import argparse
import json
import os
import sys
import time
import unittest


class MojoPythonTestRunner(object):
  """Helper class to run python tests on the bots."""

  def __init__(self, test_dir):
    self._test_dir = test_dir

  def run(self):
    parser = argparse.ArgumentParser()
    parser.usage = 'run_mojo_python_tests.py [options] [tests...]'
    parser.add_argument('-v', '--verbose', action='count', default=0)
    parser.add_argument('--metadata', action='append', default=[],
                        help=('optional key=value metadata that will be stored '
                              'in the results files (can be used for revision '
                              'numbers, etc.)'))
    parser.add_argument('--write-full-results-to', metavar='FILENAME',
                        action='store',
                        help='path to write the list of full results to.')
    parser.add_argument('tests', nargs='*')

    self.add_custom_commandline_options(parser)
    args = parser.parse_args()
    self.apply_customization(args)

    bad_metadata = False
    for val in args.metadata:
      if '=' not in val:
        print >> sys.stderr, ('Error: malformed metadata "%s"' % val)
        bad_metadata = True
    if bad_metadata:
      print >> sys.stderr
      parser.print_help()
      return 2

    chromium_src_dir = os.path.join(os.path.dirname(__file__),
                                    os.pardir,
                                    os.pardir,
                                    os.pardir)

    loader = unittest.loader.TestLoader()
    print "Running Python unit tests under %s..." % self._test_dir

    pylib_dir = os.path.abspath(os.path.join(chromium_src_dir, self._test_dir))
    if args.tests:
      if pylib_dir not in sys.path:
        sys.path.append(pylib_dir)
      suite = unittest.TestSuite()
      for test_name in args.tests:
        suite.addTests(loader.loadTestsFromName(test_name))
    else:
      suite = loader.discover(pylib_dir, pattern='*_unittest.py')

    runner = unittest.runner.TextTestRunner(verbosity=(args.verbose + 1))
    result = runner.run(suite)

    full_results = _FullResults(suite, result, args.metadata)
    if args.write_full_results_to:
      with open(args.write_full_results_to, 'w') as fp:
        json.dump(full_results, fp, indent=2)
        fp.write("\n")

    return 0 if result.wasSuccessful() else 1

  def add_custom_commandline_options(self, parser):
    """Allow to add custom option to the runner script."""
    pass

  def apply_customization(self, args):
    """Allow to apply any customization to the runner."""
    pass


TEST_SEPARATOR = '.'


def _FullResults(suite, result, metadata):
  """Convert the unittest results to the Chromium JSON test result format.

  This matches run-webkit-tests (the layout tests) and the flakiness dashboard.
  """

  full_results = {}
  full_results['interrupted'] = False
  full_results['path_delimiter'] = TEST_SEPARATOR
  full_results['version'] = 3
  full_results['seconds_since_epoch'] = time.time()
  for md in metadata:
    key, val = md.split('=', 1)
    full_results[key] = val

  all_test_names = _AllTestNames(suite)
  failed_test_names = _FailedTestNames(result)

  full_results['num_failures_by_type'] = {
      'FAIL': len(failed_test_names),
      'PASS': len(all_test_names) - len(failed_test_names),
  }

  full_results['tests'] = {}

  for test_name in all_test_names:
    value = {}
    value['expected'] = 'PASS'
    if test_name in failed_test_names:
      value['actual'] = 'FAIL'
      value['is_unexpected'] = True
    else:
      value['actual'] = 'PASS'
    _AddPathToTrie(full_results['tests'], test_name, value)

  return full_results


def _AllTestNames(suite):
  test_names = []
  # _tests is protected  pylint: disable=W0212
  for test in suite._tests:
    if isinstance(test, unittest.suite.TestSuite):
      test_names.extend(_AllTestNames(test))
    else:
      test_names.append(test.id())
  return test_names


def _FailedTestNames(result):
  return set(test.id() for test, _ in result.failures + result.errors)


def _AddPathToTrie(trie, path, value):
  if TEST_SEPARATOR not in path:
    trie[path] = value
    return
  directory, rest = path.split(TEST_SEPARATOR, 1)
  if directory not in trie:
    trie[directory] = {}
  _AddPathToTrie(trie[directory], rest, value)
