#!/usr/bin/python
# -*- coding: utf-8 -*-

# (c) 2012, Flowroute LLC
# Written by Matthew Williams <matthew@flowroute.com>
# Based on yum module written by Seth Vidal <skvidal at fedoraproject.org>
#
# This module 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 3 of the License, or
# (at your option) any later version.
#
# This software 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 software.  If not, see <http://www.gnu.org/licenses/>.
#

ANSIBLE_METADATA = {'metadata_version': '1.0',
                    'status': ['stableinterface'],
                    'supported_by': 'core'}


DOCUMENTATION = '''
---
module: apt
short_description: Manages apt-packages
description:
  - Manages I(apt) packages (such as for Debian/Ubuntu).
version_added: "0.0.2"
options:
  name:
    description:
      - A package name, like C(foo), or package specifier with version, like C(foo=1.0). Name wildcards (fnmatch) like C(apt*) and version wildcards like C(foo=1.0*) are also supported.  Note that the apt-get commandline supports implicit regex matches here but we do not because it can let typos through easier (If you typo C(foo) as C(fo) apt-get would install packages that have "fo" in their name with a warning and a prompt for the user.  Since we don't have warnings and prompts before installing we disallow this.  Use an explicit fnmatch pattern if you want wildcarding)
    required: false
    default: null
    aliases: [ 'pkg', 'package' ]
  state:
    description:
      - Indicates the desired package state. C(latest) ensures that the latest version is installed. C(build-dep) ensures the package build dependencies are installed.
    required: false
    default: present
    choices: [ "latest", "absent", "present", "build-dep" ]
  update_cache:
    description:
      - Run the equivalent of C(apt-get update) before the operation. Can be run as part of the package installation or as a separate step.
    required: false
    default: no
    choices: [ "yes", "no" ]
  cache_valid_time:
    description:
      - Update the apt cache if its older than the I(cache_valid_time). This option is set in seconds.
    required: false
    default: 0
  purge:
    description:
     - Will force purging of configuration files if the module state is set to I(absent).
    required: false
    default: no
    choices: [ "yes", "no" ]
  default_release:
    description:
      - Corresponds to the C(-t) option for I(apt) and sets pin priorities
    required: false
    default: null
  install_recommends:
    description:
      - Corresponds to the C(--no-install-recommends) option for I(apt). C(yes) installs recommended packages.  C(no) does not install recommended packages. By default, Ansible will use the same defaults as the operating system. Suggested packages are never installed.
    required: false
    default: null
    choices: [ "yes", "no" ]
  force:
    description:
      - If C(yes), force installs/removes.
    required: false
    default: "no"
    choices: [ "yes", "no" ]
  allow_unauthenticated:
    description:
      - Ignore if packages cannot be authenticated. This is useful for bootstrapping environments that manage their own apt-key setup.
    required: false
    default: "no"
    choices: [ "yes", "no" ]
    version_added: "2.1"
  upgrade:
    description:
      - 'If yes or safe, performs an aptitude safe-upgrade.'
      - 'If full, performs an aptitude full-upgrade.'
      - 'If dist, performs an apt-get dist-upgrade.'
      - 'Note: This does not upgrade a specific package, use state=latest for that.'
    version_added: "1.1"
    required: false
    default: "no"
    choices: [ "no", "yes", "safe", "full", "dist"]
  dpkg_options:
    description:
      - Add dpkg options to apt command. Defaults to '-o "Dpkg::Options::=--force-confdef" -o "Dpkg::Options::=--force-confold"'
      - Options should be supplied as comma separated list
    required: false
    default: 'force-confdef,force-confold'
  deb:
     description:
       - Path to a .deb package on the remote machine.
       - If :// in the path, ansible will attempt to download deb before installing. (Version added 2.1)
     required: false
     version_added: "1.6"
  autoremove:
    description:
      - If C(yes), remove unused dependency packages for all module states except I(build-dep). It can also be used as the only option.
    required: false
    default: no
    choices: [ "yes", "no" ]
    aliases: [ 'autoclean']
    version_added: "2.1"
  only_upgrade:
    description:
      - Only upgrade a package if it is already installed.
    required: false
    default: false
    version_added: "2.1"
requirements:
   - python-apt (python 2)
   - python3-apt (python 3)
   - aptitude
author: "Matthew Williams (@mgwilliams)"
notes:
   - Three of the upgrade modes (C(full), C(safe) and its alias C(yes)) require C(aptitude), otherwise
     C(apt-get) suffices.
'''

