# Copyright 2014 Hewlett-Packard Development Company, L.P.
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.

"""
iLO Power Driver
"""

from ironic_lib import metrics_utils
from oslo_log import log as logging
from oslo_service import loopingcall
from oslo_utils import importutils

from ironic.common import boot_devices
from ironic.common import exception
from ironic.common.i18n import _
from ironic.common import states
from ironic.conductor import task_manager
from ironic.conductor import utils as manager_utils
from ironic.conf import CONF
from ironic.drivers import base
from ironic.drivers.modules.ilo import common as ilo_common

ilo_error = importutils.try_import('proliantutils.exception')

LOG = logging.getLogger(__name__)

METRICS = metrics_utils.get_metrics_logger(__name__)


def _attach_boot_iso_if_needed(task):
    """Attaches boot ISO for a deployed node.

    This method checks the instance info of the baremetal node for a
    boot iso. If the instance info has a value of key 'ilo_boot_iso',
    it indicates that 'boot_option' is 'netboot'. Therefore it attaches
    the boot ISO on the baremetal node and then sets the node to boot from
    virtual media cdrom.

    :param task: a TaskManager instance containing the node to act on.
    """
    i_info = task.node.instance_info
    node_state = task.node.provision_state

    # NOTE: On instance rebuild, ilo_boot_iso will be present in
    # instance_info but the node will be in DEPLOYING state.
    # In such a scenario, the ilo_boot_iso shouldn't be
    # attached to the node while powering on the node (the node
    # should boot from deploy ramdisk instead, which will already
    # be attached by the deploy driver).
    if 'ilo_boot_iso' in i_info and node_state == states.ACTIVE:
        ilo_common.setup_vmedia_for_boot(task, i_info['ilo_boot_iso'])
        manager_utils.node_set_boot_device(task, boot_devices.CDROM)


def _get_power_state(node):
    """Returns the current power state of the node.

    :param node: The node.
    :returns: power state, one of :mod: `ironic.common.states`.
    :raises: InvalidParameterValue if required iLO credentials are missing.
    :raises: IloOperationError on an error from IloClient library.
    """

    ilo_object = ilo_common.get_ilo_object(node)

    # Check the current power state.
    try:
        power_status = ilo_object.get_host_power_status()

    except ilo_error.IloError as ilo_exception:
        LOG.error("iLO get_power_state failed for node %(node_id)s with "
                  "error: %(error)s.",
                  {'node_id': node.uuid, 'error': ilo_exception})
        operation = _('iLO get_power_status')
        raise exception.IloOperationError(operation=operation,
                                          error=ilo_exception)

    if power_status == "ON":
        return states.POWER_ON
    elif power_status == "OFF":
        return states.POWER_OFF
    else:
        return states.ERROR


def _wait_for_state_change(node, target_state, requested_state,
                           is_final_state=True, timeout=None):
    """Wait for the power state change to get reflected.

    :param node: The node.
    :param target_state: calculated target power state of the node.
    :param requested_state: actual requested power state of the node.
    :param is_final_state: True, if the given target state is the final
        expected power state of the node. Default is True.
    :param timeout: timeout (in seconds) positive integer (> 0) for any
      power state. ``None`` indicates default timeout.
    :returns: time consumed to achieve the power state change.
    :raises: IloOperationError on an error from IloClient library.
    :raises: PowerStateFailure if power state failed to change within timeout.
    """
    state = [None]
    retries = [0]
    interval = CONF.ilo.power_wait
    if timeout:
        max_retry = int(timeout / interval)
    else:
        # Since we are going to track server post state, we are not using
        # CONF.conductor.power_state_change_timeout as its default value
        # is too short for bare metal to reach 'finished post' state
        # during 'power on' operation. It could lead to deploy failures
        # with default ironic configuration.
        # Use conductor.soft_power_off_timeout, instead.
        max_retry = int(CONF.conductor.soft_power_off_timeout / interval)

    state_to_check = target_state
    use_post_state = False
    if _can_get_server_post_state(node):
        use_post_state = True
        if (target_state in [states.POWER_OFF, states.SOFT_POWER_OFF]
                or target_state == states.SOFT_REBOOT and not is_final_state):
            state_to_check = ilo_common.POST_POWEROFF_STATE
        else:
            # It may not be able to finish POST if no bootable device is
            # found. Track (POST_FINISHEDPOST_STATE) only for soft reboot.
            # For other power-on cases track for beginning of POST operation
            # (POST_INPOST_STATE) to return.
            state_to_check = (
                ilo_common.POST_FINISHEDPOST_STATE if
                requested_state == states.SOFT_REBOOT else
                ilo_common.POST_INPOST_STATE)

    def _wait(state):
        if use_post_state:
            state[0] = ilo_common.get_server_post_state(node)
        else:
            state[0] = _get_power_state(node)

