#!/bin/bash
# KVM 虚拟机 QEMU Guest Agent 一键安装脚本
# 用法: ./install-guest-agent.sh [VM_NAME]

set -e

AGENT_XML="/tmp/ga-channel.xml"
CONTROLLER_XML="/tmp/ga-controller.xml"

# 检查 virtio-serial controller 是否存在
check_controller() {
    local vm="$1"
    if virsh dumpxml "$vm" | grep -q "type='virtio-serial'"; then
        return 0  # 存在
    fi
    return 1  # 不存在
}

# 添加 virtio-serial controller
add_controller() {
    local vm="$1"
    cat > "$CONTROLLER_XML" << 'EOF'
<controller type='virtio-serial' index='0'/>
EOF
    virsh attach-device "$vm" "$CONTROLLER_XML" --config 2>/dev/null || true
    rm -f "$CONTROLLER_XML"
}

# 添加 guest agent channel
add_channel() {
    local vm="$1"
    cat > "$AGENT_XML" << 'EOF'
<channel type='unix'>
  <source mode='bind'/>
  <target type='virtio' name='org.qemu.guest_agent.0'/>
</channel>
EOF
    virsh attach-device "$vm" "$AGENT_XML" --live --config 2>/dev/null
    rm -f "$AGENT_XML"
}

# 安装 guest agent 到虚拟机内部
install_agent_in_vm() {
    local vm="$1"
    echo "安装 Guest Agent 到 $vm ..."

    # 获取虚拟机 IP（用于 SSH）
    local ip=""
    if command -v virsh &>/dev/null; then
        ip=$(virsh domifaddr "$vm" 2>/dev/null | grep -oP '(\d+\.){3}\d+' | head -1)
    fi

    if [ -z "$ip" ]; then
        echo "  无法获取 $vm 的 IP 地址，跳过 Agent 安装"
        echo "  请手动在虚拟机内执行以下命令安装 Agent:"
        echo "    CentOS/RHEL: yum install qemu-guest-agent"
        echo "    Ubuntu/Debian: apt install qemu-guest-agent"
        return 0
    fi

    # 尝试 SSH 连接并安装
    ssh -o StrictHostKeyChecking=no -o ConnectTimeout=5 "$ip" "command -v yum &>/dev/null && yum install -y qemu-guest-agent || (command -v apt &>/dev/null && apt update && apt install -y qemu-guest-agent) || echo 'Agent 安装失败，请手动安装'" 2>/dev/null || true
}

# 单个虚拟机配置
setup_one_vm() {
    local vm="$1"
    echo "=========================================="
    echo "配置虚拟机: $vm"

    # 检查虚拟机是否存在
    if ! virsh domstate "$vm" &>/dev/null; then
        echo "  错误: 虚拟机 $vm 不存在"
        return 1
    fi

    local state=$(virsh domstate "$vm")
    echo "  当前状态: $state"

    # 检查是否已有 guest-agent channel
    if virsh dumpxml "$vm" | grep -q "org.qemu.guest_agent"; then
        echo "  ✓ Guest Agent channel 已配置，跳过"
        if [ "$state" = "running" ]; then
            echo "  检测 Guest Agent 连接状态..."
            virsh qemu-agent-command "$vm" '{"execute":"guest-info"}' 2>/dev/null && echo "  ✓ Guest Agent 运行正常" || echo "  ✗ Guest Agent 未响应"
        fi
        return 0
    fi

    # 检查 controller
    if ! check_controller "$vm"; then
        echo "  添加 virtio-serial 控制器..."
        add_controller "$vm"
        echo "  ✓ 控制器添加成功（需要重启生效）"
    else
        echo "  ✓ virtio-serial 控制器已存在"
    fi

    # 添加 channel
    echo "  添加 Guest Agent channel..."
    if add_channel "$vm"; then
        echo "  ✓ Channel 配置成功"
    else
        echo "  ✗ Channel 配置失败（虚拟机可能需要关机）"
        echo "  建议: virsh shutdown $vm && virsh edit $vm"
        return 1
    fi

    # 如果运行中，尝试安装 Agent
    if [ "$state" = "running" ]; then
        install_agent_in_vm "$vm"
    fi

    echo "=========================================="
    echo ""
}

# 批量配置所有运行中的虚拟机
setup_all_vms() {
    echo "===== 批量配置所有虚拟机 ====="
    echo ""

    local vms=$(virsh list --all --name 2>/dev/null)
    
    if [ -z "$vms" ]; then
        echo "没有找到虚拟机"
        return
    fi

    for vm in $vms; do
        # 跳过模板和特殊虚拟机
        [[ "$vm" =~ ^(Template|base|.*-template)$ ]] && continue
        
        setup_one_vm "$vm"
    done

    echo "===== 配置完成 ====="
    echo ""
    echo "提示: 如果 Guest Agent 未响应，请重启虚拟机:"
    echo "  virsh reboot <VM_NAME>"
}

# 主程序
main() {
    echo "=========================================="
    echo "  KVM Guest Agent 一键安装脚本"
    echo "=========================================="
    echo ""

    if [ -z "$1" ]; then
        echo "用法:"
        echo "  $0 <VM_NAME>     # 配置单个虚拟机"
        echo "  $0 --all        # 配置所有虚拟机"
        echo ""
        echo "示例:"
        echo "  $0 myvm"
        echo "  $0 --all"
        echo ""
        setup_all_vms
    elif [ "$1" = "--all" ]; then
        setup_all_vms
    else
        setup_one_vm "$1"
    fi
}

main "$@"