EXAMPLES = '''
- name: Update repositories cache and install "foo" package
  apt:
    name: foo
    update_cache: yes

- name: Remove "foo" package
  apt:
    name: foo
    state: absent

- name: Install the package "foo"
  apt:
    name: foo
    state: present

- name: Install the version '1.00' of package "foo"
  apt:
    name: foo=1.00
    state: present

- name: Update the repository cache and update package "nginx" to latest version using default release squeeze-backport
  apt:
    name: nginx
    state: latest
    default_release: squeeze-backports
    update_cache: yes

- name: Install latest version of "openjdk-6-jdk" ignoring "install-recommends"
  apt:
    name: openjdk-6-jdk
    state: latest
    install_recommends: no

- name: Update all packages to the latest version
  apt:
    upgrade: dist

- name: Run the equivalent of "apt-get update" as a separate step
  apt:
    update_cache: yes

- name: Only run "update_cache=yes" if the last one is more than 3600 seconds ago
  apt:
    update_cache: yes
    cache_valid_time: 3600

- name: Pass options to dpkg on run
  apt:
    upgrade: dist
    update_cache: yes
    dpkg_options: 'force-confold,force-confdef'

- name: Install a .deb package
  apt:
    deb: /tmp/mypackage.deb

- name: Install the build dependencies for package "foo"
  apt:
    pkg: foo
    state: build-dep

- name: Install a .deb package from the internet.
  apt:
    deb: https://example.com/python-ppq_0.1-1_all.deb
'''

RETURN = '''
cache_updated:
    description: if the cache was updated or not
    returned: success, in some cases
    type: boolean
    sample: True
cache_update_time:
    description: time of the last cache update (0 if unknown)
    returned: success, in some cases
    type: datetime
    sample: 1425828348000
stdout:
    description: output from apt
    returned: success, when needed
    type: string
    sample: "Reading package lists...\nBuilding dependency tree...\nReading state information...\nThe following extra packages will be installed:\n  apache2-bin ..."
stderr:
    description: error output from apt
    returned: success, when needed
    type: string
    sample: "AH00558: apache2: Could not reliably determine the server's fully qualified domain name, using 127.0.1.1. Set the 'ServerName' directive globally to ..."
'''

# added to stave off future warnings about apt api
import warnings
warnings.filterwarnings('ignore', "apt API not stable yet", FutureWarning)

import datetime
import fnmatch
import itertools
import os
import re
import sys
import time

from ansible.module_utils.basic import AnsibleModule
from ansible.module_utils.pycompat24 import get_exception
from ansible.module_utils._text import to_bytes, to_native
from ansible.module_utils.urls import fetch_url

# APT related constants
APT_ENV_VARS = dict(
    DEBIAN_FRONTEND = 'noninteractive',
    DEBIAN_PRIORITY = 'critical',
    # We screenscrape apt-get and aptitude output for information so we need
    # to make sure we use the C locale when running commands
    LANG = 'C',
    LC_ALL = 'C',
    LC_MESSAGES = 'C',
    LC_CTYPE = 'C',
)

DPKG_OPTIONS = 'force-confdef,force-confold'
APT_GET_ZERO = "\n0 upgraded, 0 newly installed"
APTITUDE_ZERO = "\n0 packages upgraded, 0 newly installed"
APT_LISTS_PATH = "/var/lib/apt/lists"
APT_UPDATE_SUCCESS_STAMP_PATH = "/var/lib/apt/periodic/update-success-stamp"

