#!/usr/bin/python3

# Copyright (C) 2016  Canonical Ltd.
# Author: Steve Langasek <steve.langasek@canonical.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; version 3 of the License.
#
# 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, see <http://www.gnu.org/licenses/>.

"""Show and approve changes in an unapproved kernel upload.

Generate a debdiff between current source package in a given release and the
version in the canonical-kernel ppa, and ask whether or not to approve the
upload.

The debdiff is filtered for noise (abi/* directories; mechanical changes of
ABI strings in debian/control et al.)

USAGE:
    kernel-sru-review <bug number>
"""

import glob
import datetime
import os
import pytz
import re
import shutil
import subprocess
import sys
import time
from contextlib import ExitStack
from tempfile import mkdtemp
from optparse import OptionParser

from launchpadlib.launchpad import Launchpad
from kernel_workflow import *


def get_master_kernel(lp, bugnum):
    current = lp.bugs[bugnum]
    master = None
    backport_re = re.compile(r'^kernel-sru-backport-of-(\d+)$')
    derivative_re = re.compile(r'^kernel-sru-derivative-of-(\d+)$')

    for tag in current.tags:
        num = derivative_re.match(tag)
        if not num:
            num = backport_re.match(tag)
        if num:
            master = lp.bugs[num.group(1)]

    if not master:
        print("No master kernel.")
        return (None, None)
    return get_name_and_version_from_bug(master)


def get_kernel_dsc(me, archive, source, series=None, version=None):
    kwargs = {
        'order_by_date': True,
        'exact_match': True,
        'source_name': source
    }
    if version:
        kwargs['version'] = version
    if series:
        kwargs['status'] = 'Published'
        kwargs['distro_series'] = series

    # in cases where we have a separate archive for proposed and release,
    # we need to check both places in the order proposed -> release
    target = archive['proposed']
    srcpkgs = target.getPublishedSources(**kwargs)
    if len(srcpkgs) == 0:
        target = archive['release']
        srcpkgs = target.getPublishedSources(**kwargs)
        if len(srcpkgs) == 0 and 'non-esm' in archive:
            target = archive['non-esm']
            srcpkgs = target.getPublishedSources(**kwargs)
    if len(srcpkgs) == 0:
        raise KernelWorkflowError(
            "Selected %s kernel could not be found" % source)
    srcpkg = srcpkgs[0]
    source_ver = srcpkg.source_package_version
    source_dsc = list(filter(
                         lambda x: x.endswith('.dsc'),
                         srcpkg.sourceFileUrls()))[0]
    if target.private:
        priv_url = me.getArchiveSubscriptionURL(archive=target)
        dsc_file = os.path.basename(source_dsc)
        source_dsc = os.path.join(priv_url, 'pool/main/l', source, dsc_file)

    return (source_dsc, source_ver)


def generate_diff_from_master(me, archive, master_source, master_version,
                              new_source, new_upstream,
                              work_dir, tardir, start_dir):
    master_upstream = master_version.split('-')[0]

    try:
        master_dsc, master_version = get_kernel_dsc(
            me, archive, master_source, version=master_version)
    except KernelWorkflowError:
        print("A master kernel diff was requested but the listed master "
              "kernel could not be found in any known archive.",
              end="")
        sys.stdout.flush()
        sys.stdin.readline()
        return

    # we need to pull in the master kernel into a separate directory as
    # it might have the same name (flavor) as the one we are reviewing
    master_dir = os.path.join(work_dir, 'master')
    os.mkdir(master_dir)
    # this is a bit ugly, since we actually have to chdir for a moment
    # because dget has no option of declaring the output directory
    os.chdir(master_dir)

    fetch_tarball_from_cache(
        master_dir, tardir, master_source, master_upstream, start_dir)

    # grab the old source first
    dget_cmd = ['dget', '-u', master_dsc]
    try:
        subprocess.check_call(dget_cmd)
    except subprocess.CalledProcessError as e:
        print("Failed to get master source for %s at version %s" %
              (master_source, master_version))
        raise e

    os.chdir(work_dir)

