# Copyright 2017 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 to manage stage failure messages."""

from __future__ import print_function

import collections
import json
import re

from chromite.lib import cros_logging as logging
from chromite.lib import failures_lib


# These keys must exist as column names from failureView in cidb.
FAILURE_KEYS = (
    'id', 'build_stage_id', 'outer_failure_id', 'exception_type',
    'exception_message', 'exception_category', 'extra_info',
    'timestamp', 'stage_name', 'board', 'stage_status', 'build_id',
    'master_build_id', 'builder_name', 'waterfall', 'build_number',
    'build_config', 'build_status', 'important', 'buildbucket_id')


# A namedtuple containing values fetched from CIDB failureView.
_StageFailure = collections.namedtuple('_StageFailure', FAILURE_KEYS)


class StageFailure(_StageFailure):
  """A class presenting values of a failure fetched from CIDB failureView."""

  @classmethod
  def GetStageFailureFromMessage(cls, stage_failure_message):
    """Create StageFailure from a StageFailureMessage instance.

    Args:
      stage_failure_message: An instance of StageFailureMessage.

    Returns:
      An instance of StageFailure.
    """
    return StageFailure(
        stage_failure_message.failure_id,
        stage_failure_message.build_stage_id,
        stage_failure_message.outer_failure_id,
        stage_failure_message.exception_type,
        stage_failure_message.exception_message,
        stage_failure_message.exception_category,
        stage_failure_message.extra_info, None,
        stage_failure_message.stage_name, None, None, None, None, None, None,
        None, None, None, None, None)


class StageFailureMessage(object):
  """Message class contains information of a general stage failure.

  Failed stages report stage failures to CIDB failureTable (see more details
  in failures_lib.ReportStageFailureToCIDB). This class constructs a failure
  message instance from the stage failure information stored in CIDB.
  """

  def __init__(self, stage_failure, extra_info=None, stage_prefix_name=None):
    """Construct a StageFailureMessage instance.

    Args:
      stage_failure: An instance of StageFailure.
      extra_info: The extra info of the origin failure, default to None.
      stage_prefix_name: The prefix name (string) of the failed stage,
        default to None.
    """
    self.failure_id = stage_failure.id
    self.build_stage_id = stage_failure.build_stage_id
    self.stage_name = stage_failure.stage_name
    self.exception_type = stage_failure.exception_type
    self.exception_message = stage_failure.exception_message
    self.exception_category = stage_failure.exception_category
    self.outer_failure_id = stage_failure.outer_failure_id

    if extra_info is not None:
      self.extra_info = extra_info
    else:
      # No extra_info provided, decode extra_info from stage_failure.
      self.extra_info = self._DecodeExtraInfo(stage_failure.extra_info)

    if stage_prefix_name is not None:
      self.stage_prefix_name = stage_prefix_name
    else:
      # No stage_prefix_name provided, extra prefix name from stage_failure.
      self.stage_prefix_name = self._ExtractStagePrefixName(self.stage_name)

  def __str__(self):
    return ('[failure id] %s [stage name] %s [stage prefix name] %s '
            '[exception type] %s [exception category] %s [exception message] %s'
            ' [extra info] %s' %
            (self.failure_id, self.stage_name, self.stage_prefix_name,
             self.exception_type, self.exception_category,
             self.exception_message, self.extra_info))

  def _DecodeExtraInfo(self, extra_info):
    """Decode extra info json into dict.

    Args:
      extra_info: The extra_info of the origin exception, default to None.

    Returns:
      An empty dict if extra_info is None; extra_info itself if extra_info is
      a dict; else, load the json string into a dict and return it.
    """
    if not extra_info:
      return {}
    elif isinstance(extra_info, dict):
      return extra_info
    else:
      try:
        return  json.loads(extra_info)
      except ValueError as e:
        logging.error('Cannot decode extra_info: %s', e)
        return {}

  # TODO(nxia): Force format checking on stage names when they're created
  def _ExtractStagePrefixName(self, stage_name):
    """Extract stage prefix name given a full stage name.

    Format examples in our current CIDB buildStageTable:
      HWTest [arc-bvt-cq] -> HWTest
      HWTest -> HWTest
      ImageTest -> ImageTest
      ImageTest [amd64-generic] -> ImageTest
      VMTest (attempt 1) -> VMTest
      VMTest [amd64-generic] (attempt 1) -> VMTest

    Args:
      stage_name: The full stage name (string) recorded in CIDB.

