#!/bin/bash

# 无依赖客户端脚本 - 使用系统自带工具
# 支持: Debian, Ubuntu, CentOS, RHEL, Fedora, Alpine

SERVER_IP="159.138.58.239"  # 你的服务器IP
SERVER_PORT=5555
CLIENT_PORT=5556
HEARTBEAT_INTERVAL=30

# 获取系统信息
get_system_info() {
    if [[ -f /etc/os-release ]]; then
        local distro=$(grep -oP '(?<=^ID=).+' /etc/os-release | tr -d '"')
        local version=$(grep -oP '(?<=^VERSION_ID=).+' /etc/os-release | tr -d '"')
        echo "$distro $version"
    else
        echo "unknown"
    fi
}

# 生成客户端序列号
generate_serial() {
    if [[ -f /etc/machine-id ]]; then
        cat /etc/machine-id | md5sum | cut -c1-8
    else
        date +%s | sha256sum | base64 | head -c 8
    fi
}

SERIAL=$(generate_serial)
HOSTNAME=$(hostname)
SYSTEM_INFO=$(get_system_info)

# 颜色输出
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
BLUE='\033[0;34m'
NC='\033[0m'

log() {
    echo -e "$(date '+%Y-%m-%d %H:%M:%S') - $1"
}

print_color() {
    echo -e "${2}${1}${NC}"
}

# 检查可用工具
check_tool() {
    for tool in "$@"; do
        if command -v "$tool" &> /dev/null; then
            echo "$tool"
            return 0
        fi
    done
    echo ""
}

# 发送数据到服务器
send_data() {
    local data="$1"
    local port="$2"
    
    # 尝试多种方法发送数据
    local tool=$(check_tool nc netcat telnet)
    
    if [[ -n "$tool" ]]; then
        # 使用netcat或telnet
        if [[ "$tool" == "telnet" ]]; then
            echo "$data" | timeout 5 telnet "$SERVER_IP" "$port" 2>/dev/null
        else
            echo "$data" | timeout 5 "$tool" "$SERVER_IP" "$port" 2>/dev/null
        fi
    elif command -v bash &> /dev/null && command -v cat &> /dev/null; then
        # 使用bash内置的TCP功能
        exec 3<>/dev/tcp/$SERVER_IP/$port 2>/dev/null
        if [[ $? -eq 0 ]]; then
            echo "$data" >&3
            cat <&3 2>/dev/null &
            sleep 1
            exec 3>&-
            return 0
        fi
    elif command -v /bin/echo &> /dev/null && [[ -e /dev/tcp ]]; then
        # 另一种TCP方法
        /bin/echo "$data" > /dev/tcp/$SERVER_IP/$port 2>/dev/null &
    fi
    
    return 1
}

# 监听端口
listen_port() {
    local port="$1"
    
    # 尝试多种监听方法
    local tool=$(check_tool nc netcat)
    
    if [[ -n "$tool" ]]; then
        # 使用netcat监听
        $tool -l -p "$port" -c 'read -r data; echo "$data"'
    elif command -v bash &> /dev/null; then
        # 使用bash监听（简单版本）
        while true; do
            {
                while read -r line; do
                    echo "$line"
                    break
                done
            } < /dev/tcp/0.0.0.0/"$port" 2>/dev/null || sleep 1
        done
    else
        # 最后的方法：使用临时文件轮询
        local temp_file="/tmp/client_cmd_$$"
        while true; do
            if [[ -f "$temp_file" ]]; then
                cat "$temp_file"
                rm -f "$temp_file"
            fi
            sleep 1
        done
    fi
}

# 发送心跳包
send_heartbeat() {
    while true; do
        if send_data "HEARTBEAT|$SERIAL|$HOSTNAME|$SYSTEM_INFO" "$SERVER_PORT"; then
            log "心跳包发送成功"
        else
            print_color "无法连接到服务器 $SERVER_IP:$SERVER_PORT" "$RED"
            print_color "将在 ${HEARTBEAT_INTERVAL} 秒后重试..." "$YELLOW"
        fi
        sleep $HEARTBEAT_INTERVAL
    done
}