    # generate the diff
    master_path = os.path.join(master_dir, master_source)
    print("Generating brief diff between new kernel and master (%s) to %s" %
          (master_version, os.path.join(work_dir, 'master_diff')))
    diff_cmd = ('diff -rq --label master "{}-{}" "{}-{}" >master_diff').format(
        master_path, master_upstream, new_source, new_upstream)
    subprocess.call(diff_cmd, shell=True)


def review_task_callback(lp, bugnum, task, context):
    if str(task.target) != \
       ('%skernel-sru-workflow/promote-to-proposed' % str(lp._root_uri)):
        return {}
    if task.status == 'Confirmed':
        return {'proposed': task}
    elif task.status == 'In Progress':
        if lp.me.self_link != task.assignee_link:
            print("This bug is in progress and not assigned to you.  Do you "
                  "still want to review \nit? [yN]",
                  end="")
            sys.stdout.flush()
            response = sys.stdin.readline()
            if not response.strip().lower().startswith('y'):
                raise KernelWorkflowError("Skipping bug %s" % bugnum)
        return {'proposed': task}

    raise KernelWorkflowError(
              "Ignoring bug %s, not ready to promote-to-proposed"
              % bugnum)


def review_source_callback(lp, bugnum, tasks, full_packages, release, context):
    # as per LP: #1290543, we need to evaluate (load) lp.me for
    # getArchiveSubscritionURL to work
    me = lp.load(lp.me.self_link)
    master_source = None
    master_version = None
    if context['diff']:
        master_source, master_version = get_master_kernel(lp, bugnum)
    should_sign = any('-signed' in pkg for pkg in full_packages)
    for source in full_packages:
        process_source_package(
            source, release, me, context['archive'], context['ppa'],
            context['ubuntu'], context['startdir'], context['workdir'],
            context['tardir'], context['esm'], context['tarcache'],
            master_source, master_version, should_sign)
    tasks['proposed'].status = 'Fix Committed'
    tasks['proposed'].assignee = me
    tasks['proposed'].lp_save()


def fetch_tarball_from_cache(directory, tardir, source, version, cwd):
    actual_tardir = None
    tarballs = []

    glob_pattern = '%s_%s.orig.tar.*' % (source, version)
    # first we look in the current working directory where the command was
    # called from
    actual_tardir = cwd
    tarballs = glob.glob(os.path.join(cwd, glob_pattern))
    if not tarballs:
        actual_tardir = tardir
        tarballs = glob.glob(os.path.join(tardir, glob_pattern))
    if tarballs:
        target = os.path.join(directory, os.path.basename(tarballs[0]))
        try:
            os.link(tarballs[0], target)
        except FileExistsError:
            pass
        except:
            # if the hard linking fails, do a copy operation
            shutil.copy(tarballs[0], target)
    else:
        actual_tardir = None
    return actual_tardir


def save_tarball_to_cache(directory, tardir, source, version):
    glob_pattern = '%s_%s.orig.tar.*' % (source, version)
    to_copy = glob.glob(os.path.join(directory, glob_pattern))
    for tarball in to_copy:
        target = os.path.join(tardir, os.path.basename(tarball))
        try:
            os.link(tarball, target)
        except FileExistsError:
            pass
        except:
            # if the hard linking fails, do a copy operation
            shutil.copy(tarball, target)


def process_source_package(source, release, me, archive, ppa, ubuntu,
                           start_dir, work_dir, tardir,
                           esm=False, tar_cache=False,
                           master_source=None, master_version=None,
                           should_sign=False):
    series = ubuntu.getSeries(name_or_version=release)

    ppa_src = ppa.getPublishedSources(order_by_date=True,
                                      status='Published', exact_match=True,
                                      distro_series=series,
                                      source_name=source)[0]
    ppa_ver = ppa_src.source_package_version
    ppa_dsc = list(filter(
                  lambda x: x.endswith('.dsc'), ppa_src.sourceFileUrls()))[0]
    if ppa.private:
        priv_url = me.getArchiveSubscriptionURL(archive=ppa)
        dsc_file = os.path.basename(ppa_dsc)
        ppa_dsc = os.path.join(priv_url, 'pool/main/l', source, dsc_file)

