#
# Copyright 2006-2009  Red Hat, Inc.
# Daniel P. Berrange <berrange@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 logging
import os
import shutil
import subprocess
import tempfile

import urlgrabber

import Storage
import support
import _util
import Installer
from VirtualDisk import VirtualDisk
from User import User
import OSDistro


def _is_url(url, is_local):
    """
    Check if passed string is a (pseudo) valid http, ftp, or nfs url.
    """
    if is_local and os.path.exists(url):
        if os.path.isdir(url):
            return True
        else:
            return False

    return (url.startswith("http://") or url.startswith("ftp://") or
            url.startswith("nfs:"))

def _sanitize_url(url):
    """
    Do nothing for http or ftp, but make sure nfs is in the expected format
    """
    if url.startswith("nfs://"):
        # Convert RFC compliant NFS      nfs://server/path/to/distro
        # to what mount/anaconda expect  nfs:server:/path/to/distro
        # and carry the latter form around internally
        url = "nfs:" + url[6:]

        # If we need to add the : after the server
        index = url.find("/", 4)
        if index == -1:
            raise ValueError(_("Invalid NFS format: No path specified."))
        if url[index - 1] != ":":
            url = url[:index] + ":" + url[index:]

    return url

def _build_pool(conn, meter, path):
    pool = _util.lookup_pool_by_path(conn, path)
    if pool:
        logging.debug("Existing pool '%s' found for %s", pool.name(), path)
        pool.refresh(0)
        return pool

    name = _util.generate_name("boot-scratch",
                               conn.storagePoolLookupByName)
    logging.debug("Building storage pool: path=%s name=%s", path, name)
    poolbuild = Storage.DirectoryPool(conn=conn, name=name,
                                      target_path=path)

    # Explicitly don't build? since if we are creating this directory
    # we probably don't have correct perms
    return poolbuild.install(meter=meter, create=True, build=False,
                             autostart=True)


def _upload_file(conn, meter, destpool, src):
    # Build stream object
    stream = conn.newStream(0)
    def safe_send(data):
        while True:
            ret = stream.send(data)
            if ret == 0 or ret == len(data):
                break
            data = data[ret:]

    if meter is None:
        meter = urlgrabber.progress.BaseMeter()

    # Build placeholder volume
    size = os.path.getsize(src)
    basename = os.path.basename(src)
    poolpath = _util.get_xml_path(destpool.XMLDesc(0), "/pool/target/path")
    name = Storage.StorageVolume.find_free_name(basename,
                                                pool_object=destpool)
    if name != basename:
        logging.debug("Generated non-colliding volume name %s", name)

    disk = VirtualDisk(conn=conn,
                       path=os.path.join(poolpath, name),
                       sizebytes=size,
                       sparse=True)

    disk.setup_dev(meter=meter)
    vol = disk.vol_object
    if not vol:
        raise RuntimeError(_("Failed to lookup scratch media volume"))

    try:
        # Register upload
        offset = 0
        length = size
        flags = 0
        stream.upload(vol, offset, length, flags)

        # Open source file
        fileobj = file(src, "r")

        # Start transfer
        total = 0
        meter.start(size=size,
                    text=_("Transferring %s") % os.path.basename(src))
        while True:
            #blocksize = (1024 ** 2)
            blocksize = 1024
            data = fileobj.read(blocksize)
            if not data:
                break

            safe_send(data)
            total += len(data)
            meter.update(total)

        # Cleanup
        stream.finish()
        meter.end(size)
    except:
        if vol:
            vol.delete(0)
        raise

    return vol


class DistroInstaller(Installer.Installer):
    def __init__(self, type="xen", location=None, boot=None,
                 extraargs=None, os_type=None,
                 conn=None, caps=None):
        Installer.Installer.__init__(self, type, location, boot, extraargs,
                                     os_type, conn=conn, caps=caps)

        self._livecd = False

        # True == location is a filesystem path
        # False == location is a url
        self._location_is_path = True

    # DistroInstaller specific methods/overwrites

    def _get_livecd(self):
        return self._livecd
    def _set_livecd(self, val):
        self._livecd = bool(val)
    livecd = property(_get_livecd, _set_livecd)

    def get_location(self):
        return self._location
    def set_location(self, val):
        """
        Valid values for location:

        1) it can be a local file (ex. boot.iso), directory (ex. distro
        tree) or physical device (ex. cdrom media)

        2) tuple of the form (poolname, volname) pointing to a file or
        device which will set location as that path

