##
# Copyright 2016-2021 Ghent University
#
# This file is part of EasyBuild,
# originally created by the HPC team of Ghent University (http://ugent.be/hpc/en),
# with support of Ghent University (http://ugent.be/hpc),
# the Flemish Supercomputer Centre (VSC) (https://www.vscentrum.be),
# Flemish Research Foundation (FWO) (http://www.fwo.be/en)
# and the Department of Economy, Science and Innovation (EWI) (http://www.ewi-vlaanderen.be/en).
#
# https://github.com/easybuilders/easybuild
#
# EasyBuild is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation v2.
#
# EasyBuild is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with EasyBuild.  If not, see <http://www.gnu.org/licenses/>.
# #

"""
Style tests for easyconfig files using pycodestyle.

:author: Ward Poelmans (Ghent University)
"""
import re
import sys

from easybuild.base import fancylogger
from easybuild.framework.easyconfig.easyconfig import EasyConfig
from easybuild.tools.build_log import EasyBuildError, print_msg
from easybuild.tools.py2vs3 import reload, string_type
from easybuild.tools.utilities import only_if_module_is_available

try:
    import pycodestyle
    from pycodestyle import StyleGuide, register_check, trailing_whitespace
except ImportError:
    try:
        # fallback to importing from 'pep8', which was renamed to pycodestyle in 2016
        import pep8
        from pep8 import StyleGuide, register_check, trailing_whitespace
    except ImportError:
        pass

_log = fancylogger.getLogger('easyconfig.style', fname=False)

EB_CHECK = '_eb_check_'

COMMENT_REGEX = re.compile(r'^\s*#')
PARAM_DEF_REGEX = re.compile(r"^(?P<key>[a-z_]+)\s*=\s*")

MAX_LINE_LENGTH = 120


# Any function starting with _eb_check_ (see EB_CHECK variable) will be
# added to the tests if the test number is added to the select list.
#
# Note: only functions that have a first argument named 'physical_line' or 'logical_line'
# will actually be used!
#
# The test number is definied as WXXX and EXXX (for warnings and errors)
# where XXX is a 3 digit number.
#
# It should be mentioned in the docstring as a single word.
# Read the pycodestyle docs to understand the arguments of these functions:
# https://pycodestyle.readthedocs.io or more specifically:
# https://pycodestyle.readthedocs.io/en/latest/developer.html#contribute

def _eb_check_trailing_whitespace(physical_line, lines, line_number, checker_state):  # pylint:disable=unused-argument
    """
    W299
    Warn about trailing whitespace, except for the description and comments.
    This differs from the standard trailing whitespace check as that
    will warn for any trailing whitespace.
    The arguments are explained at
    https://pycodestyle.readthedocs.io/en/latest/developer.html#contribute
    """
    # apparently this is not the same as physical_line line?!
    line = lines[line_number - 1]

    if COMMENT_REGEX.match(line):
        return None

    result = trailing_whitespace(line)
    if result:
        result = (result[0], result[1].replace('W291', 'W299'))

    # keep track of name of last parameter that was defined
    param_def = PARAM_DEF_REGEX.search(line)
    if param_def:
        checker_state['eb_last_key'] = param_def.group('key')

    # if the warning is about the multiline string of description
    # we will not issue a warning
    if checker_state.get('eb_last_key') == 'description':
        result = None

    return result


@only_if_module_is_available(('pycodestyle', 'pep8'))
def check_easyconfigs_style(easyconfigs, verbose=False):
    """
    Check the given list of easyconfigs for style
    :param: easyconfigs list of file paths to easyconfigs
    :param: verbose print our statistics and be verbose about the errors and warning
    :return: the number of warnings and errors
    """
    # importing autopep8 changes some pep8 functions.
    # We reload it to be sure to get the real pep8 functions.
    if 'pycodestyle' in sys.modules:
        reload(pycodestyle)
    else:
        reload(pep8)

    # register the extra checks before using pep8:
    # any function in this module starting with `_eb_check_` will be used.
    cands = globals()
    for check_function in sorted([cands[f] for f in cands if callable(cands[f]) and f.startswith(EB_CHECK)]):
        _log.debug("Adding custom style check %s", check_function)
        register_check(check_function)

    styleguide = StyleGuide(quiet=False, config_file=None)
    options = styleguide.options
    # we deviate from standard pep8 and allow 120 chars
    # on a line: the default of 79 is too narrow.
    options.max_line_length = MAX_LINE_LENGTH
    # we ignore some tests
    # note that W291 has been replaced by our custom W299
    options.ignore = (
        'W291',  # replaced by W299
    )
    options.verbose = int(verbose)

    result = styleguide.check_files(easyconfigs)

    if verbose:
        result.print_statistics()

    return result.total_errors


def cmdline_easyconfigs_style_check(ecs):
    """
    Run easyconfigs style check of each of the specified easyconfigs, triggered from 'eb' command line

    :param ecs: list of easyconfigs to check, could be either file paths or EasyConfig instances
    :return: True when style check passed on all easyconfig files, False otherwise
    """
    print_msg("\nRunning style check on %d easyconfig(s)...\n" % len(ecs), prefix=False)
    style_check_passed = True
    for ec in ecs:
        # if an EasyConfig instance is provided, just grab the corresponding file path
        if isinstance(ec, EasyConfig):
            path = ec.path
        elif isinstance(ec, string_type):
            path = ec
        else:
            raise EasyBuildError("Value of unknown type encountered in cmdline_easyconfigs_style_check: %s (type: %s)",
                                 ec, type(ec))

        if check_easyconfigs_style([path]) == 0:
            res = 'PASS'
        else:
            res = 'FAIL'
            style_check_passed = False
        print_msg('[%s] %s' % (res, path), prefix=False)

    return style_check_passed
