import argparse
import os
import logging
import time

from textwrap import dedent

from ceph_volume import decorators, terminal, process
from ceph_volume.api import lvm as api
from ceph_volume.util import system, encryption, disk, arg_validators, str_to_int, merge_dict
from ceph_volume.util.device import Device
from ceph_volume.systemd import systemctl

logger = logging.getLogger(__name__)
mlogger = terminal.MultiLogger(__name__)


def wipefs(path):
    """
    Removes the filesystem from an lv or partition.

    Environment variables supported::

    * ``CEPH_VOLUME_WIPEFS_TRIES``: Defaults to 8
    * ``CEPH_VOLUME_WIPEFS_INTERVAL``: Defaults to 5

    """
    tries = str_to_int(
        os.environ.get('CEPH_VOLUME_WIPEFS_TRIES', 8)
    )
    interval = str_to_int(
        os.environ.get('CEPH_VOLUME_WIPEFS_INTERVAL', 5)
    )

    for trying in range(tries):
        stdout, stderr, exit_code = process.call([
            'wipefs',
            '--all',
            path
        ])
        if exit_code != 0:
            # this could narrow the retry by poking in the stderr of the output
            # to verify that 'probing initialization failed' appears, but
            # better to be broad in this retry to prevent missing on
            # a different message that needs to be retried as well
            terminal.warning(
                'failed to wipefs device, will try again to workaround probable race condition'
            )
            time.sleep(interval)
        else:
            return
    raise RuntimeError("could not complete wipefs on device: %s" % path)


def zap_data(path):
    """
    Clears all data from the given path. Path should be
    an absolute path to an lv or partition.

    10M of data is written to the path to make sure that
    there is no trace left of any previous Filesystem.
    """
    process.run([
        'dd',
        'if=/dev/zero',
        'of={path}'.format(path=path),
        'bs=1M',
        'count=10',
        'conv=fsync'
    ])


def find_associated_devices(osd_id=None, osd_fsid=None):
    """
    From an ``osd_id`` and/or an ``osd_fsid``, filter out all the LVs in the
    system that match those tag values, further detect if any partitions are
    part of the OSD, and then return the set of LVs and partitions (if any).
    """
    lv_tags = {}
    if osd_id:
        lv_tags['ceph.osd_id'] = osd_id
    if osd_fsid:
        lv_tags['ceph.osd_fsid'] = osd_fsid

    lvs = api.get_lvs(tags=lv_tags)
    if not lvs:
        raise RuntimeError('Unable to find any LV for zapping OSD: '
                           '%s' % osd_id or osd_fsid)

    devices_to_zap = ensure_associated_lvs(lvs, lv_tags)
    return [Device(path) for path in set(devices_to_zap) if path]


def ensure_associated_lvs(lvs, lv_tags={}):
    """
    Go through each LV and ensure if backing devices (journal, wal, block)
    are LVs or partitions, so that they can be accurately reported.
    """
    # look for many LVs for each backing type, because it is possible to
    # receive a filtering for osd.1, and have multiple failed deployments
    # leaving many journals with osd.1 - usually, only a single LV will be
    # returned

    db_lvs = api.get_lvs(tags=merge_dict(lv_tags, {'ceph.type': 'db'}))
    wal_lvs = api.get_lvs(tags=merge_dict(lv_tags, {'ceph.type': 'wal'}))
    backing_devices = [(db_lvs, 'db'),
                       (wal_lvs, 'wal')]

    verified_devices = []

    for lv in lvs:
        # go through each lv and append it, otherwise query `blkid` to find
        # a physical device. Do this for each type (journal,db,wal) regardless
        # if they have been processed in the previous LV, so that bad devices
        # with the same ID can be caught
        for ceph_lvs, _type in backing_devices:
            if ceph_lvs:
                verified_devices.extend([l.lv_path for l in ceph_lvs])
                continue

            # must be a disk partition, by querying blkid by the uuid we are
            # ensuring that the device path is always correct
            try:
                device_uuid = lv.tags['ceph.%s_uuid' % _type]
            except KeyError:
                # Bluestore will not have ceph.journal_uuid, and Filestore
                # will not not have ceph.db_uuid
                continue

            osd_device = disk.get_device_from_partuuid(device_uuid)
            if not osd_device:
                # if the osd_device is not found by the partuuid, then it is
                # not possible to ensure this device exists anymore, so skip it
                continue
            verified_devices.append(osd_device)

        verified_devices.append(lv.lv_path)

