#!/bin/bash
# Name: ipfn
# Version: 1.0.4
# Date: 2026-01-22
# Description: Automatic list display after addition with highlighting.

# sudo権限チェック
if [ "$(id -u)" -ne 0 ]; then
    exec sudo "$0" "$@"
fi

TABLE_NAME="ipf_wrapper"
QUIET=false
PROTO="tcp"

# --- コンテナ検出 ---
is_container() {
    if command -v systemd-detect-virt &> /dev/null; then
        if systemd-detect-virt --quiet | grep -qE "container|vm"; then
            return 0
        fi
    fi
    return 1
}

# --- 初期化 ---
init_nft() {
    nft add table inet ${TABLE_NAME} 2>/dev/null
    nft add chain inet ${TABLE_NAME} prerouting { type nat hook prerouting priority -100 \; } 2>/dev/null
    nft add chain inet ${TABLE_NAME} output { type nat hook output priority -100 \; } 2>/dev/null
    nft add chain inet ${TABLE_NAME} postrouting { type nat hook postrouting priority 100 \; } 2>/dev/null
    nft add chain inet ${TABLE_NAME} forward { type filter hook forward priority 0 \; policy accept \; } 2>/dev/null
}

# --- ルール表示 (強調表示対応) ---
# 引数 $1 に UUID を渡すと、その行を強調する
list_rules() {
    local highlight_uuid=$1
    init_nft
    echo "Forwarding Rules (ipfn):"
    printf "%-8s %-6s %-20s %-20s %-10s\n" "HANDLE" "PROTO" "LOCAL" "TARGET" "UUID"
    echo "---------------------------------------------------------------------------------"
    
    nft -a list chain inet ${TABLE_NAME} prerouting | grep "dnat" | while read -r line; do
        handle=$(echo "$line" | grep -o 'handle [0-9]*' | awk '{print $2}')
        proto=$(echo "$line" | grep -q "udp" && echo "udp" || echo "tcp")
        target=$(echo "$line" | grep -oE '[0-9.]*:[0-9]+' | head -n 1)
        lport=$(echo "$line" | grep -o 'dport [0-9]*' | awk '{print $2}')
        full_uuid=$(echo "$line" | grep -o 'ipf-id:[a-z0-9-]*' | cut -d':' -f2)
        short_uuid="${full_uuid:0:8}"

        # 強調判定
        if [[ -n "$highlight_uuid" && "$full_uuid" == "$highlight_uuid" ]]; then
            # シアンの太字で表示
            printf "\e[1;36m%-8s %-6s %-20s %-20s %-10s\e[0m\n" "$handle" "$proto" ":$lport" "$target" "$short_uuid"
        else
            printf "%-8s %-6s %-20s %-20s %-10s\n" "$handle" "$proto" ":$lport" "$target" "$short_uuid"
        fi
    done
}

# --- 疎通確認 ---
test_rule() {
    local handle=$1
    local rule_line=$(nft -a list chain inet ${TABLE_NAME} prerouting | grep "handle $handle")
    if [[ -z "$rule_line" ]]; then
        echo "Error: Rule handle $handle not found."
        exit 1
    fi
    local lport=$(echo "$rule_line" | grep -o 'dport [0-9]*' | awk '{print $2}')
    echo "Testing connectivity to local port :$lport (via nc -z)..."
    if nc -z -v -w 3 127.0.0.1 "$lport" 2>&1; then
        echo -e "\e[32mSuccess: Port :$lport is responding.\e[0m"
    else
        echo -e "\e[31mFailed: Port :$lport is NOT responding.\e[0m"
    fi
}

