#!/usr/bin/python3

from __future__ import print_function

import optparse
import datetime
import distro_info
import os
import re
import subprocess
import sys

import apt
from UpdateManager.Core.utils import twrap, get_dist

# set locale early so that the subsequent imports have localized
# strings
import locale
try:
    locale.setlocale(locale.LC_ALL, "")
except:
    pass

from gettext import gettext as _
import gettext
gettext.textdomain("update-manager")


from HweSupportStatus.consts import (
    Messages,
    LTS_EOL_DATE,
    HWE_EOL_DATE,
    NEXT_LTS_DOT1_DATE,
)


# HWE stack with a short support period
HWE_UNSUPPORTED_BACKPORTS = (
    "-lts-utopic",
    "-lts-vivid",
    "-lts-wily"
)
# from https://wiki.ubuntu.com/Kernel/LTSEnablementStack
UNSUPPORTED_KERNEL_IMAGE_REGEX = \
    r'linux-image.*-(3\.16|3\.19|4\.2)(\.[0-9]+)?-.*'

# HWE stack with a long support period
HWE_SUPPORTED_BACKPORT = "-hwe-20.04"
SUPPORTED_KERNEL_IMAGE_REGEX = r'^$' # No fixed backported kernel yet


KERNEL_METAPKGS = (
    "linux-generic",
    "linux-image-generic",
    "linux-signed-generic",
    "linux-signed-image-generic",
)
XORG_METAPKGS = (
    "xserver-xorg",
    "libgl1-mesa-glx",
    # LP: #1610434 - Ubuntu GNOME needed libwayland
    "libwayland-egl1-mesa",
)
VBOX_METAPKGS = (
    "virtualbox-guest-utils",
    "virtualbox-guest-source"
)
METAPKGS = KERNEL_METAPKGS + XORG_METAPKGS + VBOX_METAPKGS


class Package:
    """A lightweight apt package """
    def __init__(self, name, version, arch, foreign=False):
        self.name = name
        self.installed_version = version
        self.arch = arch
        self.foreign = foreign


def find_hwe_packages(installed_packages):
    unsupported_hwe_packages = set()
    supported_hwe_packages = set()
    for pkg in installed_packages:
        # metapackages and X are marked with the -lts-$distro string
        for name in HWE_UNSUPPORTED_BACKPORTS:
            if pkg.name.endswith(name):
                unsupported_hwe_packages.add(pkg)
        # The individual backported kernels have names like
        #   linux-image-3.11.0-17-generic
        # so we match via a regexp.
        #
        # The linux-image-generic-lts-$distro metapkg has additional
        #  dependencies (like linux-firmware) so we can't just walk the
        # dependency chain.
        if re.match(UNSUPPORTED_KERNEL_IMAGE_REGEX, pkg.name):
            unsupported_hwe_packages.add(pkg)
        # SUPPORTED
        if pkg.name.endswith(HWE_SUPPORTED_BACKPORT):
            supported_hwe_packages.add(pkg)
        if re.match(SUPPORTED_KERNEL_IMAGE_REGEX, pkg.name):
            supported_hwe_packages.add(pkg)
    return unsupported_hwe_packages, supported_hwe_packages


def is_unsupported_hwe_kernel_running(unsupported_hwe_package):
    # kernels do not conflict with each other, so we need to check
    # what version is actually running
    running_kernel_ver = os.uname()[2]
    # the running kernel without the abi or buildver
    running_kernel_ver = running_kernel_ver.split("-")[0]
    for pkg in unsupported_hwe_package:
        if not pkg.name.startswith("linux-"):
            continue
        # we only care about the version, not abi or build
        if pkg.installed_version.startswith(running_kernel_ver):
            return True
    return False


def is_unsupported_xstack_running(unsupported_hwe_packages):
    # the HWE xstacks conflict with each other, so we can simply test
    # for existence in the installed unsupported hwe packages
    for pkg in unsupported_hwe_packages:
        for xorg_meta in XORG_METAPKGS:
            if pkg.name.startswith(xorg_meta):
                return True
    return False


def find_supported_replacement_hwe_packages(unsupported_hwe_packages,
                                            installed_packages):
    unsupported_metapkg_names = set()
    replacement_names = set()
    for metapkg in METAPKGS:
        for unsupported_backport in HWE_UNSUPPORTED_BACKPORTS:
            metapkg_name = metapkg + unsupported_backport
            for pkg in unsupported_hwe_packages:
                if pkg.name == metapkg_name:
                    replacement_name = metapkg + HWE_SUPPORTED_BACKPORT
                    if (replacement_name, pkg.arch) not in \
                            [(p.name, p.arch) for p in installed_packages]:
                        if pkg.foreign:
                            replacement_name += ':' + pkg.arch
                        replacement_names.add(replacement_name)
                    unsupported_metapkg_names.add(metapkg_name)
    return unsupported_metapkg_names, replacement_names


def is_unsupported_hwe_running(unsupported_hwe_packages):
    return (is_unsupported_hwe_kernel_running(unsupported_hwe_packages) or
            is_unsupported_xstack_running(unsupported_hwe_packages))


