# vim:fileencoding=utf-8:noet
from __future__ import (unicode_literals, division, absolute_import, print_function)

import shutil
import os

from time import sleep
from functools import partial

from powerline.lib.watcher import create_file_watcher, create_tree_watcher, INotifyError
from powerline.lib.watcher.uv import UvNotFound
from powerline import get_fallback_logger
from powerline.lib.monotonic import monotonic

from tests import TestCase, SkipTest


INOTIFY_DIR = 'inotify' + os.environ.get('PYTHON', '')


def clear_dir(dir):
	for root, dirs, files in list(os.walk(dir, topdown=False)):
		for f in files:
			os.remove(os.path.join(root, f))
		for d in dirs:
			os.rmdir(os.path.join(root, d))


class TestFilesystemWatchers(TestCase):
	def do_test_for_change(self, watcher, path):
		st = monotonic()
		while monotonic() - st < 1:
			if watcher(path):
				return
			sleep(0.1)
		self.fail('The change to {0} was not detected'.format(path))

	def test_file_watcher(self):
		try:
			w = create_file_watcher(pl=get_fallback_logger(), watcher_type='inotify')
		except INotifyError:
			raise SkipTest('This test is not suitable for a stat based file watcher')
		return self.do_test_file_watcher(w)

	def do_test_file_watcher(self, w):
		try:
			f1, f2, f3 = map(lambda x: os.path.join(INOTIFY_DIR, 'file%d' % x), (1, 2, 3))
			with open(f1, 'wb'):
				with open(f2, 'wb'):
					with open(f3, 'wb'):
						pass
			ne = os.path.join(INOTIFY_DIR, 'notexists')
			self.assertRaises(OSError, w, ne)
			self.assertTrue(w(f1))
			self.assertTrue(w(f2))
			os.utime(f1, None), os.utime(f2, None)
			self.do_test_for_change(w, f1)
			self.do_test_for_change(w, f2)
			# Repeat once
			os.utime(f1, None), os.utime(f2, None)
			self.do_test_for_change(w, f1)
			self.do_test_for_change(w, f2)
			# Check that no false changes are reported
			self.assertFalse(w(f1), 'Spurious change detected')
			self.assertFalse(w(f2), 'Spurious change detected')
			# Check that open the file with 'w' triggers a change
			with open(f1, 'wb'):
				with open(f2, 'wb'):
					pass
			self.do_test_for_change(w, f1)
			self.do_test_for_change(w, f2)
			# Check that writing to a file with 'a' triggers a change
			with open(f1, 'ab') as f:
				f.write(b'1')
			self.do_test_for_change(w, f1)
			# Check that deleting a file registers as a change
			os.unlink(f1)
			self.do_test_for_change(w, f1)
			# Test that changing the inode of a file does not cause it to stop
			# being watched
			os.rename(f3, f2)
			self.do_test_for_change(w, f2)
			self.assertFalse(w(f2), 'Spurious change detected')
			os.utime(f2, None)
			self.do_test_for_change(w, f2)
		finally:
			clear_dir(INOTIFY_DIR)

	def test_uv_file_watcher(self):
		raise SkipTest('Uv watcher tests are not stable')
		try:
			w = create_file_watcher(pl=get_fallback_logger(), watcher_type='uv')
		except UvNotFound:
			raise SkipTest('Pyuv is not available')
		return self.do_test_file_watcher(w)

	def test_tree_watcher(self):
		tw = create_tree_watcher(get_fallback_logger())
		return self.do_test_tree_watcher(tw)

	def do_test_tree_watcher(self, tw):
		try:
			subdir = os.path.join(INOTIFY_DIR, 'subdir')
			os.mkdir(subdir)
			try:
				if tw.watch(INOTIFY_DIR).is_dummy:
					raise SkipTest('No tree watcher available')
			except UvNotFound:
				raise SkipTest('Pyuv is not available')
			self.assertTrue(tw(INOTIFY_DIR))
			self.assertFalse(tw(INOTIFY_DIR))
			changed = partial(self.do_test_for_change, tw, INOTIFY_DIR)
			open(os.path.join(INOTIFY_DIR, 'tree1'), 'w').close()
			changed()
			open(os.path.join(subdir, 'tree1'), 'w').close()
			changed()
			os.unlink(os.path.join(subdir, 'tree1'))
			changed()
			os.rmdir(subdir)
			changed()
			os.mkdir(subdir)
			changed()
			os.rename(subdir, subdir + '1')
			changed()
			shutil.rmtree(subdir + '1')
			changed()
			os.mkdir(subdir)
			f = os.path.join(subdir, 'f')
			open(f, 'w').close()
			changed()
			with open(f, 'a') as s:
				s.write(' ')
			changed()
			os.rename(f, f + '1')
			changed()
		finally:
			clear_dir(INOTIFY_DIR)

	def test_uv_tree_watcher(self):
		raise SkipTest('Uv watcher tests are not stable')
		tw = create_tree_watcher(get_fallback_logger(), 'uv')
		return self.do_test_tree_watcher(tw)

	def test_inotify_file_watcher_is_watching(self):
		try:
			w = create_file_watcher(pl=get_fallback_logger(), watcher_type='inotify')
		except INotifyError:
			raise SkipTest('INotify is not available')
		return self.do_test_file_watcher_is_watching(w)

	def test_stat_file_watcher_is_watching(self):
		w = create_file_watcher(pl=get_fallback_logger(), watcher_type='stat')
		return self.do_test_file_watcher_is_watching(w)

	def test_uv_file_watcher_is_watching(self):
		try:
			w = create_file_watcher(pl=get_fallback_logger(), watcher_type='uv')
		except UvNotFound:
			raise SkipTest('Pyuv is not available')
		return self.do_test_file_watcher_is_watching(w)

	def do_test_file_watcher_is_watching(self, w):
		try:
			f1, f2, f3 = map(lambda x: os.path.join(INOTIFY_DIR, 'file%d' % x), (1, 2, 3))
			with open(f1, 'wb'):
				with open(f2, 'wb'):
					with open(f3, 'wb'):
						pass
			ne = os.path.join(INOTIFY_DIR, 'notexists')
			self.assertRaises(OSError, w, ne)
			self.assertTrue(w(f1))
			self.assertFalse(w.is_watching(ne))
			self.assertTrue(w.is_watching(f1))
			self.assertFalse(w.is_watching(f2))
		finally:
			clear_dir(INOTIFY_DIR)


old_cwd = None


def setUpModule():
	global old_cwd
	old_cwd = os.getcwd()
	os.chdir(os.path.dirname(__file__))
	os.mkdir(INOTIFY_DIR)


def tearDownModule():
	shutil.rmtree(INOTIFY_DIR)
	os.chdir(old_cwd)


if __name__ == '__main__':
	from tests import main
	main()