HAS_PYTHON_APT = True
try:
    import apt
    import apt.debfile
    import apt_pkg
except ImportError:
    HAS_PYTHON_APT = False

if sys.version_info[0] < 3:
    PYTHON_APT = 'python-apt'
else:
    PYTHON_APT = 'python3-apt'


def package_split(pkgspec):
    parts = pkgspec.split('=', 1)
    if len(parts) > 1:
        return parts[0], parts[1]
    else:
        return parts[0], None


def package_versions(pkgname, pkg, pkg_cache):
    try:
        versions = set(p.version for p in pkg.versions)
    except AttributeError:
        # assume older version of python-apt is installed
        # apt.package.Package#versions require python-apt >= 0.7.9.
        pkg_cache_list = (p for p in pkg_cache.Packages if p.Name == pkgname)
        pkg_versions = (p.VersionList for p in pkg_cache_list)
        versions = set(p.VerStr for p in itertools.chain(*pkg_versions))

    return versions


def package_version_compare(version, other_version):
    try:
        return apt_pkg.version_compare(version, other_version)
    except AttributeError:
        return apt_pkg.VersionCompare(version, other_version)


def package_status(m, pkgname, version, cache, state):
    try:
        # get the package from the cache, as well as the
        # low-level apt_pkg.Package object which contains
        # state fields not directly accessible from the
        # higher-level apt.package.Package object.
        pkg = cache[pkgname]
        ll_pkg = cache._cache[pkgname] # the low-level package object
    except KeyError:
        if state == 'install':
            try:
                provided_packages = cache.get_providing_packages(pkgname)
                if provided_packages:
                    is_installed = False
                    upgradable = False
                    # when virtual package providing only one package, look up status of target package
                    if cache.is_virtual_package(pkgname) and len(provided_packages) == 1:
                        package = provided_packages[0]
                        installed, upgradable, has_files = package_status(m, package.name, version, cache, state='install')
                        if installed:
                            is_installed = True
                    return is_installed, upgradable, False
                m.fail_json(msg="No package matching '%s' is available" % pkgname)
            except AttributeError:
                # python-apt version too old to detect virtual packages
                # mark as upgradable and let apt-get install deal with it
                return False, True, False
        else:
            return False, False, False
    try:
        has_files = len(pkg.installed_files) > 0
    except UnicodeDecodeError:
        has_files = True
    except AttributeError:
        has_files = False  # older python-apt cannot be used to determine non-purged

    try:
        package_is_installed = ll_pkg.current_state == apt_pkg.CURSTATE_INSTALLED
    except AttributeError: # python-apt 0.7.X has very weak low-level object
        try:
            # might not be necessary as python-apt post-0.7.X should have current_state property
            package_is_installed = pkg.is_installed
        except AttributeError:
            # assume older version of python-apt is installed
            package_is_installed = pkg.isInstalled

    if version:
        versions = package_versions(pkgname, pkg, cache._cache)
        avail_upgrades = fnmatch.filter(versions, version)

        if package_is_installed:
            try:
                installed_version = pkg.installed.version
            except AttributeError:
                installed_version = pkg.installedVersion

            # Only claim the package is installed if the version is matched as well
            package_is_installed = fnmatch.fnmatch(installed_version, version)

            # Only claim the package is upgradable if a candidate matches the version
            package_is_upgradable = False
            for candidate in avail_upgrades:
                if package_version_compare(candidate, installed_version) > 0:
                    package_is_upgradable = True
                    break
        else:
            package_is_upgradable = bool(avail_upgrades)
    else:
        try:
            package_is_upgradable = pkg.is_upgradable
        except AttributeError:
            # assume older version of python-apt is installed
            package_is_upgradable = pkg.isUpgradable

    return package_is_installed, package_is_upgradable, has_files


def expand_dpkg_options(dpkg_options_compressed):
    options_list = dpkg_options_compressed.split(',')
    dpkg_options = ""
    for dpkg_option in options_list:
        dpkg_options = '%s -o "Dpkg::Options::=--%s"' \
                       % (dpkg_options, dpkg_option)
    return dpkg_options.strip()


def expand_pkgspec_from_fnmatches(m, pkgspec, cache):
    # Note: apt-get does implicit regex matching when an exact package name
    # match is not found.  Something like this:
    # matches = [pkg.name for pkg in cache if re.match(pkgspec, pkg.name)]
    # (Should also deal with the ':' for multiarch like the fnmatch code below)
    #
    # We have decided not to do similar implicit regex matching but might take
    # a PR to add some sort of explicit regex matching:
    # https://github.com/ansible/ansible-modules-core/issues/1258
    new_pkgspec = []
    if pkgspec:
        for pkgspec_pattern in pkgspec:
            pkgname_pattern, version = package_split(pkgspec_pattern)