def advice_about_hwe_status(unsupported_hwe_packages, supported_hwe_packages,
                            installed_packages, has_update_manager, today,
                            verbose):
    unsupported_hwe_stack_running = is_unsupported_hwe_running(
        unsupported_hwe_packages)
    unsupported_hwe_metapkgs, supported_replacement_hwe = \
        find_supported_replacement_hwe_packages(unsupported_hwe_packages,
                                                installed_packages)
    # we need the "-p" option until the next LTS point release is available
    if today < NEXT_LTS_DOT1_DATE:
        do_release_upgrade_option = "-p"
    else:
        do_release_upgrade_option = ""

    if unsupported_hwe_stack_running:
        if today < HWE_EOL_DATE:
            s = Messages.HWE_SUPPORT_ENDS
        else:
            s = Messages.HWE_SUPPORT_HAS_ENDED
        if has_update_manager:
            print(s + Messages.UM_UPGRADE)
        else:
            # bug #1341320 - if no metapkg is left we need to show
            #                what is no longer supported
            if supported_replacement_hwe:
                print(s + Messages.APT_UPGRADE % (
                    do_release_upgrade_option,
                    " ".join(supported_replacement_hwe)))
            else:
                print(s + Messages.APT_SHOW_UNSUPPORTED % (
                    " ".join([pkg.name for pkg in unsupported_hwe_packages])))

    # some unsupported package installed but not running and not superseded
    # - this is worth reporting
    elif (unsupported_hwe_packages and
          not supported_hwe_packages and
          not unsupported_hwe_stack_running):
        s = _("""
You have packages from the Hardware Enablement Stack (HWE) installed that
are going out of support on %s.
        """) % HWE_EOL_DATE
        if has_update_manager:
            print(s + Messages.UM_UPGRADE)
        else:
            print(s + Messages.APT_UPGRADE % (
                do_release_upgrade_option,
                " ".join(supported_replacement_hwe)))
    elif supported_hwe_packages:
        print(Messages.HWE_SUPPORTED)
    elif verbose:
        print(
            _("You are not running a system with a Hardware Enablement Stack. "
              "Your system is supported until %(month)s %(year)s.") % {
                  'month': LTS_EOL_DATE.strftime("%B"),
                  'year': LTS_EOL_DATE.year})


if __name__ == "__main__":
    parser = optparse.OptionParser(description=_("Check HWE support status"))
    parser.add_option('--quiet', action='store_true', default=False,
                      help="No output, exit code 10 on unsupported HWE "
                      "packages")
    parser.add_option('--verbose', action='store_true', default=False,
                      help="more verbose output")
    parser.add_option('--show-all-unsupported', action='store_true',
                      default=False,
                      help="Show unsupported HWE packages")
    parser.add_option('--show-replacements', action='store_true',
                      default=False,
                      help="show what packages need installing to be "
                      "supported")
    # hidden, only useful for testing
    parser.add_option(
        '--disable-hwe-check-semaphore-file',
        default="/var/lib/update-notifier/disable-hwe-eol-messages",
        help=optparse.SUPPRESS_HELP)
    options, args = parser.parse_args()

    if options.quiet:
        nullfd = os.open(os.devnull, os.O_WRONLY)
        os.dup2(nullfd, sys.stdout.fileno())

    # Check to see if we are an LTS release
    di = distro_info.UbuntuDistroInfo()
    codename = get_dist()
    lts = di.is_lts(codename)
    if not lts:
        if options.verbose:
            print("Only LTS releases have Hardware Enablement stacks",
                  file=sys.stderr)
        sys.exit(0)

    # request from PSE to be able to disable the hwe check via a special
    # semaphore file
    HWE_CHECK_DISABLED_FILE = options.disable_hwe_check_semaphore_file
    if os.path.exists(HWE_CHECK_DISABLED_FILE):
        if options.verbose:
            print("Forcefully disabled hwe-support-status via file %s" %
                  HWE_CHECK_DISABLED_FILE, file=sys.stderr)
        sys.exit(0)

    foreign_archs = set(subprocess.check_output(
        ['dpkg', '--print-foreign-architectures'],
        universal_newlines=True).split())

    # do the actual check
    installed_packages = set()
    today = datetime.date.today()
    tagf = apt.apt_pkg.TagFile("/var/lib/dpkg/status")
    while tagf.step():
        if tagf.section.find("Status", "") != "install ok installed":
            continue
        pkgname = tagf.section.find("Package")
        version = tagf.section.find("Version")
        arch = tagf.section.find("Architecture")
        foreign = arch in foreign_archs
        installed_packages.add(Package(pkgname, version, arch, foreign))

    has_update_manager = "update-manager" in [
        pkg.name for pkg in installed_packages]
    unsupported_hwe_packages, supported_hwe_packages = find_hwe_packages(
        installed_packages)

    if options.show_all_unsupported:
        if today > HWE_EOL_DATE:
            print(twrap(" ".join([
                pkg.foreign and pkg.name + ':' + pkg.arch or pkg.name
                        for pkg in unsupported_hwe_packages])))

    if options.show_replacements:
        unsupported, replacements = find_supported_replacement_hwe_packages(
            unsupported_hwe_packages, installed_packages)
        if replacements:
            print(" ".join(replacements))

    if not options.show_all_unsupported and not options.show_replacements:
        advice_about_hwe_status(
            unsupported_hwe_packages, supported_hwe_packages,
            installed_packages, has_update_manager, today,
            options.verbose)
    if is_unsupported_hwe_running(unsupported_hwe_packages) and \
            today > HWE_EOL_DATE:
        sys.exit(10)

    sys.exit(0)