"""虚拟机 XML 模板和工具函数"""
import uuid
import libvirt
from lxml import etree


def generate_vm_xml(
    name: str,
    memory_mb: int,
    vcpus: int,
    disk_path: str,
    disk_size_gb: int = 20,
    iso_path: str = None,
    network: str = "default",
    vnc_port: int = -1,
    os_type: str = "hvm",
    arch: str = "x86_64",
    machine: str = "pc",
) -> str:
    """生成虚拟机 XML 定义"""

    vm_uuid = str(uuid.uuid4())

    # 基础 XML 结构
    xml_parts = f"""<domain type='kvm'>
  <name>{name}</name>
  <uuid>{vm_uuid}</uuid>
  <memory unit='MiB'>{memory_mb}</memory>
  <currentMemory unit='MiB'>{memory_mb}</currentMemory>
  <vcpu placement='static'>{vcpus}</vcpu>
  <os>
    <type arch='{arch}' machine='{machine}'>{os_type}</type>
    <boot dev='hd'/>
    <boot dev='cdrom'/>
  </os>
  <features>
    <acpi/>
    <apic/>
  </features>
  <cpu mode='host-passthrough'/>
  <clock offset='utc'>
    <timer name='rtc' tickpolicy='catchup'/>
    <timer name='pit' tickpolicy='delay'/>
    <timer name='hpet' present='no'/>
  </clock>
  <on_poweroff>destroy</on_poweroff>
  <on_reboot>restart</on_reboot>
  <on_crash>destroy</on_crash>
  <devices>
    <emulator>/usr/bin/qemu-system-x86_64</emulator>
    <disk type='file' device='disk'>
      <driver name='qemu' type='qcow2'/>
      <source file='{disk_path}'/>
      <target dev='vda' bus='virtio'/>
    </disk>"""

    # 光驱（ISO安装）
    if iso_path:
        xml_parts += f"""
    <disk type='file' device='cdrom'>
      <driver name='qemu' type='raw'/>
      <source file='{iso_path}'/>
      <target dev='hda' bus='ide'/>
      <readonly/>
    </disk>"""

    # VNC
    if vnc_port == -1:
        vnc_port = 5900  # auto-allocate by libvirt
    xml_parts += f"""
    <graphics type='vnc' port='{vnc_port}' autoport='yes' listen='0.0.0.0' passwd=''>
      <listen type='address' address='0.0.0.0'/>
    </graphics>
    <video>
      <model type='virtio' heads='1' primary='yes'/>
    </video>
    <serial type='pty'>
      <target port='0'/>
    </serial>
    <console type='pty'>
      <target type='serial' port='0'/>
    </console>"""

    # 网络
    xml_parts += f"""
    <interface type='network'>
      <source network='{network}'/>
      <model type='virtio'/>
    </interface>
    <controller type='usb' model='qemu-xhci'/>
    <input type='tablet' bus='usb'/>
    <memballoon model='virtio'/>
  </devices>
</domain>"""

    return xml_parts


def parse_vm_info(dom, host_id: str = "local", include_ip: bool = False) -> dict:
    """从 libvirt domain 对象提取虚拟机信息
    
    Args:
        dom: libvirt domain 对象
        host_id: 主机ID
        include_ip: 是否获取IP地址（开启会明显变慢，默认关闭）
    """
    from app.libvirt_conn import libvirt_conn

    # 基本信息
    info = {
        "id": dom.ID(),
        "name": dom.name(),
        "uuid": dom.UUIDString(),
        "state": _get_state(dom),
        "autostart": False,
    }

    try:
        info["autostart"] = dom.autostart() == 1
    except Exception:
        pass

    # 解析 XML
    xml_desc = dom.XMLDesc(0)
    tree = etree.fromstring(xml_desc.encode())

    # 内存和CPU
    mem = tree.find(".//memory")
    cur_mem = tree.find(".//currentMemory")
    vcpu = tree.find(".//vcpu")

    mem_unit = mem.get("unit", "KiB") if mem is not None else "KiB"
    mem_val = int(mem.text) if mem is not None else 0
    info["memory_mb"] = _to_mb(mem_val, mem_unit)

    cur_unit = cur_mem.get("unit", "KiB") if cur_mem is not None else "KiB"
    cur_val = int(cur_mem.text) if cur_mem is not None else 0
    info["current_memory_mb"] = _to_mb(cur_val, cur_unit)

    info["vcpus"] = int(vcpu.text) if vcpu is not None else 1

    # CPU type
    cpu = tree.find(".//cpu")
    if cpu is not None:
        info["cpu_mode"] = cpu.get("mode", "unknown")
    else:
        info["cpu_mode"] = "unknown"

    # 磁盘
    disks = []
    for disk in tree.findall(".//disk"):
        if disk.get("device") == "disk":
            source = disk.find("source")
            target = disk.find("target")
            driver = disk.find("driver")
            disk_info = {
                "file": source.get("file", "") if source is not None else "",
                "dev": target.get("dev", "") if target is not None else "",
                "bus": target.get("bus", "") if target is not None else "",
                "format": driver.get("type", "") if driver is not None else "",
            }
            disks.append(disk_info)
    info["disks"] = disks

    # 网络
    interfaces = []
    for iface in tree.findall(".//interface"):
        source = iface.find("source")
        model = iface.find("model")
        target = iface.find("target")
        iface_info = {
            "type": iface.get("type", ""),
            "network": source.get("network", "") if source is not None else "",
            "bridge": source.get("bridge", "") if source is not None else "",
            "model": model.get("type", "") if model is not None else "",
            "dev": target.get("dev", "") if target is not None else "",
        }
        mac_elem = iface.find("mac")
        if mac_elem is not None:
            iface_info["mac"] = mac_elem.get("address", "")
        interfaces.append(iface_info)
    info["interfaces"] = interfaces

