# -*- coding: utf-8 -*-
##############################################################################
#
# Copyright (c) 2018 Vifib SARL and Contributors. All Rights Reserved.
#
# WARNING: This program as such is intended to be used by professional
# programmers who take the whole responsibility of assessing all potential
# consequences resulting from its eventual inadequacies and bugs
# End users who are looking for a ready-to-use solution with commercial
# guarantees and support are strongly adviced to contract a Free Software
# Service Company
#
# 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, write to the Free Software
# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
#
##############################################################################

import socket
import hashlib
import unittest
import os
import logging
import multiprocessing
import shutil
import subprocess
import tempfile
import sys
import json
from contextlib import closing
from six.moves import BaseHTTPServer
from six.moves import urllib_parse

try:
  import typing
  if typing.TYPE_CHECKING:
    from PIL import Image # pylint:disable=unused-import
    from .testcase import SlapOSInstanceTestCase
except ImportError:
  pass


# Utility functions
def findFreeTCPPort(ip=''):
  # type: (str) -> int
  """Find a free TCP port to listen to.
  """
  s = socket.socket(
      socket.AF_INET6 if ':' in ip else socket.AF_INET, socket.SOCK_STREAM)
  with closing(s):
    s.bind((ip, 0))
    return s.getsockname()[1]


def getPortFromPath(path):
  # type: (str) -> int
  """A stable port using a hash from path.
  """
  return 1024 + int(
      hashlib.md5(path.encode('utf-8', 'backslashreplace')).hexdigest(),
      16) % (65535 - 1024)


def getPromisePluginParameterDict(filepath):
  # type: (str) -> dict
  """Load the slapos monitor plugin and returns the configuration used by this plugin.

  This allow to check that monitoring plugin are using a proper config.
  """
  extra_config_dict_json = subprocess.check_output([
      sys.executable,
      "-c",
      """
import json, sys
with open(sys.argv[1]) as f:
  exec(f.read())
print(json.dumps(extra_config_dict))
""",
      filepath,
  ])
  return json.loads(extra_config_dict_json)


class ManagedResource(object):
  """A resource that will be available for the lifetime of test.
  """
  def __init__(self, slapos_instance_testcase_class, resource_name):
    # type: (typing.Type[SlapOSInstanceTestCase], str) -> None
    self._cls = slapos_instance_testcase_class
    self._name = resource_name
  def open(self):
    NotImplemented
  def close(self):
    NotImplemented


class ManagedHTTPServer(ManagedResource):
  """Simple HTTP Server for testing.
  """
  # Request Handler, needs to be defined by subclasses.
  RequestHandler = None # type: typing.Type[BaseHTTPServer.BaseHTTPRequestHandler]

  proto = 'http'
  # hostname to listen to, default to ipv4 address of the current test
  hostname = None # type: str
  # port to listen to, default
  port = None # type: int

  @property
  def url(self):
    # type: () -> str
    return '{self.proto}://{self.hostname}:{self.port}'.format(self=self)

  @property
  def netloc(self):
    # type: () -> str
    return urllib_parse.urlparse(self.url).netloc

  def _makeServer(self):
    # type: () -> BaseHTTPServer.HTTPServer
    """build the server class.

    This is a method to make it possible to subclass to add https support.
    """
    logger = self._cls.logger

    class ErrorLoggingHTTPServer(BaseHTTPServer.HTTPServer):
      def handle_error(self, request , client_addr):
        # redirect errors to log
        logger.info("Error processing request from %s", client_addr, exc_info=True)

    logger.debug(
        "starting %s (%s) on %s:%s",
        self.__class__.__name__,
        self._name,
        self.hostname,
        self.port,
    )
    server = ErrorLoggingHTTPServer(
        (self.hostname, self.port),
        self.RequestHandler,
    )

    return server

  def open(self):
    # type: () -> None
    if not self.hostname:
      self.hostname = self._cls._ipv4_address
    if not self.port:
      self.port = findFreeTCPPort(self.hostname)

    server = self._makeServer()
    self._process = multiprocessing.Process(
        target=server.serve_forever,
        name=self._name,
    )
    self._process.start()

  def close(self):
    # type: () -> None
    self._process.terminate()
    self._process.join()


class ManagedHTTPSServer(ManagedHTTPServer):
  """An HTTPS Server
  """
  proto = 'https'
  certificate_file = None # type: str

  def _makeServer(self):
    # type: () -> BaseHTTPServer.HTTPServer
    server = super(ManagedHTTPSServer, self)._makeServer()
    raise NotImplementedError("TODO")
    return server

class ManagedTemporaryDirectory(ManagedResource):
  path = None # type: str
  def open(self):
    self.path = tempfile.mkdtemp()
  def close(self):
    shutil.rmtree(self.path)


class CrontabMixin(object):

  def _getCrontabCommand(self, crontab_name):
    # type: (str) -> str
    """Read a crontab and return the command that is executed.
    """
    with open(
        os.path.join(
            self.compute_partition_root_path,
            'etc',
            'cron.d',
            crontab_name,
        )) as f:
      crontab_spec, = f.readlines()
    self.assertNotEqual(crontab_spec[0], '@', crontab_spec)
    return crontab_spec.split(None, 5)[-1]

  def _executeCrontabAtDate(self, crontab_name, date):
    # type: (str, str) -> None
    """Executes a crontab as if the current date was `date`.

    `date` will be passed to faketime time command, it can also
    be a relative time.
    """
    crontab_command =  self._getCrontabCommand(crontab_name)
    try:
      crontab_output = subprocess.check_output(
        ("faketime", date, '/bin/sh', '-c', crontab_command),
        stderr=subprocess.STDOUT,
      )
    except subprocess.CalledProcessError as e:
      self.logger.debug('error executing crontab %s output: %s',
                        crontab_command, e.output)
      raise
    else:
      self.logger.debug("crontab %s output: %s",
                        crontab_command, crontab_output)


class ImageComparisonTestCase(unittest.TestCase):
  """TestCase with utility method to compare images.

  The images must be passed as instances of `PIL.Image`
  """
  def assertImagesSimilar(self, i1, i2, tolerance=5):
    # type: (Image, Image, float) -> None
    """Assert images difference between images is less than `tolerance` %.
    taken from https://rosettacode.org/wiki/Percentage_difference_between_images
    """
    pairs = zip(i1.getdata(), i2.getdata())
    if len(i1.getbands()) == 1:
      # for gray-scale jpegs
      dif = sum(abs(p1 - p2) for p1, p2 in pairs)
    else:
      dif = sum(abs(c1 - c2) for p1, p2 in pairs for c1, c2 in zip(p1, p2))

    ncomponents = i1.size[0] * i1.size[1] * 3
    self.assertLessEqual((dif / 255.0 * 100) / ncomponents, tolerance)

  def assertImagesSame(self, i1, i2):
    # type: (Image, Image) -> None
    """Assert images are exactly same."""
    self.assertImagesSimilar(i1, i2, 0)
