#
# Copyright 2008, 2013 Red Hat, Inc.
# Cole Robinson <crobinso@redhat.com>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
# MA 02110-1301 USA.

import os
import threading
import time
import logging

import libvirt
import urlgrabber

from .xmlbuilder import XMLBuilder, XMLChildProperty, XMLProperty
from . import util


DEFAULT_DEV_TARGET = "/dev"
DEFAULT_LVM_TARGET_BASE = "/dev/"
DEFAULT_DIR_TARGET_BASE = "/var/lib/libvirt/images/"
DEFAULT_SCSI_TARGET = "/dev/disk/by-path"
DEFAULT_MPATH_TARGET = "/dev/mapper"


class _StoragePermissions(XMLBuilder):
    _XML_ROOT_NAME = "permissions"
    _XML_PROP_ORDER = ["mode", "owner", "group", "label"]

    mode = XMLProperty("./mode")
    owner = XMLProperty("./owner")
    group = XMLProperty("./group")
    label = XMLProperty("./label")


class _StorageObject(XMLBuilder):
    """
    Base class for building any libvirt storage object.

    Meaningless to directly instantiate.
    """

    ######################
    # Validation helpers #
    ######################

    def _check_name_collision(self, name):
        raise NotImplementedError()

    def _validate_name(self, name):
        if name == self.name:
            return
        util.validate_name(_("Storage object"), name)
        self._check_name_collision(name)
        return name


    ##############
    # Properties #
    ##############

    name = XMLProperty("./name", validate_cb=_validate_name,
                      doc=_("Name for the storage object."))
    permissions = XMLChildProperty(_StoragePermissions,
                                   relative_xpath="./target",
                                   is_single=True)


def _get_default_pool_path(conn):
    path = "/var/lib/libvirt/images"
    if conn.is_session_uri():
        path = os.path.expanduser("~/VirtualMachines")
    return path


class StoragePool(_StorageObject):
    """
    Base class for building and installing libvirt storage pool xml
    """
    # @group Types: TYPE_*
    TYPE_DIR     = "dir"
    TYPE_FS      = "fs"
    TYPE_NETFS   = "netfs"
    TYPE_LOGICAL = "logical"
    TYPE_DISK    = "disk"
    TYPE_ISCSI   = "iscsi"
    TYPE_SCSI    = "scsi"
    TYPE_MPATH   = "mpath"
    TYPE_GLUSTER = "gluster"

    # Pool type descriptions for use in higher level programs
    _descs = {}
    _descs[TYPE_DIR]     = _("Filesystem Directory")
    _descs[TYPE_FS]      = _("Pre-Formatted Block Device")
    _descs[TYPE_NETFS]   = _("Network Exported Directory")
    _descs[TYPE_LOGICAL] = _("LVM Volume Group")
    _descs[TYPE_DISK]    = _("Physical Disk Device")
    _descs[TYPE_ISCSI]   = _("iSCSI Target")
    _descs[TYPE_SCSI]    = _("SCSI Host Adapter")
    _descs[TYPE_MPATH]   = _("Multipath Device Enumerator")
    _descs[TYPE_GLUSTER] = _("Gluster Filesystem")

    @staticmethod
    def get_pool_types():
        """
        Return list of appropriate pool types
        """
        return StoragePool._descs.keys()

    @staticmethod
    def get_pool_type_desc(pool_type):
        """
        Return human readable description for passed pool type
        """
        return StoragePool._descs.get(pool_type, "%s pool" % pool_type)

    @staticmethod
    def pool_list_from_sources(conn, pool_type, host=None):
        """
        Return a list of StoragePool instances built from libvirt's pool
        source enumeration (if supported).