            # note that none of these chars is allowed in a (debian) pkgname
            if frozenset('*?[]!').intersection(pkgname_pattern):
                # handle multiarch pkgnames, the idea is that "apt*" should
                # only select native packages. But "apt*:i386" should still work
                if ":" not in pkgname_pattern:
                    # Filter the multiarch packages from the cache only once
                    try:
                        pkg_name_cache = _non_multiarch
                    except NameError:
                        pkg_name_cache = _non_multiarch = [pkg.name for pkg in cache if ':' not in pkg.name]  # noqa: F841
                else:
                    # Create a cache of pkg_names including multiarch only once
                    try:
                        pkg_name_cache = _all_pkg_names
                    except NameError:
                        pkg_name_cache = _all_pkg_names = [pkg.name for pkg in cache]  # noqa: F841

                matches = fnmatch.filter(pkg_name_cache, pkgname_pattern)

                if len(matches) == 0:
                    m.fail_json(msg="No package(s) matching '%s' available" % str(pkgname_pattern))
                else:
                    new_pkgspec.extend(matches)
            else:
                # No wildcards in name
                new_pkgspec.append(pkgspec_pattern)
    return new_pkgspec


def parse_diff(output):
    diff = to_native(output).splitlines()
    try:
        # check for start marker from aptitude
        diff_start = diff.index('Resolving dependencies...')
    except ValueError:
        try:
            # check for start marker from apt-get
            diff_start = diff.index('Reading state information...')
        except ValueError:
            # show everything
            diff_start = -1
    try:
        # check for end marker line from both apt-get and aptitude
        diff_end = next(i for i, item in enumerate(diff) if re.match('[0-9]+ (packages )?upgraded', item))
    except StopIteration:
        diff_end = len(diff)
    diff_start += 1
    diff_end += 1
    return {'prepared': '\n'.join(diff[diff_start:diff_end])}


def install(m, pkgspec, cache, upgrade=False, default_release=None,
            install_recommends=None, force=False,
            dpkg_options=expand_dpkg_options(DPKG_OPTIONS),
            build_dep=False, autoremove=False, only_upgrade=False,
            allow_unauthenticated=False):
    pkg_list = []
    packages = ""
    pkgspec = expand_pkgspec_from_fnmatches(m, pkgspec, cache)
    for package in pkgspec:
        if build_dep:
            # Let apt decide what to install
            pkg_list.append("'%s'" % package)
            continue

        name, version = package_split(package)
        installed, upgradable, has_files = package_status(m, name, version, cache, state='install')
        if not installed or (upgrade and upgradable):
            pkg_list.append("'%s'" % package)
        if installed and upgradable and version:
            # This happens when the package is installed, a newer version is
            # available, and the version is a wildcard that matches both
            #
            # We do not apply the upgrade flag because we cannot specify both
            # a version and state=latest.  (This behaviour mirrors how apt
            # treats a version with wildcard in the package)
            pkg_list.append("'%s'" % package)
    packages = ' '.join(pkg_list)

    if len(packages) != 0:
        if force:
            force_yes = '--force-yes'
        else:
            force_yes = ''

        if m.check_mode:
            check_arg = '--simulate'
        else:
            check_arg = ''

        if autoremove:
            autoremove = '--auto-remove'
        else:
            autoremove = ''

        if only_upgrade:
            only_upgrade = '--only-upgrade'
        else:
            only_upgrade = ''

        if build_dep:
            cmd = "%s -y %s %s %s %s build-dep %s" % (APT_GET_CMD, dpkg_options, only_upgrade, force_yes, check_arg, packages)
        else:
            cmd = "%s -y %s %s %s %s %s install %s" % (APT_GET_CMD, dpkg_options, only_upgrade, force_yes, autoremove, check_arg, packages)

