#!/bin/bash
# chmod +x 00-disable-password.sh && ./00-disable-password.sh
# curl -sS -O https://gitea.tohub.top/Share/vps/raw/branch/main/init/00-disable-password.sh && chmod +x 00-disable-password.sh && ./00-disable-password.sh

set -e  # 遇到错误立即退出

# 颜色输出
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
NC='\033[0m' # No Color

# 日志函数
log_info() {
    echo -e "${GREEN}[INFO]${NC} $1"
}

log_warn() {
    echo -e "${YELLOW}[WARN]${NC} $1"
}

log_error() {
    echo -e "${RED}[ERROR]${NC} $1"
}

# 用户设置
NEW_SSH_PORT="4399"  # 根据需求修改端口
BACKUP_DIR="/root/ssh_backup_$(date +%Y%m%d_%H%M%S)"

# 检查是否为root用户
if [ "$EUID" -ne 0 ]; then
    log_error "请使用 root 用户运行此脚本"
    exit 1
fi

# 创建备份目录
mkdir -p "$BACKUP_DIR"
log_info "备份目录: $BACKUP_DIR"

# 1. 检查公钥是否存在
check_ssh_keys() {
    log_info "检查 SSH 公钥..."

    if [ ! -f ~/.ssh/authorized_keys ] || [ ! -s ~/.ssh/authorized_keys ]; then
        log_error "未找到 SSH 公钥文件或文件为空！"
        log_error "路径: ~/.ssh/authorized_keys"
        echo ""
        log_warn "如果继续，您将无法通过 SSH 登录服务器！"
        read -p "是否要继续？(输入 YES 继续): " confirm
        if [ "$confirm" != "YES" ]; then
            log_info "操作已取消"
            exit 0
        fi
    else
        log_info "找到 SSH 公钥，密钥数量: $(grep -c "^ssh-" ~/.ssh/authorized_keys || echo 0)"
        echo "密钥内容预览:"
        head -n 2 ~/.ssh/authorized_keys
    fi
}

# 2. 检查端口是否被占用
check_port() {
    log_info "检查端口 $NEW_SSH_PORT 是否可用..."

    if ss -tlnp | grep -q ":$NEW_SSH_PORT "; then
        log_error "端口 $NEW_SSH_PORT 已被占用！"
        ss -tlnp | grep ":$NEW_SSH_PORT "
        exit 1
    fi
    log_info "端口 $NEW_SSH_PORT 可用"
}

# 3. 关闭 SSH 密码登录并启用密钥认证
disable_password_login() {
    log_info "开始配置 SSH..."

    # 备份原始配置
    cp /etc/ssh/sshd_config "$BACKUP_DIR/sshd_config.bak"
    log_info "已备份 SSH 配置到: $BACKUP_DIR/sshd_config.bak"

    # 创建新配置
    cp /etc/ssh/sshd_config /etc/ssh/sshd_config.tmp

    # 修改配置（更安全的方式）
    # 1. 禁止 root 密码登录，但允许密钥登录
    if grep -q "^PermitRootLogin" /etc/ssh/sshd_config.tmp; then
        sed -i 's/^PermitRootLogin.*/PermitRootLogin prohibit-password/' /etc/ssh/sshd_config.tmp
    else
        echo "PermitRootLogin prohibit-password" >> /etc/ssh/sshd_config.tmp
    fi

    # 2. 禁用密码认证
    if grep -q "^PasswordAuthentication" /etc/ssh/sshd_config.tmp; then
        sed -i 's/^PasswordAuthentication.*/PasswordAuthentication no/' /etc/ssh/sshd_config.tmp
    else
        echo "PasswordAuthentication no" >> /etc/ssh/sshd_config.tmp
    fi

    # 3. 启用公钥认证
    if grep -q "^PubkeyAuthentication" /etc/ssh/sshd_config.tmp; then
        sed -i 's/^PubkeyAuthentication.*/PubkeyAuthentication yes/' /etc/ssh/sshd_config.tmp
    else
        echo "PubkeyAuthentication yes" >> /etc/ssh/sshd_config.tmp
    fi

    # 4. 修改端口
    if grep -q "^Port " /etc/ssh/sshd_config.tmp; then
        sed -i "s/^Port [0-9]\+/Port $NEW_SSH_PORT/" /etc/ssh/sshd_config.tmp
    else
        sed -i "s/^#Port 22/Port $NEW_SSH_PORT/" /etc/ssh/sshd_config.tmp
    fi

