# Copyright 2016 Google Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""This module has classes for test result collection, and test result output.
"""

import collections
import copy
import enum
import functools
import io
import logging
import threading
import time
import traceback
import yaml

from mobly import signals
from mobly import utils

# File names for the output files.
OUTPUT_FILE_INFO_LOG = 'test_log.INFO'
OUTPUT_FILE_DEBUG_LOG = 'test_log.DEBUG'
OUTPUT_FILE_SUMMARY = 'test_summary.yaml'


class Error(Exception):
  """Raised for errors in record module members."""


def uid(uid):
  """Decorator specifying the unique identifier (UID) of a test case.

  The UID will be recorded in the test's record when executed by Mobly.

  If you use any other decorator for the test method, you may want to use
  this as the outer-most one.

  Note a common UID system is the Universal Unitque Identifier (UUID), but
  we are not limiting people to use UUID, hence the more generic name `UID`.

  Args:
    uid: string, the uid for the decorated test function.
  """
  if uid is None:
    raise ValueError('UID cannot be None.')

  def decorate(test_func):

    @functools.wraps(test_func)
    def wrapper(*args, **kwargs):
      return test_func(*args, **kwargs)

    setattr(wrapper, 'uid', uid)
    return wrapper

  return decorate


class TestSummaryEntryType(enum.Enum):
  """Constants used to identify the type of entries in test summary file.

  Test summary file contains multiple yaml documents. In order to parse this
  file efficiently, the write adds the type of each entry when it writes the
  entry to the file.

  The idea is similar to how `TestResult.json_str` categorizes different
  sections of a `TestResult` object in the serialized format.
  """
  # A list of all the tests requested for a test run.
  # This is dumped at the beginning of a summary file so we know what was
  # requested in case the test is interrupted and the final summary is not
  # created.
  TEST_NAME_LIST = 'TestNameList'
  # Records of test results.
  RECORD = 'Record'
  # A summary of the test run stats, e.g. how many test failed.
  SUMMARY = 'Summary'
  # Information on the controllers used in a test class.
  CONTROLLER_INFO = 'ControllerInfo'
  # Additional data added by users during test.
  # This can be added at any point in the test, so do not assume the location
  # of these entries in the summary file.
  USER_DATA = 'UserData'


class TestSummaryWriter:
  """Writer for the test result summary file of a test run.

  For each test run, a writer is created to stream test results to the
  summary file on disk.

  The serialization and writing of the `TestResult` object is intentionally
  kept out of `TestResult` class and put in this class. Because `TestResult`
  can be operated on by suites, like `+` operation, and it is difficult to
  guarantee the consistency between `TestResult` in memory and the files on
  disk. Also, this separation makes it easier to provide a more generic way
  for users to consume the test summary, like via a database instead of a
  file.
  """

  def __init__(self, path):
    self._path = path
    self._lock = threading.Lock()

  def __copy__(self):
    """Make a "copy" of the object.

    The writer is merely a wrapper object for a path with a global lock for
    write operation. So we simply return the object itself for copy
    operations.
    """
    return self

  def __deepcopy__(self, *args):
    return self.__copy__()

  def dump(self, content, entry_type):
    """Dumps a dictionary as a yaml document to the summary file.

    Each call to this method dumps a separate yaml document to the same
    summary file associated with a test run.

    The content of the dumped dictionary has an extra field `TYPE` that
    specifies the type of each yaml document, which is the flag for parsers
    to identify each document.

    Args:
      content: dictionary, the content to serialize and write.
      entry_type: a member of enum TestSummaryEntryType.

    Raises:
      recoreds.Error: An invalid entry type is passed in.
    """
    new_content = copy.deepcopy(content)
    new_content['Type'] = entry_type.value
    # Both user code and Mobly code can trigger this dump, hence the lock.
    with self._lock:
      # For Python3, setting the encoding on yaml.safe_dump does not work
      # because Python3 file descriptors set an encoding by default, which
      # PyYAML uses instead of the encoding on yaml.safe_dump. So, the
      # encoding has to be set on the open call instead.
      with io.open(self._path, 'a', encoding='utf-8') as f:
        # Use safe_dump here to avoid language-specific tags in final
        # output.
        yaml.safe_dump(new_content,
                       f,
                       explicit_start=True,
                       allow_unicode=True,
                       indent=4)


class TestResultEnums:
  """Enums used for TestResultRecord class.

