# Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

"""Module that contains the interface for au_test_harness workers.

An au test harnss worker is a class that contains the logic for performing
and validating updates on a target.  This should be subclassed to handle
various types of target.  Types of targets include VM's, real devices, etc.
"""

import inspect
import os

from chromite.lib import cros_build_lib
from chromite.lib import cros_logging as logging
from chromite.lib import dev_server_wrapper
from crostestutils.au_test_harness import update_exception


class AUWorker(object):
  """Interface for a worker that updates and verifies images."""
  # Mapping between cached payloads to directory locations.
  update_cache = None

  # --- INTERFACE ---

  def __init__(self, options, test_results_root):
    """Processes options for the specific-type of worker."""
    self.board = options.board
    self.test_results_root = test_results_root
    self.all_results_root = os.path.join(test_results_root, 'all')
    self.fail_results_root = os.path.join(test_results_root, 'failed')
    self.use_delta_updates = options.delta
    self.verbose = options.verbose
    self.vm_image_path = None
    if options.quick_test:
      self.verify_suite = 'build_RootFilesystemSize'
    else:
      self.verify_suite = 'suite:%s' % (options.verify_suite_name or 'smoke')

  def CleanUp(self):
    """Called at the end of every test."""

  def GetUpdateMessage(self, update_target, update_base, from_vm, proxy):
    """Returns the update message that should be printed out for this update."""
    if update_base:
      msg = 'Performing a delta update from %s to %s' % (
          update_base, update_target)
    else:
      msg = 'Performing a full update to %s' % update_target

    if from_vm: msg += ' in a VM'
    if proxy: msg += ' using a proxy on port ' + str(proxy)
    return msg

  def PrepareBase(self, image_path, signed_base):
    """Method to be called to prepare target for testing this test.

    Subclasses must override this method with the correct procedure for
    preparing the test target.

    Returns the path to the base image (might have changed for vm's).

`   Args:
      image_path: The image that should reside on the target before the test.
      signed_base: If True, use the signed image rather than the actual image.
    """

  def UpdateImage(self, image_path, src_image_path='', stateful_change='old',
                  proxy_port=None, private_key_path=None):
    """Implementation of an actual update.

    Subclasses must override this method with the correct update procedure for
    the class.

    Args:
      See PerformUpdate for description of args.
    """

  def UpdateUsingPayload(self, update_path, stateful_change='old',
                         proxy_port=None):
    """Updates target with the pre-generated update stored in update_path.

    Subclasses must override this method with the correct update procedure for
    the class.

    Args:
      update_path:  Path to the image to update with. This directory should
        contain both update.gz, and stateful.image.gz
      stateful_change: How to perform the stateful update.
      proxy_port:  Port to have the client connect to. For use with
        CrosTestProxy.
    """

  def VerifyImage(self, unittest, percent_required_to_pass=100, test=''):
    """Verifies the image with tests.

    Verifies that the test images passes the percent required.  Subclasses must
    override this method with the correct update procedure for the class.

    Args:
      unittest: pointer to a unittest to fail if we cannot verify the image.
      percent_required_to_pass:  percentage required to pass.  This should be
        fall between 0-100.
      test: test that will be used to verify the image. If omitted or equal to
        the empty string the code will use self.verify_suite.

    Returns:
      Returns the percent that passed.
    """

  # --- INTERFACE TO AU_TEST ---

  def PerformUpdate(self, image_path, src_image_path='', stateful_change='old',
                    proxy_port=None, private_key_path=None):
    """Performs an update using  _UpdateImage and reports any error.

    Subclasses should not override this method but override _UpdateImage
    instead.

    Args:
      image_path:  Path to the image to update with.  This image must be a test
        image.
      src_image_path:  Optional.  If set, perform a delta update using the
        image specified by the path as the source image.
      stateful_change: How to modify the stateful partition.  Values are:
          'old':  Don't modify stateful partition.  Just update normally.
          'clean':  Uses clobber-state to wipe the stateful partition with the
            exception of code needed for ssh.
      proxy_port:  Port to have the client connect to. For use with
        CrosTestProxy.
      private_key_path:  Path to a private key to use with update payload.
    Raises an update_exception.UpdateException if _UpdateImage returns an error.
    """
    if not self.use_delta_updates: src_image_path = ''
    key_to_use = private_key_path

    self.UpdateImage(image_path, src_image_path, stateful_change, proxy_port,
                     key_to_use)

  @classmethod
  def SetUpdateCache(cls, update_cache):
    """Sets the global update cache for getting paths to devserver payloads."""
    cls.update_cache = update_cache

  # --- METHODS FOR SUB CLASS USE ---

  def PrepareRealBase(self, image_path, signed_base):
    """Prepares a remote device for worker test by updating it to the image."""
    real_image_path = image_path
    if not signed_base:
      self.UpdateImage(real_image_path)
    else:
      real_image_path = real_image_path + '.signed'
      self.UpdateImage(real_image_path)

    return real_image_path

  def PrepareVMBase(self, image_path, signed_base):
    """Prepares a VM image for worker test."""
    # Tells the VM tests to use the Qemu image as the start point.
    self.vm_image_path = os.path.join(os.path.dirname(image_path),
                                      'chromiumos_qemu_image.bin')
    if signed_base:
      self.vm_image_path = self.vm_image_path + '.signed'

    return self.vm_image_path

  def GetStatefulChangeFlag(self, stateful_change):
    """Returns the flag to pass to image_to_vm for the stateful change."""
    stateful_change_flag = ''
    if stateful_change:
      stateful_change_flag = '--stateful_update_flag=%s' % stateful_change

    return stateful_change_flag

  def AppendUpdateFlags(self, cmd, image_path, src_image_path, proxy_port,
                        private_key_path, for_vm=False):
    """Appends common args to an update cmd defined by an array.