        @param conn: Libvirt connection
        @param name: Name for the new pool
        @param pool_type: Pool type string from I{Types}
        @param host: Option host string to poll for sources
        """
        if not conn.check_support(conn.SUPPORT_CONN_FINDPOOLSOURCES):
            return []

        if host:
            source_xml = "<source><host name='%s'/></source>" % host
        else:
            source_xml = "<source/>"

        try:
            xml = conn.findStoragePoolSources(pool_type, source_xml, 0)
        except libvirt.libvirtError, e:
            if util.is_error_nosupport(e):
                return []
            raise

        def source_parser(node):
            ret = []

            child = node.children
            while child:
                if child.name == "source":
                    xml = "<pool>\n%s\n</pool>" % (
                        util.xml_indent(child.serialize(format=1), 2))
                    parseobj = StoragePool(conn, parsexml=xml)
                    parseobj.type = pool_type

                    obj = StoragePool(conn)
                    obj.type = pool_type
                    obj.source_path = parseobj.source_path
                    obj.host = parseobj.host
                    obj.source_name = parseobj.source_name
                    obj.format = parseobj.format
                    ret.append(obj)
                child = child.next
            return ret

        return util.parse_node_helper(xml, "sources", source_parser)

    @staticmethod
    def build_default_pool(conn):
        """
        Helper to build the 'default' storage pool
        """
        if not conn.check_support(conn.SUPPORT_CONN_STORAGE):
            return

        pool = None
        name = "default"
        path = _get_default_pool_path(conn)

        try:
            pool = conn.storagePoolLookupByName(name)
        except libvirt.libvirtError:
            pass

        if pool:
            return

        try:
            logging.debug("Attempting to build default pool with target '%s'",
                          path)
            defpool = StoragePool(conn)
            defpool.type = defpool.TYPE_DIR
            defpool.name = name
            defpool.target_path = path
            defpool.install(build=True, create=True, autostart=True)
            conn.clear_cache(pools=True)
            return defpool
        except Exception, e:
            raise RuntimeError(
                _("Couldn't create default storage pool '%s': %s") %
                (path, str(e)))


    @staticmethod
    def get_default_path(conn, build=True):
        """
        Return the default storage path. If there's a 'default' pool,
        report that. If there's no default pool, return the path we would
        use for the default.
        """
        path = _get_default_pool_path(conn)
        if not conn.check_support(conn.SUPPORT_CONN_STORAGE):
            os.makedirs(path)
            return path

        try:
            poolobj = conn.storagePoolLookupByName("default")
            return StoragePool(conn, parsexml=poolobj.XMLDesc(0)).target_path
        except:
            pass

        if build:
            return StoragePool.build_default_pool(conn).target_path
        return _get_default_pool_path(conn)


    @staticmethod
    def lookup_pool_by_path(conn, path, use_source=False):
        """
        Return the first pool with matching matching target path.
        return the first we find, active or inactive. This iterates over
        all pools and dumps their xml, so it is NOT quick.

        @use_source: If true, compare against pool source path, not
            target path.

        @returns: virStoragePool object if found, None otherwise
        """
        if not conn.check_support(conn.SUPPORT_CONN_STORAGE):
            return None

        def check_pool(pool, path):
            if use_source:
                xml_path = pool.source_path
            else:
                xml_path = pool.target_path
            if xml_path is not None and os.path.abspath(xml_path) == path:
                return True

        for pool in conn.fetch_all_pools():
            if check_pool(pool, path):
                return conn.storagePoolLookupByName(pool.name)
        return None

    @staticmethod
    def find_free_name(conn, basename, **kwargs):
        """
        Finds a name similar (or equal) to passed 'basename' that is not
        in use by another pool. Extra params are passed to generate_name
        """
        return util.generate_name(basename,
                                  conn.storagePoolLookupByName,
                                  **kwargs)


    def __init__(self, *args, **kwargs):
        _StorageObject.__init__(self, *args, **kwargs)
        self._random_uuid = None


    ######################
    # Validation helpers #
    ######################

    def _check_name_collision(self, name):
        pool = None
        try:
            pool = self.conn.storagePoolLookupByName(name)
        except libvirt.libvirtError:
            pass
        if pool:
            raise ValueError(_("Name '%s' already in use by another pool." %
                                name))