    # reduce the list from all the duplicates that were added
    return list(set(verified_devices))


class Zap(object):

    help = 'Removes all data and filesystems from a logical volume or partition.'

    def __init__(self, argv):
        self.argv = argv

    def unmount_lv(self, lv):
        if lv.tags.get('ceph.cluster_name') and lv.tags.get('ceph.osd_id'):
            lv_path = "/var/lib/ceph/osd/{}-{}".format(lv.tags['ceph.cluster_name'], lv.tags['ceph.osd_id'])
        else:
            lv_path = lv.lv_path
        dmcrypt_uuid = lv.lv_uuid
        dmcrypt = lv.encrypted
        if system.path_is_mounted(lv_path):
            mlogger.info("Unmounting %s", lv_path)
            system.unmount(lv_path)
        if dmcrypt and dmcrypt_uuid:
            self.dmcrypt_close(dmcrypt_uuid)

    def zap_lv(self, device):
        """
        Device examples: vg-name/lv-name, /dev/vg-name/lv-name
        Requirements: Must be a logical volume (LV)
        """
        lv = api.get_single_lv(filters={'lv_name': device.lv_name, 'vg_name':
                                        device.vg_name})
        self.unmount_lv(lv)

        wipefs(device.path)
        zap_data(device.path)

        if self.args.destroy:
            lvs = api.get_lvs(filters={'vg_name': device.vg_name})
            if lvs == []:
                mlogger.info('No LVs left, exiting', device.vg_name)
                return
            elif len(lvs) <= 1:
                mlogger.info('Only 1 LV left in VG, will proceed to destroy '
                             'volume group %s', device.vg_name)
                pvs = api.get_pvs(filters={'lv_uuid': lv.lv_uuid})
                api.remove_vg(device.vg_name)
                for pv in pvs:
                    api.remove_pv(pv.pv_name)
            else:
                mlogger.info('More than 1 LV left in VG, will proceed to '
                             'destroy LV only')
                mlogger.info('Removing LV because --destroy was given: %s',
                             device.path)
                api.remove_lv(device.path)
        elif lv:
            # just remove all lvm metadata, leaving the LV around
            lv.clear_tags()

    def zap_partition(self, device):
        """
        Device example: /dev/sda1
        Requirements: Must be a partition
        """
        if device.is_encrypted:
            # find the holder
            holders = [
                '/dev/%s' % holder for holder in device.sys_api.get('holders', [])
            ]
            for mapper_uuid in os.listdir('/dev/mapper'):
                mapper_path = os.path.join('/dev/mapper', mapper_uuid)
                if os.path.realpath(mapper_path) in holders:
                    self.dmcrypt_close(mapper_uuid)

        if system.device_is_mounted(device.path):
            mlogger.info("Unmounting %s", device.path)
            system.unmount(device.path)

        wipefs(device.path)
        zap_data(device.path)

        if self.args.destroy:
            mlogger.info("Destroying partition since --destroy was used: %s" % device.path)
            disk.remove_partition(device)

    def zap_lvm_member(self, device):
        """
        An LVM member may have more than one LV and or VG, for example if it is
        a raw device with multiple partitions each belonging to a different LV

        Device example: /dev/sda
        Requirements: An LV or VG present in the device, making it an LVM member
        """
        for lv in device.lvs:
            if lv.lv_name:
                mlogger.info('Zapping lvm member {}. lv_path is {}'.format(device.path, lv.lv_path))
                self.zap_lv(Device(lv.lv_path))
            else:
                vg = api.get_single_vg(filters={'vg_name': lv.vg_name})
                if vg:
                    mlogger.info('Found empty VG {}, removing'.format(vg.vg_name))
                    api.remove_vg(vg.vg_name)



    def zap_raw_device(self, device):
        """
        Any whole (raw) device passed in as input will be processed here,
        checking for LVM membership and partitions (if any).