    # since we can have one archive for more than one 'pocket', no need to do
    # API calls more than once
    scanned = set()
    for pocket in archive.values():
        if pocket.self_link in scanned:
            continue
        archive_uploads = series.getPackageUploads(version=ppa_ver,
                                                   name=source,
                                                   archive=pocket,
                                                   exact_match=True)
        for upload in archive_uploads:
            if upload.status != 'Rejected':
                print("%s_%s already copied to Ubuntu archive (%s), skipping" %
                      (source, ppa_ver, upload.status))
                return
        scanned.add(pocket.self_link)

    source_dsc, source_ver = get_kernel_dsc(me, archive, source, series=series)

    new_fullabi = ppa_ver.split('~')[0]
    new_majorabi = re.sub(r"\.[^.]+$", '', new_fullabi)
    new_upstream = new_fullabi.split('-')[0]

    old_fullabi = source_ver.split('~')[0]
    old_majorabi = re.sub(r"\.[^.]+$", '', old_fullabi)
    old_upstream = old_fullabi.split('-')[0]

    real_tardir = fetch_tarball_from_cache(
        work_dir, tardir, source, old_upstream, start_dir)

    # grab the old source first
    if esm:
        pull_cmd = ['dget', '-u', source_dsc]
    else:
        # for non-ESM cases, it's just more reliable to use pull-lp-source
        pull_cmd = ['pull-lp-source', source, source_ver]

    try:
        subprocess.check_call(pull_cmd)
    except subprocess.CalledProcessError as e:
        print("Failed to get archive source for %s at version %s" %
              (source, source_ver))
        raise e

    # update contents to match what we think the new ABI should be
    sed_cmd = ('grep -rl "{}" "{}-{}"/debian* | grep -v changelog '
               + '| xargs -r sed -i -e"s/{}/{}/g" -e"s/{}/{}/g"').format(
                  re.escape(old_majorabi), source, old_upstream,
                  re.escape(old_fullabi), re.escape(new_fullabi),
                  re.escape(old_majorabi), re.escape(new_majorabi))
    try:
        subprocess.check_call(sed_cmd, shell=True)
    except subprocess.CalledProcessError as e:
        print("Failed to postprocess archive source for %s at version %s" %
              (source, source_ver))
        raise e

    if not real_tardir and tar_cache:
        save_tarball_to_cache(work_dir, tardir, source, old_upstream)

    # move the source dir aside so that it doesn't clobber.
    os.rename(source + '-' + old_upstream, source + '-' + old_upstream + '.old')

    real_tardir = fetch_tarball_from_cache(
        work_dir, tardir, source, new_upstream, start_dir)

    # grab the new source
    dget_cmd = ['dget', '-u', ppa_dsc]
    try:
        subprocess.check_call(dget_cmd)
    except subprocess.CalledProcessError as e:
        print("Failed to get ppa source for %s at version %s" %
              (source, ppa_ver))
        raise e

    if not real_tardir and tar_cache:
        save_tarball_to_cache(work_dir, tardir, source, new_upstream)

    if (master_source and master_version and
            '-meta' not in source and '-signed' not in source and
            '-restricted-modules' not in source):
        # if requested, we also generate a brief diff between the new kernel
        # and its 'master' kernel
        generate_diff_from_master(
            me, archive, master_source, master_version, source, new_upstream,
            work_dir, tardir, start_dir)

    # generate the diff
    raw_diff_cmd = ('diff -uNr "{}-{}.old" "{}-{}" | filterdiff -x'
                    + ' \'**/abi/**\' >raw_diff').format(
                        source, old_upstream, source, new_upstream)
    subprocess.call(raw_diff_cmd, shell=True)

    # look at the diff
    view_cmd = ('(diffstat raw_diff; cat raw_diff) | sensible-pager').format(
                    source, old_upstream, source, new_upstream)
    subprocess.call(view_cmd, shell=True)

    print("Accept the package into -proposed? [yN] ", end="")
    sys.stdout.flush()
    response = sys.stdin.readline()
    if response.strip().lower().startswith('y'):
        copy_cmd = ['copy-proposed-kernel', release, source]
        if esm:
            copy_cmd.append('--esm')
        copy_time = datetime.datetime.now(tz=pytz.utc)
        try:
            subprocess.check_call(copy_cmd)
        except subprocess.CalledProcessError as e:
            print("Failed to copy source for %s at version %s" %
                  (source, ppa_ver))
            raise e
        print("Accepted")
        # we only care about accepting signed bits if there is a -signed
        # package in the handled sources and when we're not working with
        # ESM (as those don't go through the queue)
        if not should_sign or esm:
            return
        # we know this isn't a kernel package containing signed bits,
        # so don't subject ourselves to extra delays
        if ('-meta' in source or '-signed' in source or
                '-restricted-modules' in source):
            return
        print("Checking for UEFI binaries in the Unapproved queue")
        uefis = []
        # we try looking for signed bits a few times after short, constant
        # delays.  The binaries nowadays appear after some seconds, but
        # having a constant delay is suboptimal.
        for n in range(5):
            time.sleep(3)
            # accept any related uefi binaries.  We filter as closely as
            # possible on name without hard-coding architecture, and we also
            # filter to only include uefi binaries that have appeared since we
            # started the copy to avoid accepting something that might have
            # been improperly copied into the queue by an "attacker" with
            # upload rights.
            for signed_type in ('uefi', 'signing'):
                uefis.extend(series.getPackageUploads(
                    archive=archive['release'],
                    pocket='Proposed',
                    status='Unapproved',
                    custom_type=signed_type,
                    name='{}_{}_'.format(source, ppa_ver),
                    created_since_date=copy_time))