    def _get_default_target_path(self):
        if not self.supports_property("target_path"):
            return None
        if (self.type == self.TYPE_DIR or
            self.type == self.TYPE_NETFS or
            self.type == self.TYPE_FS):
            return (DEFAULT_DIR_TARGET_BASE + self.name)
        if self.type == self.TYPE_LOGICAL:
            name = self.name
            if self.source_name:
                name = self.source_name
            return DEFAULT_LVM_TARGET_BASE + name
        if self.type == self.TYPE_DISK:
            return DEFAULT_DEV_TARGET
        if self.type == self.TYPE_ISCSI or self.type == self.TYPE_SCSI:
            return DEFAULT_SCSI_TARGET
        if self.type == self.TYPE_MPATH:
            return DEFAULT_MPATH_TARGET
        raise RuntimeError("No default target_path for type=%s" % self.type)

    def _get_default_uuid(self):
        if self._random_uuid is None:
            self._random_uuid = util.generate_uuid(self.conn)
        return self._random_uuid

    def _make_source_xpath(self):
        if self.type == self.TYPE_NETFS:
            return "./source/dir/@path"
        if self.type == self.TYPE_SCSI:
            return "./source/adapter/@name"
        return "./source/device/@path"

    def _default_source_name(self):
        if not self.supports_property("source_name"):
            return None

        # If a source name isn't explicitly set, try to determine it from
        # existing parameters
        srcname = self.name

        if ("target_path" in self._propstore and
            self.target_path and
            self.target_path.startswith(DEFAULT_LVM_TARGET_BASE)):
            # If there is a target path, parse it for an expected VG
            # location, and pull the name from there
            vg = self.target_path[len(DEFAULT_LVM_TARGET_BASE):]
            srcname = vg.split("/", 1)[0]

        return srcname

    def _default_format_cb(self):
        if not self.supports_property("format"):
            return None
        return "auto"


    ##############
    # Properties #
    ##############

    _XML_ROOT_NAME = "pool"
    _XML_PROP_ORDER = ["name", "type", "uuid",
                       "capacity", "allocation", "available",
                       "format", "host",
                       "source_path", "source_name", "target_path",
                       "source_dir", "permissions"]

    type = XMLProperty("./@type",
        doc=_("Storage device type the pool will represent."))
    uuid = XMLProperty("./uuid",
                       validate_cb=lambda s, v: util.validate_uuid(v),
                       default_cb=_get_default_uuid)

    capacity = XMLProperty("./capacity", is_int=True)
    allocation = XMLProperty("./allocation", is_int=True)
    available = XMLProperty("./available", is_int=True)

    format = XMLProperty("./source/format/@type",
                         default_cb=_default_format_cb)
    host = XMLProperty("./source/host/@name")
    iqn = XMLProperty("./source/initiator/iqn/@name",
                      doc=_("iSCSI initiator qualified name"))
    source_path = XMLProperty(name="source path",
                              make_xpath_cb=_make_source_xpath)
    source_name = XMLProperty("./source/name",
                              default_cb=_default_source_name,
                              doc=_("Name of the Volume Group"))

    target_path = XMLProperty("./target/path",
                              default_cb=_get_default_target_path)
    source_dir = XMLProperty("./source/dir/@path")


    ######################
    # Public API helpers #
    ######################

    def supports_property(self, propname):
        users = {
            "source_path": [self.TYPE_FS, self.TYPE_NETFS, self.TYPE_LOGICAL,
                            self.TYPE_DISK, self.TYPE_ISCSI, self.TYPE_SCSI],
            "source_name": [self.TYPE_LOGICAL, self.TYPE_GLUSTER],
            "source_dir" : [self.TYPE_GLUSTER, self.TYPE_NETFS],
            "host": [self.TYPE_NETFS, self.TYPE_ISCSI, self.TYPE_GLUSTER],
            "format": [self.TYPE_FS, self.TYPE_NETFS, self.TYPE_DISK],
            "iqn": [self.TYPE_ISCSI],
            "target_path" : [self.TYPE_DIR, self.TYPE_FS, self.TYPE_NETFS,
                             self.TYPE_LOGICAL, self.TYPE_DISK, self.TYPE_ISCSI,
                             self.TYPE_SCSI, self.TYPE_MPATH]
        }

        if users.get(propname):
            return self.type in users[propname]
        return hasattr(self, propname)

