#!/bin/bash
# Usage: ./init_adhoc.sh <PHYNAME> <DEVNAME> <SSID> <CHANNEL> <TXPOWER> <NOISEFLOOR>
# Example: ./init_adhoc.sh phy0 wlan0 adhocnet 149 200 -95

# set -e
set -xv

### === INPUT ARGUMENTS ===
PHYNAME=$1
DEVNAME=$2
SSID=$3
CHANNEL=$4
TXPOWER=$5
NOISEFLOOR=$6
shift 6
NODES=("$@")

# dev_number="${2//[!0-9]/}"
dev_number=$(echo "$DEVNAME" | grep -o '[0-9]\+$')
echo "dev_number is: $dev_number"

if [ -z "$PHYNAME" ] || [ -z "$DEVNAME" ] || [ -z "$SSID" ] || [ -z "$CHANNEL" ] || [ -z "$TXPOWER" ] || [ -z "$NOISEFLOOR" ]; then
    echo "Usage: $0 <PHYNAME> <DEVNAME> <SSID> <CHANNEL> <TXPOWER> <NOISEFLOOR>"
    exit 1
fi

### === PATHS ===
devPath="/sys/class/net/"
phyPath="/sys/kernel/debug/ieee80211/"

### === SYSTEM TUNING ===
echo "[*] Applying system TCP/UDP/queue optimizations..."
sysctl -w net.core.rmem_max=8388608
sysctl -w net.core.wmem_max=8388608
sysctl -w net.core.rmem_default=8388608
sysctl -w net.core.wmem_default=8388608
sysctl -w net.core.optmem_max=8388608
sysctl -w net.ipv4.tcp_mem="8388608 8388608 8388608"
sysctl -w net.ipv4.tcp_rmem="4096 87380 8388608"
sysctl -w net.ipv4.tcp_wmem="4096 65536 8388608"
sysctl -w net.ipv4.udp_mem="8388608 8388608 8388608"
sysctl -w net.ipv4.udp_rmem_min=4096
sysctl -w net.ipv4.udp_wmem_min=4096
sysctl -w net.core.netdev_max_backlog=5000
sysctl -w net.ipv4.tcp_max_syn_backlog=5000
sysctl -w net.ipv4.tcp_syn_retries=9
sysctl -w net.ipv4.tcp_synack_retries=9
sysctl -w net.ipv4.tcp_no_metrics_save=1
sysctl -w net.ipv4.route.flush=1
echo 0 > /sys/module/tcp_cubic/parameters/hystart
echo 0 > /sys/module/tcp_cubic/parameters/hystart_detect
sysctl -w net.ipv4.neigh.default.base_reachable_time_ms=1200000
sysctl -w net.ipv4.neigh.default.mcast_solicit=25
sysctl -w net.ipv4.neigh.default.ucast_solicit=25

### === DEVICE SETUP ===
echo "[*] Checking and cleaning wireless devices..."

# Remove existing device if needed
if [ -e "$devPath$DEVNAME" ]; then
    echo "[*] Removing existing interface $DEVNAME"
    ip link set $DEVNAME down || true
    iw dev $DEVNAME del || true
fi

# Check if PHY exists
if [ ! -e "$phyPath$PHYNAME" ]; then
    echo "[!] PHY $PHYNAME not found! Exiting."
    exit 1
fi

# Remove current devs from PHY if needed
current_dev_on_phy=$(iw dev | awk -v phy="${PHYNAME//[!0-9]/}" '$0 ~ "phy#"phy {getline; while ($1 == "Interface") {print $2; getline}}')
if [ ! -z "$current_dev_on_phy" ]; then
    echo "[*] Removing device $current_dev_on_phy on $PHYNAME"
    ip link set $current_dev_on_phy down || true
    iw dev $current_dev_on_phy del || true
fi

echo "[*] Creating new IBSS interface $DEVNAME..."
iw phy ${PHYNAME} interface add ${DEVNAME} type ibss

# Set device parameters
ip link set ${DEVNAME} down
iw dev ${DEVNAME} set type ibss
iw phy ${PHYNAME} set antenna 3 3
iw phy ${PHYNAME} set retry short 7 long 4
iw phy ${PHYNAME} set rts off
iw dev ${DEVNAME} set power_save off
iw dev ${DEVNAME} set txpower fixed ${TXPOWER}
ip link set ${DEVNAME} up

sleep 1

# --- Clean DHCP/ARP spam on adhoc interface ---
echo "[*] Suppressing unsolicited ARP on $DEVNAME"
sysctl -w net.ipv4.conf.${DEVNAME}.arp_ignore=1
sysctl -w net.ipv4.conf.${DEVNAME}.arp_announce=2

echo "[*] Stopping potential DHCP client on $DEVNAME"
pkill -f "dhclient.*$DEVNAME" || true

### === FREQUENCY LOOKUP ===
source /opt/scripts/mesh/freq.sh

FREQ=${chan[$CHANNEL]}

if [[ -z "$FREQ" ]]; then
    echo "[!] Error: Channel $CHANNEL not found in freq.sh mapping!"
    exit 1
fi

echo "Joining IBSS network SSID='$SSID' on ${FREQ} MHz (channel ${CHANNEL})..."