        if default_release:
            cmd += " -t '%s'" % (default_release,)

        if install_recommends is False:
            cmd += " -o APT::Install-Recommends=no"
        elif install_recommends is True:
            cmd += " -o APT::Install-Recommends=yes"
        # install_recommends is None uses the OS default

        if allow_unauthenticated:
            cmd += " --allow-unauthenticated"

        rc, out, err = m.run_command(cmd)
        if m._diff:
            diff = parse_diff(out)
        else:
            diff = {}
        if rc:
            return (False, dict(msg="'%s' failed: %s" % (cmd, err), stdout=out, stderr=err, rc=rc))
        else:
            return (True, dict(changed=True, stdout=out, stderr=err, diff=diff))
    else:
        return (True, dict(changed=False))


def get_field_of_deb(m, deb_file, field="Version"):
    cmd_dpkg = m.get_bin_path("dpkg", True)
    cmd = cmd_dpkg + " --field %s %s" % (deb_file, field)
    rc, stdout, stderr = m.run_command(cmd)
    if rc != 0:
        m.fail_json(msg="%s failed" % cmd, stdout=stdout, stderr=stderr)
    return to_native(stdout).strip('\n')


def install_deb(m, debs, cache, force, install_recommends, allow_unauthenticated, dpkg_options):
    changed=False
    deps_to_install = []
    pkgs_to_install = []
    for deb_file in debs.split(','):
        try:
            pkg = apt.debfile.DebPackage(deb_file)
            pkg_name = get_field_of_deb(m, deb_file, "Package")
            pkg_version = get_field_of_deb(m, deb_file, "Version")
            try:
                installed_pkg = apt.Cache()[pkg_name]
                installed_version = installed_pkg.installed.version
                if package_version_compare(pkg_version, installed_version) == 0:
                    # Does not need to down-/upgrade, move on to next package
                    continue
            except Exception:
                # Must not be installed, continue with installation
                pass
            # Check if package is installable
            if not pkg.check() and not force:
                m.fail_json(msg=pkg._failure_string)

            # add any missing deps to the list of deps we need
            # to install so they're all done in one shot
            deps_to_install.extend(pkg.missing_deps)

        except Exception:
            e = get_exception()
            m.fail_json(msg="Unable to install package: %s" % str(e))

        # and add this deb to the list of packages to install
        pkgs_to_install.append(deb_file)

    # install the deps through apt
    retvals = {}
    if len(deps_to_install) > 0:
        (success, retvals) = install(m=m, pkgspec=deps_to_install, cache=cache,
                                     install_recommends=install_recommends,
                                     dpkg_options=expand_dpkg_options(dpkg_options))
        if not success:
            m.fail_json(**retvals)
        changed = retvals.get('changed', False)

    if len(pkgs_to_install) > 0:
        options = ' '.join(["--%s"% x for x in dpkg_options.split(",")])
        if m.check_mode:
            options += " --simulate"
        if force:
            options += " --force-all"

        cmd = "dpkg %s -i %s" % (options, " ".join(pkgs_to_install))
        rc, out, err = m.run_command(cmd)
        if "stdout" in retvals:
            stdout = retvals["stdout"] + out
        else:
            stdout = out
        if "diff" in retvals:
            diff = retvals["diff"]
            if 'prepared' in diff:
                diff['prepared'] += '\n\n' + out
        else:
            diff = parse_diff(out)
        if "stderr" in retvals:
            stderr = retvals["stderr"] + err
        else:
            stderr = err

        if rc == 0:
            m.exit_json(changed=True, stdout=stdout, stderr=stderr, diff=diff)
        else:
            m.fail_json(msg="%s failed" % cmd, stdout=stdout, stderr=stderr)
    else:
        m.exit_json(changed=changed, stdout=retvals.get('stdout',''), stderr=retvals.get('stderr',''), diff=retvals.get('diff', ''))


