#!/usr/bin/env bash
###
# @Author: 星空
# @Date: 2024-06-19 16:33:01
 # @LastEditTime: 2024-06-21 12:12:04
 # @LastEditors: 星空
# @Description: 一键添加/删除swap脚本
# QQ: 1595601223
# Mail: pluto@xkzs.cc
# Copyright (c) 2024 by xkzs.cc All Rights Reserved.
###
PATH=/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/local/sbin:~/bin
export PATH

# fonts color
Green="\033[32m"
Red="\033[31m"
Font="\033[0m"
# fonts color

#root权限
root_need() {
    if [[ $EUID -ne 0 ]]; then
        echo -e "${Red}Error:This script must be run as root!${Font}"
        exit 1
    fi
}

#检测ovz
ovz_no() {
    if [[ -d "/proc/vz" ]]; then
        echo -e "${Red}Your VPS is based on OpenVZ，not supported!${Font}"
        exit 1
    fi
}

add_swap() {
    echo -e "${Green}请输入需要添加的 Swap 值,单位为 MB ,建议为内存的 2 倍.(例如输入:4096)${Font}"
    read -p "请输入 Swap 数值:" swapsize

    #检查是否存在swapfile
    grep -q "swap" /etc/fstab

    #如果不存在将为其创建swap
    if [ $? -ne 0 ]; then
        echo -e "${Green}swapfile 未发现，正在为其创建 swapfile${Font}"
        dd if=/dev/zero of=/swapfile bs=1M count=${swapsize}
        chmod 600 /swapfile
        mkswap /swapfile
        swapon /swapfile
        echo '/swapfile none swap defaults 0 0' >>/etc/fstab
        echo -e "${Green}swap 创建成功，并查看信息：${Font}"
        cat /proc/swaps
        cat /proc/meminfo | grep Swap
    else
        echo -e "${Red}swapfile 已存在，swap 设置失败，请先运行脚本删除 swap 后重新设置！${Font}"
    fi
}

del_swap() {
    #检查是否存在swapfile
    grep -q "swap" /etc/fstab

    #如果存在就将其移除
    if [ $? -eq 0 ]; then
        echo -e "${Green}swapfile 已发现，正在将其移除...${Font}"
        sed -i '/swap/d' /etc/fstab
        echo "3" >/proc/sys/vm/drop_caches
        swapoff -a
        rm -f /swapfile
        echo -e "${Green}swap 已删除！${Font}"
    else
        echo -e "${Red}swapfile 未发现，swap 删除失败！${Font}"
    fi
}

#开始菜单
main() {
    root_need
    ovz_no
    clear
    echo -e "———————————————————————————————————————"
    echo -e "${Green}一键添加/删除swap脚本${Font}"
    echo -e "${Green}1、添加swap${Font}"
    echo -e "${Green}2、删除swap${Font}"
    echo -e "———————————————————————————————————————"
    read -p "请输入数字 [1-2]:" num
    case "$num" in
    1)
        add_swap
        ;;
    2)
        del_swap
        ;;
    *)
        clear
        echo -e "${Green}请输入正确数字 [1-2]${Font}"
        sleep 2s
        main
        ;;
    esac
}
main