    def list_formats(self):
        if self.type == self.TYPE_FS:
            return ["auto", "ext2", "ext3", "ext4", "ufs", "iso9660", "udf",
                    "gfs", "gfs2", "vfat", "hfs+", "xfs"]
        if self.type == self.TYPE_NETFS:
            return ["auto", "nfs", "glusterfs"]
        if self.type == self.TYPE_DISK:
            return ["auto", "bsd", "dos", "dvh", "gpt", "mac", "pc98", "sun"]
        return []

    def supports_volume_creation(self):
        return self.type in [
            StoragePool.TYPE_DIR, StoragePool.TYPE_FS,
            StoragePool.TYPE_NETFS, StoragePool.TYPE_LOGICAL,
            StoragePool.TYPE_DISK, StoragePool.TYPE_GLUSTER]

    def get_vm_disk_type(self):
        """
        Return the /disk/@type value if the pool source is used as
        VirtualDisk path
        """
        xpath = self._make_source_xpath()
        if "/dir/" in xpath:
            return "dir"
        return "block"


    ##################
    # Build routines #
    ##################

    def validate(self):
        if self.supports_property("host") and not self.host:
            raise RuntimeError(_("Hostname is required"))
        if (self.supports_property("source_path") and
            not self.type == self.TYPE_LOGICAL and
            not self.source_path):
            raise RuntimeError(_("Source path is required"))

        if (self.type == self.TYPE_DISK and self.format == "auto"):
            # There is no explicit "auto" type for disk pools, but leaving out
            # the format type seems to do the job for existing formatted disks
            self.format = None

    def install(self, meter=None, create=False, build=False, autostart=False):
        """
        Install storage pool xml.
        """
        if (self.type == self.TYPE_LOGICAL and
            build and not self.source_path):
            raise ValueError(_("Must explicitly specify source path if "
                               "building pool"))
        if (self.type == self.TYPE_DISK and
            build and self.format == "auto"):
            raise ValueError(_("Must explicitly specify disk format if "
                               "formatting disk device."))

        xml = self.get_xml_config()
        logging.debug("Creating storage pool '%s' with xml:\n%s",
                      self.name, xml)

        if not meter:
            meter = urlgrabber.progress.BaseMeter()

        try:
            pool = self.conn.storagePoolDefineXML(xml, 0)
        except Exception, e:
            raise RuntimeError(_("Could not define storage pool: %s" % str(e)))

        errmsg = None
        if build:
            try:
                pool.build(libvirt.VIR_STORAGE_POOL_BUILD_NEW)
            except Exception, e:
                errmsg = _("Could not build storage pool: %s" % str(e))

        if create and not errmsg:
            try:
                pool.create(0)
            except Exception, e:
                errmsg = _("Could not start storage pool: %s" % str(e))

        if autostart and not errmsg:
            try:
                pool.setAutostart(True)
            except Exception, e:
                errmsg = _("Could not set pool autostart flag: %s" % str(e))

        if errmsg:
            # Try and clean up the leftover pool
            try:
                pool.undefine()
            except Exception, e:
                logging.debug("Error cleaning up pool after failure: " +
                              "%s" % str(e))
            raise RuntimeError(errmsg)

        return pool



class StorageVolume(_StorageObject):
    """
    Base class for building and installing libvirt storage volume xml
    """
    ALL_FORMATS = ["raw", "bochs", "cloop", "cow", "dmg", "iso", "qcow",
                   "qcow2", "qed", "vmdk", "vpc", "fat", "vhd", "vdi"]

    @staticmethod
    def get_file_extension_for_format(fmt):
        if not fmt:
            return ""
        if fmt == "raw":
            return ".img"
        return "." + fmt

    @staticmethod
    def find_free_name(pool_object, basename, **kwargs):
        """
        Finds a name similar (or equal) to passed 'basename' that is not
        in use by another volume. Extra params are passed to generate_name
        """
        pool_object.refresh(0)
        return util.generate_name(basename,
                                  pool_object.storageVolLookupByName,
                                  **kwargs)

