# Copyright (C) 2009-2015  Lars Wirzenius
#
# 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, either version 3 of the License, or
# (at your option) any later version.
#
# 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/>.


import os
import stat
import tempfile
import unittest

import obnamlib


class FakeFS(object):

    def __init__(self):
        self.st_atime_sec = 1
        self.st_atime_nsec = 11
        self.st_blocks = 2
        self.st_dev = 3
        self.st_gid = 4
        self.st_ino = 5
        self.st_mode = 6
        self.st_mtime_sec = 7
        self.st_mtime_nsec = 71
        self.st_nlink = 8
        self.st_size = 9
        self.st_uid = 10
        self.groupname = 'group'
        self.username = 'user'
        self.target = 'target'

    def lstat(self, filename):
        return self

    def readlink(self, filename):
        return 'target'

    def getpwuid(self, uid):
        return (self.username, None, self.st_uid, self.st_gid,
                None, None, None)

    def getgrgid(self, gid):
        return (self.groupname, None, self.st_gid, None)

    def fail_getpwuid(self, uid):
        raise KeyError(uid)

    def fail_getgrgid(self, gid):
        raise KeyError(gid)

    def llistxattr(self, filename):
        return []


class MetadataTests(unittest.TestCase):

    def test_sets_mtime_from_kwarg(self):
        metadata = obnamlib.Metadata(st_mtime_sec=123)
        self.assertEqual(metadata.st_mtime_sec, 123)

    def test_isdir_returns_false_for_regular_file(self):
        metadata = obnamlib.Metadata(st_mode=stat.S_IFREG)
        self.assertFalse(metadata.isdir())

    def test_isdir_returns_true_for_directory(self):
        metadata = obnamlib.Metadata(st_mode=stat.S_IFDIR)
        self.assert_(metadata.isdir())

    def test_isdir_returns_false_when_st_mode_is_not_set(self):
        metadata = obnamlib.Metadata()
        self.assertFalse(metadata.isdir())

    def test_islink_returns_false_for_regular_file(self):
        metadata = obnamlib.Metadata(st_mode=stat.S_IFREG)
        self.assertFalse(metadata.islink())

    def test_islink_returns_true_for_symlink(self):
        metadata = obnamlib.Metadata(st_mode=stat.S_IFLNK)
        self.assert_(metadata.islink())

    def test_islink_returns_false_when_st_mode_is_not_set(self):
        metadata = obnamlib.Metadata()
        self.assertFalse(metadata.islink())

    def test_isfile_returns_true_for_regular_file(self):
        metadata = obnamlib.Metadata(st_mode=stat.S_IFREG)
        self.assert_(metadata.isfile())

    def test_isfile_returns_false_when_st_mode_is_not_set(self):
        metadata = obnamlib.Metadata()
        self.assertFalse(metadata.isfile())

    def test_has_no_md5_by_default(self):
        metadata = obnamlib.Metadata()
        self.assertEqual(metadata.md5, None)

    def test_sets_md5(self):
        metadata = obnamlib.Metadata(md5='checksum')
        self.assertEqual(metadata.md5, 'checksum')

    def test_is_equal_to_itself(self):
        metadata = obnamlib.Metadata(st_mode=stat.S_IFREG)
        self.assertEqual(metadata, metadata)

    def test_less_than_works(self):
        m1 = obnamlib.Metadata(st_size=1)
        m2 = obnamlib.Metadata(st_size=2)
        self.assert_(m1 < m2)

    def test_greater_than_works(self):
        m1 = obnamlib.Metadata(st_size=1)
        m2 = obnamlib.Metadata(st_size=2)
        self.assert_(m2 > m1)


class ReadMetadataTests(unittest.TestCase):

    def setUp(self):
        self.fakefs = FakeFS()

    def test_returns_stat_fields_correctly(self):
        metadata = obnamlib.read_metadata(self.fakefs, 'foo',
                                          getpwuid=self.fakefs.getpwuid,
                                          getgrgid=self.fakefs.getgrgid)
        fields = ['st_atime_sec', 'st_atime_nsec', 'st_blocks', 'st_dev',
                  'st_gid', 'st_ino', 'st_mode', 'st_mtime_sec',
                  'st_mtime_nsec', 'st_nlink', 'st_size', 'st_uid',
                  'groupname', 'username']
        for field in fields:
            self.assertEqual(getattr(metadata, field),
                             getattr(self.fakefs, field),
                             field)

    def test_returns_symlink_fields_correctly(self):
        self.fakefs.st_mode |= stat.S_IFLNK
        metadata = obnamlib.read_metadata(self.fakefs, 'foo',
                                          getpwuid=self.fakefs.getpwuid,
                                          getgrgid=self.fakefs.getgrgid)
        fields = ['st_mode', 'target']
        for field in fields:
            self.assertEqual(getattr(metadata, field),
                             getattr(self.fakefs, field),
                             field)

