from ipaddress import ip_address

from django.db.models import CharField, IntegerField, Model
from django.utils.functional import cached_property
from django.utils.translation import gettext_lazy as _
from libvirt import virConnect

from computes.validators import validate_hostname, validate_login, validate_migration_address
from vrtManager.connection import connection_manager
from vrtManager.hostdetails import wvmHostDetails


class Compute(Model):
    name = CharField(_("name"), max_length=64, unique=True)
    hostname = CharField(_("hostname"), max_length=64, validators=[validate_hostname])
    login = CharField(_("login"), max_length=20, blank=True, validators=[validate_login])
    password = CharField(_("password"), max_length=14, blank=True, null=True)
    details = CharField(_("details"), max_length=64, null=True, blank=True)
    type = IntegerField()
    migration_address = CharField(
        _("migration address"),
        max_length=64,
        blank=True,
        default="",
        validators=[validate_migration_address],
        help_text=_(
            "IP address or host name the other hosts send migrating VMs to; "
            "empty: the host's own host name, which they must be able to resolve"
        ),
    )

    @property
    def migration_uri(self):
        """The native migration URI for VMs migrated to this host, or None for
        libvirt's default."""
        if not self.migration_address:
            return None
        try:
            if ip_address(self.migration_address).version == 6:
                return f"tcp://[{self.migration_address}]"
        except ValueError:
            pass
        return f"tcp://{self.migration_address}"

    @cached_property
    def status(self):
        """True if WebVirtCloud can connect to the host (within the connect
        timeout; a host that failed recently is not tried again at once)."""
        return isinstance(self.connection, virConnect)

    @cached_property
    def connection_error(self):
        """Why the host cannot be reached, or None."""
        return None if self.status else str(self.connection)

    @cached_property
    def connection(self):
        try:
            return connection_manager.get_connection(
                self.hostname,
                self.login,
                self.password,
                self.type,
            )
        except Exception as e:
            return e

    @cached_property
    def proxy(self):
        return wvmHostDetails(
            self.hostname,
            self.login,
            self.password,
            self.type,
        )

    @cached_property
    def cpu_count(self):
        return self.proxy.get_node_info()[3]
    
    @cached_property
    def ram_size(self):
        return self.proxy.get_node_info()[2]

    @cached_property
    def ram_usage(self):
        return self.proxy.get_memory_usage()["percent"]

    def __str__(self):
        return self.name