    Returns:
      The prefix stage name (string).
    """
    pattern = r'([^ ]+)( +\[([^]]+)\])?( +\(([^)]+)\))?'
    m = re.compile(pattern).match(stage_name)
    if m is not None:
      return m.group(1)
    else:
      return stage_name


class BuildScriptFailureMessage(StageFailureMessage):
  """Message class contains information of a BuildScriptFailure."""

  def __init__(self, stage_failure, **kwargs):
    """Construct a BuildScriptFailureMessage instance.

    Args:
      stage_failure: An instance of StageFailure.
      kwargs: Extra message information to pass to StageFailureMessage.
    """
    super(BuildScriptFailureMessage, self).__init__(stage_failure, **kwargs)

  def GetShortname(self):
    """Return the short name (string) of the run command."""
    return self.extra_info.get('shortname')


class PackageBuildFailureMessage(StageFailureMessage):
  """Message class contains information of a PackagebuildFailure."""

  def __init__(self, stage_failure, **kwargs):
    """Construct a PackageBuildFailureMessage instance.

    Args:
      stage_failure: An instance of StageFailure.
      kwargs: Extra message information to pass to StageFailureMessage.
    """
    super(PackageBuildFailureMessage, self).__init__(
        stage_failure, **kwargs)

  def GetShortname(self):
    """Return the short name (string) of the run command."""
    return self.extra_info.get('shortname')

  def GetFailedPackages(self):
    """Return a list of packages (strings) that failed to build."""
    return self.extra_info.get('failed_packages', [])


class CompoundFailureMessage(StageFailureMessage):
  """Message class contains information of a CompoundFailureMessage."""

  def __init__(self, stage_failure, **kwargs):
    """Construct a CompoundFailureMessage instance.

    Args:
      stage_failure: An instance of StageFailure.
      kwargs: Extra message information to pass to StageFailureMessage.
    """
    super(CompoundFailureMessage, self).__init__(stage_failure, **kwargs)

    self.inner_failures = []

  def __str__(self):
    msg_str = super(CompoundFailureMessage, self).__str__()

    for failure in self.inner_failures:
      msg_str += ('(Inner Stage Failure Message) %s' % str(failure))

    return msg_str

  @staticmethod
  def GetFailureMessage(failure_message):
    """Convert a regular failure message instance to CompoundFailureMessage.

    Args:
      failure_message: An instance of StageFailureMessage.

    Returns:
      A CompoundFailureMessage instance.
    """
    return CompoundFailureMessage(
        StageFailure.GetStageFailureFromMessage(failure_message),
        extra_info=failure_message.extra_info,
        stage_prefix_name=failure_message.stage_prefix_name)

  def HasEmptyList(self):
    """Check whether the inner failure list is empty.

    Returns:
      True if self.inner_failures is empty; else, False.
    """
    return not bool(self.inner_failures)

  def HasFailureType(self, exception_type):
    """Check whether any of the inner failures matches the exception type.

    Args:
      exception_type: The class name (string) of the origin exception.

    Returns:
      True if any of the inner failures matches exception_type; else, False.
    """
    return any(x.exception_type == exception_type for x in self.inner_failures)

  def MatchesFailureType(self, exception_type):
    """Check whether all of the inner failures match the exception type.

    Args:
      exception_type: The class name (string) of the origin exception.

    Returns:
      True if all of the inner failures match exception_type; else, False.
    """
    return (not self.HasEmptyList() and
            all(x.exception_type == exception_type
                for x in self.inner_failures))

  def HasExceptionCategory(self, exception_category):
    """Check whether any of the inner failures matches the exception category.

    Args:
      exception_category: The category of the origin exception (one of
        constants.EXCEPTION_CATEGORY_ALL_CATEGORIES).

    Returns:
      True if any of the inner failures matches exception_category; else, False.
    """
    return any(x.exception_category == exception_category
               for x in self.inner_failures)

  def MatchesExceptionCategory(self, exception_category):
    """Check whether all of the inner failures matches the exception category.

    Args:
      exception_category: The category of the origin exception (one of
        constants.EXCEPTION_CATEGORY_ALL_CATEGORIES).

    Returns:
      True if all of the inner failures match exception_category; else, False.
    """
    return (not self.HasEmptyList() and
            all(x.exception_category == exception_category
                for x in self.inner_failures))


class FailureMessageManager(object):
  """Manager class to create a failure message or reconstruct messages."""

  @classmethod
  def CreateMessage(cls, stage_failure, **kwargs):
    """Create a failure message instance depending on the exception type.