BSSID="02:11:87:7B:5E:01"  # Locally administered MAC address
iw dev ${DEVNAME} ibss join ${SSID} ${FREQ} HT40+ fixed-freq ${BSSID}
# iw dev ${DEVNAME} ibss join ${SSID} ${FREQ} HT20

### === IP ADDRESS ASSIGNMENT ===
echo "[*] Setting IP address based on node identity..."
source /opt/scripts/mesh/node_addresses.sh

# Find hostname and corresponding IP
HOSTNAME=$(uname -n)
echo "HOSTNAME is: '$HOSTNAME'"
NODE_NAME=$(echo $HOSTNAME | sed 's/\..*//') # strip domain if present
echo "NODE_NAME is: '$NODE_NAME'"
# IP_ADDR=${phy0IP["$NODE_NAME"]}

# NODE_ID=$(echo "$NODE_NAME" | grep -o '[0-9]\+' | sed 's/^0*//')  # Extract numeric ID
NODE_ID=$(echo "$NODE_NAME" | sed -E 's/[^0-9]*([0-9]+)$/\1/')
NODE_ID=$((10#$NODE_ID))  # Converts to decimal safely
echo "NODEID: $NODE_ID"
NODE_INDEX=-1

for idx in "${!NODES[@]}"; do
  if [[ "${NODES[$idx]}" -eq "$NODE_ID" ]]; then
    NODE_INDEX=$idx
    break
  fi
done

if [[ "$NODE_INDEX" -lt 0 ]]; then
  echo "Error: Node ID $NODE_ID not found in node list."
  exit 1
fi

# get the dev corresponding IP
if [[ "$dev_number" -eq 0 ]]; then
	IP_ADDR=${phy0IP["$NODE_NAME"]}
    BROADCAST_IP=${phy0IP["broadcast"]}
fi
if [[ "$dev_number" -eq 1 ]]; then
	IP_ADDR=${phy1IP["$NODE_NAME"]}
    BROADCAST_IP=${phy1IP["broadcast"]}
fi

if [[ -z "$IP_ADDR" ]]; then
    echo "[!] Error: No IP address found for $NODE_NAME in phy0IP."
    exit 1
fi

# Remove any existing IPs
ip addr flush dev ${DEVNAME}

# Set IP address
# ip addr add ${IP_ADDR}/24 dev ${DEVNAME}
ip addr add ${IP_ADDR}/24 broadcast $BROADCAST_IP dev ${DEVNAME}

echo "Assigned IP ${IP_ADDR}/24 to ${DEVNAME} with broadcast $BROADCAST_IP"
# Set the interface up

if (( NODE_INDEX > 0 && NODE_INDEX < ${#NODES[@]} - 1 )); then
  echo "[*] Enabling IP forwarding..."
  sysctl -w net.ipv4.ip_forward=1
fi

# Set static routes to other nodes
for target_idx in "${!NODES[@]}"; do
    target_node="${NODES[$target_idx]}"
    if [[ "$target_node" -eq "$NODE_ID" ]]; then continue; fi

    if (( target_idx < NODE_INDEX )); then # Left neighbor
        next_hop="${NODES[$((NODE_INDEX - 1))]}"
    else # Right neighbor
        next_hop="${NODES[$((NODE_INDEX + 1))]}"
    fi

    target_ip=${phy0IP["apu$(printf "%02d" $target_node)"]}
    next_ip=${phy0IP["apu$(printf "%02d" $next_hop)"]}

    echo "[*] Adding route to $target_ip via $next_ip"
    ip route add "$target_ip/32" via "$next_ip" dev "$DEVNAME" 2>/dev/null || true
done


### === NOISE FLOOR SETTING ===
echo "Setting manual noise floor and ani..."
echo 0 > /sys/kernel/debug/ieee80211/${PHYNAME}/ath9k/ani
echo ${NOISEFLOOR} > /sys/kernel/debug/ieee80211/${PHYNAME}/ath9k/nf_override

echo 198 > /sys/kernel/debug/ieee80211/${PHYNAME}/rc/fixed_rate_idx

echo "IBSS Ad-Hoc wireless initialization complete."

set +x