS"
echo "  信道:    $AP_CHANNEL (2.4GHz)"
echo "  网关:    $AP_IP"
echo "  DHCP:    $AP_DHCP_START ~ $AP_DHCP_END"

echo ""
echo "hostapd 状态:"
systemctl is-active hostapd && echo "  ✅ 运行中" || echo "  ❌ 未运行"

echo ""
echo "验证命令:"
echo "  iw dev                    # 查看所有接口"
echo "  systemctl status hostapd  # 查看AP状态"
echo "  cat /var/lib/misc/dnsmasq.leases  # 查看已连接设备"
echo ""
echo "停止AP:"
echo "  systemctl stop hostapd"
echo "  ip link set $AP_IFACE down"
echo ""