        Device example: /dev/sda
        Requirements: None
        """
        if not self.args.destroy:
            # the use of dd on a raw device causes the partition table to be
            # destroyed
            mlogger.warning(
                '--destroy was not specified, but zapping a whole device will remove the partition table'
            )

        # look for partitions and zap those
        for part_name in device.sys_api.get('partitions', {}).keys():
            self.zap_partition(Device('/dev/%s' % part_name))

        wipefs(device.path)
        zap_data(device.path)

    @decorators.needs_root
    def zap(self, devices=None):
        devices = devices or self.args.devices

        for device in devices:
            mlogger.info("Zapping: %s", device.path)
            if device.is_mapper and not device.is_mpath:
                terminal.error("Refusing to zap the mapper device: {}".format(device))
                raise SystemExit(1)
            if device.is_lvm_member:
                self.zap_lvm_member(device)
            if device.is_lv:
                self.zap_lv(device)
            if device.is_partition:
                self.zap_partition(device)
            if device.is_device:
                self.zap_raw_device(device)

        if self.args.devices:
            terminal.success(
                "Zapping successful for: %s" % ", ".join([str(d) for d in self.args.devices])
            )
        else:
            identifier = self.args.osd_id or self.args.osd_fsid
            terminal.success(
                "Zapping successful for OSD: %s" % identifier
            )

    @decorators.needs_root
    def zap_osd(self):
        if self.args.osd_id and not self.args.no_systemd:
            osd_is_running = systemctl.osd_is_active(self.args.osd_id)
            if osd_is_running:
                mlogger.error("OSD ID %s is running, stop it with:" % self.args.osd_id)
                mlogger.error("systemctl stop ceph-osd@%s" % self.args.osd_id)
                raise SystemExit("Unable to zap devices associated with OSD ID: %s" % self.args.osd_id)
        devices = find_associated_devices(self.args.osd_id, self.args.osd_fsid)
        self.zap(devices)

    def dmcrypt_close(self, dmcrypt_uuid):
        dmcrypt_path = "/dev/mapper/{}".format(dmcrypt_uuid)
        mlogger.info("Closing encrypted path %s", dmcrypt_path)
        encryption.dmcrypt_close(dmcrypt_path)

    def main(self):
        sub_command_help = dedent("""
        Zaps the given logical volume(s), raw device(s) or partition(s) for reuse by ceph-volume.
        If given a path to a logical volume it must be in the format of vg/lv. Any
        filesystems present on the given device, vg/lv, or partition will be removed and
        all data will be purged.

        If the logical volume, raw device or partition is being used for any ceph related
        mount points they will be unmounted.

        However, the lv or partition will be kept intact.

        Example calls for supported scenarios:

          Zapping a logical volume:

              ceph-volume lvm zap {vg name/lv name}

          Zapping a partition:

              ceph-volume lvm zap /dev/sdc1

          Zapping many raw devices:

              ceph-volume lvm zap /dev/sda /dev/sdb /db/sdc

          Zapping devices associated with an OSD ID:

              ceph-volume lvm zap --osd-id 1

            Optionally include the OSD FSID

              ceph-volume lvm zap --osd-id 1 --osd-fsid 55BD4219-16A7-4037-BC20-0F158EFCC83D

        If the --destroy flag is given and you are zapping a raw device or partition
        then all vgs and lvs that exist on that raw device or partition will be destroyed.

        This is especially useful if a raw device or partition was used by ceph-volume lvm create
        or ceph-volume lvm prepare commands previously and now you want to reuse that device.

        For example:

          ceph-volume lvm zap /dev/sda --destroy

        If the --destroy flag is given and you are zapping an lv then the lv is still
        kept intact for reuse.

        """)
        parser = argparse.ArgumentParser(
            prog='ceph-volume lvm zap',
            formatter_class=argparse.RawDescriptionHelpFormatter,
            description=sub_command_help,
        )

        parser.add_argument(
            'devices',
            metavar='DEVICES',
            nargs='*',
            type=arg_validators.ValidZapDevice(gpt_ok=True),
            default=[],
            help='Path to one or many lv (as vg/lv), partition (as /dev/sda1) or device (as /dev/sda)'
        )

        parser.add_argument(
            '--destroy',
            action='store_true',
            default=False,
            help='Destroy all volume groups and logical volumes if you are zapping a raw device or partition',
        )

        parser.add_argument(
            '--osd-id',
            type=arg_validators.valid_osd_id,
            help='Specify an OSD ID to detect associated devices for zapping',
        )

        parser.add_argument(
            '--osd-fsid',
            help='Specify an OSD FSID to detect associated devices for zapping',
        )

        parser.add_argument(
            '--no-systemd',
            dest='no_systemd',
            action='store_true',
            help='Skip systemd unit checks',
        )

        if len(self.argv) == 0:
            print(sub_command_help)
            return

        self.args = parser.parse_args(self.argv)

        if self.args.osd_id or self.args.osd_fsid:
            self.zap_osd()
        else:
            self.zap()
