# Copyright (C) 2017 Linaro Limited
#
# Author: Remi Duraffort <remi.duraffort@linaro.org>
#
# This file is part of Lava Server.
#
# Lava Server is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License version 3
# as published by the Free Software Foundation
#
# Lava Server 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 Affero General Public License
# along with Lava Server.  If not, see <http://www.gnu.org/licenses/>.

import os
import subprocess

from django.core.checks import Debug, Error, register
from django.db.models import Q
from lava_scheduler_app.models import Device, validate_job
from lava_scheduler_app.schema import SubmissionException


@register(deploy=True)
def check_health_checks(app_configs, **kwargs):
    errors = []

    for device in Device.objects.filter(is_pipeline=True):
        ht = device.get_health_check()
        ht_disabled = device.device_type.disable_health_check

        # All active devices should have a health check,
        # provided that health checks are not disabled for this device type.
        if device.status == Device.RETIRED:
            continue
        if ht is None and not ht_disabled:
            errors.append(Debug("No health check", obj=device.hostname))
            continue

        # An empty file is an error, provided health checks are not disabled
        # for this device type.
        if not ht and not ht_disabled:
            errors.append(Error("Empty health check", obj=device.hostname))
            continue

        # Check that the health check job is valid
        if ht:
            try:
                validate_job(ht)
            except SubmissionException as exc:
                errors.append(Error("Invalid health check: '%s'" % exc,
                                    obj=device.hostname))

    return errors


@register(deploy=True)
def check_device_configuration(app_configs, **kwargs):
    errors = []

    for device in Device.objects.filter(Q(is_pipeline=True), ~Q(status=Device.RETIRED)):
        if not device.is_valid():
            errors.append(Error('Invalid configuration', obj=device.hostname))

    return errors


def _package_status(name, errors):
    try:
        out = subprocess.check_output(["dpkg-query", "--status", name],
                                      stderr=subprocess.STDOUT).decode("utf-8").split("\n")
        if out[1] != "Status: install ok installed":
            errors.append(Error('not installed correctly', obj=name))
    except subprocess.CalledProcessError:
        errors.append(Error('not installed from a Debian package', obj=name))


def _package_symlinks(name, errors):
    dirname = os.path.join("/usr/lib/python2.7/dist-packages/", name)
    if os.path.islink(dirname):
        errors.append(Error('symlink to %s' % os.path.realpath(dirname), obj=name))


@register(deploy=True)
def check_packaging(app_configs, **kwargs):
    errors = []

    _package_status("lava-dispatcher", errors)
    _package_status("lava-server", errors)

    _package_symlinks("lava_dispatcher", errors)
    _package_symlinks("lava_results_app", errors)
    _package_symlinks("lava_scheduler_app", errors)
    _package_symlinks("lava_scheduler_daemon", errors)
    _package_symlinks("lava_server", errors)
    _package_symlinks("", errors)

    return errors