    Args:
      stage_failure: An instance of StageFailure.
      kwargs: Extra message information to pass to StageFailureMessage.

    Returns:
      A failure message instance of StageFailureMessage class (or its
        sub-class)
    """
    if stage_failure.exception_type in failures_lib.BUILD_SCRIPT_FAILURE_TYPES:
      return BuildScriptFailureMessage(stage_failure, **kwargs)
    elif (stage_failure.exception_type in
          failures_lib.PACKAGE_BUILD_FAILURE_TYPES):
      return PackageBuildFailureMessage(stage_failure, **kwargs)
    else:
      return StageFailureMessage(stage_failure, **kwargs)

  @classmethod
  def ReconstructMessages(cls, failure_messages):
    """Reconstruct failure messages by nesting messages.

    A failure message with not none outer_failure_id is an inner failure of its
    outer failure message(failure_id == outer_failure_id). This method takes a
    list of failure messages, reconstructs the list by 1) converting the outer
    failure message into a CompoundFailureMessage instance 2) insert the inner
    failure messages to the inner_failures list of their outer failure messages.
    CompoundFailures in CIDB aren't nested
    (see failures_lib.ReportStageFailureToCIDB), so there isn't another
    inner failure list layer in a inner failure message and there're no circular
    dependencies.

    For example, given failure_messages list
      [A(failure_id=1),
       B(failure_id=2, outer_failure_id=1),
       C(failure_id=3, outer_failure_id=1),
       D(failure_id=4),
       E(failure_id=5, outer_failure_id=4),
       F(failure_id=6)]
    this method returns a reconstructed list:
      [A(failure_id=1, inner_failures=[B(failure_id=2, outer_failure_id=1),
                                       C(failure_id=3, outer_failure_id=1)]),
       D(failure_id=4, inner_failures=[E(failure_id=5, outer_failure_id=4)]),
       F(failure_id=6)]

    Args:
      failure_messages: A list a failure message instances not nested.

    Returns:
      A list of failure message instances of StageFailureMessage class (or its
        sub-class). Failure messages with not None outer_failure_id are nested
        into the inner_failures list of their outer failure messages.
    """
    failure_message_dict = {x.failure_id: x for x in failure_messages}

    for failure in failure_messages:
      if failure.outer_failure_id is not None:
        assert failure.outer_failure_id in failure_message_dict
        outer_failure = failure_message_dict[failure.outer_failure_id]
        if not isinstance(outer_failure, CompoundFailureMessage):
          outer_failure = CompoundFailureMessage.GetFailureMessage(
              outer_failure)
          failure_message_dict[outer_failure.failure_id] = outer_failure

        outer_failure.inner_failures.append(failure)
        del failure_message_dict[failure.failure_id]

    return failure_message_dict.values()

  @classmethod
  def ConstructStageFailureMessages(cls, stage_failures):
    """Construct stage failure messages from failure entries from CIDB.

    Args:
      stage_failures: A list of StageFailure instances.

    Returns:
      A list of stage failure message instances of StageFailureMessage class
      (or its sub-class). See return type of ReconstructMessages().
    """
    failure_messages = [cls.CreateMessage(f) for f in stage_failures]

    return cls.ReconstructMessages(failure_messages)


class BuildFailureMessage(object):
  """Message indicating that changes failed to be validated.

  A failure message for a failed build, which is used to trige failures and
  detect bad changes.
  """

  def __init__(self, message_summary, failure_messages, internal, reason,
               builder):
    """Create a BuildFailureMessage instance.

    Args:
      message_summary: The message summary string to print.
      failure_messages: A list of failure messages (instances of
        StageFailureMessage), if any.
      internal: Whether this failure occurred on an internal builder.
      reason: A string describing the failure.
      builder: The builder the failure occurred on.
    """
    self.message_summary = str(message_summary)
    self.failure_messages = failure_messages or []
    self.internal = bool(internal)
    self.reason = str(reason)
    # builder should match build_config, e.g. self._run.config.name.
    self.builder = str(builder)

  def __str__(self):
    return self.message_summary

  def BuildFailureMessageToStr(self):
    """Return a string presenting the information in the BuildFailureMessage."""
    to_str = ('[builder] %s [message summary] %s [reason] %s [internal] %s\n' %
              (self.builder, self.message_summary, self.reason, self.internal))
    for f in self.failure_messages:
      to_str += '[failure message] ' + str(f) + '\n'

    return to_str

  def GetFailingStages(self):
    """Get a list of the failing stage prefixes from failure_messages.

