import os
import stat

import errno
import logging
import hashlib
from typing import Dict, Union
from pathlib import Path

import cephfs

from ..pin_util import pin
from .subvolume_attrs import SubvolumeTypes
from .metadata_manager import MetadataManager
from ..trash import create_trashcan, open_trashcan
from ...fs_util import get_ancestor_xattr
from ...exception import MetadataMgrException, VolumeException
from .auth_metadata import AuthMetadataManager
from .subvolume_attrs import SubvolumeStates

log = logging.getLogger(__name__)


class SubvolumeBase(object):
    LEGACY_CONF_DIR = "_legacy"

    def __init__(self, mgr, fs, vol_spec, group, subvolname, legacy=False):
        self.mgr = mgr
        self.fs = fs
        self.auth_mdata_mgr = AuthMetadataManager(fs)
        self.cmode = None
        self.user_id = None
        self.group_id = None
        self.vol_spec = vol_spec
        self.group = group
        self.subvolname = subvolname
        self.legacy_mode = legacy
        self.load_config()

    @property
    def uid(self):
        return self.user_id

    @uid.setter
    def uid(self, val):
        self.user_id = val

    @property
    def gid(self):
        return self.group_id

    @gid.setter
    def gid(self, val):
        self.group_id = val

    @property
    def mode(self):
        return self.cmode

    @mode.setter
    def mode(self, val):
        self.cmode = val

    @property
    def base_path(self):
        return os.path.join(self.group.path, self.subvolname.encode('utf-8'))

    @property
    def config_path(self):
        return os.path.join(self.base_path, b".meta")

    @property
    def legacy_dir(self):
        return (os.path.join(self.vol_spec.base_dir.encode('utf-8'),
                SubvolumeBase.LEGACY_CONF_DIR.encode('utf-8')))

    @property
    def legacy_config_path(self):
        try:
            m = hashlib.md5(self.base_path)
        except ValueError:
            try:
                m = hashlib.md5(self.base_path, usedforsecurity=False) # type: ignore
            except TypeError:
                raise VolumeException(-errno.EINVAL,
                                      "require python's hashlib library to support usedforsecurity flag in FIPS enabled systems")

        meta_config = "{0}.meta".format(m.hexdigest())
        return os.path.join(self.legacy_dir, meta_config.encode('utf-8'))

    @property
    def namespace(self):
        return "{0}{1}".format(self.vol_spec.fs_namespace, self.subvolname)

    @property
    def group_name(self):
        return self.group.group_name

    @property
    def subvol_name(self):
        return self.subvolname

    @property
    def legacy_mode(self):
        return self.legacy

    @legacy_mode.setter
    def legacy_mode(self, mode):
        self.legacy = mode

    @property
    def path(self):
        """ Path to subvolume data directory """
        raise NotImplementedError

    @property
    def features(self):
        """
        List of features supported by the subvolume,
        containing items from SubvolumeFeatures
        """
        raise NotImplementedError

    @property
    def state(self):
        """ Subvolume state, one of SubvolumeStates """
        return SubvolumeStates.from_value(self.metadata_mgr.get_global_option(MetadataManager.GLOBAL_META_KEY_STATE))

    @property
    def subvol_type(self):
        return (SubvolumeTypes.from_value(self.metadata_mgr.get_global_option
                (MetadataManager.GLOBAL_META_KEY_TYPE)))

    @property
    def purgeable(self):
        """ Boolean declaring if subvolume can be purged """
        raise NotImplementedError

    def clean_stale_snapshot_metadata(self):
        """ Clean up stale snapshot metadata """
        raise NotImplementedError

    def load_config(self):
        try:
            self.fs.stat(self.legacy_config_path)
            self.legacy_mode = True
        except cephfs.Error as e:
            pass

        log.debug("loading config "
                  "'{0}' [mode: {1}]".format(self.subvolname, "legacy"
                                             if self.legacy_mode else "new"))
        if self.legacy_mode:
            self.metadata_mgr = MetadataManager(self.fs,
                                                self.legacy_config_path,
                                                0o640)
        else:
            self.metadata_mgr = MetadataManager(self.fs,
                                                self.config_path, 0o640)

    def get_attrs(self, pathname):
        # get subvolume attributes
        attrs = {}  # type: Dict[str, Union[int, str, None]]
        stx = self.fs.statx(pathname,
                            cephfs.CEPH_STATX_UID | cephfs.CEPH_STATX_GID
                            | cephfs.CEPH_STATX_MODE,
                            cephfs.AT_SYMLINK_NOFOLLOW)

        attrs["uid"] = int(stx["uid"])
        attrs["gid"] = int(stx["gid"])
        attrs["mode"] = int(int(stx["mode"]) & ~stat.S_IFMT(stx["mode"]))