def remove(m, pkgspec, cache, purge=False, force=False,
           dpkg_options=expand_dpkg_options(DPKG_OPTIONS), autoremove=False):
    pkg_list = []
    pkgspec = expand_pkgspec_from_fnmatches(m, pkgspec, cache)
    for package in pkgspec:
        name, version = package_split(package)
        installed, upgradable, has_files = package_status(m, name, version, cache, state='remove')
        if installed or (has_files and purge):
            pkg_list.append("'%s'" % package)
    packages = ' '.join(pkg_list)

    if len(packages) == 0:
        m.exit_json(changed=False)
    else:
        if force:
            force_yes = '--force-yes'
        else:
            force_yes = ''

        if purge:
            purge = '--purge'
        else:
            purge = ''

        if autoremove:
            autoremove = '--auto-remove'
        else:
            autoremove = ''

        if m.check_mode:
            check_arg = '--simulate'
        else:
            check_arg = ''

        cmd = "%s -q -y %s %s %s %s %s remove %s" % (APT_GET_CMD, dpkg_options, purge, force_yes ,autoremove, check_arg, packages)

        rc, out, err = m.run_command(cmd)
        if m._diff:
            diff = parse_diff(out)
        else:
            diff = {}
        if rc:
            m.fail_json(msg="'apt-get remove %s' failed: %s" % (packages, err), stdout=out, stderr=err, rc=rc)
        m.exit_json(changed=True, stdout=out, stderr=err, diff=diff)


def upgrade(m, mode="yes", force=False, default_release=None,
            dpkg_options=expand_dpkg_options(DPKG_OPTIONS)):
    if m.check_mode:
        check_arg = '--simulate'
    else:
        check_arg = ''

    apt_cmd = None
    prompt_regex = None
    if mode == "dist":
        # apt-get dist-upgrade
        apt_cmd = APT_GET_CMD
        upgrade_command = "dist-upgrade"
    elif mode == "full":
        # aptitude full-upgrade
        apt_cmd = APTITUDE_CMD
        upgrade_command = "full-upgrade"
    else:
        # aptitude safe-upgrade # mode=yes # default
        apt_cmd = APTITUDE_CMD
        upgrade_command = "safe-upgrade"
        prompt_regex = r"(^Do you want to ignore this warning and proceed anyway\?|^\*\*\*.*\[default=.*\])"

    if force:
        if apt_cmd == APT_GET_CMD:
            force_yes = '--force-yes'
        else:
            force_yes = '--assume-yes --allow-untrusted'
    else:
        force_yes = ''

    apt_cmd_path = m.get_bin_path(apt_cmd, required=True)

    cmd = '%s -y %s %s %s %s' % (apt_cmd_path, dpkg_options,
                                    force_yes, check_arg, upgrade_command)

    if default_release:
        cmd += " -t '%s'" % (default_release,)

    rc, out, err = m.run_command(cmd, prompt_regex=prompt_regex)
    if m._diff:
        diff = parse_diff(out)
    else:
        diff = {}
    if rc:
        m.fail_json(msg="'%s %s' failed: %s" % (apt_cmd, upgrade_command, err), stdout=out, rc=rc)
    if (apt_cmd == APT_GET_CMD and APT_GET_ZERO in out) or (apt_cmd == APTITUDE_CMD and APTITUDE_ZERO in out):
        m.exit_json(changed=False, msg=out, stdout=out, stderr=err)
    m.exit_json(changed=True, msg=out, stdout=out, stderr=err, diff=diff)


def download(module, deb):
    tempdir = os.path.dirname(__file__)
    package = os.path.join(tempdir, str(deb.rsplit('/', 1)[1]))
    # When downloading a deb, how much of the deb to download before
    # saving to a tempfile (64k)
    BUFSIZE = 65536

    try:
        rsp, info = fetch_url(module, deb)
        # Ensure file is open in binary mode for Python 3
        f = open(package, 'wb')
        # Read 1kb at a time to save on ram
        while True:
            data = rsp.read(BUFSIZE)
            data = to_bytes(data, errors='surrogate_or_strict')

            if len(data) < 1:
                break # End of file, break while loop

            f.write(data)
        f.close()
        deb = package
    except Exception:
        e = get_exception()
        module.fail_json(msg="Failure downloading %s, %s" % (deb, e))