    Returns:
      A list of failing stage prefixes if there are failure_messages; None
      otherwise.
    """
    failing_stages = None
    if self.failure_messages:
      failing_stages = set(x.stage_prefix_name for x in self.failure_messages)
    return failing_stages

  def MatchesExceptionCategory(self, exception_category):
    """Check if all of the failure_messages match the exception_category.

    Args:
      exception_category: The category of the origin exception (one of
        constants.EXCEPTION_CATEGORY_ALL_CATEGORIES).

    Returns:
      True if all of the failure_messages match the exception_category; else,
      False.
    """
    for failure in self.failure_messages:
      if failure.exception_category != exception_category:
        if (isinstance(failure, CompoundFailureMessage) and
            failure.MatchesExceptionCategory(exception_category)):
          continue
        else:
          return False

    return True

  def HasExceptionCategory(self, exception_category):
    """Check if any of the failure_messages match the exception_category.

    Args:
      exception_category: The category of the origin exception (one of
        constants.EXCEPTION_CATEGORY_ALL_CATEGORIES).

    Returns:
      True if any of the failure_messages match the exception_category; else,
      False.
    """
    for failure in self.failure_messages:
      if failure.exception_category == exception_category:
        return True

      if (isinstance(failure, CompoundFailureMessage) and
          failure.HasExceptionCategory(exception_category)):
        return True

    return False

  def MatchesFailureType(self, exception_type):
    """Check if all of the failure_messages match the exception_type.

    Args:
      exception_type: The class name (string) of the origin exception.

    Returns:
      True if all the failure_messages match the exception_type; else,
      False.
    """
    for failure in self.failure_messages:
      if failure.exception_type != exception_type:
        if (isinstance(failure, CompoundFailureMessage) and
            failure.MatchesFailureType(exception_type)):
          continue
        else:
          return False

    return True

  def HasFailureType(self, exception_type):
    """Check if any of the failure_messages match the exception_type.

    Args:
      exception_type: The class name (string) of the origin exception.

    Returns:
      True if any of the failure_messages match the exception_type; else,
      False.
    """
    for failure in self.failure_messages:
      if failure.exception_type == exception_type:
        return True

      if (isinstance(failure, CompoundFailureMessage) and
          failure.HasExceptionCategory(exception_type)):
        return True

    return False

  def IsPackageBuildFailure(self):
    """Check if all of the failures are package build failures."""
    return self.MatchesFailureType(failures_lib.PackageBuildFailure.__name__)

  def FindPackageBuildFailureSuspects(self, changes, sanity):
    """Figure out what changes probably caused our failures.

    We use a fairly simplistic algorithm to calculate breakage: If you changed
    a package, and that package broke, you probably broke the build. If there
    were multiple changes to a broken package, we fail them all.

    Some safeguards are implemented to ensure that bad changes are kicked out:
      1) Changes to overlays (e.g. ebuilds, eclasses, etc.) are always kicked
         out if the build fails.
      2) If a package fails that nobody changed, we kick out all of the
         changes.
      3) If any failures occur that we can't explain, we kick out all of the
         changes.

    It is certainly possible to trick this algorithm: If one developer submits
    a change to libchromeos that breaks the power_manager, and another developer
    submits a change to the power_manager at the same time, only the
    power_manager change will be kicked out. That said, in that situation, the
    libchromeos change will likely be kicked out on the next run, thanks to
    safeguard #2 above.

    Args:
      changes: List of changes to examine.
      sanity: The sanity checker builder passed and the tree was open when
              the build started.

    Returns:
      Set of changes that likely caused the failure.
    """
    # Import portage_util here to avoid circular imports.
    # portage_util -> parallel -> failures_lib
    from chromite.lib import portage_util
    blame_everything = False
    suspects = set()
    for failure in self.failure_messages:
      # Only look at PackageBuildFailure objects.
      failed_packages = []

      if failure.exception_type == failures_lib.PackageBuildFailure.__name__:
        failed_packages = failure.GetFailedPackages()
      else:
        blame_everything = True

      for package in failed_packages:
        failed_projects = portage_util.FindWorkonProjects([package])
        blame_assigned = False
        for change in changes:
          if change.project in failed_projects:
            blame_assigned = True
            suspects.add(change)
        if not blame_assigned:
          blame_everything = True

    # Only do broad-brush blaming if the tree is sane.
    if sanity:
      if blame_everything or not suspects:
        suspects = changes[:]
      else:
        # Never treat changes to overlays as innocent.
        suspects.update(change for change in changes
                        if '/overlays/' in change.project)

    return suspects