    TYPE_FILE = getattr(libvirt, "VIR_STORAGE_VOL_FILE", 0)
    TYPE_BLOCK = getattr(libvirt, "VIR_STORAGE_VOL_BLOCK", 1)


    def __init__(self, *args, **kwargs):
        _StorageObject.__init__(self, *args, **kwargs)

        self._input_vol = None
        self._pool = None
        self._pool_type = None

        # Indicate that the volume installation has finished. Used to
        # definitively tell the storage progress thread to stop polling.
        self._install_finished = True


    ######################
    # Non XML properties #
    ######################

    def _get_pool(self):
        return self._pool
    def _set_pool(self, newpool):
        if newpool.info()[0] != libvirt.VIR_STORAGE_POOL_RUNNING:
            raise ValueError(_("pool '%s' must be active." % newpool.name()))
        self._pool = newpool
        self._pool_type = StoragePool(self.conn,
                                      parsexml=self._pool.XMLDesc(0)).type
    pool = property(_get_pool, _set_pool)

    def _get_input_vol(self):
        return self._input_vol
    def _set_input_vol(self, vol):
        if vol is None:
            self._input_vol = None
            return

        if not isinstance(vol, libvirt.virStorageVol):
            raise ValueError(_("input_vol must be a virStorageVol"))

        if not self.conn.check_support(
            self.conn.SUPPORT_POOL_CREATEVOLFROM, self.pool):
            raise ValueError(_("Creating storage from an existing volume is"
                               " not supported by this libvirt version."))

        self._input_vol = vol
    input_vol = property(_get_input_vol, _set_input_vol,
                         doc=_("virStorageVolume pointer to clone/use as "
                               "input."))

    def sync_input_vol(self):
        # Pull parameters from input vol into this class
        parsevol = StorageVolume(self.conn,
                                 parsexml=self._input_vol.XMLDesc(0))

        self.pool = self._input_vol.storagePoolLookupByVolume()
        self.capacity = parsevol.capacity
        self.allocation = parsevol.allocation
        self.format = parsevol.format


    ##########################
    # XML validation helpers #
    ##########################

    def _check_name_collision(self, name):
        vol = None
        try:
            vol = self.pool.storageVolLookupByName(name)
        except libvirt.libvirtError:
            pass
        if vol:
            raise ValueError(_("Name '%s' already in use by another volume." %
                                name))

    def _validate_allocation(self, val):
        ret = self.is_size_conflict(allocation=val)
        if ret[0]:
            raise ValueError(ret[1])
        elif ret[1]:
            logging.warn(ret[1])
        return val

    def _validate_capacity(self, val):
        ret = self.is_size_conflict(capacity=val)
        if ret[0]:
            raise ValueError(ret[1])
        elif ret[1]:
            logging.warn(ret[1])
        return val

    def _default_format(self):
        if self.file_type == self.TYPE_FILE:
            return "raw"
        return None

    def _get_vol_type(self):
        if (self._pool_type == StoragePool.TYPE_DISK or
            self._pool_type == StoragePool.TYPE_LOGICAL):
            return self.TYPE_BLOCK
        return self.TYPE_FILE
    file_type = property(_get_vol_type)


    ##################
    # XML properties #
    ##################

    _XML_ROOT_NAME = "volume"
    _XML_PROP_ORDER = ["name", "key", "capacity", "allocation", "format",
                       "target_path", "permissions"]

    key = XMLProperty("./key")
    capacity = XMLProperty("./capacity", is_int=True,
                           validate_cb=_validate_capacity)
    allocation = XMLProperty("./allocation", is_int=True,
                             validate_cb=_validate_allocation)
    format = XMLProperty("./target/format/@type", default_cb=_default_format)
    target_path = XMLProperty("./target/path")
    backing_store = XMLProperty("./backingStore/path")

    def _lazy_refcounts_default_cb(self):
        if self.format != "qcow2":
            return False
        return self.conn.check_support(
            self.conn.SUPPORT_CONN_QCOW2_LAZY_REFCOUNTS)
    lazy_refcounts = XMLProperty("./target/features/lazy_refcounts",
        is_bool=True, default_cb=_lazy_refcounts_default_cb)