    return deb


def get_cache_mtime():
    """Return mtime of a valid apt cache file.
    Stat the apt cache file and if no cache file is found return 0
    :returns: ``int``
    """
    if os.path.exists(APT_UPDATE_SUCCESS_STAMP_PATH):
        return os.stat(APT_UPDATE_SUCCESS_STAMP_PATH).st_mtime
    elif os.path.exists(APT_LISTS_PATH):
        return os.stat(APT_LISTS_PATH).st_mtime
    else:
        return 0


def get_updated_cache_time():
    """Return the mtime time stamp and the updated cache time.
    Always retrieve the mtime of the apt cache or set the `cache_mtime`
    variable to 0
    :returns: ``tuple``
    """
    cache_mtime = get_cache_mtime()
    mtimestamp = datetime.datetime.fromtimestamp(cache_mtime)
    updated_cache_time = int(time.mktime(mtimestamp.timetuple()))
    return mtimestamp, updated_cache_time


# https://github.com/ansible/ansible-modules-core/issues/2951
def get_cache(module):
    '''Attempt to get the cache object and update till it works'''
    cache = None
    try:
        cache = apt.Cache()
    except SystemError:
        e = get_exception()
        if '/var/lib/apt/lists/' in str(e).lower():
            # update cache until files are fixed or retries exceeded
            retries = 0
            while retries < 2:
                (rc, so, se) = module.run_command(['apt-get', 'update', '-q'])
                retries += 1
                if rc == 0:
                    break
            if rc != 0:
                module.fail_json(msg='Updating the cache to correct corrupt package lists failed:\n%s\n%s' % (str(e), str(so) + str(se)), rc=rc)
            # try again
            cache = apt.Cache()
        else:
            module.fail_json(msg=str(e))
    return cache


def main():
    module = AnsibleModule(
        argument_spec = dict(
            state = dict(default='present', choices=['installed', 'latest', 'removed', 'absent', 'present', 'build-dep']),
            update_cache = dict(aliases=['update-cache'], type='bool'),
            cache_valid_time = dict(type='int', default=0),
            purge = dict(default=False, type='bool'),
            package = dict(default=None, aliases=['pkg', 'name'], type='list'),
            deb = dict(default=None, type='path'),
            default_release = dict(default=None, aliases=['default-release']),
            install_recommends = dict(default=None, aliases=['install-recommends'], type='bool'),
            force = dict(default='no', type='bool'),
            upgrade = dict(choices=['no', 'yes', 'safe', 'full', 'dist']),
            dpkg_options = dict(default=DPKG_OPTIONS),
            autoremove = dict(type='bool', aliases=['autoclean']),
            only_upgrade = dict(type='bool', default=False),
            allow_unauthenticated = dict(default='no', aliases=['allow-unauthenticated'], type='bool'),
        ),
        mutually_exclusive = [['package', 'upgrade', 'deb']],
        required_one_of = [['package', 'upgrade', 'update_cache', 'deb', 'autoremove']],
        supports_check_mode = True
    )

    module.run_command_environ_update = APT_ENV_VARS

    if not HAS_PYTHON_APT:
        if module.check_mode:
            module.fail_json(msg="%s must be installed to use check mode. "
                                 "If run normally this module can auto-install it." % PYTHON_APT)
        try:
            module.run_command(['apt-get', 'update'], check_rc=True)
            module.run_command(['apt-get', 'install', PYTHON_APT, '-y', '-q'], check_rc=True)
            global apt, apt_pkg
            import apt
            import apt.debfile
            import apt_pkg
        except ImportError:
            module.fail_json(msg="Could not import python modules: apt, apt_pkg. "
                                 "Please install %s package." % PYTHON_APT)

    global APTITUDE_CMD
    APTITUDE_CMD = module.get_bin_path("aptitude", False)
    global APT_GET_CMD
    APT_GET_CMD = module.get_bin_path("apt-get")

    p = module.params

    if p['upgrade'] == 'no':
        p['upgrade'] = None

    if not APTITUDE_CMD and p.get('upgrade', None) in [ 'full', 'safe', 'yes' ]:
        module.fail_json(msg="Could not find aptitude. Please ensure it is installed.")