        3) http, ftp, or nfs path for an install tree
        """
        is_tuple = False
        validated = True
        self._location_is_path = True
        is_local = (not self.conn or not self.is_remote())

        # Basic validation
        if type(val) is not str and (type(val) is not tuple and len(val) != 2):
            raise ValueError(_("Invalid 'location' type %s." % type(val)))

        if type(val) is tuple and len(val) == 2:
            logging.debug("DistroInstaller location is a (poolname, volname)"
                          " tuple")
            if not self.conn:
                raise ValueError(_("'conn' must be specified if 'location' is"
                                   " a storage tuple."))
            is_tuple = True

        elif _is_url(val, is_local):
            val = _sanitize_url(val)
            self._location_is_path = False
            logging.debug("DistroInstaller location is a network source.")

        elif os.path.exists(os.path.abspath(val)) and is_local:
            val = os.path.abspath(val)
            logging.debug("DistroInstaller location is a local "
                          "file/path: %s", val)

        else:
            # Didn't determine anything about the location
            validated = False

        if self._location_is_path or (validated == False and self.conn and
                                      _util.is_storage_capable(self.conn)):
            # If user passed a storage tuple, OR
            # We couldn't determine the location type and a storage capable
            #   connection was passed:
            # Pass the parameters off to VirtualDisk to validate, and pull
            # out the path
            stuple = (is_tuple and val) or None
            path = (not is_tuple and val) or None

            try:
                d = VirtualDisk(path=path,
                                device=VirtualDisk.DEVICE_CDROM,
                                transient=True,
                                readOnly=True,
                                conn=self.conn,
                                volName=stuple)
                val = d.path
            except:
                logging.debug("Error validating install location",
                              exc_info=True)
                raise ValueError(_("Checking installer location failed: "
                                   "Could not find media '%s'." % str(val)))
        elif not validated:
            raise ValueError(_("Install media location must be an NFS, HTTP "
                               "or FTP network install source, or an existing "
                               "file/device"))

        if (not self._location_is_path and val.startswith("nfs:") and not
            User.current().has_priv(User.PRIV_NFS_MOUNT,
                                    (self.conn and self.get_uri()))):
            raise ValueError(_('Privilege is required for NFS installations'))

        self._location = val
    location = property(get_location, set_location)


    # Private helper methods

    def _prepare_cdrom(self, guest, meter):
        transient = not self.livecd
        if not self._location_is_path:
            # Xen needs a boot.iso if its a http://, ftp://, or nfs: url
            (store_ignore, os_type_ignore, os_variant_ignore, media) = \
             OSDistro.acquireBootDisk(guest, self.location, meter,
                                      self.scratchdir)
            cdrom = media

            self._tmpfiles.append(cdrom)
            transient = True
        else:
            cdrom = self.location

        disk = VirtualDisk(path=cdrom,
                           conn=guest.conn,
                           device=VirtualDisk.DEVICE_CDROM,
                           readOnly=True,
                           transient=transient)
        self.install_devices.append(disk)

    def _perform_initrd_injections(self, initrd):
        """
        Insert files into the root directory of the initial ram disk
        """
        tempdir = tempfile.mkdtemp(dir=self.scratchdir)
        os.chmod(tempdir, 0775)

        for filename in self._initrd_injections:
            logging.debug("Copying %s to the initrd.", filename)
            shutil.copy(filename, tempdir)

        logging.debug("Appending to the initrd.")
        find_proc = subprocess.Popen(['find', '.', '-print0'],
                                     stdout=subprocess.PIPE,
                                     stderr=subprocess.PIPE,
                                     cwd=tempdir)
        cpio_proc = subprocess.Popen(['cpio', '-o', '--null', '-Hnewc', '--quiet'],
                                     stdin=find_proc.stdout,
                                     stdout=subprocess.PIPE,
                                     stderr=subprocess.PIPE,
                                     cwd=tempdir)
        f = open(initrd, 'ab')
        gzip_proc = subprocess.Popen(['gzip'], stdin=cpio_proc.stdout,
                                     stdout=f, stderr=subprocess.PIPE)
        cpio_proc.wait()
        find_proc.wait()
        gzip_proc.wait()
        f.close()
        shutil.rmtree(tempdir)

        finderr = find_proc.stderr.read()
        cpioerr = cpio_proc.stderr.read()
        gziperr = gzip_proc.stderr.read()
        if finderr:
            logging.debug("find stderr=%s", finderr)
        if cpioerr:
            logging.debug("cpio stderr=%s", cpioerr)
        if gziperr:
            logging.debug("gzip stderr=%s", gziperr)