        # NOTE(rameshg87): For reboot operations, initially the state
        # will be same as the final state. So defer the check for one retry.
        if retries[0] != 0 and state[0] == state_to_check:
            raise loopingcall.LoopingCallDone()

        if retries[0] > max_retry:
            state[0] = states.ERROR
            raise loopingcall.LoopingCallDone()

        LOG.debug("%(tim)s secs elapsed while waiting for power state "
                  "of '%(target_state)s', current state of server %(node)s "
                  "is '%(cur_state)s'.",
                  {'tim': int(retries[0] * interval),
                   'target_state': state_to_check,
                   'node': node.uuid,
                   'cur_state': state[0]})
        retries[0] += 1

    # Start a timer and wait for the operation to complete.
    timer = loopingcall.FixedIntervalLoopingCall(_wait, state)
    timer.start(interval=interval).wait()
    if state[0] == state_to_check:
        return int(retries[0] * interval)
    else:
        timeout = int(max_retry * interval)
        LOG.error("iLO failed to change state to %(tstate)s "
                  "within %(timeout)s sec for node %(node)s",
                  {'tstate': target_state, 'node': node.uuid,
                   'timeout': int(max_retry * interval)})
        raise exception.PowerStateFailure(pstate=target_state)


def _set_power_state(task, target_state, timeout=None):
    """Turns the server power on/off or do a reboot.

    :param task: a TaskManager instance containing the node to act on.
    :param target_state: target state of the node.
    :param timeout: timeout (in seconds) positive integer (> 0) for any
      power state. ``None`` indicates default timeout.
    :raises: InvalidParameterValue if an invalid power state was specified.
    :raises: IloOperationError on an error from IloClient library.
    :raises: PowerStateFailure if the power couldn't be set to target_state.
    """
    node = task.node
    ilo_object = ilo_common.get_ilo_object(node)

    # Check if its soft power operation
    soft_power_op = target_state in [states.SOFT_POWER_OFF, states.SOFT_REBOOT]

    requested_state = target_state
    if target_state == states.SOFT_REBOOT:
        if _get_power_state(node) == states.POWER_OFF:
            target_state = states.POWER_ON

    # Trigger the operation based on the target state.
    try:
        if target_state == states.POWER_OFF:
            ilo_object.hold_pwr_btn()
        elif target_state == states.POWER_ON:
            _attach_boot_iso_if_needed(task)
            ilo_object.set_host_power('ON')
        elif target_state == states.REBOOT:
            _attach_boot_iso_if_needed(task)
            ilo_object.reset_server()
            target_state = states.POWER_ON
        elif target_state in (states.SOFT_POWER_OFF, states.SOFT_REBOOT):
            ilo_object.press_pwr_btn()
        else:
            msg = _("_set_power_state called with invalid power state "
                    "'%s'") % target_state
            raise exception.InvalidParameterValue(msg)

    except ilo_error.IloError as ilo_exception:
        LOG.error("iLO set_power_state failed to set state to %(tstate)s "
                  " for node %(node_id)s with error: %(error)s",
                  {'tstate': target_state, 'node_id': node.uuid,
                   'error': ilo_exception})
        operation = _('iLO set_power_state')
        raise exception.IloOperationError(operation=operation,
                                          error=ilo_exception)