            if uefis:
                for uefi in uefis:
                    print("Accepting {}".format(uefi))
                    uefi.acceptFromQueue()
                break
        else:
            print("No UEFI binaries found after %s tries.  Please manually "
                  "check for their existance and approve before accepting the "
                  "signed sources." % n)
            print("Press enter to continue.")
            sys.stdout.flush()
            sys.stdin.readline()


if __name__ == '__main__':

    default_release = 'focal'

    parser = OptionParser(
        usage="Usage: %prog [options] bug [bug ...]")

    xdg_cache = os.getenv('XDG_CACHE_HOME', '~/.cache')
    cachedir = os.path.expanduser(
        os.path.join(xdg_cache, 'ubuntu-archive-tools/kernel-tarballs'))

    parser.add_option(
        "-l", "--launchpad", dest="launchpad_instance", default="production")
    parser.add_option(
        "-k", "--keep-files", dest="keep_files", action="store_true")
    parser.add_option(
        "-C", "--cache-tarballs", dest="caching", action="store_true")
    parser.add_option(
        "-t", "--tarball-directory", dest="tardir", default=cachedir)
    parser.add_option(
        "-e", "--esm", dest="esm", action="store_true")
    parser.add_option(
        "-d", "--diff-against-master", dest="diff_master",
        action="store_true")
    parser.add_option(
        "--skip-name-check", dest="nonamecheck",
        action="store_true")

    opts, bugs = parser.parse_args()

    if len(bugs) < 1:
        parser.error('Need to specify at least one bug number')

    tardir = os.path.abspath(opts.tardir)

    if opts.caching:
        # if we enabled tarball caching, make sure the tarball directory exists
        if not os.path.isdir(tardir):
            try:
                os.makedirs(tardir)
            except:
                parser.error(
                    'Invalid tarball directory specified (%s)' % tardir)

    launchpad = Launchpad.login_with(
        'ubuntu-archive-tools', opts.launchpad_instance, version='devel')

    ubuntu = launchpad.distributions['ubuntu']
    # for ESM (precise) we use special PPAs for CKT testing, -proposed and
    # release
    archive = {}
    if opts.esm:
        team = 'canonical-kernel-esm'
        archive['proposed'] = launchpad.people[team].getPPAByName(
            distribution=ubuntu, name='proposed')
        archive['release'] = launchpad.people['ubuntu-esm'].getPPAByName(
            distribution=ubuntu, name='esm')
        archive['non-esm'] = ubuntu.main_archive
    else:
        team = 'canonical-kernel-team'
        archive['proposed'] = archive['release'] = ubuntu.main_archive
    ppa = launchpad.people[team].getPPAByName(
        distribution=ubuntu, name='ppa')

    start_dir = os.getcwd()
    context = {
      'archive': archive, 'ppa': ppa, 'ubuntu': ubuntu,
      'tardir': tardir, 'tarcache': opts.caching, 'startdir': start_dir,
      'esm': opts.esm, 'diff': opts.diff_master,
      'skipnamecheck': opts.nonamecheck
      }
    for bugnum in bugs:
        with ExitStack() as resources:
            cwd = mkdtemp(prefix='kernel-sru-%s-' % bugnum, dir=start_dir)
            if not opts.keep_files:
                resources.callback(shutil.rmtree, cwd)
            os.chdir(cwd)
            context['workdir'] = cwd
            process_sru_bug(
                launchpad, bugnum, review_task_callback,
                review_source_callback, context)
            os.chdir(start_dir)