    def support_remote_url_install(self):
        if not self.conn:
            return False
        if hasattr(self.conn, "_virtinst__fake_conn"):
            return False
        return support.check_stream_support(self.conn,
                                            support.SUPPORT_STREAM_UPLOAD)

    def _upload_media(self, guest, meter, kernel, initrd):
        conn = guest.conn
        system_scratchdir = self._get_system_scratchdir()

        if (not guest.is_remote() and
            (self.is_session_uri() or self.scratchdir == system_scratchdir)):
            # We have access to system scratchdir, don't jump through hoops
            logging.debug("Have access to preferred scratchdir so"
                          " nothing to upload")
            return kernel, initrd

        if not self.support_remote_url_install():
            logging.debug("Media upload not supported")
            return kernel, initrd

        # Build pool
        logging.debug("Uploading kernel/initrd media")
        pool = _build_pool(conn, meter, system_scratchdir)

        kvol = _upload_file(conn, meter, pool, kernel)
        newkernel = kvol.path()
        self._tmpvols.append(kvol)

        ivol = _upload_file(conn, meter, pool, initrd)
        newinitrd = ivol.path()
        self._tmpvols.append(ivol)

        return newkernel, newinitrd

    def _prepare_kernel_and_initrd(self, guest, meter):
        disk = None

        # If installing off a local path, map it through to a virtual CD/disk
        if (self.location is not None and
            self._location_is_path and
            not os.path.isdir(self.location)):

            device = VirtualDisk.DEVICE_CDROM
            if (self.is_xenpv() and
                not guest._lookup_osdict_key('pv_cdrom_install')):
                device = VirtualDisk.DEVICE_DISK

            disk = VirtualDisk(conn=guest.conn,
                               device=device,
                               path=self.location,
                               readOnly=True,
                               transient=True)

        # Make sure we always fetch kernel here if required
        if self._install_bootconfig.kernel and not self.scratchdir_required():
            return disk

        # Need to fetch the kernel & initrd from a remote site, or
        # out of a loopback mounted disk image/device
        ignore, os_type, os_variant, media = OSDistro.acquireKernel(guest,
                                                self.location, meter,
                                                self.scratchdir,
                                                self.os_type)
        (kernelfn, initrdfn, args) = media

        if guest.get_os_autodetect():
            if os_type:
                logging.debug("Auto detected OS type as: %s", os_type)
                guest.os_type = os_type

            if (os_variant and guest.os_type == os_type):
                logging.debug("Auto detected OS variant as: %s", os_variant)
                guest.os_variant = os_variant

        self._tmpfiles.append(kernelfn)
        if initrdfn:
            self._tmpfiles.append(initrdfn)

        if self._initrd_injections:
            self._perform_initrd_injections(initrdfn)

        # If required, upload media to an accessible guest location
        kernelfn, initrdfn = self._upload_media(guest, meter,
                                                kernelfn, initrdfn)

        self._install_bootconfig.kernel = kernelfn
        self._install_bootconfig.initrd = initrdfn
        self._install_bootconfig.kernel_args = args

        return disk

    def _persistent_cd(self):
        return (self._location_is_path and self.cdrom and self.livecd)

    def _get_bootdev(self, isinstall, guest):
        if isinstall or self._persistent_cd():
            bootdev = self.bootconfig.BOOT_DEVICE_CDROM
        else:
            bootdev = self.bootconfig.BOOT_DEVICE_HARDDISK
        return bootdev

    # General Installer methods

    def scratchdir_required(self):
        if not self.location:
            return False

        is_url = not self._location_is_path
        mount_dvd = self._location_is_path and not self.cdrom

        return bool(is_url or mount_dvd)

    def prepare(self, guest, meter):
        self.cleanup()

        dev = None
        if self.cdrom:
            if self.location:
                dev = self._prepare_cdrom(guest, meter)
            else:
                # Booting from a cdrom directly allocated to the guest
                pass
        else:
            dev = self._prepare_kernel_and_initrd(guest, meter)

        if dev:
            self.install_devices.append(dev)

    def check_location(self):
        if self._location_is_path:
            # We already mostly validated this
            return True
        else:
            # This will throw an error for us
            OSDistro.detectMediaDistro(location=self.location, arch=self.arch)
        return True

    def detect_distro(self):
        try:
            dist_info = OSDistro.detectMediaDistro(location=self.location,
                                                   arch=self.arch)
        except:
            logging.exception("Error attempting to detect distro.")
            return (None, None)

        # detectMediaDistro should only return valid values
        dtype, dvariant = dist_info
        return (dtype, dvariant)