# 执行命令
execute_command() {
    local command="$1"
    log "执行命令: $command"
    
    # 执行命令并捕获输出
    result=$(eval "$command" 2>&1)
    echo "命令执行结果: $result"
}

# 执行预定义脚本
execute_script() {
    local script_name="$1"
    
    case "$script_name" in
        "shutdown")
            print_color "执行关机命令..." "$RED"
            shutdown -h now
            ;;
        "reboot")
            print_color "执行重启命令..." "$YELLOW"
            reboot
            ;;
        "restart_services")
            print_color "重启系统服务..." "$YELLOW"
            systemctl restart networking 2>/dev/null || systemctl restart network 2>/dev/null
            systemctl restart ssh 2>/dev/null || systemctl restart sshd 2>/dev/null
            ;;
        "system_info")
            print_color "收集系统信息..." "$GREEN"
            echo "=== 系统信息 ==="
            echo "主机名: $(hostname)"
            echo "序列号: $SERIAL"
            echo "系统: $SYSTEM_INFO"
            echo "内核: $(uname -r)"
            echo "架构: $(uname -m)"
            echo "上线时间: $(uptime -p 2>/dev/null || uptime)"
            echo "内存使用:"
            free -h 2>/dev/null || cat /proc/meminfo | head -5
            echo "磁盘使用:"
            df -h 2>/dev/null || df
            ;;
        "update_system")
            print_color "开始系统更新..." "$YELLOW"
            if command -v apt-get &> /dev/null; then
                apt-get update && apt-get upgrade -y
            elif command -v yum &> /dev/null; then
                yum update -y
            elif command -v dnf &> /dev/null; then
                dnf update -y
            elif command -v apk &> /dev/null; then
                apk update && apk upgrade
            else
                echo "未找到包管理器"
            fi
            echo "系统更新完成!"
            ;;
        "network_info")
            print_color "网络信息..." "$GREEN"
            ip addr show 2>/dev/null || ifconfig 2>/dev/null || echo "无法获取网络信息"
            ;;
        "process_info")
            print_color "进程信息..." "$GREEN"
            ps aux 2>/dev/null | head -20
            ;;
        *)
            print_color "未知命令: $script_name" "$RED"
            echo "可用命令: shutdown, reboot, restart_services, system_info, update_system, network_info, process_info"
            ;;
    esac
}

# 启动命令监听
start_listener() {
    print_color "启动命令监听器在端口 $CLIENT_PORT..." "$GREEN"
    print_color "客户端信息: $SERIAL - $HOSTNAME - $SYSTEM_INFO" "$BLUE"
    print_color "使用通信方法: $(check_tool nc netcat || echo "bash TCP")" "$BLUE"
    
    while true; do
        log "等待命令..."
        command_data=$(listen_port "$CLIENT_PORT")
        
        if [[ -n "$command_data" ]]; then
            log "收到命令: $command_data"
            
            if echo "$command_data" | grep -q "^COMMAND:"; then
                cmd=$(echo "$command_data" | cut -d: -f2-)
                echo "执行命令: $cmd"
                execute_command "$cmd"
            elif echo "$command_data" | grep -q "^SCRIPT:"; then
                script_name=$(echo "$command_data" | cut -d: -f2-)
                echo "执行脚本: $script_name"
                execute_script "$script_name"
            else
                echo "未知命令格式: $command_data"
            fi
        fi
        
        sleep 1
    done
}

# 清理函数
cleanup() {
    print_color "客户端停止" "$RED"
    exit 0
}

# 设置信号处理
trap cleanup INT TERM

# 主函数
main() {
    print_color "=== 无依赖控制器客户端 ===" "$BLUE"
    print_color "序列号: $SERIAL" "$GREEN"
    print_color "主机名: $HOSTNAME" "$GREEN"
    print_color "系统: $SYSTEM_INFO" "$GREEN"
    print_color "服务器: $SERVER_IP:$SERVER_PORT" "$BLUE"
    
    # 显示可用工具
    print_color "检测到以下通信工具:" "$YELLOW"
    for tool in nc netcat telnet bash; do
        if command -v "$tool" &> /dev/null; then
            echo "  ✓ $tool"
        fi
    done
    
    # 启动心跳包发送（后台进程）
    print_color "启动心跳服务..." "$GREEN"
    send_heartbeat &
    
    # 启动命令监听
    print_color "启动命令监听..." "$GREEN"
    start_listener
}

# 脚本入口
case "${1:-}" in
    "execute_script")
        execute_script "$2"
        ;;
    "heartbeat")
        send_heartbeat
        ;;
    "test")
        echo "测试连接到服务器..."
        send_data "TEST|$SERIAL" "$SERVER_PORT"
        ;;
    *)
        main
        ;;
esac