    # 5. 额外的安全加固
    # 禁用空密码
    if grep -q "^PermitEmptyPasswords" /etc/ssh/sshd_config.tmp; then
        sed -i 's/^PermitEmptyPasswords.*/PermitEmptyPasswords no/' /etc/ssh/sshd_config.tmp
    else
        echo "PermitEmptyPasswords no" >> /etc/ssh/sshd_config.tmp
    fi

    # 禁用质询响应认证
    if grep -q "^ChallengeResponseAuthentication" /etc/ssh/sshd_config.tmp; then
        sed -i 's/^ChallengeResponseAuthentication.*/ChallengeResponseAuthentication no/' /etc/ssh/sshd_config.tmp
    fi

    # 验证配置文件语法
    log_info "验证 SSH 配置文件语法..."
    if sshd -t -f /etc/ssh/sshd_config.tmp; then
        log_info "SSH 配置文件语法正确"
        mv /etc/ssh/sshd_config.tmp /etc/ssh/sshd_config
    else
        log_error "SSH 配置文件语法错误！"
        rm /etc/ssh/sshd_config.tmp
        exit 1
    fi
}

# 4. 重启 SSH 服务（兼容多种系统）
restart_ssh() {
    log_info "重启 SSH 服务..."

    # 保持当前连接
    log_warn "注意: SSH 服务将重启，但当前连接会保持"

    if command -v systemctl &> /dev/null; then
        systemctl restart sshd || systemctl restart ssh
        log_info "SSH 服务已通过 systemctl 重启"
    elif command -v service &> /dev/null; then
        service sshd restart || service ssh restart
        log_info "SSH 服务已通过 service 重启"
    else
        /etc/init.d/sshd restart || /etc/init.d/ssh restart
        log_info "SSH 服务已通过 init.d 重启"
    fi
}

# 5. 配置防火墙
configure_firewall() {
    log_info "配置防火墙..."

    # 检查系统并安装 UFW
    if ! command -v ufw &> /dev/null; then
        log_info "安装 UFW 防火墙..."
        apt-get update -y && apt-get install -y ufw
    fi

    # 备份当前防火墙规则
    ufw status numbered > "$BACKUP_DIR/ufw_rules.bak" 2>/dev/null || true

    # 配置防火墙规则
    log_info "设置防火墙规则..."

    # 先允许新端口，避免锁死
    ufw allow $NEW_SSH_PORT/tcp comment "SSH"

    # 询问是否允许其他常用端口
    read -p "是否允许 HTTP (80) 和 HTTPS (443) 端口? (y/n): " allow_web
    if [[ $allow_web =~ ^[Yy]$ ]]; then
        ufw allow 80/tcp comment "HTTP"
        ufw allow 443/tcp comment "HTTPS"
        log_info "已允许 HTTP 和 HTTPS 端口"
    fi

    # 启用防火墙
    ufw --force enable

    log_info "防火墙状态:"
    ufw status verbose
}

# 6. 显示最终信息
show_summary() {
    echo ""
    echo "========================================"
    log_info "SSH 安全配置完成！"
    echo "========================================"
    echo ""
    echo "修改后的配置:"
    echo "  - SSH 端口: $NEW_SSH_PORT"
    echo "  - 密码登录: 已禁用"
    echo "  - 密钥登录: 已启用"
    echo "  - Root 密码登录: 已禁用"
    echo ""
    echo "备份信息:"
    echo "  - 备份目录: $BACKUP_DIR"
    echo "  - SSH 配置备份: $BACKUP_DIR/sshd_config.bak"
    echo ""
    echo "重要提示:"
    echo "  1. 请勿关闭当前 SSH 连接"
    echo "  2. 在新终端测试登录: ssh -p $NEW_SSH_PORT root@your_server_ip"
    echo "  3. 确认新连接成功后再关闭此窗口"
    echo "  4. 如果无法登录，可以使用以下命令恢复:"
    echo "     cp $BACKUP_DIR/sshd_config.bak /etc/ssh/sshd_config"
    echo "     systemctl restart sshd"
    echo ""
    echo "========================================"
}

# 主流程
main() {
    log_info "开始 SSH 安全配置..."
    echo ""

    # 显示当前配置
    log_info "当前 SSH 配置:"
    echo "  - 当前端口: $(grep "^Port " /etc/ssh/sshd_config 2>/dev/null || echo "22 (默认)")"
    echo "  - 将修改为: $NEW_SSH_PORT"
    echo ""

    # 确认执行
    read -p "是否继续执行? (y/n): " confirm
    if [[ ! $confirm =~ ^[Yy]$ ]]; then
        log_info "操作已取消"
        exit 0
    fi

    check_ssh_keys
    check_port
    disable_password_login
    restart_ssh
    configure_firewall
    show_summary
}

# 执行主函数
main