"""libvirt 连接管理 - 使用连接池模式"""
import libvirt
from contextlib import contextmanager
from app.config import settings
import logging

logger = logging.getLogger(__name__)


class LibvirtConnection:
    """libvirt 连接管理器（只读连接保持，写操作用短连接）"""

    def __init__(self):
        self._conn = None

    def _connect(self):
        """建立新的 libvirt 连接"""
        try:
            conn = libvirt.openReadOnly(settings.LIBVIRT_URI)
            if conn is None:
                raise ConnectionError(f"无法连接到 libvirt: {settings.LIBVIRT_URI}")
            return conn
        except libvirt.libvirtError as e:
            logger.error(f"libvirt 连接错误: {e}")
            raise

    def _connect_rw(self):
        """建立可读写连接"""
        try:
            conn = libvirt.open(settings.LIBVIRT_URI)
            if conn is None:
                raise ConnectionError(f"无法连接到 libvirt (RW): {settings.LIBVIRT_URI}")
            return conn
        except libvirt.libvirtError as e:
            logger.error(f"libvirt RW 连接错误: {e}")
            raise

    @property
    def conn(self):
        """获取只读连接（带自动重连）"""
        try:
            if self._conn is None or not self._conn.isAlive():
                self._conn = self._connect()
        except Exception:
            self._conn = self._connect()
        return self._conn

    @contextmanager
    def get_rw(self):
        """获取读写连接（短连接，用完关闭）"""
        conn = None
        try:
            conn = self._connect_rw()
            yield conn
        finally:
            if conn is not None:
                try:
                    conn.close()
                except Exception:
                    pass

    def get_host_info(self):
        """获取宿主机信息"""
        c = self.conn
        return {
            "hostname": c.getHostname(),
            "hypervisor": c.getType(),
            "libvirt_version": c.getLibVersion(),
            "hypervisor_version": c.getVersion(),
            "cpu_model": c.getInfo()[5] if len(c.getInfo()) > 5 else "Unknown",
            "cpu_cores": c.getInfo()[2],
            "memory_total": c.getInfo()[1],  # KB
            "cpu_speed": c.getInfo()[3],  # MHz
        }


# 全局单例
libvirt_conn = LibvirtConnection()