  Includes the tokens to mark test result with, and the string names for each
  field in TestResultRecord.
  """

  RECORD_NAME = 'Test Name'
  RECORD_CLASS = 'Test Class'
  RECORD_BEGIN_TIME = 'Begin Time'
  RECORD_END_TIME = 'End Time'
  RECORD_RESULT = 'Result'
  RECORD_UID = 'UID'
  RECORD_EXTRAS = 'Extras'
  RECORD_EXTRA_ERRORS = 'Extra Errors'
  RECORD_DETAILS = 'Details'
  RECORD_STACKTRACE = 'Stacktrace'
  RECORD_SIGNATURE = 'Signature'
  RECORD_RETRY_PARENT = 'Retry Parent'
  RECORD_POSITION = 'Position'
  TEST_RESULT_PASS = 'PASS'
  TEST_RESULT_FAIL = 'FAIL'
  TEST_RESULT_SKIP = 'SKIP'
  TEST_RESULT_ERROR = 'ERROR'


class ControllerInfoRecord:
  """A record representing the controller info in test results."""

  KEY_TEST_CLASS = TestResultEnums.RECORD_CLASS
  KEY_CONTROLLER_NAME = 'Controller Name'
  KEY_CONTROLLER_INFO = 'Controller Info'
  KEY_TIMESTAMP = 'Timestamp'

  def __init__(self, test_class, controller_name, info):
    self.test_class = test_class
    self.controller_name = controller_name
    self.controller_info = info
    self.timestamp = time.time()

  def to_dict(self):
    result = {}
    result[self.KEY_TEST_CLASS] = self.test_class
    result[self.KEY_CONTROLLER_NAME] = self.controller_name
    result[self.KEY_CONTROLLER_INFO] = self.controller_info
    result[self.KEY_TIMESTAMP] = self.timestamp
    return result

  def __repr__(self):
    return str(self.to_dict())


class ExceptionRecord:
  """A record representing exception objects in TestResultRecord.

  Attributes:
    exception: Exception object, the original Exception.
    stacktrace: string, stacktrace of the Exception.
    extras: optional serializable, this corresponds to the
      `TestSignal.extras` field.
    position: string, an optional label specifying the position where the
      Exception ocurred.
  """

  def __init__(self, e, position=None):
    self.exception = e
    self.stacktrace = None
    self.extras = None
    self.position = position
    self.is_test_signal = isinstance(e, signals.TestSignal)
    # Record stacktrace of the exception.
    # This check cannot be based on try...except, which messes up
    # `exc_info`.
    exc_traceback = e.__traceback__
    if exc_traceback:
      self.stacktrace = ''.join(
          traceback.format_exception(e.__class__, e, exc_traceback))
    # Populate fields based on the type of the termination signal.
    if self.is_test_signal:
      self._set_details(e.details)
      self.extras = e.extras
    else:
      self._set_details(e)

  def _set_details(self, content):
    """Sets the `details` field.

    Args:
      content: the content to extract details from.
    """
    try:
      self.details = str(content)
    except UnicodeEncodeError:
      # We should never hit this in Py3, But if this happens, record
      # an encoded version of the content for users to handle.
      logging.error('Unable to decode "%s" in Py3, encoding in utf-8.', content)
      self.details = content.encode('utf-8')

  def to_dict(self):
    result = {}
    result[TestResultEnums.RECORD_DETAILS] = self.details
    result[TestResultEnums.RECORD_POSITION] = self.position
    result[TestResultEnums.RECORD_STACKTRACE] = self.stacktrace
    result[TestResultEnums.RECORD_EXTRAS] = copy.deepcopy(self.extras)
    return result

  def __deepcopy__(self, memo):
    """Overrides deepcopy for the class.