    # Wait till the soft power state change gets reflected.
    time_consumed = 0
    if soft_power_op:
        # For soft power-off, bare metal reaches final state with one
        # power operation. In case of soft reboot it takes two; soft
        # power-off followed by power-on. Also, for soft reboot we
        # need to ensure timeout does not expire during power-off
        # and power-on operation.
        is_final_state = target_state in (states.SOFT_POWER_OFF,
                                          states.POWER_ON)
        time_consumed = _wait_for_state_change(
            node, target_state, requested_state,
            is_final_state=is_final_state, timeout=timeout)
        if target_state == states.SOFT_REBOOT:
            _attach_boot_iso_if_needed(task)
            try:
                ilo_object.set_host_power('ON')
            except ilo_error.IloError as ilo_exception:
                operation = (_('Powering on failed after soft power off for '
                               'node %s') % node.uuid)
                raise exception.IloOperationError(operation=operation,
                                                  error=ilo_exception)
            # Re-calculate timeout available for power-on operation
            rem_timeout = timeout - time_consumed
            time_consumed += _wait_for_state_change(
                node, states.SOFT_REBOOT, requested_state, is_final_state=True,
                timeout=rem_timeout)
    else:
        time_consumed = _wait_for_state_change(
            node, target_state, requested_state, is_final_state=True,
            timeout=timeout)
    LOG.info("The node %(node_id)s operation of '%(state)s' "
             "is completed in %(time_consumed)s seconds.",
             {'node_id': node.uuid, 'state': target_state,
              'time_consumed': time_consumed})


def _can_get_server_post_state(node):
    """Checks if POST state can be retrieved.

    Returns True if the POST state of the server can be retrieved.
    It cannot be retrieved for older ProLiant models.
    :param node: The node.
    :returns: True if POST state can be retrieved, else Flase.
    :raises: IloOperationError on an error from IloClient library.
    """
    try:
        ilo_common.get_server_post_state(node)
        return True
    except exception.IloOperationNotSupported as exc:
        LOG.debug("Node %(node)s does not support retrieval of "
                  "boot post state. Reason: %(reason)s",
                  {'node': node.uuid, 'reason': exc})
        return False


class IloPower(base.PowerInterface):

    def get_properties(self):
        return ilo_common.COMMON_PROPERTIES

    @METRICS.timer('IloPower.validate')
    def validate(self, task):
        """Check if node.driver_info contains the required iLO credentials.

        :param task: a TaskManager instance.
        :param node: Single node object.
        :raises: InvalidParameterValue if required iLO credentials are missing.
        """
        ilo_common.parse_driver_info(task.node)

    @METRICS.timer('IloPower.get_power_state')
    def get_power_state(self, task):
        """Gets the current power state.

        :param task: a TaskManager instance.
        :param node: The Node.
        :returns: one of :mod:`ironic.common.states` POWER_OFF,
            POWER_ON or ERROR.
        :raises: InvalidParameterValue if required iLO credentials are missing.
        :raises: IloOperationError on an error from IloClient library.
        """
        return _get_power_state(task.node)

    @METRICS.timer('IloPower.set_power_state')
    @task_manager.require_exclusive_lock
    def set_power_state(self, task, power_state, timeout=None):
        """Turn the current power state on or off.

        :param task: a TaskManager instance.
        :param power_state: The desired power state POWER_ON,POWER_OFF or
            REBOOT from :mod:`ironic.common.states`.
        :param timeout: timeout (in seconds). Unsupported by this interface.
        :raises: InvalidParameterValue if an invalid power state was specified.
        :raises: IloOperationError on an error from IloClient library.
        :raises: PowerStateFailure if the power couldn't be set to power_state.
        """
        _set_power_state(task, power_state, timeout=timeout)

    @METRICS.timer('IloPower.reboot')
    @task_manager.require_exclusive_lock
    def reboot(self, task, timeout=None):
        """Reboot the node

        :param task: a TaskManager instance.
        :param timeout: timeout (in seconds). Unsupported by this interface.
        :raises: PowerStateFailure if the final state of the node is not
            POWER_ON.
        :raises: IloOperationError on an error from IloClient library.
        """
        node = task.node
        current_pstate = _get_power_state(node)
        if current_pstate == states.POWER_ON:
            _set_power_state(task, states.REBOOT, timeout=timeout)
        elif current_pstate == states.POWER_OFF:
            _set_power_state(task, states.POWER_ON, timeout=timeout)

    @METRICS.timer('IloPower.get_supported_power_states')
    def get_supported_power_states(self, task):
        """Get a list of the supported power states.

        :param task: A TaskManager instance containing the node to act on.
            currently not used.
        :returns: A list with the supported power states defined
                  in :mod:`ironic.common.states`.
        """
        return [states.POWER_OFF, states.POWER_ON, states.REBOOT,
                states.SOFT_POWER_OFF, states.SOFT_REBOOT]
