"""
Implementation
"""

import os as _os
import shlex as _shlex
import contextlib as _contextlib
import sys as _sys

import pkg_resources
import setuptools.command.test as orig


@_contextlib.contextmanager
def _save_argv(repl=None):
	saved = _sys.argv[:]
	if repl is not None:
		_sys.argv[:] = repl
	try:
		yield saved
	finally:
		_sys.argv[:] = saved


class PyTest(orig.test):
	user_options = [
		('extras', None, "Install (all) setuptools extras when running tests"),
		('index-url=', None, "Specify an index url from which to retrieve "
			"dependencies"),
		('allow-hosts=', None, "Whitelist of comma-separated hosts to allow "
			"when retrieving dependencies"),
		('addopts=', None, "Additional options to be passed verbatim to the "
			"pytest runner")
	]

	def initialize_options(self):
		self.extras = False
		self.index_url = None
		self.allow_hosts = None
		self.addopts = []

	def finalize_options(self):
		if self.addopts:
			self.addopts = _shlex.split(self.addopts)

	@staticmethod
	def marker_passes(marker):
		"""
		Given an environment marker, return True if the marker is valid
		and matches this environment.
		"""
		return (
			marker
			and not pkg_resources.invalid_marker(marker)
			and pkg_resources.evaluate_marker(marker)
		)

	def run(self):
		"""
		Override run to ensure requirements are available in this session (but
		don't install them anywhere).
		"""
		self._build_egg_fetcher()
		if self.distribution.install_requires:
			self.distribution.fetch_build_eggs(self.distribution.install_requires)
		if self.distribution.tests_require:
			self.distribution.fetch_build_eggs(self.distribution.tests_require)
		extras_require = self.distribution.extras_require or {}
		for spec, reqs in extras_require.items():
			name, sep, marker = spec.partition(':')
			if not self.marker_passes(marker):
				continue
			# always include unnamed extras
			if not name or self.extras:
				self.distribution.fetch_build_eggs(reqs)
		if self.dry_run:
			self.announce('skipping tests (dry run)')
			return
		self.with_project_on_sys_path(self.run_tests)
		if self.result_code:
			raise SystemExit(self.result_code)
		return self.result_code

	def _build_egg_fetcher(self):
		"""Build an egg fetcher that respects index_url and allow_hosts"""
		# modified from setuptools.dist:Distribution.fetch_build_egg
		from setuptools.command.easy_install import easy_install
		main_dist = self.distribution
		# construct a fake distribution to store the args for easy_install
		dist = main_dist.__class__({'script_args': ['easy_install']})
		dist.parse_config_files()
		opts = dist.get_option_dict('easy_install')
		keep = (
			'find_links', 'site_dirs', 'index_url', 'optimize',
			'site_dirs', 'allow_hosts'
		)
		for key in opts.keys():
			if key not in keep:
				del opts[key]   # don't use any other settings
		if main_dist.dependency_links:
			links = main_dist.dependency_links[:]
			if 'find_links' in opts:
				links = opts['find_links'][1].split() + links
			opts['find_links'] = ('setup', links)
		if self.allow_hosts:
			opts['allow_hosts'] = ('test', self.allow_hosts)
		if self.index_url:
			opts['index_url'] = ('test', self.index_url)
		install_dir_func = getattr(dist, 'get_egg_cache_dir', _os.getcwd)
		install_dir = install_dir_func()
		cmd = easy_install(
			dist, args=["x"], install_dir=install_dir, exclude_scripts=True,
			always_copy=False, build_directory=None, editable=False,
			upgrade=False, multi_version=True, no_report = True
		)
		cmd.ensure_finalized()
		main_dist._egg_fetcher = cmd

	def run_tests(self):
		"""
		Invoke pytest, replacing argv.
		"""
		with _save_argv(_sys.argv[:1] + self.addopts):
			self.result_code = __import__('pytest').main()
