# 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.

import logging
import yaml

class ParseKnownCTSFailures(object):
    """A class to parse known failures in CTS test."""

    def __init__(self, failure_files):
        self.waivers_yaml = self._load_failures(failure_files)

    def _validate_waiver_config(self, arch, board, config):
        """Validate if the test environment matches the test config.

        @param arch: DUT's arch type.
        @param board: DUT's board name.
        @param config: config for an expected failing test.
        @return True if test arch or board is part of the config, else False.
        """
        dut_config = ['all', arch, board]
        return len(set(dut_config).intersection(config)) > 0

    def _load_failures(self, failure_files):
        """Load failures from files.

        @param failure_files: files with failure configs.
        @return a dictionary of failures config in yaml format.
        """
        waivers_yaml = {}
        for failure_file in failure_files:
            try:
                logging.info('Loading expected failure file: %s.', failure_file)
                with open(failure_file) as wf:
                    waivers_yaml.update(yaml.load(wf.read()))
            except IOError as e:
                logging.error('Error loading %s (%s).',
                              failure_file,
                              e.strerror)
                continue
            logging.info('Finished loading expected failure file: %s',
                         failure_file)
        return waivers_yaml

    def find_waivers(self, arch, board):
        """Finds waivers for the test board.

        @param arch: DUT's arch type.
        @param board: DUT's board name.
        @return a set of waivers/no-test-modules applied to the test board.
        """
        applied_waiver_list = set()
        for test, config in self.waivers_yaml.iteritems():
            if self._validate_waiver_config(arch, board, config):
                applied_waiver_list.add(test)
        logging.info('Excluding tests/packages from rerun: %s.',
                     applied_waiver_list)
        return applied_waiver_list