    def test_reads_username_as_None_if_lookup_fails(self):
        metadata = obnamlib.read_metadata(self.fakefs, 'foo',
                                          getpwuid=self.fakefs.fail_getpwuid,
                                          getgrgid=self.fakefs.fail_getgrgid)
        self.assertEqual(metadata.username, None)


class SetMetadataTests(unittest.TestCase):

    def setUp(self):
        self.metadata = obnamlib.Metadata()
        self.metadata.st_atime_sec = 12765
        self.metadata.st_atime_nsec = 0
        self.metadata.st_mode = 42 | stat.S_IFREG
        self.metadata.st_mtime_sec = 10**9
        self.metadata.st_mtime_nsec = 0
        # make sure the uid/gid magic numbers aren't the current users
        self.metadata.st_uid = os.getuid() + 1234
        self.metadata.st_gid = 5678
        while self.metadata.st_gid in os.getgroups():
            self.metadata.st_gid += 1

        fd, self.filename = tempfile.mkstemp()
        os.close(fd)
        # On some systems (e.g. FreeBSD) /tmp is apparently setgid and
        # default gid of files is therefore not the user's gid.
        os.chown(self.filename, os.getuid(), os.getgid())

        self.fs = obnamlib.LocalFS('/')
        self.fs.connect()

        self.uid_set = None
        self.gid_set = None
        self.fs.lchown = self.fake_lchown

        obnamlib.set_metadata(self.fs, self.filename, self.metadata)

        self.st = os.stat(self.filename)

    def tearDown(self):
        self.fs.close()
        os.remove(self.filename)

    def fake_lchown(self, filename, uid, gid):
        # lchown(2) If the owner or group is specified as -1,
        # then that ID is not changed.
        # fake_lchown assumes it is running as root and it succeeds
        if uid != -1:
            self.uid_set = uid
        if gid != -1:
            self.gid_set = gid

    def oserror_lchown(self, filename, uid, gid):
        self.oserror_lchown_called = True
        raise OSError("fake permission denied")

    def test_sets_atime(self):
        self.assertEqual(self.st.st_atime, self.metadata.st_atime_sec)

    def test_sets_mode(self):
        self.assertEqual(self.st.st_mode, self.metadata.st_mode)

    def test_sets_mtime(self):
        self.assertEqual(self.st.st_mtime, self.metadata.st_mtime_sec)

    def test_does_not_set_uid_when_not_running_as_root(self):
        self.assertEqual(self.uid_set, None)

    def test_sets_uid_when_running_as_root(self):
        obnamlib.set_metadata(self.fs, self.filename, self.metadata,
                              getuid=lambda: 0)
        self.assertEqual(self.uid_set, self.metadata.st_uid)

    def test_sets_gid_when_running_as_root(self):
        obnamlib.set_metadata(self.fs, self.filename, self.metadata,
                              getuid=lambda: 0)
        self.assertEqual(self.gid_set, self.metadata.st_gid)

    def test_catches_lchown_throw(self):
        self.fs.lchown = self.oserror_lchown
        obnamlib.set_metadata(self.fs, self.filename, self.metadata)
        self.assert_(self.oserror_lchown_called)
        self.fs.lchown = self.fake_lchown

    def test_sets_gid_when_not_running_as_root(self):
        # Root can set it to any group, non-root can only set it to a group
        # they are part of.  Set it with the real lchown and check the file.
        # Generally only meaningful if the user is in multiple groups.
        self.fs.lchown = os.lchown
        for gid in os.getgroups():
            self.metadata.st_gid = gid
            obnamlib.set_metadata(self.fs, self.filename, self.metadata)
            self.st = os.stat(self.filename)
            self.assertEqual(self.st.st_gid, gid)
        self.fs.lchown = self.fake_lchown

    def test_sets_symlink_target(self):
        self.fs.remove(self.filename)
        self.metadata.st_mode = 0777 | stat.S_IFLNK
        self.metadata.target = 'target'
        obnamlib.set_metadata(self.fs, self.filename, self.metadata)
        self.assertEqual(self.fs.readlink(self.filename), 'target')

    def test_sets_symlink_mtime_perms(self):
        self.fs.remove(self.filename)
        self.metadata.st_mode = 0777 | stat.S_IFLNK
        self.metadata.target = 'target'
        obnamlib.set_metadata(self.fs, self.filename, self.metadata)
        st = os.lstat(self.filename)
        self.assertEqual(st.st_mode, self.metadata.st_mode)
        self.assertEqual(st.st_mtime, self.metadata.st_mtime_sec)

    def test_sets_setuid_and_setgid_when_told_to(self):
        self.metadata.st_mode = 0777 | stat.S_ISUID | stat.S_ISGID
        obnamlib.set_metadata(self.fs, self.filename, self.metadata,
                              always_set_id_bits=True)
        st = os.stat(self.filename)

        self.assertEqual(st.st_mode & stat.S_ISUID, stat.S_ISUID)
        self.assertEqual(st.st_mode & stat.S_ISGID, stat.S_ISGID)