    Modifies cmd in places by appending appropriate items given args.

    Args:
      See PerformUpdate for description of args.
      for_vm: Additional optional argument to say that the payload is intended
        for vm usage (so we don't patch the kernel).
    """
    if proxy_port: cmd.append('--proxy_port=%s' % proxy_port)
    update_id = dev_server_wrapper.GenerateUpdateId(
        image_path, src_image_path, private_key_path,
        for_vm=for_vm)
    cache_path = self.update_cache.get(update_id)
    if cache_path:
      update_url = dev_server_wrapper.DevServerWrapper.GetDevServerURL(
          port=proxy_port, sub_dir=cache_path)
      cmd.append('--update_url=%s' % update_url)
    else:
      raise update_exception.UpdateException(
          1, 'No payload found for %s' % update_id)

  def RunUpdateCmd(self, cmd, log_directory=None):
    """Runs the given update cmd given verbose options.

    Raises an update_exception.UpdateException if the update fails.

    Args:
      cmd:  The shell cmd to run.
      log_directory:  Where to store the logs for this cmd.
    """
    kwds = dict(print_cmd=False, combine_stdout_stderr=True, error_code_ok=True)
    if not self.verbose:
      kwds['redirect_stdout'] = kwds['redirect_stderr'] = True
    if log_directory:
      kwds['log_stdout_to_file'] = os.path.join(log_directory, 'update.log')
    result = cros_build_lib.RunCommand(cmd, **kwds)
    if result.returncode != 0:
      logging.warning(result.output)
      raise update_exception.UpdateException(result.returncode, 'Update failed')

  def AssertEnoughTestsPassed(self, unittest, output, percent_required_to_pass):
    """Helper function that asserts a sufficient number of tests passed.

    Args:
      unittest: the unittest object running this test.
      output: stdout from a test run.
      percent_required_to_pass: percentage required to pass.  This should be
        fall between 0-100.
    Returns:
      percent that passed.
    """
    percent_passed = self._ParseGenerateTestReportOutput(output)
    self.TestInfo('Percent passed: %d vs. Percent required: %d' % (
        percent_passed, percent_required_to_pass))
    if percent_passed < percent_required_to_pass:
      print output
      unittest.fail('%d percent of tests are required to pass' %
                    percent_required_to_pass)

    return percent_passed

  def TestInfo(self, message):
    logging.info('%s: %s', self.test_name, message)

  def Initialize(self, port):
    """Initializes test specific variables for each test.

    Each test needs to specify a unique ssh port.

    Args:
      port:  Unique port for ssh access.
    """
    # Initialize port vars.
    self._ssh_port = port
    self._kvm_pid_file = '/tmp/kvm.%d' % port

    # Initialize test results directory.
    self.test_name = inspect.stack()[1][3]
    self.all_results_directory = os.path.join(self.all_results_root,
                                              self.test_name)
    self.fail_results_directory = os.path.join(self.fail_results_root,
                                               self.test_name)
    self.results_count = 0

  def GetNextResultsPath(self, label):
    """Returns a tuple results directories to use for this label.

    Prefixes directory returned for worker with time called i.e. 1_label,
    2_label, etc.  The directory returned is outside the chroot so if passing
    to an script that is called with enther_chroot, make sure to use
    path_util.ToChrootPath(). The first dir returned is the one where results
    should be stored. The second is one where failed test results should be
    stored. Only the former is created as the latter should only be created if
    the test fails.

    Args:
      label: The label used to describe this test phase.
    Returns:
      Returns a path for the results directory to use for this label.
    """
    self.results_count += 1
    results_dir = os.path.join(self.all_results_directory, '%s_%s' % (
        self.results_count, label))
    fail_dir = os.path.join(self.fail_results_directory, '%s_%s' % (
        self.results_count, label))
    if not os.path.exists(results_dir):
      os.makedirs(results_dir)

    return results_dir, fail_dir

  # --- PRIVATE HELPER FUNCTIONS ---

  def _ParseGenerateTestReportOutput(self, output):
    """Returns the percentage of tests that passed based on output.

    Args:
      output: Output string for generate_test_report.py.
    Returns:
      The percentage of tests that passed.
    """
    percent_passed = 0
    lines = output.split('\n')

    for line in lines:
      if line.startswith('Total PASS:'):
        # FORMAT: ^TOTAL PASS: num_passed/num_total (percent%)$
        percent_passed = line.split()[3].strip('()%')
        break

    return int(percent_passed)