    # 获取 IP 地址（仅在需要时）
    if include_ip and info["state"] == "running":
        arp_cache = _get_arp_table(host_id)
        for iface in interfaces:
            if "mac" in iface:
                # 先尝试 Guest Agent 和 DHCP 租约
                iface["ip"] = _get_vm_ip(dom, iface["mac"], iface.get("network", ""), host_id, None)
                # 如果没找到再用 ARP 表
                if not iface.get("ip") and arp_cache:
                    mac_lower = iface["mac"].lower()
                    if mac_lower in arp_cache:
                        iface["ip"] = arp_cache[mac_lower]
    else:
        # 不获取 IP 时，初始化 ip 字段为空
        for iface in interfaces:
            iface["ip"] = ""

    # VNC
    graphics = tree.find(".//graphics[@type='vnc']")
    if graphics is not None:
        info["vnc_port"] = int(graphics.get("port", -1))
        info["vnc_listen"] = graphics.get("listen", "127.0.0.1")
    else:
        info["vnc_port"] = -1
        info["vnc_listen"] = ""

    # OS info
    os_type = tree.find(".//os/type")
    info["os_type"] = os_type.text if os_type is not None else "hvm"

    return info


def _get_arp_table(host_id: str = "local") -> dict:
    """获取 ARP 表（MAC -> IP 映射），返回 {mac_lower: ip}"""
    import subprocess
    from app.hosts import get_host as get_host_info

    host_info = get_host_info(host_id)
    is_remote = host_info and host_info.type != "local"

    try:
        if is_remote and host_info.type == "ssh":
            from urllib.parse import urlparse
            parsed = urlparse(host_info.uri)
            remote_host = parsed.hostname
            ssh_args = ["ssh", "-o", "StrictHostKeyChecking=no"]
            if host_info.ssh_key_path:
                ssh_args.extend(["-i", host_info.ssh_key_path])
            ssh_args.extend([remote_host, "ip", "neigh", "show"])
            result = subprocess.run(ssh_args, capture_output=True, text=True, timeout=5)
        else:
            result = subprocess.run(
                ["ip", "neigh", "show"],
                capture_output=True, text=True, timeout=3,
            )

        if result.returncode == 0:
            arp = {}
            for line in result.stdout.strip().split("\n"):
                parts = line.split()
                if len(parts) >= 5:
                    ip = parts[0]
                    # lladdr 行格式: IP dev IFACE lladdr MAC ...
                    for i, p in enumerate(parts):
                        if p == "lladdr" and i + 1 < len(parts) and "." in ip:
                            arp[parts[i + 1].lower()] = ip
            return arp
    except Exception:
        pass
    return {}


def _get_vm_ip(dom, mac: str, network: str = "", host_id: str = "local", arp_cache: dict = None) -> str:
    """多种方式尝试获取虚拟机 IP 地址"""
    # 方式1: QEMU Guest Agent（最准确）
    try:
        ifaces = dom.interfaceAddresses(
            libvirt.VIR_DOMAIN_INTERFACE_ADDRESSES_SRC_AGENT, 0
        )
        if ifaces:
            for ifname, ifdata in ifaces.items():
                if ifdata.get("hwaddr", "").lower() == mac.lower():
                    addrs = ifdata.get("addrs", [])
                    for a in addrs:
                        addr = a.get("addr", "")
                        # 优先返回 IPv4
                        if "." in addr:
                            return addr
                    if addrs:
                        return addrs[0].get("addr", "")
    except Exception:
        pass

    # 方式2: DHCP 租约（通过 libvirt 网络）
    try:
        ifaces = dom.interfaceAddresses(
            libvirt.VIR_DOMAIN_INTERFACE_ADDRESSES_SRC_LEASE, 0
        )
        if ifaces:
            for ifname, ifdata in ifaces.items():
                hwaddr = ifdata.get("hwaddr", "").lower()
                if hwaddr == mac.lower():
                    addrs = ifdata.get("addrs", [])
                    for a in addrs:
                        addr = a.get("addr", "")
                        if "." in addr:
                            return addr
                    if addrs:
                        return addrs[0].get("addr", "")
    except Exception:
        pass

    # 方式3: ARP 表查找（通过 MAC 地址查 IP）
    if arp_cache is not None and mac.lower() in arp_cache:
        return arp_cache[mac.lower()]

    return ""


def _get_state(dom) -> str:
    """获取虚拟机运行状态"""
    raw = dom.info()
    state = raw[0]
    state_map = {
        libvirt.VIR_DOMAIN_NOSTATE: "nostate",
        libvirt.VIR_DOMAIN_RUNNING: "running",
        libvirt.VIR_DOMAIN_BLOCKED: "blocked",
        libvirt.VIR_DOMAIN_PAUSED: "paused",
        libvirt.VIR_DOMAIN_SHUTDOWN: "shutdown",
        libvirt.VIR_DOMAIN_SHUTOFF: "shutoff",
        libvirt.VIR_DOMAIN_CRASHED: "crashed",
        libvirt.VIR_DOMAIN_PMSUSPENDED: "suspended",
    }
    return state_map.get(state, "unknown")


def _to_mb(value, unit) -> int:
    """转换为 MB"""
    unit = unit.lower()
    if unit in ("kib", "k", "kib"):
        return value // 1024
    elif unit in ("mib", "m", "mib"):
        return value
    elif unit in ("gib", "g", "gib"):
        return value * 1024
    elif unit in ("tib", "t"):
        return value * 1024 * 1024
    elif unit == "b":
        return value // (1024 * 1024)
    return value // 1024  # default KiB