    updated_cache = False
    updated_cache_time = 0
    install_recommends = p['install_recommends']
    allow_unauthenticated = p['allow_unauthenticated']
    dpkg_options = expand_dpkg_options(p['dpkg_options'])
    autoremove = p['autoremove']

    # Deal with deprecated aliases
    if p['state'] == 'installed':
        p['state'] = 'present'
    if p['state'] == 'removed':
        p['state'] = 'absent'

    # Get the cache object
    cache = get_cache(module)

    try:
        if p['default_release']:
            try:
                apt_pkg.config['APT::Default-Release'] = p['default_release']
            except AttributeError:
                apt_pkg.Config['APT::Default-Release'] = p['default_release']
            # reopen cache w/ modified config
            cache.open(progress=None)

        mtimestamp, updated_cache_time = get_updated_cache_time()
        # Cache valid time is default 0, which will update the cache if
        #  needed and `update_cache` was set to true
        updated_cache = False
        if p['update_cache']:
            now = datetime.datetime.now()
            tdelta = datetime.timedelta(seconds=p['cache_valid_time'])
            if not mtimestamp + tdelta >= now:
                # Retry to update the cache up to 3 times
                for retry in range(3):
                    try:
                        cache.update()
                        break
                    except apt.cache.FetchFailedException:
                        pass
                else:
                    module.fail_json(msg='Failed to update apt cache.')
                cache.open(progress=None)
                updated_cache = True
                mtimestamp, updated_cache_time = get_updated_cache_time()

            # If there is nothing else to do exit. This will set state as
            #  changed based on if the cache was updated.
            if not p['package'] and not p['upgrade'] and not p['deb']:
                module.exit_json(
                    changed=updated_cache,
                    cache_updated=updated_cache,
                    cache_update_time=updated_cache_time
                )

        force_yes = p['force']

        if p['upgrade']:
            upgrade(module, p['upgrade'], force_yes, p['default_release'], dpkg_options)

        if p['deb']:
            if p['state'] != 'present':
                module.fail_json(msg="deb only supports state=present")
            if '://' in p['deb']:
                p['deb'] = download(module, p['deb'])
            install_deb(module, p['deb'], cache,
                        install_recommends=install_recommends,
                        allow_unauthenticated=allow_unauthenticated,
                        force=force_yes, dpkg_options=p['dpkg_options'])

        packages = p['package']
        latest = p['state'] == 'latest'
        if packages:
            for package in packages:
                if package.count('=') > 1:
                    module.fail_json(msg="invalid package spec: %s" % package)
                if latest and '=' in package:
                    module.fail_json(msg='version number inconsistent with state=latest: %s' % package)

        if p['state'] in ('latest', 'present', 'build-dep'):
            state_upgrade = False
            state_builddep = False
            if p['state'] == 'latest':
                state_upgrade = True
            if p['state'] == 'build-dep':
                state_builddep = True

            success, retvals = install(
                module,
                packages,
                cache,
                upgrade=state_upgrade,
                default_release=p['default_release'],
                install_recommends=install_recommends,
                force=force_yes,
                dpkg_options=dpkg_options,
                build_dep=state_builddep,
                autoremove=autoremove,
                only_upgrade=p['only_upgrade'],
                allow_unauthenticated=allow_unauthenticated
            )

            # Store if the cache has been updated
            retvals['cache_updated'] = updated_cache
            # Store when the update time was last
            retvals['cache_update_time'] = updated_cache_time

            if success:
                module.exit_json(**retvals)
            else:
                module.fail_json(**retvals)
        elif p['state'] == 'absent':
            remove(module, packages, cache, p['purge'], force=force_yes, dpkg_options=dpkg_options, autoremove=autoremove)

    except apt.cache.LockFailedException:
        module.fail_json(msg="Failed to lock apt for exclusive operation")
    except apt.cache.FetchFailedException:
        module.fail_json(msg="Could not fetch updated apt files")


if __name__ == "__main__":
    main()
