#!/usr/bin/env python
import ctypes
import hashlib
import io
import os
import platform
import random
import stat as stat_mode
import time
from typing import List
from typing import Text

from absl.testing import absltest

from grr_response_client.client_actions import timeline
from grr_response_core.lib.rdfvalues import protodict as rdf_protodict
from grr_response_core.lib.rdfvalues import timeline as rdf_timeline
from grr_response_core.lib.util import temp
from grr.test_lib import client_test_lib
from grr.test_lib import skip
from grr.test_lib import testing_startup


# TODO(hanuszczak): `GRRBaseTest` is terrible, try to avoid it in any new code.
class TimelineTest(client_test_lib.EmptyActionTest):

  @classmethod
  def setUpClass(cls):
    super(TimelineTest, cls).setUpClass()
    testing_startup.TestInit()

  def testRun(self):
    file_count = 64

    with temp.AutoTempDirPath(remove_non_empty=True) as temp_dirpath:
      for idx in range(file_count):
        temp_filepath = os.path.join(temp_dirpath, "foo{}".format(idx))
        _Touch(temp_filepath, content=os.urandom(random.randint(0, 1024)))

      args = rdf_timeline.TimelineArgs()
      args.root = temp_dirpath.encode("utf-8")

      responses = self.RunAction(timeline.Timeline, args)

      results: List[rdf_timeline.TimelineResult] = []
      blobs: List[rdf_protodict.DataBlob] = []

      # The test action runner is not able to distinguish between flow replies
      # and responses sent to well-known flow handlers, so we have to do the
      # filtering ourselves.
      for response in responses:
        if isinstance(response, rdf_timeline.TimelineResult):
          results.append(response)
        elif isinstance(response, rdf_protodict.DataBlob):
          blobs.append(response)
        else:
          raise AssertionError(f"Unexpected response: f{response}")

      self.assertNotEmpty(results)
      self.assertNotEmpty(blobs)

      blob_ids = []
      for result in results:
        blob_ids.extend(result.entry_batch_blob_ids)

      for blob in blobs:
        self.assertIn(hashlib.sha256(blob.data).digest(), blob_ids)

      # Total number of entries should be one more than the file count because
      # of the entry for the root folder.
      total_entry_count = sum(result.entry_count for result in results)
      self.assertEqual(total_entry_count, file_count + 1)

      for result in results:
        # The filesystem type should be the same for every result.
        self.assertEqual(result.filesystem_type, results[0].filesystem_type)


class WalkTest(absltest.TestCase):

  def testSingleFile(self):
    with temp.AutoTempDirPath(remove_non_empty=True) as dirpath:
      filepath = os.path.join(dirpath, "foo")
      _Touch(filepath, content=b"foobar")

      entries = list(timeline.Walk(dirpath.encode("utf-8")))
      self.assertLen(entries, 2)

      self.assertTrue(stat_mode.S_ISDIR(entries[0].mode))
      self.assertEqual(entries[0].path, dirpath.encode("utf-8"))

      self.assertTrue(stat_mode.S_ISREG(entries[1].mode))
      self.assertEqual(entries[1].path, filepath.encode("utf-8"))
      self.assertEqual(entries[1].size, 6)

  def testMultipleFiles(self):
    with temp.AutoTempDirPath(remove_non_empty=True) as dirpath:
      foo_filepath = os.path.join(dirpath, "foo")
      bar_filepath = os.path.join(dirpath, "bar")
      baz_filepath = os.path.join(dirpath, "baz")

      _Touch(foo_filepath)
      _Touch(bar_filepath)
      _Touch(baz_filepath)

      entries = list(timeline.Walk(dirpath.encode("utf-8")))
      self.assertLen(entries, 4)

      paths = [_.path for _ in entries[1:]]
      self.assertIn(foo_filepath.encode("utf-8"), paths)
      self.assertIn(bar_filepath.encode("utf-8"), paths)
      self.assertIn(baz_filepath.encode("utf-8"), paths)

  def testNestedDirectories(self):
    with temp.AutoTempDirPath(remove_non_empty=True) as root_dirpath:
      foobar_dirpath = os.path.join(root_dirpath, "foo", "bar")
      os.makedirs(foobar_dirpath)

      foobaz_dirpath = os.path.join(root_dirpath, "foo", "baz")
      os.makedirs(foobaz_dirpath)

      quuxnorfthud_dirpath = os.path.join(root_dirpath, "quux", "norf", "thud")
      os.makedirs(quuxnorfthud_dirpath)

      entries = list(timeline.Walk(root_dirpath.encode("utf-8")))
      self.assertLen(entries, 7)

      paths = [_.path.decode("utf-8") for _ in entries]
      self.assertCountEqual(paths, [
          os.path.join(root_dirpath),
          os.path.join(root_dirpath, "foo"),
          os.path.join(root_dirpath, "foo", "bar"),
          os.path.join(root_dirpath, "foo", "baz"),
          os.path.join(root_dirpath, "quux"),
          os.path.join(root_dirpath, "quux", "norf"),
          os.path.join(root_dirpath, "quux", "norf", "thud"),
      ])

      for entry in entries:
        self.assertTrue(stat_mode.S_ISDIR(entry.mode))

  @skip.If(
      platform.system() == "Windows",
      reason="Symlinks are not supported on Windows.")
  def testSymlinks(self):
    with temp.AutoTempDirPath(remove_non_empty=True) as root_dirpath:
      sub_dirpath = os.path.join(root_dirpath, "foo", "bar", "baz")
      link_path = os.path.join(sub_dirpath, "quux")