# --- ルール追加 ---
add_rule() {
    init_nft
    local port_ip_port=$1
    local local_port=$(echo "$port_ip_port" | cut -d':' -f1)
    local target_ip=$(echo "$port_ip_port" | cut -d':' -f2)
    local target_port=$(echo "$port_ip_port" | cut -d':' -f3)

    local raw_uuid=$(cat /proc/sys/kernel/random/uuid)
    local uuid="ipf-id:$raw_uuid"
    local comment="comment \"$uuid\""
    local family="ip"
    [[ "$target_ip" =~ : ]] && family="ip6"

    nft add rule inet ${TABLE_NAME} prerouting "$PROTO" dport "$local_port" dnat $family to "$target_ip:$target_port" "$comment"
    nft add rule inet ${TABLE_NAME} output "$PROTO" dport "$local_port" dnat $family to "$target_ip:$target_port" "$comment"
    nft add rule inet ${TABLE_NAME} forward iifname "lo" accept "$comment"
    nft add rule inet ${TABLE_NAME} forward $family daddr "$target_ip" "$PROTO" dport "$target_port" ct state new,established,related accept "$comment"
    nft add rule inet ${TABLE_NAME} forward $family saddr "$target_ip" "$PROTO" sport "$target_port" ct state established,related accept "$comment"
    nft add rule inet ${TABLE_NAME} postrouting $family daddr "$target_ip" "$PROTO" dport "$target_port" masquerade "$comment"

    if [[ $QUIET == false ]]; then
        echo "ipfn: Rule added successfully."
        echo ""
        list_rules "$raw_uuid" # 追加したルールのUUIDを渡して強調表示
    fi
}

# --- ルール削除 ---
delete_rule() {
    init_nft
    local handle=$1
    local rule_info=$(nft -a list chain inet ${TABLE_NAME} prerouting | grep "handle $handle")
    if [[ -z "$rule_info" ]]; then
        echo "Error: Rule handle $handle not found."
        exit 1
    fi

    local uuid=$(echo "$rule_info" | grep -o 'ipf-id:[a-z0-9-]*' | head -n 1)
    local lport=$(echo "$rule_info" | grep -o 'dport [0-9]*' | awk '{print $2}')
    local target=$(echo "$rule_info" | grep -oE '[0-9.]*:[0-9]+' | head -n 1)

    echo "About to delete the following rule group:"
    echo "  Handle: $handle"
    echo "  Local:  :$lport"
    echo "  Target: $target"
    echo -n "Are you sure? (y/N): "
    read -r confirm

    if [[ "$confirm" =~ ^[yY]$ ]]; then
        for chain in prerouting output forward postrouting; do
            nft -a list chain inet ${TABLE_NAME} "$chain" | grep "$uuid" | grep -o 'handle [0-9]*' | awk '{print $2}' | while read -r h; do
                nft delete rule inet ${TABLE_NAME} "$chain" handle "$h"
            done
        done
        echo "ipfn: Rule group deleted."
        echo ""
        list_rules
    else
        echo "Aborted."
    fi
}

# --- メイン処理 ---
while [[ $# -gt 0 ]]; do
    case "$1" in
        -L|-l) list_rules; exit 0 ;;
        -d)    [[ -z "$2" ]] && { echo "Error: Handle required."; exit 1; }
               delete_rule "$2"; exit 0 ;;
        -t)    test_rule "$2"; exit 0 ;;
        -p)    PROTO="$2"; shift 2 ;;
        -q)    QUIET=true; shift ;;
        -f)    
            sysctl -w net.ipv4.ip_forward=1
            sysctl -w net.ipv4.conf.all.route_localnet=1
            sysctl -w net.ipv4.conf.default.route_localnet=1
            echo "Enabled: IP forward and Localnet routing."
            exit 0 ;;
        -v)    nft list table inet ${TABLE_NAME}; exit 0 ;;
        -*)    echo "Unknown option: $1"; exit 1 ;;
        *)     break ;;
    esac
done

if [[ -n "$1" ]]; then
    add_rule "$1"
else
    echo "Usage: ipfn [PORT:IP:PORT | -L | -d HANDLE | -t HANDLE]"
fi