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# Utility functions

from synnefo.db.models import VirtualMachine, Network
from django.conf import settings
from copy import deepcopy


def id_from_instance_name(name):
    """Returns VirtualMachine's Django id, given a ganeti machine name.

    Strips the ganeti prefix atm. Needs a better name!

    """
    sname = str(name)
    if not sname.startswith(settings.BACKEND_PREFIX_ID):
        raise VirtualMachine.InvalidBackendIdError(sname)
    ns = sname.replace(settings.BACKEND_PREFIX_ID, "", 1)
    if not ns.isdigit():
        raise VirtualMachine.InvalidBackendIdError(sname)

    return int(ns)


def id_to_instance_name(id):
    return "%s%s" % (settings.BACKEND_PREFIX_ID, str(id))


def id_from_network_name(name):
    """Returns Network's Django id, given a ganeti network name.

    Strips the ganeti prefix atm. Needs a better name!

    """
    if not str(name).startswith(settings.BACKEND_PREFIX_ID):
        raise Network.InvalidBackendIdError(str(name))
    ns = str(name).replace(settings.BACKEND_PREFIX_ID + 'net-', "", 1)
    if not ns.isdigit():
        raise Network.InvalidBackendIdError(str(name))

    return int(ns)


def id_to_network_name(id):
    return "%snet-%s" % (settings.BACKEND_PREFIX_ID, str(id))


def id_from_nic_name(name):
    """Returns NIC's Django id, given a Ganeti's NIC name.

    """
    if not str(name).startswith(settings.BACKEND_PREFIX_ID):
        raise ValueError("Invalid NIC name: %s" % name)
    ns = str(name).replace(settings.BACKEND_PREFIX_ID + 'nic-', "", 1)
    if not ns.isdigit():
        raise ValueError("Invalid NIC name: %s" % name)

    return int(ns)


def get_rsapi_state(vm):
    """Returns the API state for a virtual machine

    The API state for an instance of VirtualMachine is derived as follows:

    * If the deleted flag has been set, it is "DELETED".
    * Otherwise, it is a mapping of the last state reported by Ganeti
      (vm.operstate) through the RSAPI_STATE_FROM_OPER_STATE dictionary.

      The last state reported by Ganeti is set whenever Ganeti reports
      successful completion of an operation. If Ganeti says an
      OP_INSTANCE_STARTUP operation succeeded, vm.operstate is set to
      "STARTED".

    * To support any transitional states defined by the API (only REBOOT for
    the time being) this mapping is amended with information reported by Ganeti
    regarding any outstanding operation. If an OP_INSTANCE_STARTUP had
    succeeded previously and an OP_INSTANCE_REBOOT has been reported as in
    progress, the API state is "REBOOT".

    """
    try:
        r = VirtualMachine.RSAPI_STATE_FROM_OPER_STATE[vm.operstate]
    except KeyError:
        return "UNKNOWN"
    # A machine is DELETED if the deleted flag has been set
    if vm.deleted:
        return "DELETED"
    # A machine is in REBOOT if an OP_INSTANCE_REBOOT request is in progress
    in_reboot = (r == "ACTIVE") and\
                (vm.backendopcode == "OP_INSTANCE_REBOOT") and\
                (vm.backendjobstatus in ("queued", "waiting", "running"))
    if in_reboot:
        return "REBOOT"
    in_resize = (r == "STOPPED") and\
                (vm.backendopcode == "OP_INSTANCE_MODIFY") and\
                (vm.task == "RESIZE") and \
                (vm.backendjobstatus in ("queued", "waiting", "running"))
    if in_resize:
        return "RESIZE"
    return r


TASK_STATE_FROM_ACTION = {
    "BUILD": "BULDING",
    "START": "STARTING",
    "STOP": "STOPPING",
    "REBOOT": "REBOOTING",
    "DESTROY": "DESTROYING",
    "RESIZE": "RESIZING",
    "CONNECT": "CONNECTING",
    "DISCONNECT": "DISCONNECTING"}


def get_task_state(vm):
    if vm.task is None:
        return ""
    try:
        return TASK_STATE_FROM_ACTION[vm.task]
    except KeyError:
        return "UNKNOWN"


OPCODE_TO_ACTION = {
    "OP_INSTANCE_CREATE": "BUILD",
    "OP_INSTANCE_START": "START",
    "OP_INSTANCE_STOP": "STOP",
    "OP_INSTANCE_REBOOT": "REBOOT",
    "OP_INSTANCE_REMOVE": "DESTROY"}


def get_action_from_opcode(opcode, job_fields):
    if opcode == "OP_INSTANCE_SET_PARAMS":
        nics = job_fields.get("nics")
        beparams = job_fields.get("beparams")
        if nics:
            #TODO: check the nic format
            return "CONNECT" or "DISCONNECT"
        elif beparams:
            return "RESIZE"
        else:
            return None
    else:
        return OPCODE_TO_ACTION.get(opcode, None)


def hide_pass(kw):
    if 'osparams' in kw and 'img_passwd' in kw['osparams']:
        kw1 = deepcopy(kw)
        kw1['osparams']['img_passwd'] = 'x' * 8
        return kw1
    else:
        return kw