      # This creates a cycle, walker should be able to cope with that.
      os.makedirs(sub_dirpath)
      os.symlink(root_dirpath, os.path.join(sub_dirpath, link_path))

      entries = list(timeline.Walk(root_dirpath.encode("utf-8")))
      self.assertLen(entries, 5)

      paths = [_.path.decode("utf-8") for _ in entries]
      self.assertEqual(paths, [
          os.path.join(root_dirpath),
          os.path.join(root_dirpath, "foo"),
          os.path.join(root_dirpath, "foo", "bar"),
          os.path.join(root_dirpath, "foo", "bar", "baz"),
          os.path.join(root_dirpath, "foo", "bar", "baz", "quux")
      ])

      for entry in entries[:-1]:
        self.assertTrue(stat_mode.S_ISDIR(entry.mode))
      self.assertTrue(stat_mode.S_ISLNK(entries[-1].mode))

  @skip.Unless(hasattr(time, "time_ns"), reason="timing precision too low")
  def testTimestamp(self):
    with temp.AutoTempDirPath(remove_non_empty=True) as dirpath:
      filepath = os.path.join(dirpath, "foo")

      with open(filepath, mode="wb"):
        pass

      with open(filepath, mode="wb") as filedesc:
        filedesc.write(b"quux")

      with open(filepath, mode="rb") as filedesc:
        _ = filedesc.read()

      now_ns = time.time_ns()

      entries = list(timeline.Walk(dirpath.encode("utf-8")))
      self.assertLen(entries, 2)

      self.assertEqual(entries[0].path, dirpath.encode("utf-8"))
      self.assertEqual(entries[1].path, filepath.encode("utf-8"))

      self.assertGreater(entries[1].ctime_ns, 0)
      self.assertGreaterEqual(entries[1].mtime_ns, entries[1].ctime_ns)
      self.assertGreaterEqual(entries[1].atime_ns, entries[1].mtime_ns)
      self.assertLess(entries[1].atime_ns, now_ns)

  @skip.Unless(hasattr(time, "time_ns"), reason="timing precision too low")
  def testBirthTimestamp(self):
    if platform.system() == "Linux":
      try:
        ctypes.CDLL("libc.so.6").statx
      except AttributeError:
        raise absltest.SkipTest("`statx` not available")

    with temp.AutoTempDirPath(remove_non_empty=True) as dirpath:
      filepath = os.path.join(dirpath, "foo")

      with open(filepath, mode="wb") as filedesc:
        filedesc.write(b"foobar")

      entries = list(timeline.Walk(dirpath.encode("utf-8")))
      self.assertLen(entries, 2)

      self.assertEqual(entries[0].path, dirpath.encode("utf-8"))
      self.assertEqual(entries[1].path, filepath.encode("utf-8"))

      now_ns = time.time_ns()
      self.assertBetween(entries[1].btime_ns, 0, now_ns)

  def testIncorrectPath(self):
    with temp.AutoTempDirPath(remove_non_empty=True) as dirpath:
      not_existing_path = os.path.join(dirpath, "not", "existing", "path")

      with self.assertRaises(OSError):
        timeline.Walk(not_existing_path.encode("utf-8"))

  def testRelativePath(self):
    relpath = os.path.join("foo", "bar", "baz")

    with self.assertRaises(ValueError):
      timeline.Walk(relpath.encode("utf-8"))

  def testPathWithTrailingSeparator(self):
    with temp.AutoTempDirPath(remove_non_empty=True) as dirpath:
      seppath = dirpath + os.path.sep

      entries = list(timeline.Walk(seppath.encode("utf-8")))
      self.assertLen(entries, 1)
      self.assertEqual(entries[0].path, dirpath.encode("utf-8"))

  def testPathWithRedundantComponents(self):
    with temp.AutoTempDirPath(remove_non_empty=True) as dirpath:
      os.makedirs(os.path.join(dirpath, "foo", "bar"))
      redpath = os.path.join(dirpath, "foo", ".", "bar", "..", ".", "bar", "..")

      entries = list(timeline.Walk(redpath.encode("utf-8")))
      paths = [entry.path.decode("utf-8") for entry in entries]

      self.assertLen(paths, 2)
      self.assertEqual(paths[0], os.path.join(dirpath, "foo"))
      self.assertEqual(paths[1], os.path.join(dirpath, "foo", "bar"))


class GetFilesystemType(absltest.TestCase):

  def testReturnsForExistingPath(self):
    with temp.AutoTempFilePath() as path:
      fstype = timeline.GetFilesystemType(path.encode("utf-8"))

    # Some filesystem type should be returned for all supported platforms.
    self.assertTrue(fstype)

  @absltest.skipUnless(platform.system() == "Linux", "Linux-only test.")
  def testReturnsForExistingPathLinux(self):
    with temp.AutoTempFilePath() as path:
      fstype = timeline.GetFilesystemType(path.encode("utf-8"))

    # `/proc/filesystem` lists all filesystems supported by the kernel.
    with open("/proc/filesystems", mode="r", encoding="utf-8") as proc_fs:
      supported_fstypes = set(proc_fs.read().split())

    self.assertIn(fstype, supported_fstypes)

  @absltest.skipUnless(platform.system() == "Windows", "Windows-only test.")
  def testReturnsForExistingPathWindows(self):
    with temp.AutoTempFilePath() as path:
      fstype = timeline.GetFilesystemType(path.encode("utf-8"))

    # As far as we know these are the only filesystems supported by Windows.
    self.assertIn(fstype.lower(), ["ntfs", "fat32", "exfat", "refs"])

  def testRaisesForNonExistingPath(self):
    with temp.AutoTempDirPath() as path:
      with self.assertRaises(IOError):
        timeline.GetFilesystemType(os.path.join(path, "foobar"))


def _Touch(filepath: Text, content: bytes = b"") -> None:
  with io.open(filepath, mode="wb") as filedesc:
    filedesc.write(content)


if __name__ == "__main__":
  absltest.main()