        try:
            attrs["data_pool"] = self.fs.getxattr(pathname,
                                                  'ceph.dir.layout.pool'
                                                  ).decode('utf-8')
        except cephfs.NoData:
            attrs["data_pool"] = None

        try:
            attrs["pool_namespace"] = self.fs.getxattr(pathname,
                                                       'ceph.dir.layout'
                                                       '.pool_namespace'
                                                       ).decode('utf-8')
        except cephfs.NoData:
            attrs["pool_namespace"] = None

        try:
            attrs["quota"] = int(self.fs.getxattr(pathname,
                                                  'ceph.quota.max_bytes'
                                                  ).decode('utf-8'))
        except cephfs.NoData:
            attrs["quota"] = None

        return attrs

    def set_attrs(self, path, attrs):
        # set subvolume attributes
        # set size
        quota = attrs.get("quota")
        if quota is not None:
            try:
                self.fs.setxattr(path, 'ceph.quota.max_bytes',
                                 str(quota).encode('utf-8'), 0)
            except cephfs.InvalidValue:
                raise VolumeException(-errno.EINVAL,
                                      "invalid size specified: '{0}'".format(quota))
            except cephfs.Error as e:
                raise VolumeException(-e.args[0], e.args[1])

        # set pool layout
        data_pool = attrs.get("data_pool")
        if data_pool is not None:
            try:
                self.fs.setxattr(path, 'ceph.dir.layout.pool',
                                 data_pool.encode('utf-8'), 0)
            except cephfs.InvalidValue:
                raise VolumeException(-errno.EINVAL,
                                      "invalid pool layout '{0}'"
                                      "--need a valid data pool"
                                      .format(data_pool))
            except cephfs.Error as e:
                raise VolumeException(-e.args[0], e.args[1])

        # isolate namespace
        xattr_key = xattr_val = None
        pool_namespace = attrs.get("pool_namespace")
        if pool_namespace is not None:
            # enforce security isolation, use separate namespace
            # for this subvolume
            xattr_key = 'ceph.dir.layout.pool_namespace'
            xattr_val = pool_namespace
        elif not data_pool:
            # If subvolume's namespace layout is not set,
            # then the subvolume's pool
            # layout remains unset and will undesirably change with ancestor's
            # pool layout changes.
            xattr_key = 'ceph.dir.layout.pool'
            xattr_val = None
            try:
                self.fs.getxattr(path, 'ceph.dir.layout.pool').decode('utf-8')
            except cephfs.NoData:
                xattr_val = get_ancestor_xattr(self.fs, os.path.split(path)[0],
                                               "ceph.dir.layout.pool")
        if xattr_key and xattr_val:
            try:
                self.fs.setxattr(path, xattr_key, xattr_val.encode('utf-8'), 0)
            except cephfs.Error as e:
                raise VolumeException(-e.args[0], e.args[1])

        # set uid/gid
        uid = attrs.get("uid")
        if uid is None:
            uid = self.group.uid
        else:
            try:
                if uid < 0:
                    raise ValueError
            except ValueError:
                raise VolumeException(-errno.EINVAL, "invalid UID")

        gid = attrs.get("gid")
        if gid is None:
            gid = self.group.gid
        else:
            try:
                if gid < 0:
                    raise ValueError
            except ValueError:
                raise VolumeException(-errno.EINVAL, "invalid GID")

        if uid is not None and gid is not None:
            self.fs.chown(path, uid, gid)

        # set mode
        mode = attrs.get("mode", None)
        if mode is not None:
            self.fs.lchmod(path, mode)

    def _resize(self, path, newsize, noshrink):
        try:
            newsize = int(newsize)
            if newsize <= 0:
                raise VolumeException(-errno.EINVAL,
                                      "Invalid subvolume size")
        except ValueError:
            newsize = newsize.lower()
            if not (newsize == "inf" or newsize == "infinite"):
                raise (VolumeException(-errno.EINVAL,
                                       "invalid size option '{0}'"
                                       .format(newsize)))
            newsize = 0
            noshrink = False

        try:
            maxbytes = int(self.fs.getxattr(path,
                                            'ceph.quota.max_bytes'
                                            ).decode('utf-8'))
        except cephfs.NoData:
            maxbytes = 0
        except cephfs.Error as e:
            raise VolumeException(-e.args[0], e.args[1])

        subvolstat = self.fs.stat(path)
        if newsize > 0 and newsize < subvolstat.st_size:
            if noshrink:
                raise VolumeException(-errno.EINVAL,
                                      "Can't resize the subvolume. "
                                      "The new size '{0}' would be "
                                      "lesser than the current "
                                      "used size '{1}'"
                                      .format(newsize,
                                              subvolstat.st_size))