    ######################
    # Public API helpers #
    ######################

    def supports_property(self, propname):
        users = {
            "format": [self.TYPE_FILE],
        }

        if users.get(propname):
            return self.file_type in users[propname]
        return hasattr(self, propname)

    def list_formats(self):
        if self.file_type == self.TYPE_FILE:
            return self.ALL_FORMATS
        return []

    def list_create_formats(self):
        if self.file_type == self.TYPE_FILE:
            return ["raw", "cow", "qcow", "qcow2", "qed", "vmdk", "vpc", "vdi"]
        return None


    ##################
    # Build routines #
    ##################

    def validate(self):
        if self._pool_type == StoragePool.TYPE_LOGICAL:
            if self.allocation != self.capacity:
                logging.warn(_("Sparse logical volumes are not supported, "
                               "setting allocation equal to capacity"))
                self.allocation = self.capacity

    def install(self, meter=None):
        """
        Build and install storage volume from xml
        """
        xml = self.get_xml_config()
        logging.debug("Creating storage volume '%s' with xml:\n%s",
                      self.name, xml)

        t = threading.Thread(target=self._progress_thread,
                             name="Checking storage allocation",
                             args=(meter,))
        t.setDaemon(True)

        if not meter:
            meter = urlgrabber.progress.BaseMeter()

        cloneflags = 0
        createflags = 0
        if (self.format == "qcow2" and
            not self.backing_store and
            not self.conn.is_test() and
            self.conn.check_support(
                self.conn.SUPPORT_POOL_METADATA_PREALLOC, self.pool)):
            createflags |= libvirt.VIR_STORAGE_VOL_CREATE_PREALLOC_METADATA


        try:
            self._install_finished = False
            t.start()
            meter.start(size=self.capacity,
                        text=_("Allocating '%s'") % self.name)

            if self.input_vol:
                vol = self.pool.createXMLFrom(xml, self.input_vol, cloneflags)
            else:
                logging.debug("Using vol create flags=%s", createflags)
                vol = self.pool.createXML(xml, createflags)

            self._install_finished = True
            t.join()
            meter.end(self.capacity)
            logging.debug("Storage volume '%s' install complete.",
                          self.name)
            return vol
        except libvirt.libvirtError, e:
            if util.is_error_nosupport(e):
                raise RuntimeError("Libvirt version does not support "
                                   "storage cloning.")
            raise
        except Exception, e:
            raise RuntimeError("Couldn't create storage volume "
                               "'%s': '%s'" % (self.name, str(e)))

    def _progress_thread(self, meter):
        lookup_attempts = 10
        vol = None
        if not meter:
            return

        while lookup_attempts > 0:
            try:
                if not vol:
                    vol = self.pool.storageVolLookupByName(self.name)
                vol.info()
                break
            except:
                lookup_attempts -= 1
                time.sleep(.2)
                if self._install_finished:
                    break
                else:
                    continue
            break

        if vol is None:
            logging.debug("Couldn't lookup storage volume in prog thread.")
            return

        while not self._install_finished:
            ignore, ignore, alloc = vol.info()
            meter.update(alloc)
            time.sleep(1)


    def is_size_conflict(self, capacity=None, allocation=None):
        """
        Report if requested size exceeds its pool's available amount

        @returns: 2 element tuple:
            1. True if collision is fatal, false otherwise
            2. String message if some collision was encountered.
        @rtype: 2 element C{tuple}: (C{bool}, C{str})
        """
        if capacity is None:
            capacity = self.capacity
        if allocation is None:
            allocation = self.allocation

        if not self.pool:
            return (False, "")

        # pool info is [pool state, capacity, allocation, available]
        avail = self.pool.info()[3]
        if allocation > avail:
            return (True, _("There is not enough free space on the storage "
                            "pool to create the volume. "
                            "(%d M requested allocation > %d M available)" %
                            ((allocation / (1024 * 1024)),
                             (avail / (1024 * 1024)))))
        elif capacity > avail:
            return (False, _("The requested volume capacity will exceed the "
                             "available pool space when the volume is fully "
                             "allocated. "
                             "(%d M requested capacity > %d M available)" %
                             ((capacity / (1024 * 1024)),
                              (avail / (1024 * 1024)))))
        return (False, "")