    If the exception object has a constructor that takes extra args, deep
    copy won't work. So we need to have a custom logic for deepcopy.
    """
    try:
      exception = copy.deepcopy(self.exception)
    except TypeError:
      # If the exception object cannot be copied, use the original
      # exception object.
      exception = self.exception
    result = ExceptionRecord(exception, self.position)
    result.stacktrace = self.stacktrace
    result.details = self.details
    result.extras = copy.deepcopy(self.extras)
    result.position = self.position
    return result


class TestResultRecord:
  """A record that holds the information of a single test.

  The record object holds all information of a test, including all the
  exceptions occurred during the test.

  A test can terminate for two reasons:
    1. the test function executes to the end and completes naturally.
    2. the test is terminated by an exception, which we call
     "termination signal".

  The termination signal is treated differently. Its content are extracted
  into first-tier attributes of the record object, like `details` and
  `stacktrace`, for easy consumption.

  Note the termination signal is not always an error, it can also be explicit
  pass signal or abort/skip signals.

  Attributes:
    test_name: string, the name of the test.
    begin_time: Epoch timestamp of when the test started.
    end_time: Epoch timestamp of when the test ended.
    uid: User-defined unique identifier of the test.
    signature: string, unique identifier of a test record, the value is
      generated by Mobly.
    retry_parent: TestResultRecord, only set for retry iterations. This is the
      test result record of the previous retry iteration. Parsers can use this
      field to construct the chain of execution for each retried test.
    termination_signal: ExceptionRecord, the main exception of the test.
    extra_errors: OrderedDict, all exceptions occurred during the entire
      test lifecycle. The order of occurrence is preserved.
    result: TestResultEnum.TEAT_RESULT_*, PASS/FAIL/SKIP.
  """

  def __init__(self, t_name, t_class=None):
    self.test_name = t_name
    self.test_class = t_class
    self.begin_time = None
    self.end_time = None
    self.uid = None
    self.signature = None
    self.retry_parent = None
    self.termination_signal = None
    self.extra_errors = collections.OrderedDict()
    self.result = None

  @property
  def details(self):
    """String description of the cause of the test's termination.

    Note a passed test can have this as well due to the explicit pass
    signal. If the test passed implicitly, this field would be None.
    """
    if self.termination_signal:
      return self.termination_signal.details

  @property
  def stacktrace(self):
    """The stacktrace string for the exception that terminated the test.
    """
    if self.termination_signal:
      return self.termination_signal.stacktrace

  @property
  def extras(self):
    """User defined extra information of the test result.

    Must be serializable.
    """
    if self.termination_signal:
      return self.termination_signal.extras

  def test_begin(self):
    """Call this when the test begins execution.

    Sets the begin_time of this record.
    """
    self.begin_time = utils.get_current_epoch_time()
    self.signature = '%s-%s' % (self.test_name, self.begin_time)

  def _test_end(self, result, e):
    """Marks the end of the test logic.

    Args:
      result: One of the TEST_RESULT enums in TestResultEnums.
      e: A test termination signal (usually an exception object). It can
        be any exception instance or of any subclass of
        mobly.signals.TestSignal.
    """
    if self.begin_time is not None:
      self.end_time = utils.get_current_epoch_time()
    self.result = result
    if e:
      self.termination_signal = ExceptionRecord(e)

  def update_record(self):
    """Updates the content of a record.

    Several display fields like "details" and "stacktrace" need to be
    updated based on the content of the record object.

    As the content of the record change, call this method to update all
    the appropirate fields.
    """
    if self.extra_errors:
      if self.result != TestResultEnums.TEST_RESULT_FAIL:
        self.result = TestResultEnums.TEST_RESULT_ERROR
    # If no termination signal is provided, use the first exception
    # occurred as the termination signal.
    if not self.termination_signal and self.extra_errors:
      _, self.termination_signal = self.extra_errors.popitem(last=False)

  def test_pass(self, e=None):
    """To mark the test as passed in this record.

    Args:
      e: An instance of mobly.signals.TestPass.
    """
    self._test_end(TestResultEnums.TEST_RESULT_PASS, e)

  def test_fail(self, e=None):
    """To mark the test as failed in this record.