        if not newsize == maxbytes:
            try:
                self.fs.setxattr(path, 'ceph.quota.max_bytes',
                                 str(newsize).encode('utf-8'), 0)
            except cephfs.Error as e:
                raise (VolumeException(-e.args[0],
                                       "Cannot set new size"
                                       "for the subvolume. '{0}'"
                                       .format(e.args[1])))
        return newsize, subvolstat.st_size

    def pin(self, pin_type, pin_setting):
        return pin(self.fs, self.base_path, pin_type, pin_setting)

    def init_config(self, version, subvolume_type,
                    subvolume_path, subvolume_state):
        self.metadata_mgr.init(version, subvolume_type.value,
                               subvolume_path, subvolume_state.value)
        self.metadata_mgr.flush()

    def discover(self):
        log.debug("discovering subvolume "
                  "'{0}' [mode: {1}]".format(self.subvolname, "legacy"
                                             if self.legacy_mode else "new"))
        try:
            self.fs.stat(self.base_path)
            self.metadata_mgr.refresh()
            log.debug("loaded subvolume '{0}'".format(self.subvolname))
            subvolpath = self.metadata_mgr.get_global_option(MetadataManager.GLOBAL_META_KEY_PATH)
            # subvolume with retained snapshots has empty path, don't mistake it for
            # fabricated metadata.
            if (not self.legacy_mode and self.state != SubvolumeStates.STATE_RETAINED and
                self.base_path.decode('utf-8') != str(Path(subvolpath).parent)):
                raise MetadataMgrException(-errno.ENOENT, 'fabricated .meta')
        except MetadataMgrException as me:
            if me.errno in (-errno.ENOENT, -errno.EINVAL) and not self.legacy_mode:
                log.warn("subvolume '{0}', {1}, "
                          "assuming legacy_mode".format(self.subvolname, me.error_str))
                self.legacy_mode = True
                self.load_config()
                self.discover()
            else:
                raise
        except cephfs.Error as e:
            if e.args[0] == errno.ENOENT:
                raise (VolumeException(-errno.ENOENT,
                                       "subvolume '{0}' "
                                       "does not exist"
                                       .format(self.subvolname)))
            raise VolumeException(-e.args[0],
                                  "error accessing subvolume '{0}'"
                                  .format(self.subvolname))

    def _trash_dir(self, path):
        create_trashcan(self.fs, self.vol_spec)
        with open_trashcan(self.fs, self.vol_spec) as trashcan:
            trashcan.dump(path)
            log.info("subvolume path '{0}' moved to trashcan".format(path))

    def _link_dir(self, path, bname):
        create_trashcan(self.fs, self.vol_spec)
        with open_trashcan(self.fs, self.vol_spec) as trashcan:
            trashcan.link(path, bname)
            log.info("subvolume path '{0}' "
                     "linked in trashcan bname {1}".format(path, bname))

    def trash_base_dir(self):
        if self.legacy_mode:
            self.fs.unlink(self.legacy_config_path)
        self._trash_dir(self.base_path)

    def create_base_dir(self, mode):
        try:
            self.fs.mkdirs(self.base_path, mode)
        except cephfs.Error as e:
            raise VolumeException(-e.args[0], e.args[1])

    def info(self):
        subvolpath = (self.metadata_mgr.get_global_option(
                      MetadataManager.GLOBAL_META_KEY_PATH))
        etype = self.subvol_type
        st = self.fs.statx(subvolpath, cephfs.CEPH_STATX_BTIME
                           | cephfs.CEPH_STATX_SIZE
                           | cephfs.CEPH_STATX_UID | cephfs.CEPH_STATX_GID
                           | cephfs.CEPH_STATX_MODE | cephfs.CEPH_STATX_ATIME
                           | cephfs.CEPH_STATX_MTIME
                           | cephfs.CEPH_STATX_CTIME,
                           cephfs.AT_SYMLINK_NOFOLLOW)
        usedbytes = st["size"]
        try:
            nsize = int(self.fs.getxattr(subvolpath,
                                         'ceph.quota.max_bytes'
                                         ).decode('utf-8'))
        except cephfs.NoData:
            nsize = 0

        try:
            data_pool = self.fs.getxattr(subvolpath,
                                         'ceph.dir.layout.pool'
                                         ).decode('utf-8')
            pool_namespace = self.fs.getxattr(subvolpath,
                                              'ceph.dir.layout.pool_namespace'
                                              ).decode('utf-8')
        except cephfs.Error as e:
            raise VolumeException(-e.args[0], e.args[1])

