# -*- coding: utf-8 -*-
# vim:expandtab:autoindent:tabstop=4:shiftwidth=4:filetype=python:textwidth=0:
# License: GPL2 or later see COPYING
# Written by Jan Vcelak
# Copyright (C) 2010 Jan Vcelak <jvcelak@redhat.com>

# python library imports
import atexit
import os
import stat
import tempfile

# our imports
from mockbuild.mounts import BindMountPoint, FileSystemMountPoint
from mockbuild.trace_decorator import getLog, traceLog
import mockbuild.util

requires_api_version = "1.1"


# plugin entry point
@traceLog()
def init(plugins, conf, buildroot):
    if mockbuild.util.selinuxEnabled():
        getLog().info("selinux enabled")
        SELinux(plugins, conf, buildroot)
    else:
        getLog().info("selinux disabled")


class SELinux(object):
    """On SELinux enabled box, this plugin will pretend, that SELinux is disabled in build environment.

       - fake /proc/filesystems is mounted into build environment, excluding selinuxfs
       - fake /sys/fs/selinux directory mount point
       - option '--setopt=tsflags=nocontext' is appended to each 'yum' command
    """
    # pylint: disable=too-few-public-methods

    @traceLog()
    def __init__(self, plugins, conf, buildroot):
        self._originalUtilDo = mockbuild.util.do

        self.buildroot = buildroot
        self.config = buildroot.config
        self.state = buildroot.state
        self.conf = conf

        self.filesystems = self._selinuxCreateFauxFilesystems()
        self.chrootFilesystems = buildroot.make_chroot_path("/proc/filesystems")

        atexit.register(self._selinuxAtExit)

        self.buildroot.mounts.essential_mounts.append(
             BindMountPoint(srcpath=self.filesystems, bindpath=self.chrootFilesystems)
        )

        self.buildroot.mounts.essential_mounts.append(
            # essential mounts since we _always_ need to hide it
            FileSystemMountPoint(filetype='tmpfs',
                                 device='mock_hide_selinux_fs',
                                 path=buildroot.make_chroot_path('/sys/fs/selinux'))
        )

        plugins.add_hook("preyum", self._selinuxPreYumHook)
        plugins.add_hook("postyum", self._selinuxPostYumHook)

    @staticmethod
    @traceLog()
    def _selinuxCreateFauxFilesystems():
        (fd, path) = tempfile.mkstemp(prefix="mock-selinux-plugin.")
        with os.fdopen(fd, 'w') as out:
            with open("/proc/filesystems") as host:
                for line in host:
                    if "selinuxfs" not in line:
                        out.write(line)

        os.chmod(path, stat.S_IRUSR | stat.S_IRGRP | stat.S_IROTH)

        return path

    def _selinuxAtExit(self):
        if os.path.exists(self.filesystems):
            try:
                os.unlink(self.filesystems)
            except OSError as e:
                getLog().warning("unable to delete selinux filesystems (%s): %s", self.filesystems, e)

    @traceLog()
    def _selinuxPreYumHook(self):
        mockbuild.util.do = self._selinuxDoYum

    @traceLog()
    def _selinuxPostYumHook(self):
        mockbuild.util.do = self._originalUtilDo

    @traceLog()
    def _selinuxDoYum(self, command, *args, **kargs):
        option = "--setopt=tsflags=nocontexts"

        if isinstance(command, list):
            if command[0].startswith(self.buildroot.pkg_manager.command):
                command.append(option)
        elif isinstance(command, str):
            if command.startswith(self.buildroot.pkg_manager.command):
                command += " %s" % option

        return self._originalUtilDo(command, *args, **kargs)