    Only test_fail does instance check because we want 'assert xxx' to also
    fail the test same way assert_true does.

    Args:
      e: An exception object. It can be an instance of AssertionError or
        mobly.base_test.TestFailure.
    """
    self._test_end(TestResultEnums.TEST_RESULT_FAIL, e)

  def test_skip(self, e=None):
    """To mark the test as skipped in this record.

    Args:
      e: An instance of mobly.signals.TestSkip.
    """
    self._test_end(TestResultEnums.TEST_RESULT_SKIP, e)

  def test_error(self, e=None):
    """To mark the test as error in this record.

    Args:
      e: An exception object.
    """
    self._test_end(TestResultEnums.TEST_RESULT_ERROR, e)

  def add_error(self, position, e):
    """Add extra error happened during a test.

    If the test has passed or skipped, this will mark the test result as
    ERROR.

    If an error is added the test record, the record's result is equivalent
    to the case where an uncaught exception happened.

    If the test record has not recorded any error, the newly added error
    would be the main error of the test record. Otherwise the newly added
    error is added to the record's extra errors.

    Args:
      position: string, where this error occurred, e.g. 'teardown_test'.
      e: An exception or a `signals.ExceptionRecord` object.
    """
    if self.result != TestResultEnums.TEST_RESULT_FAIL:
      self.result = TestResultEnums.TEST_RESULT_ERROR
    if position in self.extra_errors:
      raise Error('An exception is already recorded with position "%s",'
                  ' cannot reuse.' % position)
    if isinstance(e, ExceptionRecord):
      self.extra_errors[position] = e
    else:
      self.extra_errors[position] = ExceptionRecord(e, position=position)

  def __str__(self):
    d = self.to_dict()
    kv_pairs = ['%s = %s' % (k, v) for k, v in d.items()]
    s = ', '.join(kv_pairs)
    return s

  def __repr__(self):
    """This returns a short string representation of the test record."""
    t = utils.epoch_to_human_time(self.begin_time)
    return f'{t} {self.test_name} {self.result}'

  def to_dict(self):
    """Gets a dictionary representating the content of this class.

    Returns:
      A dictionary representating the content of this class.
    """
    d = {}
    d[TestResultEnums.RECORD_NAME] = self.test_name
    d[TestResultEnums.RECORD_CLASS] = self.test_class
    d[TestResultEnums.RECORD_BEGIN_TIME] = self.begin_time
    d[TestResultEnums.RECORD_END_TIME] = self.end_time
    d[TestResultEnums.RECORD_RESULT] = self.result
    d[TestResultEnums.RECORD_UID] = self.uid
    d[TestResultEnums.RECORD_SIGNATURE] = self.signature
    d[TestResultEnums.
      RECORD_RETRY_PARENT] = self.retry_parent.signature if self.retry_parent else None
    d[TestResultEnums.RECORD_EXTRAS] = self.extras
    d[TestResultEnums.RECORD_DETAILS] = self.details
    d[TestResultEnums.RECORD_EXTRA_ERRORS] = {
        key: value.to_dict() for (key, value) in self.extra_errors.items()
    }
    d[TestResultEnums.RECORD_STACKTRACE] = self.stacktrace
    return d


class TestResult:
  """A class that contains metrics of a test run.

  This class is essentially a container of TestResultRecord objects.

  Attributes:
    requested: A list of strings, each is the name of a test requested
      by user.
    failed: A list of records for tests failed.
    executed: A list of records for tests that were actually executed.
    passed: A list of records for tests passed.
    skipped: A list of records for tests skipped.
    error: A list of records for tests with error result token.
    controller_info: list of ControllerInfoRecord.
  """

  def __init__(self):
    self.requested = []
    self.failed = []
    self.executed = []
    self.passed = []
    self.skipped = []
    self.error = []
    self.controller_info = []

  def __add__(self, r):
    """Overrides '+' operator for TestResult class.

    The add operator merges two TestResult objects by concatenating all of
    their lists together.