        return {'path': subvolpath,
                'type': etype.value,
                'uid': int(st["uid"]),
                'gid': int(st["gid"]),
                'atime': str(st["atime"]),
                'mtime': str(st["mtime"]),
                'ctime': str(st["ctime"]),
                'mode': int(st["mode"]),
                'data_pool': data_pool,
                'created_at': str(st["btime"]),
                'bytes_quota': "infinite" if nsize == 0 else nsize,
                'bytes_used': int(usedbytes),
                'bytes_pcent': "undefined"
                if nsize == 0
                else '{0:.2f}'.format((float(usedbytes) / nsize) * 100.0),
                'pool_namespace': pool_namespace,
                'features': self.features, 'state': self.state.value}

    def set_user_metadata(self, keyname, value):
        try:
            self.metadata_mgr.add_section(MetadataManager.USER_METADATA_SECTION)
            self.metadata_mgr.update_section(MetadataManager.USER_METADATA_SECTION, keyname, str(value))
            self.metadata_mgr.flush()
        except MetadataMgrException as me:
            log.error(f"Failed to set user metadata key={keyname} value={value} on subvolume={self.subvol_name} "
                      f"group={self.group_name} reason={me.args[1]}, errno:{-me.args[0]}, {os.strerror(-me.args[0])}")
            raise VolumeException(-me.args[0], me.args[1])

    def get_user_metadata(self, keyname):
        try:
            value = self.metadata_mgr.get_option(MetadataManager.USER_METADATA_SECTION, keyname)
        except MetadataMgrException as me:
            if me.errno == -errno.ENOENT:
                raise VolumeException(-errno.ENOENT, "key '{0}' does not exist.".format(keyname))
            raise VolumeException(-me.args[0], me.args[1])
        return value

    def list_user_metadata(self):
        return self.metadata_mgr.list_all_options_from_section(MetadataManager.USER_METADATA_SECTION)

    def remove_user_metadata(self, keyname):
        try:
            ret = self.metadata_mgr.remove_option(MetadataManager.USER_METADATA_SECTION, keyname)
            if not ret:
                raise VolumeException(-errno.ENOENT, "key '{0}' does not exist.".format(keyname))
            self.metadata_mgr.flush()
        except MetadataMgrException as me:
            if me.errno == -errno.ENOENT:
                raise VolumeException(-errno.ENOENT, "subvolume metadata does not exist")
            log.error(f"Failed to remove user metadata key={keyname} on subvolume={self.subvol_name} "
                      f"group={self.group_name} reason={me.args[1]}, errno:{-me.args[0]}, {os.strerror(-me.args[0])}")
            raise VolumeException(-me.args[0], me.args[1])

    def get_snap_section_name(self, snapname):
        section = "SNAP_METADATA" + "_" + snapname;
        return section;

    def set_snapshot_metadata(self, snapname, keyname, value):
        try:
            section = self.get_snap_section_name(snapname)
            self.metadata_mgr.add_section(section)
            self.metadata_mgr.update_section(section, keyname, str(value))
            self.metadata_mgr.flush()
        except MetadataMgrException as me:
            log.error(f"Failed to set snapshot metadata key={keyname} value={value} on snap={snapname} "
                      f"subvolume={self.subvol_name} group={self.group_name} "
                      f"reason={me.args[1]}, errno:{-me.args[0]}, {os.strerror(-me.args[0])}")
            raise VolumeException(-me.args[0], me.args[1])

    def get_snapshot_metadata(self, snapname, keyname):
        try:
            value = self.metadata_mgr.get_option(self.get_snap_section_name(snapname), keyname)
        except MetadataMgrException as me:
            if me.errno == -errno.ENOENT:
                raise VolumeException(-errno.ENOENT, "key '{0}' does not exist.".format(keyname))
            log.error(f"Failed to get snapshot metadata key={keyname} on snap={snapname} "
                      f"subvolume={self.subvol_name} group={self.group_name} "
                      f"reason={me.args[1]}, errno:{-me.args[0]}, {os.strerror(-me.args[0])}")
            raise VolumeException(-me.args[0], me.args[1])
        return value

    def list_snapshot_metadata(self, snapname):
        return self.metadata_mgr.list_all_options_from_section(self.get_snap_section_name(snapname))

    def remove_snapshot_metadata(self, snapname, keyname):
        try:
            ret = self.metadata_mgr.remove_option(self.get_snap_section_name(snapname), keyname)
            if not ret:
                raise VolumeException(-errno.ENOENT, "key '{0}' does not exist.".format(keyname))
            self.metadata_mgr.flush()
        except MetadataMgrException as me:
            if me.errno == -errno.ENOENT:
                raise VolumeException(-errno.ENOENT, "snapshot metadata not does not exist")
            log.error(f"Failed to remove snapshot metadata key={keyname} on snap={snapname} "
                      f"subvolume={self.subvol_name} group={self.group_name} "
                      f"reason={me.args[1]}, errno:{-me.args[0]}, {os.strerror(-me.args[0])}")
            raise VolumeException(-me.args[0], me.args[1])