    Args:
      r: another instance of TestResult to be added

    Returns:
      A TestResult instance that's the sum of two TestResult instances.
    """
    if not isinstance(r, TestResult):
      raise TypeError('Operand %s of type %s is not a TestResult.' %
                      (r, type(r)))
    sum_result = TestResult()
    for name in sum_result.__dict__:
      r_value = getattr(r, name)
      l_value = getattr(self, name)
      if isinstance(r_value, list):
        setattr(sum_result, name, l_value + r_value)
    return sum_result

  def add_record(self, record):
    """Adds a test record to test result.

    A record is considered executed once it's added to the test result.

    Adding the record finalizes the content of a record, so no change
    should be made to the record afterwards.

    Args:
      record: A test record object to add.
    """
    record.update_record()
    if record.result == TestResultEnums.TEST_RESULT_SKIP:
      self.skipped.append(record)
      return
    self.executed.append(record)
    if record.result == TestResultEnums.TEST_RESULT_FAIL:
      self.failed.append(record)
    elif record.result == TestResultEnums.TEST_RESULT_PASS:
      self.passed.append(record)
    else:
      self.error.append(record)

  def add_controller_info_record(self, controller_info_record):
    """Adds a controller info record to results.

    This can be called multiple times for each test class.

    Args:
      controller_info_record: ControllerInfoRecord object to be added to
        the result.
    """
    self.controller_info.append(controller_info_record)

  def add_class_error(self, test_record):
    """Add a record to indicate a test class has failed before any test
    could execute.

    This is only called before any test is actually executed. So it only
    adds an error entry that describes why the class failed to the tally
    and does not affect the total number of tests requrested or exedcuted.

    Args:
      test_record: A TestResultRecord object for the test class.
    """
    test_record.update_record()
    self.error.append(test_record)

  def is_test_executed(self, test_name):
    """Checks if a specific test has been executed.

    Args:
      test_name: string, the name of the test to check.

    Returns:
      True if the test has been executed according to the test result,
      False otherwise.
    """
    for record in self.executed:
      if record.test_name == test_name:
        return True
    return False

  def _count_eventually_passing_retries(self):
    """Counts the number of retry iterations that eventually passed.

    If a test is retried and eventually passed, all the associated non-passing
    iterations should not be considered when devising the final state of the
    test run.

    Returns:
      Int, the number that should be subtracted from the result altering error
      counts.
    """
    count = 0
    for record in self.passed:
      r = record
      while r.retry_parent:
        count += 1
        r = r.retry_parent
    return count

  @property
  def is_all_pass(self):
    """True if no tests failed or threw errors, False otherwise."""
    num_of_result_altering_errors = (len(self.failed) + len(self.error) -
                                     self._count_eventually_passing_retries())
    if num_of_result_altering_errors == 0:
      return True
    return False

  def requested_test_names_dict(self):
    """Gets the requested test names of a test run in a dict format.

    Note a test can be requested multiple times, so there can be duplicated
    values

    Returns:
      A dict with a key and the list of strings.
    """
    return {'Requested Tests': copy.deepcopy(self.requested)}

  def summary_str(self):
    """Gets a string that summarizes the stats of this test result.

    The summary provides the counts of how many tests fall into each
    category, like 'Passed', 'Failed' etc.

    Format of the string is:
      Requested <int>, Executed <int>, ...

    Returns:
      A summary string of this test result.
    """
    kv_pairs = ['%s %d' % (k, v) for k, v in self.summary_dict().items()]
    # Sort the list so the order is the same every time.
    msg = ', '.join(sorted(kv_pairs))
    return msg

  def summary_dict(self):
    """Gets a dictionary that summarizes the stats of this test result.

    The summary provides the counts of how many tests fall into each
    category, like 'Passed', 'Failed' etc.

    Returns:
      A dictionary with the stats of this test result.
    """
    d = {}
    d['Requested'] = len(self.requested)
    d['Executed'] = len(self.executed)
    d['Passed'] = len(self.passed)
    d['Failed'] = len(self.failed)
    d['Skipped'] = len(self.skipped)
    d['Error'] = len(self.error)
    return d